Track temps - revisited

[BLUETA#1]

I am bound an determined to fix this problem. I want to be able to run my TA 8/10ths for 25 minutes without having to take 2 laps off. I cover more mileage in a 25 minute session in my VW Golf R. (Seriously)

I have talked to other TA owners, with and without the Arrow PCM and their water temp readings match mine. (The stock ECU gives you another 5-7 minutes until hitting 240 degrees.)

I have one main theory. I am assuming that the water pump is mechanically driven, so when the RPMs are high, the water is moving too fast. My plan is to remove the thermostat, get it open with hot water and then measure the opening. Then I will make an insert with a smaller opening than the thermostat and drop that in the thermostat's place. (old stock car technology), OR I can go to an electric water pump to better control the water flow.

(I live in Texas….no cold weather issues to worry about.)

My question is this…rather than me engineering my own insert for the cooling system, is there a performance Viper parts supplier that makes parts like this?

I am getting questionable advice, like "change the headers". This is a math problem with water flow and airflow…not an exhaust problem. I was told to change the thermostat. I did that, but that was a waste…when they are open, they are open.

FYI…there was a ALMS Viper at the track and he was F%^&ing flying…his water temp never got above 225. However, his radiator is laying flat and I bet that he has other mods.

Thanks in advance for the help.

[XSnake]

What are you using for coolant?

I'd also look into the arrow engine closeout panel or something similar. It forces the air through the radiator instead of letting it escape over the top of it.

[dasvolk]

What happens at 240 degrees? I've seen the oil get that high during hard driving, but the tires usually start overheating before the rest of the car.

[BLUETA#1]

What happens at 240 degrees? I've seen the oil get that high during hard driving, but the tires usually start overheating before the rest of the car.

Warning light starts flashing, which I am sure leads to the retarding of the timing. I am running Hoosiers and the hot temps are perfect…not even close to overheating.

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What are you using for coolant?

I'd also look into the arrow engine closeout panel or something similar. It forces the air through the radiator instead of letting it escape over the top of it.


I studied the front to see if air was escaping. Where do I find that panel??

[Simms]

Arrow makes a panel for Gen IV's, no idea if they make one for V's.

[viper04]

With the HP tuner you would be able to turn on the fans at any given temps and have them stay on as long as you wanted them too, then after your track session return them back to stock setting . I would think the two stock fans are sufficient enough to keep our cars cool, just a thought. Just curious do you know what temp the Arrow ECU is set to come on with AC off?

[ViperSmith]

Something doesn't sound right, haven't read anyone having overheating issues on the track even on hot days.

[AZTVR]

OP: It seems to me that you should be asking the folks who most likely have solved the problem, such as Tomball Dodge or possibly Woodhouse or even the Chrysler engineers. The head of SRT is public making jokes about how the new ACR can run lap after lap unlike some 3 lap wonders. Either they have solved the problem you are having, or are going to look pretty stupid once the ACR comes out and folks like you or more advanced start racing it.

edit: Just saw ViperSmith's post. Agree that the other alternative is that you have a unique problem.

[BLUETA#1]

Something doesn't sound right, haven't read anyone having overheating issues on the track even on hot days.

I had a PM conversation with 2 owners and the Arrow PCM and stock ECU each hit 240. So for sure I am not the only one. I will call Arrow tomorrow and see what they can offer.

[Nemesis]

I've seen 240 a number of times with the stock ECU on my 2014 TA. I just recently put the Arrow in it and haven't seen anything near that temp. I am heading down to the track tomorrow for two days of hot running (91 degrees ambient) I will report back on what she has to say.

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Question, won't running a mixture of 100 octane help keep the engine a bit cooler?

[Jack B]

Water Wetter?

[Bruce H.]

No high track temps "yet" in up to 100 degree ambient. Heat is somewhat track and driver dependant, with tighter courses and drivers who tend to use low gears more generating more heat. I tend to prefer cornering in a gear higher than some might as the car feels more stable, and some others would do them more on the limit in a higher gear. And fans don't cool an engine at track speeds, the high airflow through the coolers does, with the fan blades likely reducing available airflow somewhat. Fans are needed to create an airflow at lower vehicle speeds, like when the car comes off the track.

[Bruce H.]

Water Wetter?

It's my understanding that running less antifreeze mix or straight water is more effective...in warm climates where it isn't required of course.

[dasvolk]

I'd love to have the fans crank to 100% power anytime I drop below 20mph > 204F on oil temp. too much to ask of an ECU mod?

[Voice of Reason]

You mention a theory that the water pump is moving too fast at high RPM. Get an underdrive crank pulley to test out your theory. They're relatively cheap (~$150) and will slow all accessories down a little.

[BLUETA#1]

Water Wetter?

Just added it. Based on the data I can find, it’s a 50/50 proposition.

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You mention a theory that the water pump is moving too fast at high RPM. Get an underdrive crank pulley to test out your theory. They're relatively cheap (~$150) and will slow all accessories down a little.

I thought about that, bit I worry about the car in hot traffic not getting enough circulation. I'll ask at Arrow when I call.

[BLUETA#1]

I've seen 240 a number of times with the stock ECU on my 2014 TA. I just recently put the Arrow in it and haven't seen anything near that temp. I am heading down to the track tomorrow for two days of hot running (91 degrees ambient) I will report back on what she has to say. Thank you.

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Question, won't running a mixture of 100 octane help keep the engine a bit cooler? Not really. The leaner mixture will have more of an impact.

[XSnake]

I'd try 80/20 water/coolant mix and some water wetter to start out with. I thought someone was making the panels for G5's, my mistake if they aren't.

[Darius]

My car never got much over 200. But the outside temps were in the 70's. I haven't ran my car in the 90's. What was the outside temp when your getting it to 240?

[steve911]

Just got back from a great weekend at Gingerman with the Central States Ferrari Club. Was at 140+mph on the the Phoenix road straight.

Ambient temps were 73-76 degrees. Stock ECU in my '13. I was seeing 229 degree water temps and oil temps of 205 degrees. I have an SRT hood so there is more room for hot engine air to get out...

On the other hand, with my own version of the Air intake mod, I never saw IAT over 82 degrees.

MY Gen 3 car even with the Gen 4 hybrid engine mods, never saw water temps above 210 even on 90 plus degree days. No one has answers, kind of frustrating.

It is unsettling to me to see temps that high for what I am doing with the car.

[Jack B]

Your comment on coolant mix % with water wetter has to drop the temps.


QUOTE=MTGTS;143238]I'd try 80/20 water/coolant mix and some water wetter to start out with. I thought someone was making the panels for G5's, my mistake if they aren't.[/QUOTE]

[BLUETA#1]

The ambient temp is in the 80s. IAT is always around 100 and the oils is 250


What is your IAT mod?

[TrackAire]

your comment on coolant mix % with water wetter has to drop the temps.


Quote=mtgts;143238]i'd try 80/20 water/coolant mix and some water wetter to start out with. I thought someone was making the panels for g5's, my mistake if they aren't.[/quote]

Jack,

Physics question about cooling and % of water vs coolant. If you were to put in 80% water/coolant mix and this was actually "cooling" the engine better (reducing the temps of the heads and block), wouldn't the water temps actually be a little higher at the water temperature sensor since the new coolant mixture is absorbing more heat from the metal in the motor? I'm not sure if the water temperature sensor reads the water coming out of the block "hot" or after it's been through the radiator and ready to go back into the motor (on a Viper)??

The 80% water/coolant should absorb more heat out of the motor and the radiator should be able to dissipate more heat due to the heat transfer efficiency of the higher percentage of water vs coolant, right? I would think you "might" be able to see a lower water temperature on your gauge if the radiator has the ability to dissipate the added btu's absorbed by they new coolant mixture.

From what I've seen from the Water Wetter, it is mainly lubrication for the pump seals, etc. I do remember the added claim of reducing the surface tension of the water, but a lot of circle track racers just add a couple of drops of dish soap to the 100% water coolant to achieve the same thing at literally no cost.

I'm not sure how the thermostat skews the results since it is artificially holding he water in the block to absorb more heat and not over cool the motor.

Any thought on this?

[BLUETA#1]

Here is a cooling primer:

http://www.saldanaracingproducts.com/Cooling%20System%20Principles.pdf

[Jack B]

In a nutshell, if the coolant transfers more heat and the radiator is sized correctly the average temp drops even though the engine inlet and outlet are diff.

Water wetter does improve the heat transfer







Jack,

Physics question about cooling and % of water vs coolant. If you were to put in 80% water/coolant mix and this was actually "cooling" the engine better (reducing the temps of the heads and block), wouldn't the water temps actually be a little higher at the water temperature sensor since the new coolant mixture is absorbing more heat from the metal in the motor? I'm not sure if the water temperature sensor reads the water coming out of the block "hot" or after it's been through the radiator and ready to go back into the motor (on a Viper)??

The 80% water/coolant should absorb more heat out of the motor and the radiator should be able to dissipate more heat due to the heat transfer efficiency of the higher percentage of water vs coolant, right? I would think you "might" be able to see a lower water temperature on your gauge if the radiator has the ability to dissipate the added btu's absorbed by they new coolant mixture.

From what I've seen from the Water Wetter, it is mainly lubrication for the pump seals, etc. I do remember the added claim of reducing the surface tension of the water, but a lot of circle track racers just add a couple of drops of dish soap to the 100% water coolant to achieve the same thing at literally no cost.

I'm not sure how the thermostat skews the results since it is artificially holding he water in the block to absorb more heat and not over cool the motor.

Any thought on this?[/QUOTE]

[Steve M]

With the HP tuner you would be able to turn on the fans at any given temps and have them stay on as long as you wanted them too, then after your track session return them back to stock setting . I would think the two stock fans are sufficient enough to keep our cars cool, just a thought. Just curious do you know what temp the Arrow ECU is set to come on with AC off?

This wouldn't solve his issue though...that would only be useful for driving around at slow speeds in the paddock area. At speed on the track, the fans simply can't move the same amount of air that driving would push through the radiator (it'd be significantly less actually).

Has no one mentioned an underdrive pulley? That would bring the water pump pulley speed down, no? IIRC, the Gen 4 race cars all used underdrive pulleys for this exact reason (getting rid of cavitation at high RPM).

[Stealth]

I had an advanced HPDE in SoCal in May and did not have any heat or other issues with my Viper. I was stock on stock Corsas. My car typically runs 190-193F (oil temp?) on the street and hit a max of 224F during the 20 min. sessions. Viper = Strong like Bull!

[steve911]

The ambient temp is in the 80s. IAT is always around 100 and the oils is 250


What is your IAT mod?

I used some DEI brand self adhesive reflective material and covered the top of the air box. I then created an aluminum heat shield also covered in the same material and mounted with 1/2" long standoffs to hold it away from the bottom of the airbox. I then sewed up 2 pieces of the DEI kevlar reflective material and velcro to create a tube to cover the intake tubes and IAT sensors. It was pretty labor intensive but worth the results.

[BLUETA#1]

I used some DEI brand self adhesive reflective material and covered the top of the air box. I then created an aluminum heat shield also covered in the same material and mounted with 1/2" long standoffs to hold it away from the bottom of the airbox. I then sewed up 2 pieces of the DEI kevlar reflective material and velcro to create a tube to cover the intake tubes and IAT sensors. It was pretty labor intensive but worth the results.

Wow…nice work. So the mods lower the IAT and that allows the car to run cooler?

My brother, who has built race cars, drove my can for the first time. He thinks that when I lowered the car, its altering the pressure of the airflow and creating a vacuum lock. He is going to do some tests to see if that is the case.

[BLUETA#1]

Arrow makes a panel for Gen IV's, no idea if they make one for V's.

I called - its cosmetic.

[cashcorn]

If your oil is 250, you've got bigger problems elsewhere.. imo I run my car hard on mountain roads (4-6500rpm's). Have never seen 220+.

[Steve M]

Wow…nice work. So the mods lower the IAT and that allows the car to run cooler?

My brother, who has built race cars, drove my can for the first time. He thinks that when I lowered the car, its altering the pressure of the airflow and creating a vacuum lock. He is going to do some tests to see if that is the case.

They would lower the IATs (by keeping the heat soak at bay), but it won't do much to help your car run cooler. At WOT at any decent rate of speed, your IATs will be close to ambient anyway, so doing what he's done won't help much.

What are the ambient temps when this is happening?

[BLUETA#1]

If your oil is 250, you've got bigger problems elsewhere.. imo I run my car hard on mountain roads (4-6500rpm's). Have never seen 220+.

I am on a track and I am never as low as 4k RPM…unless I am on a cool down lap.

[G37Sam]

Are your brakes fine during the 25 mins?

[catwood]

I"m taking mine to Willowsprings on Wednesday. It will be a high 90* day. My car is bone stock. I am planning to add a tune from A&C later and perhaps headers. I'll post up what temps I see that day in a 25 minute session. I cooked a Gen 2 motor there once so I'll be watching closely.

[BLUETA#1]

Are your brakes fine during the 25 mins?

The brakes are perfect. Carbotec pads, stainless steel brake lines and most importantly, Endless brake fluid. (I have done several 24 hour races and that brake fluid is bullet proof. I have not had 1 issue of fade and COTA has some nastily brake points!

[ViperGeorge]

Was at Hastings, NE for the Viper event in my 2015 TA 2.0. Ambient temp was easily in 80s, probably high 80s on one day. Car's temps were higher than my old Gen 4 ACR but not terrible, maybe 225 max on the oil. About the same on the coolant if memory serves.

[ViperGeorge]

Mods, why did you move this thread to the track section? While it involves a track discussion it is primarily about Gen 5 temps. Seems to me it should remain in the Gen 5 section as it is specific to the Gen 5.

[City]

There's a redirect left in the GEN V area. But it's a "track thread" nonetheless.

[Nemesis]

@City it could easily be argued it is more important for the thread to be in the primary Gen V forum than in the track forum which not everybody see's because there is not a lot of activity here.

[steve911]

The brakes are perfect. Carbotec pads, stainless steel brake lines and most importantly, Endless brake fluid. (I have done several 24 hour races and that brake fluid is bullet proof. I have not had 1 issue of fade and COTA has some nastily brake points!

CHECK YOUR PM's

[catwood]

102* at willow

Water temps 220ish
Oil 240 ish

Tires...cooked

Brakes. OEM pads marginal. Need to step up to race pads

shocks stuck now in Race Mode....won't switch back to street mode. ESC also locked. Can turn it off altogether but not switch it around.

Car was a blast to drive. Was out at Buttonwillow earlier this year with Viperdays crowd but drove easy. Know willow so went alot faster this trip.

[Nemesis]

At the track this last weekend I saw 216 water temp and 246 oil temp.. Everything was good, air temps were in the 90's.

[ViperGeorge]

102* at willow

Water temps 220ish
Oil 240 ish

Tires...cooked

Brakes. OEM pads marginal. Need to step up to race pads

shocks stuck now in Race Mode....won't switch back to street mode. ESC also locked. Can turn it off altogether but not switch it around.

Car was a blast to drive. Was out at Buttonwillow earlier this year with Viperdays crowd but drove easy. Know willow so went alot faster this trip.

Word of warning. Switching to race pads front and rear can increase the wiggle that many folks feel on hard braking. The rear feels like it will come around on hard braking. This is further exaggerated by trying to correct what you are feeling in the seat of your pants. Car feels like the rear is going left so you automatically correct but then the rear feels like it is going right. Starts to feel like a tank slapper. This is caused by an interaction between the speed sensing diff and the new 4 channel ABS (Gen IV's at a 3 channel system). The 4 channel ABS now independently activates the rear brakes. The previous 3 channel system activated the rears together. Drivers behind me could see the wiggle. I believe JD may have some video of it.

I have been advised to use very aggressive pads in the front and not very aggressive pads in the rear. I have Raybestos R45's in the front and now have OEM stock pads in the rear. Still wiggles but not quite as bad. I may need to go with R47's in the front (that's as aggressive as they get). You also need to check dynamic toe in the rear. Mark Jorgensen discovered an alignment issue with this from the factory.

At Hastings, Ralph Gilles said he had the same wiggle.

[catwood]

Good input. I would plan to run a split compound to get more brake in front. The rear did dance a little like you said. We also had some issue with someone dropping fuel so that could have made it worse. Car settled down in the 2nd and 3rd sessions.

I do need to align the car. Waiting on a front tire to arrive to do that.

[AZTVR]

You also need to check dynamic toe in the rear. Mark Jorgensen discovered an alignment issue with this from the factory.

Good discussion of the wiggle and Mark's comments about rear toe settings in the following thread
http://driveviper.com/forums/threads/8484-Track-upgrades-weak-points

[stuntman]

What times were you turning at WSIR & BW?

[Rapidrezults]

Word of warning. Switching to race pads front and rear can increase the wiggle that many folks feel on hard braking. The rear feels like it will come around on hard braking. This is further exaggerated by trying to correct what you are feeling in the seat of your pants. Car feels like the rear is going left so you automatically correct but then the rear feels like it is going right. Starts to feel like a tank slapper. This is caused by an interaction between the speed sensing diff and the new 4 channel ABS (Gen IV's at a 3 channel system). The 4 channel ABS now independently activates the rear brakes. The previous 3 channel system activated the rears together. Drivers behind me could see the wiggle. I believe JD may have some video of it.

I have been advised to use very aggressive pads in the front and not very aggressive pads in the rear. I have Raybestos R45's in the front and now have OEM stock pads in the rear. Still wiggles but not quite as bad. I may need to go with R47's in the front (that's as aggressive as they get). You also need to check dynamic toe in the rear. Mark Jorgensen discovered an alignment issue with this from the factory.

At Hastings, Ralph Gilles said he had the same wiggle.


Didn't you buy your car from Woodhouse? Did they make the adjustments to your rear toe before delivery? If so, I'm surprised you're still experiencing the rear waggle, as others have said after adjustment it improved the issue. I am planning on running xp20 front and xp10 rear this weekend at Laguna. Hopefully it doesn't aggravate the problem.

[mjorgensen]

Didn't you buy your car from Woodhouse? Did they make the adjustments to your rear toe before delivery? If so, I'm surprised you're still experiencing the rear waggle, as others have said after adjustment it improved the issue. I am planning on running xp20 front and xp10 rear this weekend at Laguna. Hopefully it doesn't agrevate the problem.


Yes he did buy from us and yes I adjust EVERY car we get to insure rear dynamic toe is acceptable to me. Running the XP20 or higher with the XP10 rears will help immensely to alleviate the unstable feel although the diff will still try to work the same way in conditions that will make one rear wheel slip more than the other like long trail braking. I'm glad we were able to figure this out for you guys that track so much. I thankful to have the correct engineering contacts to have the issue addressed at the factory once the procedure is in place for this measurement. SRT Engineers are the greatest asset I have.

[stuntman]

Does the rear toe-out significantly in droop?

[mjorgensen]

Does the rear toe-out significantly in droop?

With the toe links in front of the knuckle there is no toe out induced on the GenV in either droop or rebound if adjusted properly.

[stuntman]

My mistake. I just googled "2013 Viper suspension" and was looking at a Gen3/4 pic. Really glad to see the 5s have the link moved in front of the knuckle and it's pretty neat to see factory adjustable bumpsteer. So do you compromise increased to-in under compression for reduced toe-in during droop?

[mjorgensen]

My mistake. I just googled "2013 Viper suspension" and was looking at a Gen3/4 pic. Really glad to see the 5s have the link moved in front of the knuckle and it's pretty neat to see factory adjustable bumpsteer. So do you compromise increased to-in under compression for reduced toe-in during droop?

Ideally what you want is very little toe change in either condition, any change needs to be exactly the same for each side under braking or compression to insure stability. The GenIV cars also had adjustable bump steer just a different location and yes it would induce toe out in either direction so adjustment was critical.

[catwood]

What times were you turning at WSIR & BW?

BW I was running real easy.

Willow I didn't run a timer as it was to hot to run a decent time I felt. Also, it's not really set up to run fast times as of now. It was more of seeing how the car handled the track. My Gen 2 would have been reduced laps in the pits as was the Z06 being driven by a newbie.

[catwood]

What are you guys suggesting for Camber front and rear. I ran alot on my Gen 2 and liked it. Don't care about street compromises.

[ViperGeorge]

Just ran my 15 TA 2.0 at the track. Ambient temp was 77. Water temp after 5 minutes was 230, by 15 minutes it was 243 and oil temp was 263. I have the Arrow PCM and Bellanger headers and exhaust. By the way also threw a P2127 - Accelerator Pedal Position Sensor 2 Circuit Low. Sucks. I agree with Blue TA, the temp issue has to get fixed. I can't run the car hard for more than 15 minutes before red lights start flashing on the dash. Big problem in my mind. I don't know if the P2127 code is somehow related or just another gremlin. Between the temp issue and the squirelly brakes I'm not having as much fun on the track as I did in my old ACR.

[AZTVR]

Just ran my 15 TA 2.0 at the track. Ambient temp was 77. Water temp after 5 minutes was 230, by 15 minutes it was 243 and oil temp was 263. I have the Arrow PCM and Bellanger headers and exhaust. By the way also threw a P2127 - Accelerator Pedal Position Sensor 2 Circuit Low. Sucks. I agree with Blue TA, the temp issue has to get fixed. I can't run the car hard for more than 15 minutes before red lights start flashing on the dash. Big problem in my mind. I don't know if the P2127 code is somehow related or just another gremlin. Between the temp issue and the squirelly brakes I'm not having as much fun on the track as I did in my old ACR.

Just wondering what gear a lot of track time was spent in (i.e. what rpms is the engine being run at predominantly? That factor is difficult to compare amongst different tracks and drivers.) That would be an important factor to relate temperatures to.

[ViperGeorge]

Just wondering what gear a lot of track time was spent in (i.e. what rpms is the engine being run at predominantly? That factor is difficult to compare amongst different tracks and drivers.) That would be an important factor to relate temperatures to.

Mostly a third gear track. Long straight is 4th and a two turns are 2nd. With the gearing in the Gen 5 they do spend more time at higher rpms than the Gen IVs.

[Rapidrezults]

Just ran my 15 TA 2.0 at the track. Ambient temp was 77. Water temp after 5 minutes was 230, by 15 minutes it was 243 and oil temp was 263. I have the Arrow PCM and Bellanger headers and exhaust. By the way also threw a P2127 - Accelerator Pedal Position Sensor 2 Circuit Low. Sucks. I agree with Blue TA, the temp issue has to get fixed. I can't run the car hard for more than 15 minutes before red lights start flashing on the dash. Big problem in my mind. I don't know if the P2127 code is somehow related or just another gremlin. Between the temp issue and the squirelly brakes I'm not having as much fun on the track as I did in my old ACR.


Interesting. I was at Thunderhill a few weeks back in about 84 degree ambient and had no issues what so ever. I am only running the Arrow PCM, no headers. I also add Torco octane boost. 3rd-4th gear track.

[ViperGeorge]

I wonder if this problem is a 15 specific issue. Both Blue TA #1 and I are running 15 TA 2.0s. I wouldn't think headers would increase engine heat. I would think the opposite.

[ViperGeorge]

Interesting. I was at Thunderhill a few weeks back in about 84 degree ambient and had no issues what so ever. I am only running the Arrow PCM, no headers. I also add Torco octane boost. 3rd-4th gear track.

Your post reminded me of one thing. At Hastings for the Viper Event in June I did not have any overheating problems to speak of. Hotter than my old 09 ACR for sure but I was only getting to about 225 degrees max. And Hastings was hotter than my last trip to High Plains in Colorado. Now at High Plains I did run about a 50/50 mix of 100 octane and 91 octane, call it 95 octane average. I wonder if the higher octane allowed the Arrow PCM to generate more heat due to more advanced timing.

[AZTVR]

Your post reminded me of one thing. At Hastings for the Viper Event in June I did not have any overheating problems to speak of. Hotter than my old 09 ACR for sure but I was only getting to about 225 degrees max. And Hastings was hotter than my last trip to High Plains in Colorado. Now at High Plains I did run about a 50/50 mix of 100 octane and 91 octane, call it 95 octane average. I wonder if the higher octane allowed the Arrow PCM to generate more heat due to more advanced timing.

Maybe it was the combination of more horsepower allowed by a timing change allowed for by the higher octane, higher elevation resulting in less cooling capacity, and maybe more time in 3rd gear at higher RPMs? Sounds like a science experiment is called for; but, with a helmet involved.:)

It does seem to show how difficult it can be to engineer a car that will accommodate all situations that it might be driven in, given the time/money budget imposed.

[ViperGeorge]

Maybe it was the combination of more horsepower allowed by a timing change allowed for by the higher octane, higher elevation resulting in less cooling capacity, and maybe more time in 3rd gear at higher RPMs? Sounds like a science experiment is called for; but, with a helmet involved.:)

It does seem to show how difficult it can be to engineer a car that will accommodate all situations that it might be driven in, given the time/money budget imposed.

Agree, but the Viper is supposed to be track capable probably more than any production car. Mods to my Gen 3 o 4 never caused any concern with cooling. Heck my Gen 4 would run all day long at 210 on any track including High Plains in Colorado. It had similar mods to my TA. It just strikes me that something is not right.

[mjorgensen]

Agree, but the Viper is supposed to be track capable probably more than any production car. Mods to my Gen 3 o 4 never caused any concern with cooling. Heck my Gen 4 would run all day long at 210 on any track including High Plains in Colorado. It had similar mods to my TA. It just strikes me that something is not right.

Compare the Gen4 and Gen5 front fascia's, the Gen4 has no brake ducts incorporated into the openings and very smooth rounded flow where the Gen5 styling dictates multiple splits and the air ducts for the brakes. I would think this would possibly make the air more turbulent and reduce overall area to the radiator. I do not think the added power from the controller is significant enough to do this. Although the GTSR and the GT3R have similar fascia's they also have all the opening around the radiator sealed so ALL of the air has to go through the radiators to make it more effective. No one yet makes a closeout panel like the Gen4 had available and even if it was there the area on the sides of the radiator would still allow flow around it and not all through it.

The possibility of residual air pockets in the cooling system could also contribute to the hot temps, I have been told that even at 250 degrees there is no damage to the engine as long as the pressure cap is sound, or you can get an aftermarket cap to increase system pressure and help reduce boiling point even further. Having the warning light come on may limit this comfort and maybe if there is an air pocket the temp reading is actual steam reading and not coolant that could be why they drop so fast when you back off.

[SSGNRDZ_28]

I plan to make a closeout panel for the Gen IV soon and will explore the possibility of making one for the Gen V but not having a car to measure on will make it more of a challenge unless they were close enough to both work with a similar design. As 09viperacr mentioned to me, time to buy a Gen V. :)

[Steve M]

Someone correct me if I'm wrong, but the area between the front of the airbox and the front fascia/bumper appears to already be pretty well blocked off on the Gen 5, at least based off the pictures I've seen of Gen 5 engine bays. The Gen 4 is a completely different animal...that area is totally open, giving the air coming in an easy way around the radiator.

I'm just not sure there's as much to be closed off on the Gen 5s.

[Stealth]

My Gen V was max 224F at CA Speedway in Fontana in June (about 78F out). Stock everything on 91 Octane, 20-25 min. high speed laps. I am running again in august and will have the arrow pcm but will still just run 91--our pump gas in CA. Perhaps some of you may be unnecessarily staying near redline? Plenty of power below that.

[Nemesis]

Is anybody melting wiring harnesses?

[mjorgensen]

Is anybody melting wiring harnesses?

With the headers and PCM we have found there is a need to heat wrap both O2 wiring harnesses and connectors completely, even to the point of excess. The main trouble point is the front O2 where it goes over the frame rail to the collectors front O2 location.

[1of1TA1.0]

The ACR-X ran an under drive pulley because the increased RPM. It did cause cavitation in the water pump. The under drive pulley slowed it back down. They also ran 2 lb. heavier radiator caps. I would definitely try the under drive if you have an aftermarket PCM. Either the Arrow or the HP.


You mention a theory that the water pump is moving too fast at high RPM. Get an underdrive crank pulley to test out your theory. They're relatively cheap (~$150) and will slow all accessories down a little.

[ViperGeorge]

Someone correct me if I'm wrong, but the area between the front of the airbox and the front fascia/bumper appears to already be pretty well blocked off on the Gen 5, at least based off the pictures I've seen of Gen 5 engine bays. The Gen 4 is a completely different animal...that area is totally open, giving the air coming in an easy way around the radiator.

I'm just not sure there's as much to be closed off on the Gen 5s.

It is pretty well sealed but there is probably still some room for improvement. I will try bleeding the cooling system to evacuate any air that may be in there and I will try a higher pressure oil cap even though my car did not boil over.

[1of1TA1.0]

You should try the under drive pulley as well.


It is pretty well sealed but there is probably still some room for improvement. I will try bleeding the cooling system to evacuate any air that may be in there and I will try a higher pressure oil cap even though my car did not boil over.

[Rapidrezults]

It is pretty well sealed but there is probably still some room for improvement. I will try bleeding the cooling system to evacuate any air that may be in there and I will try a higher pressure oil cap even though my car did not boil over.

Why not just put the stock PCM back in at your next track event? I would start with the basics. The car should not be overheating under almost any circumstances. This overheating problem is mind boggling, as there as so many of us running hard with no problems. While I do not recall the exact temps I was running at my last event, I did not see a warning light. One thing I will say is that there is definitely more heat being generated on the exhaust side with the Arrow PCM. My white paint just above the rocker on the passenger side is now completely yellow and cooked, whereas before (stock PCM) it was somewhat noticeable but not getting worse.

[ViperGeorge]

You should try the under drive pulley as well.

Yea, I forgot to mention that I would also do that.

[ViperGeorge]

Why not just put the stock PCM back in at your next track event? I would start with the basics. The car should not be overheating under almost any circumstances. This overheating problem is mind boggling, as there as so many of us running hard with no problems. While I do not recall the exact temps I was running at my last event, I did not see a warning light. One thing I will say is that there is definitely more heat being generated on the exhaust side with the Arrow PCM. My white paint just above the rocker on the passenger side is now completely yellow and cooked, whereas before (stock PCM) it was somewhat noticeable but not getting worse.

If burping the cooling system and an underdrive pulley don't help I will switch out the PCM to see if that fixes the issue. I may also remove the DSE intake heat shield in case it is preventing heat from escaping the engine compartment somehow (I doubt it but I will try).

[Steve M]

If burping the cooling system and an underdrive pulley don't help I will switch out the PCM to see if that fixes the issue. I may also remove the DSE intake heat shield in case it is preventing heat from escaping the engine compartment somehow (I doubt it but I will try).

I had a similar thought, but based on the data I've logged, the DSE heat shield didn't have an impact on my ECTs.

[Nemesis]

I want badly to contribute here, but I can't at this time. All I can say is check your harnesses, 02 front and rear, abs, main bus line, abs, starter motor.

[SSGNRDZ_28]

I had a similar thought, but based on the data I've logged, the DSE heat shield didn't have an impact on my ECTs.

I haven't noticed any difference in coolant or oil temps either, the shield was designed to be tight around the airbox to reduce any side effects. Not saying it isn't possible as aerodynamics are tough to quantify with all of the various hoods and car configurations.


If burping the cooling system and an underdrive pulley don't help I will switch out the PCM to see if that fixes the issue. I may also remove the DSE intake heat shield in case it is preventing heat from escaping the engine compartment somehow (I doubt it but I will try).

MTGTS and FLATOUT both had the prototype shield on the track with no reported ECT issues. It is also worth noting that this thread was started before the shields shipped but let us know what you find. It would be good to verify either way for confirmation and removing the shield is a quick and easy change.

[ViperGeorge]

I haven't noticed any difference in coolant or oil temps either, the shield was designed to be tight around the airbox to reduce any side effects. Not saying it isn't possible as aerodynamics are tough to quantify with all of the various hoods and car configurations.



MTGTS and FLATOUT both had the prototype shield on the track with no reported ECT issues. It is also worth noting that this thread was started before the shields shipped but let us know what you find. It would be good to verify either way for confirmation and removing the shield is a quick and easy change.

Yea, I can't imagine the shield would have any impact whatsoever. I think the bigger impact has to be the Arrow PCM. Arrow says no, but more power equals more heat.

[mjorgensen]

Yea, I can't imagine the shield would have any impact whatsoever. I think the bigger impact has to be the Arrow PCM. Arrow says no, but more power equals more heat.

The only way to know for sure if any one thing is impacting temps you need to change out one thing at a time, take it out and run, put it back and take out another, run and so on till the one thing doing it is found. If it is an overall issue when added all together then the answer is to find a better way for the cooling air to flow through the radiator and out of the engine compartment just like they would with a racecar. I know it's a street car that's a good track car, but we are turning up the wick with mods and there is only so much cooling capacity in stock form.

One customer is replacing the grill insert and modifying it to allow more air volume and a direct path to the radiator. The Gen5 grill openings are more broken up than the Gen4 and the Gen4 did not have the brake ducts in the path of the air either so similar power, similar heat with less air flow...

[ViperGeorge]

The only way to know for sure if any one thing is impacting temps you need to change out one thing at a time, take it out and run, put it back and take out another, run and so on till the one thing doing it is found. If it is an overall issue when added all together then the answer is to find a better way for the cooling air to flow through the radiator and out of the engine compartment just like they would with a racecar. I know it's a street car that's a good track car, but we are turning up the wick with mods and there is only so much cooling capacity in stock form.

One customer is replacing the grill insert and modifying it to allow more air volume and a direct path to the radiator. The Gen5 grill openings are more broken up than the Gen4 and the Gen4 did not have the brake ducts in the path of the air either so similar power, similar heat with less air flow...

That is my plan. Of course it has to wait for the car to be fixed. No pedal assembly yet.

[Stubbygda]

Man u guys got me worried. I just got a ta2.0 a month ago and have been putting breakin miles on it before my next event in early sept. I just got out of a z51 c7 that always ran hot on track. It was a decent track car but with outside temps in 80s at end of 25 min sessions i was seeing water about 260, oil about 280, and tranny about 280. This was at vir which is mostly 3 and 4th gear but lots of high rpms.

I did noticed my ta2 on street runs about 188 water and 191 oil outside temp 88 at about 75 mph in 6th. If i did same in 5 th gear/2.7 rpms oil moves to 195 if i do it in 4th gear/3.6 rpms oil quickly moves to about 208 to 210. So definitely worried about track rpms which will average much higher than these so i can see track temps getting bad. I wont really know till sept and have some actual track time. My ta2 is stock except for the mcs suspension upgrade.

Could the aero on the ta be causing some of the issue or is the problem more with all gen v cars?

[Dan Cragin]

These engines are made to run north of 250 without any ill effects. The biggest problem is airflow. On the Gen 4 Race Cars we were able to eliminate all the cooling issues by going with a much bigger radiator and fully ducting the front of the radiator so no air escapes around or under the radiator. Temps dropped 8-10 degrees and never again went over 230.

This should all bleed over to the Gen 5.

[Stubbygda]

I suspect your right those changes would bring temps down solving the problems. my expectation is an umodified TA model on stock tires should perform on the track 9/10ths for 30 minute sessions without any mods to the car. And since i havent had mine on track yet im still hoping it will! I was just a bit surprised at how quickly i could get water and oil temps rising at 75 mph by increasing rpm by 1500 to 1800 rpms.

Once ya start increasing hp and adding slicks then u have gone beyond the design and it is entirely reasonable to expect to have to make other changes to account for them.

[mjorgensen]

I suspect your right those changes would bring temps down solving the problems. my expectation is an umodified TA model on stock tires should perform on the track 9/10ths for 30 minute sessions without any mods to the car. And since i havent had mine on track yet im still hoping it will! I was just a bit surprised at how quickly i could get water and oil temps rising at 75 mph by increasing rpm by 1500 to 1800 rpms.

Once ya start increasing hp and adding slicks then u have gone beyond the design and it is entirely reasonable to expect to have to make other changes to account for them.

I have heard of there being possibly some air in the system even on cars right off the truck so if this is happening the first thing to check is re burping the coolant system. We have plenty of tracking customers though and this has been pretty isolated all in all.

[Nemesis]

I suspect your right those changes would bring temps down solving the problems. my expectation is an umodified TA model on stock tires should perform on the track 9/10ths for 30 minute sessions without any mods to the car. And since i havent had mine on track yet im still hoping it will! I was just a bit surprised at how quickly i could get water and oil temps rising at 75 mph by increasing rpm by 1500 to 1800 rpms.

Once ya start increasing hp and adding slicks then u have gone beyond the design and it is entirely reasonable to expect to have to make other changes to account for them.

Stub, what is your connection between running slicks and heat??

[Stubbygda]

Only that u can definitely drive the car harder so not only more stress on brakes, drive train,hubs,etc but also higher speeds which typically equate to rpms and engine heat. I dont know from the coolant/oil heat perspective if it is a huge issue. i was only trying to say that if the car doesnt perform right in stock config there is no excuse for that. But if variables were introduced that werent expected or designed for then i can see why we might have to add extra cooling or whatever to account for it.

[Rapidrezults]

Only that u can definitely drive the car harder so not only more stress on brakes, drive train,hubs,etc but also higher speeds which typically equate to rpms and engine heat. I dont know from the coolant/oil heat perspective if it is a huge issue. i was only trying to say that if the car doesnt perform right in stock config there is no excuse for that. But if variables were introduced that werent expected or designed for then i can see why we might have to add extra cooling or whatever to account for it.

Normally I would agree, but the new ACR has essentially slicks or at least equivalent to hoosiers on it stock and is the same motor and drive-train except for the differential cooler. While I wouldn't say they were pushing them exceptionally hard at the test at VIR, I do know that it was pretty hot and a few of the drivers were pushing at good pace. No heat issues to report of in the dozen or so plus reviews. I think most of the components are engineered to withstand some serious abuse either way. I still say this overheating issue is an anomaly of some sort, but I guess we'll see.

[Stubbygda]

I agree with you. Also sounds like mark believes the same thing about it being an anomaly. I wonder if the radiator and oil cooler r identical on the acr as other gen v cars? Anybody know if acr diff cooler is easy retrofit to 2015 TA 2.0?

[Stubbygda]

I have heard of there being possibly some air in the system even on cars right off the truck so if this is happening the first thing to check is re burping the coolant system. We have plenty of tracking customers though and this has been pretty isolated all in all.

I searched the forum and didnt see a thread on the burping procedure for gen v can someone point me to a procedure or description. This is the 4th viper i have owned (93'srt10, 2000 ACR, 2003 comp coupe) but it is a very different beast than the others.

[mjorgensen]

I searched the forum and didnt see a thread on the burping procedure for gen v can someone point me to a procedure or description. This is the 4th viper i have owned (93'srt10, 2000 ACR, 2003 comp coupe) but it is a very different beast than the others.






07 - Cooling/Standard Procedure

FILLING COOLING SYSTEM

CAUTION:
Do not use well water or suspect water supply in cooling system. A 50/50 mixture of the recommended antifreeze coolant and distilled water is recommended.


NOTE:
Cooling system fill
procedure is critical to overall cooling system performance.

1.Close the radiator draincock.

2.Install the engine block drain plugs.

3.Attach one end of a 6.35 mm (0.250 in.) ID clear hose that is approximately 1200 mm (48 in.) long, to the bleed screw.

4.Route the hose away from the accessory drive belt, drive pulleys and cooling fan. Place the other end of hose into a clean container. The hose will prevent coolant from contacting the accessory drive belt when bleeding the system during the refilling operation.


NOTE:
It is imperative that the cooling system air bleed screw be opened before any coolant is added to the cooling system. Failure to open the bleed screw first will result in an incomplete fill of the system.



5.Open the cooling system bleed screw.

6.Pour a 50/50 mix of Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula and distilled water into the coolant pressure bottle.

7.Slowly fill the cooling system until a steady stream of coolant flows from the hose attached to the bleed screw

8.Close the bleed screw and continue filling the system to the top of the COLD FILL RANGE .

9.Remove the hose from bleed screw.

10.Install the cap on the coolant pressure bottle.

11.Start and run the engine until it reaches operating temperature.

12.If removed, install front belly pan. Refer to 23 - BODY/EXTERIOR/BELLY PAN - INSTALLATION.


NOTE:
The engine cooling system will push any remaining air into the coolant bottle within about an hour of normal driving. As a result, a drop in coolant level in the pressure bottle may occur.


***** From a guy who knows...

• Make sure you don’t have any air or air pockets in the cooling system. If the engine has run hot and pushed out any coolant you need to make sure you get it full again and get any air out. You can use a vacuum assist fill system or if you don’t have one of those, at least jack the right side of the car up as high as you can to get the bottle to be the high point in the system and fill and bleed the system from there. I have found once the pressure cap has relieved, it will no longer hold pressure as it should and it should be replaced. I recommend a quality aftermarket racing cap in the 28 – 30 psi range. The higher system pressure will reduce the likelihood of pump cavitation and increase the boiling temperature of the fluid as well. Pressure is your friend, just make sure your hose clamps are all tight and in good shape.

[Steve M]

Mark,

When I've done radiator fills in the past on my other vehicles, I've always left the cap off for the first start until the car is up to operating temps...any issues doing it this way since it goes contrary to the instructions posted above?

[FLATOUT]

I also cast a vote for air in the system. Interested in your findings :)

[mjorgensen]

Mark,

When I've done radiator fills in the past on my other vehicles, I've always left the cap off for the first start until the car is up to operating temps...any issues doing it this way since it goes contrary to the instructions posted above?

We use the cap that holds a funnel to add coolant when up to temp so have not just left the cap off, can't imagine it would change much, but with all these questions about it I would just follow this direction to be sure.

[ViperGeorge]

I just bled the cooling system. Clear line to the bleeder screw, opened it, no air came out. Jacked passenger side up high, still no air. Added Water Wetter and filled reservoir to max fill. Changed oil and put in Mobil 1 15w50. Now all I've got to do is get the pedal assembly replaced so I can get back to the track and experiment. I will do two things. One, remove the DSE air box heat shield, then two, switch the PCM to the OEM one. Although now I'm wondering whether the OEM one will need a throttle relearn after they replace the pedal assembly. I'll email Mark.

[mjorgensen]

Have not replaced a pedal assembly bit would guess that the electronics would need to be re calibrated George.


I just bled the cooling system. Clear line to the bleeder screw, opened it, no air came out. Jacked passenger side up high, still no air. Added Water Wetter and filled reservoir to max fill. Changed oil and put in Mobil 1 15w50. Now all I've got to do is get the pedal assembly replaced so I can get back to the track and experiment. I will do two things. One, remove the DSE air box heat shield, then two, switch the PCM to the OEM one. Although now I'm wondering whether the OEM one will need a throttle relearn after they replace the pedal assembly. I'll email Mark.

[FLATOUT]

Have not replaced a pedal assembly bit would guess that the electronics would need to be re calibrated George.

Correct you will need to do a throttle relearn. I did the pedal swap on my TA.

[Rapidrezults]

I compiled a quick list of the readings that have been presented in this thread and the additional thread in the Gen V forum. It looks like pretty consistently the water temps are between 10 and 20 degrees lower than the oil temps. My differential was as high as 25 degrees, which is interesting. The only one that looks somewhat strange is Steve911's readings where the oil is significantly lower than the coolant, however, this might have been mistakenly referenced backwards.

All in all, I think most of us are fine even running at the slightly higher temps, however, there are a few anomalies here with the very high coolant temps in short runs. With that said, this is definitely a good topic to continue to research and document.

205 oil / 229 water - 75 ambient - Steve911
240 oil / 220 water - 102 ambient - Catwood
280 oil / 240 water - 90+ ambient - Nemesis
263 oil / 243 water - 77 ambient - ViperGeorge
210 oil / 200 water - 90+ ambient - XTREME SUPERCARS
230 oil / 215 water - 90+ ambient - LA STIG
240 oil / 206 water - 75 ambient - Darius
242 oil / 220 water - ?? ambient - Erich Heuschle
244 oil / 220 water - 77 ambient - Rapidrezults

Water only readings:

224 water - 85 ambient - Stealth
240 water - ??? ambient - Blue TA#1
240 water - 106 ambient - VENOM V

[mjorgensen]

Alright, My Viper Tech Joe and I have been looking at a running car and like I said before I stayed at a Holiday Inn Express once before...

One variable that almost has to make a difference from Gen4 to Gen5 cooling and heat related:


The Gen5 (this should have been obvious to us sooner) has the huge coil covers that don't allow heat to escape up and away from the exhaust. They trap even more heat at the coolant bottle and the oil cooler lines on the passenger side which I would "think" would rapidly heat the fluids in these two critical areas. Having this area closed off from the top air flow also might be a factor to consider.

Maybe one of you should remove them when you go to the track, run them off then run them on and see if there is any real difference in temps. I could see the coolant bottle getting very hot especially in slow moving situations and since the oil cooler line is also right there it could also be suffering.

12799
12800

And then on the other side where the PDC is it traps heat also that the Gen4 didn't.
12801

Just food for thought,

[SSGNRDZ_28]

Good call on the coil covers, Mark.

[FLATOUT]

Good call on the coil covers, Mark.

I'm going to play with those on track as well and see what happens. That would be an easy and quick improvement on track days if they do impact those areas.

[Steve M]

I'd think a FLIR camera would come in handy, especially if you could look at a Gen 4 and Gen 5 side by side as they idle.

[SSGNRDZ_28]

I'd think a FLIR camera would come in handy, especially if you could look at a Gen 4 and Gen 5 side by side as they idle.

Did I mention I need a Gen V? I would sent my FLIR to Andy but I don't think he can be trusted :)

[ViperGeorge]

Track High Plains Raceway near Byers, CO. Altitude is 5088 feet. Both test days were clear and nice with low humidity.

Baseline - Last time I was at the track
Ambient Temp 77
Stock Pulley
10-40 Mobil 1
Headers
No insulation on anything except O2 wires
Doug Shelby air box shield
95 Octane
Arrow PCM
2 tow hooks
Coolant Max 243 after 15 minutes
Oil Max 263 after 15 minutes
IAT 95
Testing had to be halted due to melted wire harness

First run today
Ambient 73
Underdrive pulley
Doug Shelby air box shield removed
Headers
15-50 Mobil 1
Water Wetter
95 Octane
Arrow PCM
2 tow hooks
Insulation on most everything including cooling lines, PDC, and harness
Coolant Max 225 after 30 minutes
Oil Max 240 after 30 minutes
IAT 95

Second run today
Ambient 86
Same mods as first run except
OEM PCM
Coolant Max 226 after 30 minutes
Oil Max 246 after 30 minutes
IAT 104

Third run today
Ambient 89
Same mods as first and second run except
Arrow PCM reinstalled
Coolant Max 240 after 30 minutes
Oil Max 258 after 30 minutes
IAT 105

A friend was also at the track today with his 2014 GTS. It is bone stock. He is a comparable driver to me at this track. He was running 238 coolant with oil around 250. Seems too hot even for a bone stock car.

[Arizona Vipers]

I just ran my 2013 at INDE in Wilcox AZ.
The car had no issues as far as heat goes (gas cap got stuck though, had to break it to put gas in it).
Ambient temps were between 60-75 from morning to afternoon. Oil and water never got above 230*. Elevation is around 4500'.
I never ran the car more than 15 minutes. Car has Belangers, no cats, Arrow computer, wrapped clutch line/wires. Ran on Hoosier tires..

[Nemesis]

Have you run the R7s yet? I finally got into my R7 pile last weekend at inde after finishing my R6 pile. They are amazing.


I just ran my 2013 at INDE in Wilcox AZ.
The car had no issues as far as heat goes (gas cap got stuck though, had to break it to put gas in it).
Ambient temps were between 60-75 from morning to afternoon. Oil and water never got above 230*. Elevation is around 4500'.
I never ran the car more than 15 minutes. Car has Belangers, no cats, Arrow computer, wrapped clutch line/wires. Ran on Hoosier tires..

[Arizona Vipers]

Have you run the R7s yet? I finally got into my R7 pile last weekend at inde after finishing my R6 pile. They are amazing.

Yes sir, that's what I ran, R7's:
Front: 315-30-18
Rear 345-30-19

The car is not lowered and the fronts did NOT Rub. I took a 250 lb passenger and fronts rubbed a bit (I'm 225 lbs).
So if anyone is going to run a 315-30 up front and lower it, I'd recommend NOT taking any passengers.

The first day I ran my factory tires just for the hell of it. The car pushed so hard it was crazy... I run 335's up front on my '97 Viper, so I wasnt used to this feeling.

The 315 Hoosiers up front definitely fixed the understeer.

I'm willing to sell these tires, only ran one day, after comparing the Gen 5 to my '97, I'm going to keep my '97 for my track car. It's just as fast and much more fun!

[stuntman]

Pics of your 97?

[Arizona Vipers]

Pics of your 97?

Send me a PM with your email addy and I'll send pics. I don't want to hijack this thread! :)

[Nemesis]

After opening up the front grill and making some modifications to the under belly pan to force air up into the engine bay, I have resolved the excessive heat retention in the TA.

[Simms]

After opening up the front grill and making some modifications to the under belly pan to force air up into the engine bay, I have resolved the excessive heat retention in the TA.

Can you take some pics?

[Arizona Vipers]

Maybe it was the combination of more horsepower allowed by a timing change allowed for by the higher octane,
Is this a proven theory? This is very interesting. If you look at my thread here- http://driveviper.com/forums/threads/13600-Overheating-on-the-track that is one difference I made after the new motor was installed.
I used to run a 91/101 mix with old motor, but started running 101 straight with the new motor and have not been able to do a track event without overheating since the new motor.

[MomentaryRacing]

Don't know how much use this would be for gen5 cars, on our gen4, we set up a simple oil-air cooler in line before the oil-water exchanger (to minimize heat "recycling" in the system), and also channeled airflow from a headlight opening* to the factory oil-water heat exchanger. Oil temperatures dropped from 260+ down to 225-230 with just the extra cooler (stabilized in 6 hour race), and then further to 200-205 degrees with extra airflow to the factory heat exchanger (stabilized in 1 hour long race). This is with stock radiator AND AC condenser in front of it :)

That's probably a little too cool, so we plan to take out factory heat exchanger and run lighter oil..

* you could use any area with positive pressure, of course - fog light opening, etc

[Stealth]

I have just run 91 octane on my '14 GTS with Arrow PCM and Corsa CAT-back exhaust with no problems... .

[Arizona Vipers]

Don't know how much use this would be for gen5 cars, on our gen4, we set up a simple oil-air cooler in line before the oil-water exchanger (to minimize heat "recycling" in the system), and also channeled airflow from a headlight opening* to the factory oil-water heat exchanger. Oil temperatures dropped from 260+ down to 225-230 with just the extra cooler (stabilized in 6 hour race), and then further to 200-205 degrees with extra airflow to the factory heat exchanger (stabilized in 1 hour long race). This is with stock radiator AND AC condenser in front of it :)

That's probably a little too cool, so we plan to take out factory heat exchanger and run lighter oil..

* you could use any area with positive pressure, of course - fog light opening, etc

Thanks for the info, I might look into this for the Gen 5! Anything to get the overall temps of the car down a few degrees while on the track would be great.