It should be worse!

[ViperSmith]

Correct. I keep mentioning this, but nobody wants to listen.

To be fair, if that is the suggestion why not remove the entire grill from the car and see if that helps? the cross sections take up a lot of space as well.

[FLATOUT]

The warn starts at 240F, but the real warn begins at 270F - The audible alarm begins at that point...
The A/C will cut out above 240F to stop the A/C from adding heat to cooling system prior to the radiator. The red alert is to make it clear that things are changing to support higher temp operation. It is not a MIL lamp or DTC.

I hope everyone reads this that is concerned about elevated temps. Your 240 red light indicator is NOT an indicator that the car is overheating but that things are changing to support the higher temps.

[Darius]

The Gen 5 grille openings are smaller than the Gen 3/4 grille. Every single square inch counts on cars like this. Various performance models even got rid of mesh/screen inserts on grilles. Chevy even hollowed out their bowtie emblem on the Z28 and found gains. I noticed the tow hook blocked a good portion of the grille opening, due to its shape. I wonder if we'd benefit from an aftermarket grille insert that had less horizontal bars across the front?

BTW, that hollow Chevy emblem was worth an extra 3 cubic meters of airflow per minute, and worth 2 degrees on the coolant and engine oil temps.



CHEVROLET PRESS RELEASE

Modified Chevrolet Bowtie Makes Z/28 Even Cooler
Traditional badge modified in the name of all-out track performance.

DETROIT – In developing the 2014 Camaro Z/28, the team scrutinized every component looking for ways to improve track performance, lap after lap. Even the iconic Chevrolet bowtie faced audit.

During aerodynamics testing, Powertrain Cooling Development engineer Richard Quinn noticed that the bowtie on the Z/28's grill was displacing air away from the radiator, which can impact engine cooling – an important aspect for all vehicles, especially track-oriented cars.

Removing the bowtie altogether did not seem to be an appropriate solution. Instead, Quinn took a cut-off wheel to the gold fill of the bowtie, leaving the silver outline intact. He installed the prototype on the grill and retested to see the results.

"There are engineers in our team that race as a hobby," said Quinn, "and we used that racer's mindset to look for ways small or large to get better performance out of the Z/28. Even the smallest details on the Z/28 were weighed for cooling benefit, and this is one that stuck."

The "Flowtie," as the engineers now affectionately refer to it, is just the chrome outline of the traditional bowtie, with the center removed. This simple solution alone was enough to allow three additional cubic meters of air into the engine per minute. Engineers found the Flowtie dropped the temperatures of engine coolant and engine oil by 2°F (1.2°C) during extended track sessions. That seemingly small improvement was enough to justify making the Flowtie standard on every new Z/28.

I tracked my z28 yesterday in 80 deg temps, coolant was a little over 200 but the oil temp was 290. I was running very hard. Definitely needs a bigger oil cooler

[ViperGeorge]

I hope everyone reads this that is concerned about elevated temps. Your 240 red light indicator is NOT an indicator that the car is overheating but that things are changing to support the higher temps.

Andy, True enough but the PCM is still pulling timing and adding fuel at those temps.

[FLATOUT]

Andy, True enough but the PCM is still pulling timing and adding fuel at those temps.

Your PCM pulls timing any time it sees an IAT over 76 degrees, which happens everyday driving to the grocery store here in Texas. That doesn't mean there is anything wrong with the car or that it's overheating.

[Bugman Jeff]

I would suspect that the 240 idiot light is there for...idiots. Most non-race drivers don't pay much attention to gauges in general. If you're on the street and the 240 light comes on it's telling you that something is about to go seriously wrong. The car isn't programmed to know if you're sitting in traffic not paying attention while you're overheating or running hard on a race track watching the temp gauge like a hawk, so the light is programmed for the much more common street driving warning light situation. This is just speculation on my part, but it would make sense.

[ACR Steve]

I think we are all getting carried away . Remember this is NOT a race car its a street car that runs amazing on the street and is really fast during DE's

There has to be give and take. If you are a very fast driver of course the car will make more heat. DE sessions are mostly 20 min of track time .If the car heats up towards your last laps just slow down and/or try turning on the heater. If you spent the session in lap traffic try to get out of the draft and get clean air.

If you want a production street car to be a race car that can run all day well then gut the car ,modify the airflow, improve heat soak issues or better yet buy a race car with a proper cage.

I will track my ACR Extreme on occasions and I expect it to be fast but I can tell you it will have a hard time beating the times of my real race car that only has 350 hp to rear wheels. (996 Cup Car) especially on a consistent basis. But that whats to be expected its a STREET CAR

[ViperGeorge]

Your PCM pulls timing any time it sees an IAT over 76 degrees, which happens everyday driving to the grocery store here in Texas. That doesn't mean there is anything wrong with the car or that it's overheating.

There are other tables besides the IAT tables. One is for coolant temps and I believe one is for oil temps. Any one of the three can and will pull timing. Tables were posted in another thread.

[ViperGeorge]

From the Track Overheating Thread. Thanks Steve M. Sor

View Post
And to answer this portion of your question...

The amount of timing that gets pulled is actually controlled by two tables...there's the ECT spark table shown above, but there's a multiplier associated with it that determines how much of the value in the first table actually gets applied for a given engine RPM and amount of airflow. Both can be seen here:

Capture.jpg

So using the example you gave of an ECT value of 220°F, you look at the first table and see that it wants to pull 4° of timing, but that's not how much actually gets pulled. You have to look at the multiplier table...the x-axis is airmass (grams per cylinder), the y-axis is RPM. To make a long story short, anything greater than 0.60 grams/cylinder of airmass I'd consider to be wide open throttle for these cars (that's based on the tons of data I've logged). So looking at the multiplier, you'd see that it would multiply the first table by 0.55, or take 55% of the value being asked for in the ECT table and apply it to the timing calculation. In this case, 4° x 0.55 = 2.2°, so the PCM would pull 2.2° of timing under WOT. At idle and low airflow conditions, however, you can see that the multiplier is 0, so it wouldn't pull timing even if the ECT was sky-high.

As another example, let's say you were seeing ECTs around 250°. The ECT timing modifier table would ask 7° to be pulled...when you add in the multiplier table, you'd get:

Under part throttle, idle, or any low airflow condition: 0° pulled (7° x 0 = 0)
WOT: 3.85° pulled (7° x 0.55 = 3.85°)

So you'd be seeing about 4° of timing pulled from your WOT spark advance values under WOT conditions with an ECT of 250°F.

How much power would any of that equate to? I'm not sure to be honest. You'd need to spend some time on an engine or chassis dyno to find out.

I'm sorry if this makes your head hurt, because it has certainly made mine hurt while trying to figure it out. I've been logging lots of data over this summer, and I've gained a lot of insight into what does what with this PCM. I'm still far from fully understanding everything that goes on behind the scenes, but I'm way closer than I was.

[Rapidrezults]

Well one thing is for sure, Ralph removed the plastic hood vents on his new ACR Extreme. I'm sure he didn't do it for looks.

[FLATOUT]

Doesn't make my head hurt at all George these are all things we have known for quite sometime. I used to run HP Tuners on my TA and have also spent time with Dick watching him tune my own car with his factory software. New to you yes but not new to everyone here. You want to know how much 4 degrees is worth on the dyno, maybe 10rwhp, not much at all definitely not something you would notice for the most part which is why I can't wrap my head around why you have spent so much time researching an overheating problem when your car has yet to over heat. Again elevated temps yes, overheating no.

From the Track Overheating Thread. Thanks Steve M. Sor

View Post
And to answer this portion of your question...

The amount of timing that gets pulled is actually controlled by two tables...there's the ECT spark table shown above, but there's a multiplier associated with it that determines how much of the value in the first table actually gets applied for a given engine RPM and amount of airflow. Both can be seen here:

Capture.jpg

So using the example you gave of an ECT value of 220°F, you look at the first table and see that it wants to pull 4° of timing, but that's not how much actually gets pulled. You have to look at the multiplier table...the x-axis is airmass (grams per cylinder), the y-axis is RPM. To make a long story short, anything greater than 0.60 grams/cylinder of airmass I'd consider to be wide open throttle for these cars (that's based on the tons of data I've logged). So looking at the multiplier, you'd see that it would multiply the first table by 0.55, or take 55% of the value being asked for in the ECT table and apply it to the timing calculation. In this case, 4° x 0.55 = 2.2°, so the PCM would pull 2.2° of timing under WOT. At idle and low airflow conditions, however, you can see that the multiplier is 0, so it wouldn't pull timing even if the ECT was sky-high.

As another example, let's say you were seeing ECTs around 250°. The ECT timing modifier table would ask 7° to be pulled...when you add in the multiplier table, you'd get:

Under part throttle, idle, or any low airflow condition: 0° pulled (7° x 0 = 0)
WOT: 3.85° pulled (7° x 0.55 = 3.85°)

So you'd be seeing about 4° of timing pulled from your WOT spark advance values under WOT conditions with an ECT of 250°F.

How much power would any of that equate to? I'm not sure to be honest. You'd need to spend some time on an engine or chassis dyno to find out.

I'm sorry if this makes your head hurt, because it has certainly made mine hurt while trying to figure it out. I've been logging lots of data over this summer, and I've gained a lot of insight into what does what with this PCM. I'm still far from fully understanding everything that goes on behind the scenes, but I'm way closer than I was.

[FrgMstr]

Well one thing is for sure, Ralph removed the plastic hood vents on his new ACR Extreme. I'm sure he didn't do it for looks.

I would suggest he did it to create more downforce.

[Stealth]

You want to know how much 4 degrees is worth on the dyno, maybe 10rwhp, not much at all definitely not something you would notice for the most part which is why I can't wrap my head around why you have spent so much time researching an overheating problem when your car has yet to over heat. Again elevated temps yes, overheating no.

+1 Our cars will never have the same temps running strong for 20 minutes on a track as they have loafing on a cruise on a county road. Further, I do not think any "idiot light" came on or blinked on my dash when Oil briefly hit 240-245F during a recent HPDE. Of course, perhaps I am just too much of an idiot to have noticed it even though I constantly noted the temps. What I did notice is that on the street and in the few HPDEs I have run my Gen IV and Gen V Vipers, they have always performed like Stallions! Go SRT!

NOTE: I am all for any constructive improvements which can be made, so please do not take this the wrong way.

[7TH_SIGN]

Not sure if this helps but I took my car out last night, went on a 30 mile cruise. Didn't get on the car hard as I'm still in the break in period but I kept an eye on the gauges. Max oil temps I saw was between 185-195 and max coolant temps were 175-185.

Stock 2015 SRT

[ViperGeorge]

Doesn't make my head hurt at all George these are all things we have known for quite sometime. I used to run HP Tuners on my TA and have also spent time with Dick watching him tune my own car with his factory software. New to you yes but not new to everyone here. You want to know how much 4 degrees is worth on the dyno, maybe 10rwhp, not much at all definitely not something you would notice for the most part which is why I can't wrap my head around why you have spent so much time researching an overheating problem when your car has yet to over heat. Again elevated temps yes, overheating no.

Andy, I did not start any of the threads on track heating issues. However, I agree with BlueTA#1 that these cars are running too hot especially as compared to Gen 4s. Most people that have tracked cars would be concerned about oil hitting 265 and coolant hitting 240+ in just 15 minutes or in BlueTA#1's case a few laps. That is simply not right in a car that is designed to be driven hard on the track. How hot would they get if we ran hard for 30 minutes or 45 or an hour? I've run tests and posted results. Yes, removing the tow hooks may be another test I need to run, but damn my Gen 4 had two tow hooks, Mopar controller, and headers and it NEVER, EVER got above 210.

[ViperGeorge]

Doesn't make my head hurt at all George these are all things we have known for quite sometime. I used to run HP Tuners on my TA and have also spent time with Dick watching him tune my own car with his factory software. New to you yes but not new to everyone here. You want to know how much 4 degrees is worth on the dyno, maybe 10rwhp, not much at all definitely not something you would notice for the most part which is why I can't wrap my head around why you have spent so much time researching an overheating problem when your car has yet to over heat. Again elevated temps yes, overheating no.

Andy, A couple of other points. I did not post the tables or the text you read. It was originally posted by Steve M. I only copied it here to illustrate that the PCM is in fact pulling timing based on temps. Maybe 4 degrees isn't a lot but it is probably also adding fuel in an attempt to cool things down. Now you would likely agree that cooler is better on the track (ok within limits - the oil does need some heat to work properly). I believe the purpose of BlueTA#1 starting these threads is to get some ideas on how to make the car run cooler. Cooler equals more power and fewer problems. This is a very good reason to post on this forum.

The thread I did start had to do with heat from the headers. With the engine compartment of a Gen 5 being so tight the heat from the headers is effecting a lot of components. This heat may also contribute to coolant temps in my car but not in BlueTA#1's car as he does not have headers. I've already melted the EVAP tube and the main harness, repairs were expensive as the warranty would not cover damage due to the headers. We need an effective heat shield for the headers. Hopefully Mark will come up with something soon. As it is I have everything under my hood insulated. Looks like a science experiment but still the temps in mid 80s ambient hit 240.

Bottom line is that this is my 7th Viper and I currently have three. Not bragging I'm just pointing out that this is not my first rodeo. I want to figure this out so I'm not always looking at a flashing idiot light and wondering when the temps will rise above 250 or more. The TA is the only one that has had temps rise above 210 on the track (ok in fairness I have not tracked my 14 GTS). The ones I've tracked include my old 98 RT/10, my 03 SRT, my supercharged 06, and my 09 ACR. None of these ever got close to being warm on the track.

[Nemesis]

I'm not going along with the OP's disposition towards the car, I love my Vipers. I have a 2013 GTS and a 2014 TA. I have experienced over heating issues in both, pre mod and post mod. I have melted 02 wires, front side and back side, I've melted starter wire plugs, I've melted the main bus line, I've melted abs lines (let me town you how fun that was in the midst of a turn when it failed and the car locked up) I've blown one engine (2013). These cars generate a tremendous amount of heat under stress. If you mod them they generate even more heat. I now have both current cars heat wrapped to the hilt. It has been trial and error. It is one thing to 'track' the cars it is another to run them at full hilt. Viper built these to be a track car, not a race car on a track day. If your willing to work through the issues it is solvable. I would recommend taking the aftermarket bits off i.e. PCM and headers as I hear the heat the heat they are generating is significantly more than stock. What is of interest is that I have been following Ralph's heat wrapping solutions and most notable I noticed on his recent Instagram post with his new ACR that he actually pulled the 6 center vents out of the hood along with the tire vents... Granted the last two would only impact tire temps but I found it very interesting.. I am going to try that with my TA.

[FLATOUT]

You absolutely have to wrap everything and we do on all of our customer builds. Anything that is anywhere near the primaries gets wrapped, along with O2 wiring. It's easy to do. Ralph and I both shield much of the wiring with Lavamatt, which works very well.

[FLATOUT]

You say you have experienced overheating but didn't mention any coolant or oil temps. Melting wires is an issue separate of the elevated track temps, take the proper precautions and you're good to go.

I'm not going along with the OP's disposition towards the car, I love my Vipers. I have a 2013 GTS and a 2014 TA. I have experienced over heating issues in both, pre mod and post mod. I have melted 02 wires, front side and back side, I've melted starter wire plugs, I've melted the main bus line, I've melted abs lines (let me town you how fun that was in the midst of a turn when it failed and the car locked up) I've blown one engine (2013). These cars generate a tremendous amount of heat under stress. If you mod them they generate even more heat. I now have both current cars heat wrapped to the hilt. It has been trial and error. It is one thing to 'track' the cars it is another to run them at full hilt. Viper built these to be a track car, not a race car on a track day. If your willing to work through the issues it is solvable. I would recommend taking the aftermarket bits off i.e. PCM and headers as I hear the heat the heat they are generating is significantly more than stock. What is of interest is that I have been following Ralph's heat wrapping solutions and most notable I noticed on his recent Instagram post with his new ACR that he actually pulled the 6 center vents out of the hood along with the tire vents... Granted the last two would only impact tire temps but I found it very interesting.. I am going to try that with my TA.

[7TH_SIGN]

My personal opinion is this. Bottom line if you are going to run these cars hard, I don't mean a couple street pulls, I mean actual hard track use, you should really look in to upgrading the cooling system. Aftermarket oil cooler, larger upgraded radiator, heat wrap, and so on... I don't think there are many if any manufactured stock cars in this group that could handle heavy track use without having some heating issues.

Not blaming the owner or manufacture for the issue.

[VENOM V]

It's like I'm reading about some other model of car, these stories are foreign to me. How can it be that for two years I've been tracking my Viper and this month is the first time I've heard of this "overheating" issue? I tracked at Laguna Seca recently with 17 Vipers. No one overheated except for the C7 Z06, which went into limp mode and puked all of the coolant out right next to me in the paddock. He hit 267 F water and 309 F oil. Buttonwillow with 78 Vipers, no overheating issues on a single car. 2 C7 Z06s in limp mode at Buttonwillow in cool weather. I've tracked with other Vipers in 107 F and no one overheated. Laguna Seca, Buttonwillow, Thunderhill, Sears Point, Spring Mountain. Never had an issue other than touching 240 F coolant at Thunderhill in 106 F ambient, so I backed off for a lap and it immediately cooled. Then went hard for another 5 or 10 minutes and never touched 240 F water again. I did have an 02 sensor go that day, replaced under warranty the next week. Easy peasy. The only issue I've ever had with the Viper was that 02 sensor, no melted wires, no other issues at all. I just change the oil and brake pads, and an occasional alignment. And drive the wheels off of it, over 14,000 miles many of which are on the track.

This all seems blown out of proportion, only a couple of folks have had issues. As Darius said, Camaros run hot as his Z/28 hit 290 F oil (my modded Camaro required 2 oil coolers and custom shrouding to get the oil temps reasonable), C7 Vettes run hot. But I haven't seen it with Vipers.

And I know that this has been said, but to remind folks that Dick Winkles stated to keep the coolant temp below 255 F and oil below 300 F. I am nowhere near those values and I haven't read anyone else approaching them either.

[VENOM V]

My personal opinion is this. Bottom line if you are going to run these cars hard, I don't mean a couple street pulls, I mean actual hard track use, you should really look in to upgrading the cooling system. Aftermarket oil cooler, larger upgraded radiator, heat wrap, and so on... I don't think there are many if any manufactured stock cars in this group that could handle heavy track use without having some heating issues.

Not blaming the owner or manufacture for the issue.

Based on what, two or three folks that have had issues? With Hoosiers I have run a lap at Buttonwillow that is 3 seconds faster than the production car record, but no cooling issues. I only mention this because of this notion that only fast drivers have this issue. There are plenty of guys in NorCal that turn decent lap times but have never had a cooling issue.

I'm not worried in the slightest. Sounds like there are corner cases at some tracks, but this is not a widespread issue. I wouldn't waste my money on cooling system upgrades unless you are one of the few guys that have experienced first-hand over temp issues at your specific track.

[7TH_SIGN]

Based on what, two or three folks that have had issues? With Hoosiers I have run a lap at Buttonwillow that is 3 seconds faster than the production car record, but no cooling issues. I only mention this because of this notion that only fast drivers have this issue. There are plenty of guys in NorCal that turn decent lap times but have never had a cooling issue.

I'm not worried in the slightest. Sounds like there are corner cases at some tracks, but this is not a widespread issue. I wouldn't waste my money on cooling system upgrades unless you are one of the few guys that have experienced first-hand over temp issues at your specific track.

I think there is a lot that goes in to how and why a car is running the way it is, part modifications or lack of, tune, weather conditions, the track itself and the car itself. We can sit here and compare your car to his or others but unless we have them on the same track at the same time, its hard to really diagnosis it. So many variables. I personally don't do this type of racing however if I did and I was running the car as hard as Le Mans (exaggerating), I'd definitely looks in to making sure the cooling system is as proficient and reliable as possible.

[Bruce H.]

With Hoosiers I have run a lap at Buttonwillow that is 3 seconds faster than the production car record, but no cooling issues.

Todd, I wonder if you would have issues if you were running at that pace for many laps...or perhaps you already do.

[98intrigue]

I'm all for spreading factual information, understanding an issue, and coming up with a resolution. From what I've read here, the majority of Viper owners who track their cars do not have overheating issues. If it's a few isolated cases, it is not a widespread issue. So let's not blow this out of proportion and make this another pissing match between us and the Vette. These cars are hand built after all, so human error can occur during the production process.