Thomasmoto

I found this post to be helpful. Good accurate data that can benefit others. Thanks OP. I am installing the kit from Dewitt's the second week in April. I will post my findings with those improvements asap. I have a 2016 Z06 A8.

Ltrain925

I'd be very interested to see how an additional radiator on the 15/16 m7 Z compares to the 17. I'll be adding an additional cooler to my 16. Turning the heater on is an old trick that I've used every time I went racing, it does make a difference.

descartesfool

Great comparison info, and nice to see how the 2017 was improved. However it makes one wonder about the case where people who said their stock un-modified 2015 and 2016's have never overheated on track since the stock 2016 Z06 in this comparison did eventually overheat.

5thGear

Thanks Claude. To give you an idea. I ran this course a year ago in a 2016 Z06 with secondary radiator and Ron Davis main radiator. Ambient was in the low 70F. The coolant wouldn't go pass 220F and oil 260F. I related that to lower ambient, secondary radiator, and Ron Davis radiator. I do believe others who said they don't overheat M7's but still, the secondary radiator is a no brainer for me.


This time around it was hot. I believe ambient was showing 89F but there was hot gust blowing. It felt like 95F or more.


Ali

thebishman

Assuming all 2015s are equal and the same for 2016s, then the difference in being able to run for a full run session is due to driving style. Meaning if you know how to avoid overheating the car in high ambient temps and then drive using the torque curve versus always shifting at 6500 rpm, most of us can even get an A8 to last.

Do I wish it was otherwise; of course. But still the car is fast enough to dust off pretty much everything else in my run group.

Bish

rico750sxi

Please share how this was covered under warranty? Was it in response to an overheating issue you experienced and that's how it got covered?

Checkmate1

What we need is a 2017 A8 vs 2016 A8 on track at ambient temps over 88'. Then we can talk.

Comparing a 2017 M7 (w/secondary radiator) vs 2016 M7 (w/secondary radiator) is what needs to happen to truly know if there is difference because of the bigger lid and bricks?

5thGear

I pretty much know the answer. The A8 2017 or A8 2016 will behave the same. Sure the supercharger might not overheat on the 2017 A8 but it will not make any difference since both engine will overheat in the same manner.


Since my previous car was 2016 Z06 M7 and I had add the secondary radiator, the main difference would be no or much lower power loss after mid session. That can also be addressed on 2016 M7 by improving the supercharger cooling.

rti35

In before 15/16 owners break out the torches and pitchforks for an upgrade kit, me included...



Seriously though, great informative thread OP. I honestly wouldn't be too upset if my 650HP supercharged car overheated in 95 degree ambient temps running for multiple 30 minute sessions. That's the gauntlet in terms of tracking the car in my opinion, but if there's an upgrade available (which there obviously is) then GM needs to do right by buyers who bought as little as 3 months away from a 2017 and get the kit to us at a reasonable price

5thGear

The C7 platform is insane. Honestly we run same lap times at ACS and Spring mountain as fast as new GT3RS at one third or the price. Not taking away anything from Porsche as I love the car but the C7 package is hard to beat. In Germany and Europe they are making aftermarket parts for these cars since the platform is hard to beat.

Bill Dearborn

The secondary radiator is good for somewhere around 14 to 15 deg F reduction in temperature. That takes a fair number of cars out of the overheat situation right away. I ran hard in low 90 temps last year and never came close to overheating the engine oil or coolant.

Bill

dapopa9

5thGear great comparison post on the cooling here.

What laptimes were you running at Spring Mountain that day and when you are at ACS?

thebishman

5th Gear I would agree, except that IF detonation may be contributing to the engine overheating, the 2017 A8 may last a lap or two longer.

Bish

5thGear

Averaged low 2:39s on the mansell course . I believe the fast lap of the day if I am not mistaken was for some Spring mountain member with open wheel race car that ran 2:35.

As for ACS it depends on how the organizer sets up turn 15/16. I was able to run 1:48 with it being setup as 90 degrees turn. I would like to run my 2017 with that turn more open like speed venture layout to pickup more speed through the sweeper before the main straight and see what lap times I can get with that.

Les

That's very encouraging news! Thanks for all the info.

upcharger

At spring mountain I overheated the power steering on their car. It was smoking hot out. In the 90s. Who makes the best secondary radiator? How about who makes the best primary radiator replacement as well?

spearfish25

The heat on full blast trick is good for about 3-4F cooler water temps when standing still. Played with this the other day in traffic.

Mad Dog 24

Great side by side test!

How could I not post on a thread of track cars getting hot! I'm with Bill with a 2015, M7. Drove it hard at WG in over 90 degree temps and never a limp or hick up, 30 minute sessions! The difference though is my car has NO additional radiator NO aftermarket radiator either just good solid track prep and our oil cooler fins to help extract some unwanted heat.

I wonder and would bet that the 2015 if it was a M7 and reasonably shifted would of lasted a bit longer. Although over 95 is hot enough to overheat a **** load of cars not just our reasonably priced rockets! Sounds like the 17's have achieved some improvements that's great news.

johnglenntwo

It makes sense to me that the hot supercharger drags all the systems down, including the power steering. Engine tuning improvements, and radiator helped to a lesser extent, but, relavent of course.
The A8 will at least need the additional ZL1 type cooling as the tuners indicated way back now, and/or the keeping of all the transmission cooling in the back.

The Z07 A8 was laughable, and it probably still is, but, to a lesser degree I'm sure. These guys should get the cooling free.

The old SC is junk and it should be free, and I thought Tadge said it was.

It is good to see they made strides with this, but, they still haven't made it right! The Z07 guys should be squared away. The F'ing CC brakes says so!!!!

spearfish25

^That was the most coherent post he's ever made. Not saying it all made sense, but he's made progress.