G50 Transmission cooling (Racing)

regnihe · 10-11-2025, 09:35 AM

I have read a bunch of the posts and looked at the Patrick Motorsports kit. We have a good idea which components to use. Does anyone have data to show the location that provides the most amount of cooling? We are ready to install the cooler in the right front fender and provide air from either the headlight bucket or the indicator location, but we are also considering locating under the tail grill. This seems less ideal as we will be pulling the heat from the cooler towards the engine. Open to suggestions, and thank you!

Cory M · 10-11-2025, 04:27 PM

I didn't do any testing to compare locations, but my g50 cooler was located in the drivers rear fender well. In front of the wheel. The pump was located on the transmission crossmember. That would keep the lines a lot shorter than moving it up front.

stownsen914 · 10-12-2025, 08:10 AM

No data to support, but I'd have to agree that while that whaletail screen vent is probably a fine location from a trans cooling perspective, it's not optimal to pull that extra heat toward the engine. Probably a smallish impact, but somewhere not in the engine bay would be my personal preference.

Bill Verburg · Bill Verburg's Garage

Here's where the factory put them on 993GT@evo

very similar to the ones on late 915s

Jack Olsen · 10-12-2025, 07:59 PM

I also have one in the rear driver's-side flare, but my transaxle is a a 915.

And while this is not data, I don't think you have to optimize cooling, particularly -- simply cooling the fluid is going to help.

Bill Verburg · Bill Verburg's Garage

Here's a depiction of 964/993 air flow, 911 will be similar, should give you a clue as to where the radiator want's to be

regnihe · 10-13-2025, 11:10 AM

We are considering a few options.
1. Best cooling option front fender. Downside is that we have to run long lines, most likely through the cockpit.
2. In front of the drivers rear tire. Relatively easy installation. Poor airflow to the cooler. Would need to supplement with a electric fan.
3. NACA duct in one of the quarter windows. Ducted through the firewall to the cooler on the opposite side. Unsure the amount of air we would pull from a NACA duct.

Bill, Cory, & Jack. Thank you very much for your input.

What problem are we trying to solve?
G50, Wevo shifter & coupler (all wear parts replaced), 8-32 ring and pinion, (set up by Copans), Delvac fluid. Symptom. After 25 minutes of hard driving 3-4 & 4-5 shift get progressively stiffer and stiffer. I don't think it's grinding or synchro's. When cold/warm, shifts perfectly. Speaking to Brian, he immediately went to fluid is getting to hot.

-Levi- · -Levi-'s Garage

I think the biggest advantage is getting the transmission fluid out of the transmission, any more than that is of course better, but with diminishing gains. The factory put their coolers just off the transmission, I replicated that on my 915 using various parts from other kits or having them made. Inside has a Rsr style spray bar from CMS. For whatever it’s worth.

Cory M · 10-14-2025, 08:48 AM

We had similar lock up issues on my G50 Carrera, especially when doing back to back sessions on hot days. The cooler fixed the issue. The pump was on a switch and I would turn it near the end of the out lap. I wouldn't assume you'll need a supplemental fan in the rear fender well or on the side of the trans, we didn't. There are a lot of downsides to running the lines through the cab and the extra weight of the longer lines and fluid. Might be worth trying a simple set up first and modifying if needed. The expensive parts are the same, you'd just need to make some longer lines.

Matt Monson · 10-15-2025, 05:53 AM

Quote:

Originally Posted by regnihe

What problem are we trying to solve?
G50, Wevo shifter & coupler (all wear parts replaced), 8-32 ring and pinion, (set up by Copans), Delvac fluid. Symptom. After 25 minutes of hard driving 3-4 & 4-5 shift get progressively stiffer and stiffer. I don't think it's grinding or synchro's. When cold/warm, shifts perfectly. Speaking to Brian, he immediately went to fluid is getting to hot.

What gear oil are you running?

I see this problem frequently on cars running Redline.

regnihe · 10-15-2025, 06:28 AM

Mobil 1 Delvac. 75W 90

Quote:

Originally Posted by Matt Monson

What gear oil are you running?

I see this problem frequently on cars running Redline.

Matt Monson · 10-15-2025, 06:40 AM

Quote:

Originally Posted by regnihe

Mobil 1 Delvac. 75W 90

Carry on. You’re getting good cooler advice here.

dannobee · 10-15-2025, 08:27 AM

Did you by chance replace the 3-4-5 synchro rings with steel? The brass ones would cause shifting problems when racing. The race car boxes had steel from the factory.

As far as coolers, the area underneath has plenty of airflow for the cooler (as seen by where Porsche puts the coolers on their race cars). One other thing if plumbing up to the front is the volume of fluid. I'd be cognizant of the lube level difference at the gearbox between pump running and pump off (assuming an electric pump), and if any drains back to the box with the pump off. There's probably a few good reasons why the factory coolers are at or below the normal lube level.

regnihe · 10-15-2025, 08:34 AM

Thank you for all the comments. We are leaning towards installing similar to what Levi shows above.
We may pull air from a NACA duct in the 1/4 window and pipe through the firewall to the cooler. Trying to remember to keep it simple.

Matt Monson · 10-15-2025, 09:19 AM

Quote:

Originally Posted by regnihe

Thank you for all the comments. We are leaning towards installing similar to what Levi shows above.
We may pull air from a NACA duct in the 1/4 window and pipe through the firewall to the cooler. Trying to remember to keep it simple.

I favor this method. I know that Brian Weathered at Midwest Eurosport produced a pakcage for the 944s, but don't know if he also has a 911 version. Could save you some drain bramage.

regnihe · 10-15-2025, 09:36 AM

I'm leaning towards this kit and will modify as needed. There are G50 specific spray bars that you can add. It would be good to get cooled fluid dumped on the dif.

https://patrickmotorsports.com/products/tra901oilclkpms?srsltid=AfmBOoo5UQQUv-Fg3Qtd88LzK409xcgwpQy5Hb0tRZQhnCvdkPmDvrbJ

Quote:

Originally Posted by Matt Monson

I favor this method. I know that Brian Weathered at Midwest Eurosport produced a pakcage for the 944s, but don't know if he also has a 911 version. Could save you some drain bramage.

Matt Monson · 10-15-2025, 10:47 AM

Quote:

Originally Posted by regnihe

I'm leaning towards this kit and will modify as needed. There are G50 specific spray bars that you can add. It would be good to get cooled fluid dumped on the dif.

https://patrickmotorsports.com/products/tra901oilclkpms?srsltid=AfmBOoo5UQQUv-Fg3Qtd88LzK409xcgwpQy5Hb0tRZQhnCvdkPmDvrbJ

It's rear engine. It's 5th gear that runs dry and hot.

kevingross · 10-15-2025, 05:08 PM

I like the Patrick kit in that it both keeps the lines short and keeps the radiator away from the engine's heat. I am not sure how much airflow it gets as pictured on their web page. My approach would be to install it as they depict, monitor temps, and if they are in range, all set. If still too hot, consider ducting air to the radiator. Good luck!

ZOA NOM · ZOA NOM's Garage

I put the cooler in the tail, and it works great. Also mounted the pump back there.