jbsblownc5

While I only run my Supercharged C5 in corvette club events, and leave plenty on the table so as to drive it home in one piece, my oil and coolant temps can stay well within my comfort zone for a 20 minute track session at 90 plus degrees...

Yes, LOTS of coolers and supporting Mods:

Here is a little video I put together last year. The ZR1 is still learning the track, and has now gone MUCH faster for the record.

Fitz89

After one track weekend, no problems with my Z06/7. I have two more events coming up including Road Atlanta early May. I am a little nervous about Atlanta as so far I am very happy with my purchase. I do not feel that I should have to worry about oil and coolant temps after a few hard laps, but we will see.

thebishman

A8 or M7?

What run group are you in?

Ambient temp?

Fitz89

I am an instructor with NASA, CHIN, PCA, ++
Licensed with NASA, Grand-AM.
Temps Saturday ~ 60 , Sunday in the 50's.
A8 With Z07

ChrisN123

Fitz, did you run in Automatic, or manual/paddle shift?

Admin Gods: It might be helpful to have a sticky where people can post "just the facts" about heat results (ideally PDR lap-by-lap screen) with relevant details (ambient temps, track config, lap times, skill/speed of driver, M7/A8, if A8 then auto or manual).

Fitz89

Never considered running it in "D", other than to pre grid.

soulsea

For what it is worth I ran my M7 this weekend for a full day at Roebling Rd in GA with Just Track It. Novice group, 6 25min sessions averaging about an hour in between, low 60s, zero heat issues. I'll do a thread on it later with pics and vids but I just wanted to mention the temp topic here.

thebishman

Fitz89, thanks for the additional info.

Did you run it out through the gears or were you say shifting up at 5K rpm given the torque characteristics of the car?

0Anthony @ LGMotorsports

For those interested.





Start of the run





End of the run



It would not let me display the entire run on one screen, so you can see at the start the car was only 120 F water temp when he was rolling up to the grid. I was logging a lot of things so there are some skips in the data.

DaveN007

It will be interesting to see what the usable performance available actually is on a 90 degree plus track day.

I am thinking in terms of cars.

Will a GT4 actually be quicker because it can maintain 100 percent?

What about a Z51 C7? Will they ever have a Grand Sport? Would that be basically a Z06 with a Stingray motor? That might be one hell of a car.

I'd still want the ability to dial it up to "11" and run a few screaming laps...even if to requires a cool down.

The A8 Z06 has afterburners. You can't run them all day long. So what?

You don't want that extra power? Don't use it, then.

OHSTZ51

I know the C7 Z51 8 speed transmission tends to overheat with track use... but what about the Z06 automatic?

I know they added a second transmission cooler, is that enough? Or still heat soak issues with the Z06?

Thanks.

thebishman

So far it appears that it's the engine overheating that's the issue. I don't think any owner has posted a thread where the A8 threw an overheating code.
Bish

Hot Rod Todd

Heat soak is typically associated with hot intakes, supercharger bodies and the like when radiation or conduction causes excessive heat to build up in places that negatively affect performance.

An automatic transmission just gets plain hot. It depends a lot on how you're shifting when driving, outside temp, and even the speed of the track. A low speed track with a lot of shifting on a hot day, and I'd guess the auto will run hot. How hot is tough to say until it happens.

I had an A6 in my 2008 Z51, and if I drove it hard keeping the RPM high there was no way it could keep temps down over time. Just by changing the downshift points it would run much cooler. I'd guess the Z06 A8 will do fine, 99% of the time.

johnglenntwo

Who cares! Problem solved!

OHSTZ51

I was asking as in my 2015 Z51, the 8-speed auto overheats after the 2nd or 3rd track session.

I am hoping the Z06's 2nd cooler does in fact fix this.

anders1118

From what i have read you will probably worry more about the engine heat soaking before the transmission. Specially if they added a second trans cooler.

BobSWFL

Edit: This mod is intended to INCREASE the volume of air venting out through the existing vents in the hood. This mod is for the track. You don't need it on the street.

This free C7 Z06 mod might increase total cooling capacity by up to 20%. I can't get to the track for a few months to try this. Hopefully someone can do it before then.

(Please read my notes and disclaimer after the pictures.)

Totally remove this black plastic duct that channels air from the top of the radiator to the underhood vent shroud:



Totally remove this black plastic shroud that is attached under the hood vent:



Note 1: I'm not sure if the radiator duct bolts support anything besides the duct. If they do, then re-install the bolts (without the duct) to hold everything in place.

Note 2 The hood liner might flap around if you leave it loose after removing the plastic shroud. Try re-installing just the shroud screws with fender washers or some other type of washer. Or remove the hood liner.

Disclaimer: This mod cannot be approved by GM, since it may expose the user to a few new (possibly) dangerous situations. For example, if a radiator hose fails, coolant now has a quick path through the unshielded hood vents and onto the windshield.

Also, in winter climates water could drip in through the exposed hood vents and freeze on the front of the engine.

Final Thoughts: I suggest someone try this simple mod after confirming they can get their car to overheat on a track day. Then remove the duct and shroud and see if the overheating is diminished.

The results of this experiment will determine the next area of concern. For example, is overheating caused by insufficient underhood air flow/extraction, or an inadequate radiator?

Nevadagame

1. What is your theory as to why this would help?

2. Has anyone tried expanding the size of or adding a second hood vent to increase evacuation of under hood air/heat?

Dabigsnake

I'm sure GM worked hard on the correct way to move air in the engine compartment. Yes they have restrictions, as noted above w water intrusion, etc. I agree w experimenting, but I remember once dealing w a friends firebird that overheated only when at highway speeds. Ended up being the small air deflector mounted way up under the radiator that was removed or knocked off. It created the low pressure needed to draw the air out of the engine compartment. I would be cautious, but give it a try, while waiting that temp gauge closely.

Arctic Blastoff

I would just remove the hood liner at that point.what are normal operating temps im off today an might try seeing i live in tx where it gets 110