JBond214

I'm also following this thread, and interested in a "no cut" "no bumper" removal cooling improvement for my 2015 A8 Z06 that sees track duty 2-3 times a year.

0Tom@Dewitt

Well I finished the core building project and I am back on the C7 development. A few things have changed since my last update and I like the way things are looking. The biggest change we made to the original approach is the combo cooler is now going to be a EC/TOC (Engine coolant/TransOilCooler) unit. The grille mounted EOC will most likely be discontinued as this is going to be relocated to the engine compartment behind the radiator. We will offer two version of the belly mounted cooler, 1. a combo EC/TOC for A8 model and 2. A single auxiliary EC similar to the GMPP but much larger in capacity.

Here is our flow diagram



The the flow comparison

Viking0728

I'm in. When can I buy one? I have a 2016 Z06 A8 and I'm in Florida, I would be a perfect test case since I have a couple of track days this summer planned.

0Tom@Dewitt

Now that I'm back on it I'll be posting weekly progress. We are going to have something for this season!
Just to be clear, this IS going to require some trimming of the radiator shroud. A cut template will be included for all versions. Cutting is pretty simple as you follow the natural contours. I used a hacksaw blade and it took about five minutes.

lgsdds

Tom--
Will this enable us to keep the stock engine oil cooler? If so, I definitely want to be on the list.

0Tom@Dewitt

Yes, you can keep the stock EOC unchanged if you like. With that said, I feel the fault eliminating solution is going to achieved by a combination of changes, including the stock EOC. Using the coolant to remove oil heat is just transferring one problem area to another. Changing the EOC to an air type not only improves the oil cooling capacity but it also removes this load from the engine coolant. That is part of the total solution. I feel the Z06 A8 cars are going to need the following to eliminate faults.
1. 70mm HP DeWitt Radiator
2. Belly mounted Aux. Radiator
3. Air-to-Oil EOC
M7 cars can retain the stock EOC package because the newer Aux EC is so large you will only need to have #1. and #2

JBond214

Excited to try this solution. Please make and sell an "all in kit" for A8 cars -- one kit that includes all necessary components (with the option for others to buy components separately if they so choose). You should probably consider including an oil thermostat too, because it is important to make sure the oil can get up to temperature in normal street driving. But retain the ability to have vastly increased oil cooling when the circumstances require (on track, or even on street on very hot days/in traffic).

Even with cutting the shroud, does the A8 solution require bumper removal? I agree with others that eliminating the need for bumper removal will be a huge plus. (Not to mention, no cutting or trimming of the bumper or other visible body pieces).

Thanks for working on this.

0Tom@Dewitt

We already are using the Improved Racing adapter with built in thermostat.

No bumper removal or modification with newer EOC! More on this component and location shortly.

LagunaSecaZ06

Tom,

Thanks for he update. I already have your 70mm radiator. I am ready to place an order for your larger belly radiator to replace my GMPP radiator. Hopefully that will keep my M7 cooler and not need the EOC relocation.

Do you replace the GMPP coolant lines or re-use them?

Thanks, Mike

thebishman

Tom,

I don't own my Z06 anymore, but for A8 owners why wouldn't you just make the combined cooler a combo EOC/TOC? Adding an additional water heat sink isn't a bad thing, but an additional water radiator/TOC is not going to solve the problem for A8 owners; they will be forced to purchase a stand alone EOC as well as the above.

Bish

BrunoTheMellow

Have you tested an oil cooler behind the radiator? You need a pretty massive unit to effectively cool the oil. I tried something back there and while it kept coolant in check (25 degrees cooler) , it was nowhere near enough for oil. This is on supercharged z51 with otherwise stock cooling. LGs kit uses a 27k BTU/HR max setrab oil cooler and it is inadequate at that location. You need at least twice the size which is tough to fit.

Air going out of the stock radiator is at least the average of ambient and coolant temp (I've tested this). With a more efficient radiator, air out is even hotter. If you use this idea as an estimate for the oil cooler, at 220 coolant and 80 ambient, air out of radiator is 150. rather than 80, or just about twice the temperature. that much less Delta T.

An oil cooler in the grill getting ambient temp can be much smaller. It might still be worth to keep it there even if it blocks a little bit of the radiator flow. Specially if the aux cooler is taking a lot of the grunt.

0Tom@Dewitt

That was pretty much my first concept but the EOC/TOC combo didn't work out that way. It wouldn't solve the ECT faults when driven by top racers with the HP radiator alone. They would have been forced to buy a secondary radiator anyway and find a place to make it work, so pretty much the same thing. When I increased the belly mounted TOC to 23 tubes, the passenger side mate was actually too big for an EOC. The concept of a belly mounted Aux radiator was already proven to be a big help as this heat is removed under the car and not returned to the stack of heat exchangers. As a manufacturer, it makes more sense to offer the exact same EOC for both manual and automatic cars, so the same unit, hoses and mounting kit are used on all models. The last reason I went this way is that it does take much to improve on the GM EOC design and as requested above, some people may want to just keep the stock EOC. Remember limp mode faults are a combination of ambient temperature and the drivers capability to hold continuous high outputs. That is way some people say this or that solved the issue when others say it didn't work for them.

BrunoTheMellow

Tom, have you toyed with the idea of just laying the supercharger heat exchanger flat? Can you really not get something big enough in there to control IATs?

0Tom@Dewitt

No I haven't but I understand your concern. One thing that you have proven is by removing the oil heat load from the coolant and using air media there was a significant decrease in coolant temperature. For now, I'm focused on the belly mount kit and completing it so people waiting for this can get started. This allows racers to do #1 70mm radiator and #2 Aux radiator. For some drivers and tracks, this might be all they need.
When that's done I am going to do something with the EOC. DeWitts still offers the front grille EOC and you could use that but the instructions say the front facia needs to come off. I have a couple shops that said they installed it without pulling the facia but I don't know how they tightened the fittings through the grille. Apparently it can be done.
Back to the EOC mount behind the radiator. Everything you said was correct but there is one item missing. A long time ago one CF member here (Lockheed martin engineer) pointed out, and we've confirmed, the upper 1/3 of the radiator where the hood duct goes does very little (almost nothing) until wind speeds hit 90 mph and the hood creates a suction. If you remove the duct then it does almost nothing all the time because the fan draws all the air available after the stack up of heat exchangers. My focus in this area is going to be two fold.... #1 make the upper portion of the radiator work, and #2 get air flow through the rear mounted EOC.

0Tom@Dewitt

I'm not really looking at the heat exchanger. DeWitts has a oversized unit that provides an added boost and this a performance issue for Z06. I am more focused on how to get these cars to track continuously under extreme driving conditions

BrunoTheMellow

I am not sure I quite believe that. Air will follow the path of least restriction. The fan turns off above 35 mph anyhow. But yes, I am sure putting the cooler horizontal right below the hood vent would have been better for a lt4 or NA lt1 as I've tested that air billows out of that vent at highway speed.

My supercharger piping blocked me from doing that.

BrunoTheMellow

Well largely the reason they can't hang is because of the heat exchanger is it not? Would free airflow to the radiator fix it? Same conversation as the oil cooler behind the radiator. I mean, this is what G speed and LG do. Get the heat exchanger out of the way. Just wondering if putting it at the bottom rather than the aux cooler is a better bet.

0Tom@Dewitt

Moving the HE has it's advantages and the bumper corners they offer is a great solution. We are just taking a different approach.

HNK

Tom, I have a 2015 M7 with GM aux, so did I understand you correctly that all I need is your 70mm rad and your Aux??

0Tom@Dewitt

That depends, do you want to replace the GMPP aux radiator? It's already paid for and installed and they do work. Do still get any faults (ECT or EOT) the way it is? If not, I wouldn't change anything.