0Tom@Dewitt

Ok "on the fence" guy....4th of July sale with free shipping is about a $200 savings!

formula80_ca

Haha, I guess I might qualify as an "on the fence guy" or maybe more accurately a "which one of these solutions to choose guy"

I have been waiting for more tests to chose combo engine oil / coolant or the large aux rad. X25 's upcoming test of the large aux rad is highly anticipated.

I have a 2015 Z51 A8 (without the GM aux cooler). I have installed an aftermarket trans oil cooler in front of the rad laying flat(ish) just above where your Dewitts large aux rad or combo coolers would be installed. It is relatively small compared to the Dewitts solution but has greatly reduced my trans temps from limp mode after approx. 4 laps to no issues since. So I want to keep that... Maybe move it slightly to accommodate some air flow to the Dewitts solution I choose.

My problem is high coolant temps and high engine oil temps after 3 or 4 hot laps. I get the dash warning and you can feel the engine pulling power. Data shows oil temp over 300 at times and always over 290, coolant is 245-250.

My main questions are...
1. how does the aux rad connect?
2. Can the aux rad co-exist with my trans cooler above it partially blocking air flow?

Would like to take advantage of this special but want to make the right choice.

0Tom@Dewitt

The C7Aux would tap into the 5/8" coolant return hose from the oil cooler (brick)
I see no reason why the Aux couldn't co-exist with your add on.

With that said, I think you have to address the oil temperatures, and while adding more cooling and lowering coolant temperature will have an effect on that, nothing will work as good as the independent oil cooler..
I do not see how you could go wrong with the 32-TO option. You would get equal or better trans cooling than your add-on, much better oil temperatures, and an improvement in coolant.. At that point, you could be done but if you needed additional engine cooling, just add one of the upgrade radiators.
If you are totally happy with the trans cooler install and performance, then just go with the 32-OC.

formula80_ca

Thanks for the response on your holiday Tom, and happy 4th!

I'm quite happy with the trans oil cooler.

While I agree that attacking the oil temps makes sense I'm also a little leery of adding an engine oil cooler that removes the stock brick... I'm only a sound engineer so I defer to other knowledgeable people when it comes to mechanical engineering but I have a 7 year warranty and voiding that when maybe all I need is the large aux rad, seems unnecessary. I feel it would be harder for GM to argue that the aux rad was a problem if something goes wrong with the engine on track than if I change the oil system.

I think I will order the large aux rad and hope that X25 or others prove it is enough by mid month. If it can do a good job of bringing temps down on a Z06 it should definitely be enough for my normally aspirated Z51.

Is there any special part number I need to order seeing as my car is an early 2015 Z51 A8 without any aux cooler?

0Tom@Dewitt

No special part number, same kit. Just download the combo kit instructions and follow the duct cut out portion. It will seem like you are cutting out this huge hole since there is no existing cooler but the cooler and baffle will close it all back up.

INSTRUCTIONS

olblue75

Tom,

I have a 2017 A8 GS with AUX chin cooler and when I tracked the car back at the end of May the oil temp got rather hot in my opinion, so my question is will the EOC/TOC combo work on a GS?

0Tom@Dewitt

Yes, it will work. If the Aux chin cooler you are using is for coolant, you will need to extend the trans lines up to the front. Kits are available to do that.

BrunoTheMellow

If you share a pic of your trans cooler we can help you decide if it will work...

badhabit_wb

Your cooler is a transmission cooler so you will need a toc/ec combo.

Cobraken

Another on the fence guy watching this topic and noting the holiday sale. 2016 M7 stock z07 that I want to prep to enter local So Cal track days.

Am I better off first pursuing the 32-c7aux or one of the two replacement radiator upgrades? I prefer to only do one of these upgrades for now. Either way, I plan to do the work myself.

X25

If you don't have the OEM aux radiator installed, yet, the AUX cooler would definitely help the most. As with some of the others, I don't like messing with the oil system, which also makes it easier to void warranty for GM, not to mention the possible leaks, so C32-AUX would be what I'd recommend. The others might have different opinions, though : )

badhabit_wb

I think the aux cooler with trans cooler will probably do what you need without worrying about voiding the warranty. Didn't realize you had an a8.

NTMD8R

Hey, with these various suggestions guys.....

For formula80_ca, realize he has a 2015 Z51 A8 (not a Z06 A8), and he was still encountering some "limp" mode (he drives it HARD).

0Tom@Dewitt

I am starting to buy in to this idea. We know the GMPP Aux cooler and the A8 trans cooler works good with no venting. It's worth a try

NTMD8R

Just placed my order for 32-TO

Thanks Tom, for all your hard work, and research.

And thanks to all those who are trying things out, and contributing to this solution.

Cobraken

Just placed my c7AUX order going to San Diego. In case this makes a bracket or hose difference, my car is a 2016 m7 that does not have an aux radiator. Thanks!

formula80_ca

Just placed my order for the 32-C7Aux.

I have the perfect test track days coming up July 31st - Aug. 2nd in the Okanagan desert where temps hit 38° C (100F) a week ago.

So Tom, is there any chance you have one of these ready to go and can ship out soon to enable me to install in time to try it at this event?... and report back to the group how much cooling it provides.

Again, thanks for your commitment to the development of cooling solutions for our cars and your level of involvement in this forum, especially the quick responses to all of our questions.

Cheers,
Clive

X25

I'll hopefully be with Clive on Aug 2nd event, too. It'd be nice to see how it works on both a Z51 and Z06 during the same event : )

I did an even at almost sea level at Ridge Motorsports Park, today. At around 75 degrees F ambient temp, the car stabilized (same max coolant temps at 3 consecutive hot laps) at 232 degrees F coolant, 270 degrees F oil. It'll likely run much hotter at 90+ degrees F.

formula80_ca

Have you added the new larger Dewitts aux cooler already?

X25

No, I'll receive it mid-week. My next event is next Saturday, and if the kit is not missing anything, I should get to install it before that event.