It should be worse!

[FLATOUT]

The new ACR's do not have diff coolers, but the X diff coolers bolt up to the Gen V's without much fanfair.

I know that we had one other owner at COTA the day I was there with them that mentioned to me that he saw some really high temps but after we got to talking he told me he was running the S's at COTA in second gear (he would have run that entire section at like 5000-6000 rpm). He went out next session and ran that stint faster in third gear and didn't see any where near the temps he saw running that section in 2nd.

- - - Updated - - -

The new ACR's do not have diff or tranny coolers, but the X diff coolers bolt up to the Gen V's without much fanfair.

I know that we had one other owner at COTA the day I was there with them that mentioned to me that he saw some really high temps but after we got to talking he told me he was running the S's at COTA in second gear (he would have run that entire section at like 5000-6000 rpm). He went out next session and ran that stint faster in third gear and didn't see any where near the temps he saw running that section in 2nd.

- - - Updated - - -

The new ACR's do not have diff or tranny coolers, but the X diff coolers bolt up to the Gen V's without much fanfair.

I know that we had one other owner at COTA the day I was there with them that mentioned to me that he saw some really high temps but after we got to talking he told me he was running the S's at COTA in second gear (he would have run that entire section at like 5000-6000 rpm). He went out next session and ran that stint faster in third gear and didn't see any where near the temps he saw running that section in 2nd.

[ViperGeorge]

The Gen 5s run hotter than a similarly equipped Gen 4 in the same hands. My 09 ACR had headers, Mopar controller, two tow hooks up front and never, never went above 210 on the track here in Colorado. My TA 2.0 regularly hits 240+ and I would wager I am not as quick as Blue TA #1. A friend in a bone stock 14 GTS was seeing 238 on the same day I was there. Now I know Dick says that these temps are ok BUT why does the idiot light flash then when it hits 240? Are we just supposed to ignore it? Why does the PCM pull timing and add fuel at temps well below that? Why is a Gen 5 hotter than a Gen 4 even though the radiator is better sealed?

Blue TA#! is correct. When I see the idiot light flashing I back off I don't want to risk blowing something. I can see it now, you blow the engine and the warranty department reads your PCM and says "oh, you drove this when the warning light was flashing, claim denied."

Look I am a huge Viperholic. I have three including two Gen 5s. BUT these newer cars run hotter when driven hard - modded or not. Period. I would love to see a fix for this. I was really hoping the bigger radiator was the answer.

Any chance there is a bad batch of thermostats that don't open fully? Just wondering.

[Stealth]

Are you guys seeing the flashing "idiot light" on the dash or on the separate SRT Gage Pack Display? Maybe I have been watching the road and just missed the light?

[ViperGeorge]

SRT will rightfully not address heating issues with cars that have been modified (PCM, slicks, tow hooks, whatever). If Karl returns his car to stock (street tires and all) and still sees higher temps then maybe SRT would comment. I believe their threshold for temps is 250 in 100 ambient for a 20 minute session. If Karl hits those temps in 10 minutes or 15 then maybe we could get SRT to look into this. I would try this myself but my car has headers and they would be more difficult to swap out.

[ViperGeorge]

Are you guys seeing the flashing "idiot light" on the dash or on the separate SRT Gage Pack Display? Maybe I have been watching the road and just missed the light?

On the dash. Upper right above tach. The location may be configurable as might be the choice of even displaying coolant temp. I think you may be able to display voltage there as well. Not sure what happens to idiot light if you are not displaying coolant temp.

[TrackAire]

Wouldn't hard metal coolant lines just heat the coolant more once they are hot and coolant is passing through them? Not sure if I would do that. Putting a spring in the rubber ones is the way to go imo.

Aluminum tubing would actually dissipate the heat out of the coolant as long as the coolant was hotter than the under hood ambient temps. Apparently in this situation, the coolant is way hotter than the under hood ambient temps.

[FLATOUT]

On the dash. Upper right above tach. The location may be configurable as might be the choice of even displaying coolant temp. I think you may be able to display voltage there as well. Not sure what happens to idiot light if you are not displaying coolant temp.

George have you tried running without 2 front tow hooks?

[RAY W]

It is possible that the difference in temperature between Gen IV and the V running at the same tracks is the 3:55 rear gear.

[BLUETA#1]

I read all the posts….

2nd gear in the esses caught my eye…yikes that's scary! I use 3rd all the way.

Ben's car had the lowering caps on…it was not technically stock.

My back-to-back ECU test will be on the first Saturday of November.

The fastest video lap of a Viper that I can find is a 2:23 by Mike Skeen in an older ACR. I wonder how long that car would run at that level for? It sounds a bit like he has street tires on so I bet in Hoosiers he's a 2:20 at least. That's fast…..

https://www.youtube.com/watch?v=sp7hTuLoog0

[TrackAire]

I hate that video of Mike Skeen.......he makes it look too easy and smooth, lol.

[XSnake]

I hate that video of Mike Skeen.......he makes it look too easy and smooth, lol.

Thats the fastest way to drive these cars, no need to be on the limiter driving like a maniac. You will just get bit.

[ViperGeorge]

George have you tried running without 2 front tow hooks?

That was another test I was going to run but didn't have the time. On the other hand my friend with the bone stock GTS only had one tow hook and his temps were almost as high as mine (within 2 degrees). Mark from IPSCO was at the track with me and we had looked at the tow hooks prior to that. While they block a little of the radiator, it is a very little. Given the stock GTS was running hot too I don't think that is the problem. Does Blue TA#1 run hooks up front? Given he has a larger radiator I would think if he was the radiator would make up for them easily but they didn't.

I'd still like an answer though to my previous questions - Why have an idiot light that goes on at 240 if the car is safe to 250 or 255? If the PCM pulls timing and adds fuel at temps below 240 (which has been confirmed by the tables that have been posted) then power will be lower. So even if 250-255 is safe we are losing power - no? And why are Gen 5s running hotter than similarly equipped Gen 4s?

[Nine Ball]

I believe that car currently has full factory exhaust and one tow hook up front. Upgraded radiator, hard coolant lines, coolant is 1/3 coolant and 2/3rds water. We also replaced the temp sensors just as a precaution.

Read closer.

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

[Nine Ball]

That was another test I was going to run but didn't have the time. On the other hand my friend with the bone stock GTS only had one tow hook and his temps were almost as high as mine (within 2 degrees). Mark from IPSCO was at the track with me and we had looked at the tow hooks prior to that. While they block a little of the radiator, it is a very little. Given the stock GTS was running hot too I don't think that is the problem. Does Blue TA#1 run hooks up front? Given he has a larger radiator I would think if he was the radiator would make up for them easily but they didn't.

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.

[FLATOUT]

I was talking about Blue TA 1's car.

Read closer.

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

[Nine Ball]

I was talking about Blue TA 1's car.

So am I. Read post #88

[FLATOUT]

So am I. Read post #88

He cut and pasted ViperGeorges track day info from Colorado in that post, that's not his cars data. The two front tow hook car is George's at altitude. Karl's COTA car was in my shop a couple weeks ago getting the larger radiator put in. Karl's car has a single tow hook up front.

[BLUETA#1]

Thats the fastest way to drive these cars, no need to be on the limiter driving like a maniac. You will just get bit.

I agree…I shift at 6000 or lower.

[Nine Ball]

He cut and pasted ViperGeorges track day info from Colorado in that post, that's not his cars data. The two front tow hook car is George's at altitude. Karl's COTA car was in my shop a couple weeks ago getting the larger radiator put in. Karl's car has a single tow hook up front.

This shit is confusing. All you comp blue guys ruin the thread.

[roadrunner]

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.

[Simms]

I seem to remember reading how SRT had to eliminate the honeycomb from the grill of the Gen V prototype on the production version because it limited airflow too much. On the production car, the honeycomb is only in the center "V" of the grill. This supports how crucial airflow is on the front of this car.

[Nine Ball]

I seem to remember reading how SRT had to eliminate the honeycomb from the grill of the Gen V prototype on the production version because it limited airflow too much. On the production car, the honeycomb is only in the center "V" of the grill. This supports how crucial airflow is on the front of this car.

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

[ViperGeorge]

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

So if we cut out the honeycomb in the V that should add some airflow. It won't be a "Flowtie" it will be "FlowVie".

[darbgnik]

Might be talking out of my ass here, but would it be possible to remove the whole black plastic grille section, run the car, and see if there is any improvement before taking the sawzall to it?

[SSGNRDZ_28]

So if we cut out the honeycomb in the V that should add some airflow. It won't be a "Flowtie" it will be "FlowVie".

FlowVee?

flowbee.jpg

Anyway, exploring the airflow through the front opening I think is a good direction.