i was thinking about adding an oil cooler to my z51 m7. has anyone done this? problems with doing so?

 

Doesn't look like anyone has done it. I'm also looking to do the same. It will require an adaptor to plumb into the oil circuit. In other model applications a sandwitch adaptor under the oil filter could be used but, in the C7 the oil filter sits low enough where a sandwitch would lower it to the point of sticking out under the car, subject to being hit and damaged by road obsticles.

Could replace the present water/oil heat exchanger but, again, a special adaptor is needed. Not sure where else you could plumb into the oil circuit.

Would also likely loose some oil pressure due to the extended oil flow circuits.

Still, looks like the real solution to the overheating issues. Once the oil temps are under control, the water temps may also be reduced enough where the stock radiator may be sufficient.

Hope the aftermarket wakes up and produces a kit soon.

 

thanks. hopefully someone will come up with a solution soon.

 

The difficulty is the need to essentially create an exchanger with an additional inlet/outlet to go to an external cooler. That's a pretty tall order, and would take one heck of a designer and CNC mill to really get it right.

The trick will have to be in finding another tap point, a least in my opinion. Too much work and cost involved otherwise.

Pressure drop would depend on how large of a cooler you'd add, and how far you'd want to go with it.

 

Would it not be possible and much easier to replace the present heat exchanger with a remote, thermostat-controlled, Setrab type cooler? That way we could also avoid the coolant being heated by the oil.

 

That's a double-edged sword, because beside from the coolant cooling the oil, the oil also helps to warm the coolant (which you want in some situations). It's homeostatic to a point, but cooler oil is a big priority for those racing the C7/C7Z. Removing that balance could create issues for some.

 

I always had air-to-oil coolers on my racing and performance street cars and never really had any issues with warm-up, as long as I was willing to lay off the throttle during the initial period. I would gladly get rid of the exchanger for an external cooler.

Theta - I also read your post regarding the DeWitts radiator, agreeing with leadville(?) that the new radiator was sufficient in controlling your track temperatures. Could you please be more specific as to what temps you were getting with the new radiator vs. stock? It seems from today's posts that the ZO6 still overheats with the DeWitts but, I have a NA C7 and, in case I get some other good feedbacks, I'd be happy to go the DeWitt's way. I don't track this car but, use if frequently over my local winding roads, mostly 2nd, 3rd gear driving at high RPMs. The oil reaches 290F in a matter of a very few minutes even when ambient temps are in the 70s. Probably would go higher but, I back off at those temps.

Thanks in advance for any info on this subject.

 

Bingo - that's the trade-off, but to the general public, this is an anomaly. Most get it, crank it up, and floor it. I quite enjoy BMW's approach of forced limiting on the M line. It protects the driver from him/herself.

A majority of my driving is done on 'back roads' that are fairly well known for their challenge and twists - we have a sort of mini-Dragon here. I'd say 90% of my driving is done in 2nd, 3rd, and 4th going back up and down those gears through the turns and straights. My usual cruise RPM is around 3500 to already be in boost/meth territory when I want to punch it.

I have had zero issues with coolant temps in conjunction with the LMR 160 T-stat (which may or may not be helping, that's been argued to death) during hot-lapping or two-hour excursions that leave me more thirsty and overheated than the car ever becomes. I can't speak to the changes that were made during my build process, but I'm extremely fortunate that my oil and coolant temperatures consistently stay low, even at the aforementioned cruising RPM (which is relatively high).

I'd yet to see the post about the Z06 overheating with the DeWitt's radiator, but I find it difficult to believe that there is anything that could help a car that is overheating with that radiator installed. Either they will need a very custom solution, or something elsewhere is causing a problem.

 

Here is today's post from "tryntogofast" with ZO6 PDR comparison data between stock vs. DeWitts radiators for comparable track usage. Small differences, end result is that the car still running far too hot. This is the best documented comparison I have seen so far on this subject.

https://www.corvetteforum.com/forums...adiator-4.html

Like I said, I don't have the ZO6 which likely generates a fair amount more heat than my NA C7 so, the DeWitts "might" be sufficient. I didn't realize all the built changes you had on your car. That makes it harder to compare to my stock engine. When "leadville" stated that his oil temps dropped to 210 F on the track with the DeWitts, that sounded either too good to believe or as a typo...? Some of the other NA posts I had seen with the Ron Davis radiator only showed about a 5F degree reduction in oil temps for track usage.

 

I was just looking at this cooler but wondering where it would be mounted. I can't place it infornt of the radiator because I already have an aftermarket transmission cooler there.

http://dougrippie.com/products/stand...il-cooler-kit/

 

For non-supercharged cars, you could use the front-rad-area horizontal-placement idea, though the hose runs would be a bit long.

 

Is that a C7 specific kit? Where would you plumb into the engine oil flow?

 

That's just a generic kit from the looks of it.

 

My 2014 Z51, all stock, has definite overheating issues on track. My 2009 GT-R has zero overheating issues on track, but I had to add two coolers to it, and I can run it all day flat out on track, and now it never overheats, and it's actually faster than my Z51. Both cars are real fun on track, as long as they don't overheat. I think seeing how that was done on the GT-R is informative for the Corvette's future cooling upgrades.

GT-R comes with a transmission cooler from the factory, which is identical in type to the C7's engine oil cooler. It is a fluid to fluid cooler, bolted right on the casing, with oil flowing in and out of it with no oil hoses or external oil fittings. Engine coolant taken from the engine block and rubber lines to the radiator flows into the transmission's OEM fluid to fluid cooler to first heat the transmission oil on startup and then cool the transmission once the transmission oil gets hotter than the engine coolant. So it's identical in concept to the C7's engine oil cooling circuit. Multiple vendors tried various solutions to improve cooling of the transmission with limited success. Then HKS, a top Japanese manufacturer of very high quality aftermarket parts came up with a totally plug-and-play kit to cool the transmission that had a new cast fitting that goes between the transmission case and the factory fluid to fluid cooler. And it works fantastic. Lines (combo of AN hoses and performed aluminum tubing) are plumbed all the way from the back of the car to the front (really, really long lines), carrying transmission oil to a regular type of heat exchanger/radiator, front mounted, like a Mocal or Setrab core. This cooling core sits inside the driver's side front bumper, and fresh air is fed to it via a supplied plastic air duct from an inlet on a high pressure zone on the bumper. Transmission overheating totally solved. Original fluid to fluid cooler is retained, and add-on oil cooler only comes into action when its built in thermostat valve opens at 80 C to allow oil flow to the front mounted cooling core. A brilliant execution of an add-on cooler. Virtually everyone who drives older (circa 2009-2011) GT-R fast on track has this mod. Later on, the factory increased the inlet area on the bumper to the radiator for more cooling airflow and added much larger coolant lines toward the transmission cooler, mostly solving the problem. (GM, hint, hint!)

Here are a few pictures of my installation of that HKS cooler for my GT-R. The best part is that add-on cast and machined fitting with the thermostat that allows plumbing the extra air to fluid cooler. That is the secret to the conversion, everything else just being plumbing lines, cooling core and mounts.





Complete HKS GT-R transmission cooler kit





Cast and machined oil flow fitting with thermostat that bolts between case and OEM fluid to fluid cooler





Front mounted HKS oil cooling radiator





plastic air duct to bumper inlet over radiator and add-on windshield reservoir tank





Oil flow diagram for add-on cast fitting with thermostat.





Add-on cast fitting with braided oil lines bolted to case on right. OEM fluid to fluid cooler is the circular part.





Laser cut stainless mounting brackets supplied with kit





External view of cast fitting supplied for connection to AN fittings. Mechanical thermostat is under the brass coloured cap.





Bottom view of cast fitting that bolts to transmission case showing the two oil ports that normally go directly to the OEM fluid to fluid cooler





Cast fitting mounted between round OEM finned fluid to fluid cooler and transmission case on bottom. Black rubber coolant lines to engine coolant are retained to heat transmission oil on startup.

 

Indeed, that is a beautifully crafted and engineered kit from HKS. I am familiar with their products from my previous experiences with Japanese cars. Would it be too much to expect a similarly executed kit from a Chevy aftermarket manufacturer?

Knowing that I have zero abilities to make such castings and adapters, I am looking into simply replacing the stock heat exchanger with a Setrab cooler. If anyone knows or have an oil and water flow diagram that describes the coolant and oil flow circuits in the C7 heat exchanger, that would be appreaciated and a good start. Also, I will be looking to see if there is any adapter available that could be mounted in the place of the removed factory heat exchanger with IN and OUT oil lines to the cooler.

Searching for adapters I can find plenty listed for previous models of Corvettes with the LS engines. Since this is my very first GM car, I am not familiar with the differences between the LS and LT series engines so, I need to find out if any of the available LS adapers would fit the LT in the C7. If anyone have any info on this it would be greatly appreciated.

Once I get an adaptor I can fabricate the rest of the cooler assembly as I had done that with a number of my racing cars and street cars. I could care less about the advantages of quick warmup provided by the heat exchanger. I always baby my cars until all fluids get to full operating temperatures and only then step on it. Doing so, I never had any engine failures even with cars that were famous for scattering their engines.

 

If it helps anyone, here are some high-res shots of the C7/Z oil cooler/exchange system:

 

Thanks, Theta, I was going to make a run at at this until just found out that both Ben and Tom Dewitts are at work on the oil cooler project. Now, I will just lay back and wait... :-)

Looks to me from your pictures that the adapter to the engine block would be the same (or very similar) as listed for the LS engines. As far as I am concerned, that is the main issue here, the rest is simply trying to find a good mounting spot and room to run the two oil lines.

 

this is for ls engine but i was told by salesman this would probably work