DeWitts TOC/EOC Combination system
06-10-2019, 07:59 PM
#261
Melting Slicks
1: Buy the DeWitt’s combination Transmission cooler and Engine Oil Cooler. This, along with using ‘M’ mode on track and remembering that you don’t really always need to wind the car up to 6,500 rpm due to its prodigious torque should mean you can run for a full session in the Advanced run group without any issues. It’s important that you keep a secondary transmission cooler in the circuit, as in this way you won’t have any issues with the transmission overheating; (I never did once)
If with the above it still seems as if the water temps are running a little hot, then:
2: purchase the largest DeWitt’s radiator and install it also.
If you’re still overheating with the above, call Penske for a try-out.
The following 2 users liked this post by thebishman:
jonparks (06-23-2019),
Torque Obsessed (05-14-2022)
06-11-2019, 08:32 AM
#263
Advanced
As someone who tracked his ‘15 A8 Z06/7 extensively for two years in hot ambient temps, I’d suggest this:
1: Buy the DeWitt’s combination Transmission cooler and Engine Oil Cooler. This, along with using ‘M’ mode on track and remembering that you don’t really always need to wind the car up to 6,500 rpm due to its prodigious torque should mean you can run for a full session in the Advanced run group without any issues. It’s important that you keep a secondary transmission cooler in the circuit, as in this way you won’t have any issues with the transmission overheating; (I never did once)
If with the above it still seems as if the water temps are running a little hot, then:
2: purchase the largest DeWitt’s radiator and install it also.
If you’re still overheating with the above, call Penske for a try-out.
1: Buy the DeWitt’s combination Transmission cooler and Engine Oil Cooler. This, along with using ‘M’ mode on track and remembering that you don’t really always need to wind the car up to 6,500 rpm due to its prodigious torque should mean you can run for a full session in the Advanced run group without any issues. It’s important that you keep a secondary transmission cooler in the circuit, as in this way you won’t have any issues with the transmission overheating; (I never did once)
If with the above it still seems as if the water temps are running a little hot, then:
2: purchase the largest DeWitt’s radiator and install it also.
If you’re still overheating with the above, call Penske for a try-out.
With that, do you think the coolant/trans combo would still help along with the 70mm Dewitt? I am kinda leaning towards that option right now because of the ease of it primarily and from what I understand it should indirectly help keep the oil slightly cooler as well.
06-11-2019, 09:33 AM
#264
Thanks for your input. Seems like there are valid reasons for using either the oil or coolant options...and I still don't know! I think I have to weigh what might be easier and that this isn't a dedicated track car either. Using the M mode and shifting less/earlier is something I made a mistake with and likely something that contributed to the overheat I had a few days ago. I used full auto and didn't touch the paddles.
With that, do you think the coolant/trans combo would still help along with the 70mm Dewitt? I am kinda leaning towards that option right now because of the ease of it primarily and from what I understand it should indirectly help keep the oil slightly cooler as well.
With that, do you think the coolant/trans combo would still help along with the 70mm Dewitt? I am kinda leaning towards that option right now because of the ease of it primarily and from what I understand it should indirectly help keep the oil slightly cooler as well.
Directly not indirectly. The engine is heating the water virtually the same amount since you're not changing it (might drive harder or softer dependent on temps). Delta T of the water across the engine and radiator isn't much. About 8 degrees per Gspeed testing, so water temps are pretty consistent. Let's use 10 degrees for simplicity.
We will be using GM advertised 25 degrees cooler water and 15 degrees cooler oil for the aux radiator install for this example.
So if your coolant is 190 out of the radiator and 200 out of the engine into the oil cooler after installing aux radiator. This would be better than 215 out of the radiator, 225 out of the engine and into the oil cooler.
My procharged z51 would run 250 coolant and 300 oil for example. So maybe i would then get 225 and 285?
Last edited by BrunoTheMellow; 06-11-2019 at 09:38 AM.
06-11-2019, 09:40 AM
#265
Advanced
I would do the coolant/trans combo first. It's FAR easier to install. It's cheaper too. It should provide quite a bit of help and might be enough for you.
Directly not indirectly. The engine is heating the water virtually the same amount since you're not changing it (might drive harder or softer dependent on temps). Delta T of the water across the engine and radiator isn't much. About 8 degrees per Gspeed testing, so water temps are pretty consistent. Let's use 10 degrees for simplicity.
We will be using GM advertised 25 degrees cooler water and 15 degrees cooler oil for the aux radiator install for this example.
So if your coolant is 190 out of the radiator and 200 out of the engine into the oil cooler after installing aux radiator. This would be better than 225 into the oil cooler and you could expect oil to be 15 degrees cooler.
On my car oil was about 300 when coolant was 250 with stock cooling, so coolant would drop to 225 and oil to 285. Theoretically. There's a lot more to it (the hotter the coolant the less cooling it will have on oil).
Directly not indirectly. The engine is heating the water virtually the same amount since you're not changing it (might drive harder or softer dependent on temps). Delta T of the water across the engine and radiator isn't much. About 8 degrees per Gspeed testing, so water temps are pretty consistent. Let's use 10 degrees for simplicity.
We will be using GM advertised 25 degrees cooler water and 15 degrees cooler oil for the aux radiator install for this example.
So if your coolant is 190 out of the radiator and 200 out of the engine into the oil cooler after installing aux radiator. This would be better than 225 into the oil cooler and you could expect oil to be 15 degrees cooler.
On my car oil was about 300 when coolant was 250 with stock cooling, so coolant would drop to 225 and oil to 285. Theoretically. There's a lot more to it (the hotter the coolant the less cooling it will have on oil).
Question on doing the coolant first if that's what I go with - if I find its not substantial enough, I wonder how easy it could then be to change this later to the oil cooler? May be a question for Tom.
06-11-2019, 10:33 AM
#266
Racer
Just ordered the 32-TO (trans and oil) this morning! Thanks Tom, can't wait to get this installed!
06-11-2019, 12:08 PM
#267
Melting Slicks
Thanks for your input. Seems like there are valid reasons for using either the oil or coolant options...and I still don't know! I think I have to weigh what might be easier and that this isn't a dedicated track car either. Using the M mode and shifting less/earlier is something I made a mistake with and likely something that contributed to the overheat I had a few days ago. I used full auto and didn't touch the paddles.
With that, do you think the coolant/trans combo would still help along with the 70mm Dewitt? I am kinda leaning towards that option right now because of the ease of it primarily and from what I understand it should indirectly help keep the oil slightly cooler as well.
With that, do you think the coolant/trans combo would still help along with the 70mm Dewitt? I am kinda leaning towards that option right now because of the ease of it primarily and from what I understand it should indirectly help keep the oil slightly cooler as well.
Bish
06-11-2019, 12:22 PM
#269
Sr.Random input generator
TC (transmission/coolant) for A8 will have almost exact (coolant/oil) cooling as M7 cars with OEM aux radiator, which you guys state that it works; I think it'd work well on A8, too. I worry that removing OEM oil cooler might tax that oil cooler half of this new system more than it can handle.
06-11-2019, 01:06 PM
#270
There is a marked difference in the M7’s and A8’s ability to dissipate heat. The M7’s have done well on track even with the GM secondary water radiator in the nose of the car, but even running a much more efficient main (water) radiator has done nothing to help keep the A8’s cool. For that reason I believe that one needs to remove the engine oil from the water cooling circuit, and install a dedicated EOC. Hence I would personally only use the combo TC/EOC. My back up plan would then be a more efficient water radiator if necessary. YMMV.
Bish
Bish
Here is Gspeed's testing of Dewitts original kit before they made a hardcore kit, i'll only include the relevant section. they are going harder than anyone else out there with a professional driver in arguably the hottest track in the nation (happens to be my home track also):
Our car is a 2015 Z06 Z07 with A8 Automatic.
Programing is stock
Dewitt’s C7 Z06 Kit, 2nd Gen Radiator, Intercooler and Engine Oil Cooler. Installed by GSpeed, Notice there is no aux radiator.
....
lots of suspension and handling mods
...
Testing was performed at MSR in Cresson TX on May 28th & 29th, both days the high was 91-100deg, 60-70% humidity
...
Session 2:36PM Data Acquired from HP Data Logging
Max H2O Temp 264
Max OIL Temp 277
...
Dewitt’s C7 Cooling kit is an improvement over the factory products. In particular, the Oil cooler has made a major improvement, the highest oil logged was 277deg (265 was high for most laps) and we were intentionally pushing the car to overheat.
...
Programing is stock
Dewitt’s C7 Z06 Kit, 2nd Gen Radiator, Intercooler and Engine Oil Cooler. Installed by GSpeed, Notice there is no aux radiator.
....
lots of suspension and handling mods
...
Testing was performed at MSR in Cresson TX on May 28th & 29th, both days the high was 91-100deg, 60-70% humidity
...
Session 2:36PM Data Acquired from HP Data Logging
Max H2O Temp 264
Max OIL Temp 277
...
Dewitt’s C7 Cooling kit is an improvement over the factory products. In particular, the Oil cooler has made a major improvement, the highest oil logged was 277deg (265 was high for most laps) and we were intentionally pushing the car to overheat.
...
FYI, with a OEM oil cooler and multiple radiators Gspeed maxed out the oil reading at 302 while water was 220. It's a double edge sword. But they were TRYING to overheat the car.
anyhow, my plan is:
twin LG intercoolers
LG standalone oil cooler (setrab 420-10 or might go up to 420-14)
Dewitt aux radiator (come out come out wherever you are!)
2019 auto radiator
Last edited by BrunoTheMellow; 06-11-2019 at 01:49 PM.
06-11-2019, 02:46 PM
#273
They have the same surface area but air is not forced through it. I already have the 420-10, trying to work with LG for changes to that. If I can get my money back for that kit I'll buy the Dewitt Oil/coolant kit. If I can't get my money back I'll buy the oversized aux kit.
Last edited by BrunoTheMellow; 06-11-2019 at 02:50 PM.
06-11-2019, 05:10 PM
#276
Advanced
06-11-2019, 05:59 PM
#278
Former Vendor
Thread Starter
Not a chance! Cooling with 90 degree air is going to work better than 250 degree water every time. And the oil heat doesn't go into the water or coolant in this case.
The following users liked this post:
thebishman (06-11-2019)
06-11-2019, 06:30 PM
#279
Former Vendor
Thread Starter
TC vs TO I've been emailed a few times for my opinion on this issue so here is my explanation
The goal was to make faults impossible, no matter how good or bad of a driver you are and how hot it is outside. Time will tell if that's the case but I dare someone to tell me the TO kit and with the 70mm faulted.
This should work because it (TO) takes care of oil faults and increases cooling by subtracting load. The 70mm radiator is a beast and you cannot put anything bigger in there.
It's been said the TC in a A8 is just like having a GMPP in the M7. This is true and most people said that it works for cooling. This takes care of 98% of the drivers. Now I might sound like Bernie Sanders, but what about the other 2%. They are going to end up adding a bigger radiator and if you add that, you don't really need the half cooler anymore. The TC has value and it will have an effect on oil temps but my personal preference is to have a dedicated cooler for coolant (radiator) transmission, and oil.. That's just me, six of one, half a dozen.
The goal was to make faults impossible, no matter how good or bad of a driver you are and how hot it is outside. Time will tell if that's the case but I dare someone to tell me the TO kit and with the 70mm faulted.
This should work because it (TO) takes care of oil faults and increases cooling by subtracting load. The 70mm radiator is a beast and you cannot put anything bigger in there.
It's been said the TC in a A8 is just like having a GMPP in the M7. This is true and most people said that it works for cooling. This takes care of 98% of the drivers. Now I might sound like Bernie Sanders, but what about the other 2%. They are going to end up adding a bigger radiator and if you add that, you don't really need the half cooler anymore. The TC has value and it will have an effect on oil temps but my personal preference is to have a dedicated cooler for coolant (radiator) transmission, and oil.. That's just me, six of one, half a dozen.
The following users liked this post:
thebishman (06-12-2019)
06-11-2019, 06:36 PM
#280
Advanced
TC vs TO I've been emailed a few times for my opinion on this issue so here is my explanation
The goal was to make faults impossible, no matter how good or bad of a driver you are and how hot it is outside. Time will tell if that's the case but I dare someone to tell me the TO kit and with the 70mm faulted.
This should work because it (TO) takes care of oil faults and increases cooling by subtracting load. The 70mm radiator is a beast and you cannot put anything bigger in there.
It's been said the TC in a A8 is just like having a GMPP in the M7. This is true and most people said that it works for cooling. This takes care of 98% of the drivers. Now I might sound like Bernie Sanders, but what about the other 2%. They are going to end up adding a bigger radiator and if you add that, you don't really need the half cooler anymore. The TC has value and it will have an effect on oil temps but my personal preference is to have a dedicated cooler for coolant (radiator) transmission, and oil.. That's just me, six of one, half a dozen.
The goal was to make faults impossible, no matter how good or bad of a driver you are and how hot it is outside. Time will tell if that's the case but I dare someone to tell me the TO kit and with the 70mm faulted.
This should work because it (TO) takes care of oil faults and increases cooling by subtracting load. The 70mm radiator is a beast and you cannot put anything bigger in there.
It's been said the TC in a A8 is just like having a GMPP in the M7. This is true and most people said that it works for cooling. This takes care of 98% of the drivers. Now I might sound like Bernie Sanders, but what about the other 2%. They are going to end up adding a bigger radiator and if you add that, you don't really need the half cooler anymore. The TC has value and it will have an effect on oil temps but my personal preference is to have a dedicated cooler for coolant (radiator) transmission, and oil.. That's just me, six of one, half a dozen.