StreetSpeed

Folks,

I'm definitely buying an oil cooler and tranny cooler from DRM this off season. However I don't hear about too many people popping for the diff cooler - any particular reason why? I don't feel the need to spend another $650 if the consensus is that the diff cooler is not needed. FYI this is going on an 04 Z06 track only car. I'm an instructor, do about 20 days a year, will start TTing this year, and hope to progress to W2W next year. I plan on sprint races when I get there and not endurance races. Any advice is appreciated.

taken19

A quick point of reference...

I bought a track only C5Z that had previously been setup up for competition. It had oil and tranny coolers. My very first HPDE the diff fluid overheated, melted the speed sensor, sprayed fluid all over the hot exhaust pipes.... You get the picture. The diff was destroyed (brand new Quaife) and the car wiring harness was replaced from the transmission back. I added the DRM cooler after that!

HPDEs are a bit unique compared with competition in that there is much more driving time in a typical day. Sometimes you can get in 3 hours of seat time in a 8 hour event - not a lot of time to naturally cool fluids that done have a cooler. Therefore, the various oils will heat up and only have a limited time to cool between sessions. Competition differs in that there are several hours or even a day between "sessions".

Does that make sense? Don't make the same mistake I did... Pick up a diff cooler.

argonaut

I burned up a diff at Watkins Glen several years ago. Installed new diff and DRM cooler - no issues since.

CHJ In Virginia

Cooling is the problem with our cars. Large radiator and coolers for all fluids are needed if you are going to RELIABLY race the car. I have the separate DRM oil and tranny coolers now and will probably add the diff cooler this winter. There is no temp sensor on the diff, so you don't have a way to accurately gauge how hot it is getting. With the added cooling, I can run a 30 minute session at VIR in August with 100+ degree ambient temp without a problem.

Gman57

Get the DRM diff cooler too!!!

redtopz

A quaife diff runs cooler than a clutch style diff and I ran for years without cooling mine. However, if the diff fluid gets low in a quaife it will overheat and melt the speed sensor and destroy the diff. I'm currently running the LG diff/trans cooler with 2 pumps mounted to the back of the diff and it's a great system. I much prefer the mechanical pumps over separate electric pumps which I had in my T1 car. I have 2 coolers but I'm only ducting air to the trans cooler. The diff cooler is strictly cooling by radiant heat transfer. If I was running a clutch style diff I would add ducting to the diff cooler also.

BTW, I recently installed a new engine in my ST2 car replacing my original 2004 LS6 which is still running after 5+ years of track use. The new engine is running cooler than my stock one did. I have a dry sump with a separate oil cooler behind the right front bumper where one of the screened openings are. It didn't seem like it was getting good airflow, so I used naca ducts and ducting to force air from the bumper opening directly through the oil cooler. Now after a couple test days it appears that my oil temps are literally 30-40 degrees cooler and my water temps are 15-20 degrees cooler.

SunnydayDILYSI

Comes down to how long you run, how hard you run, and at what ambient temp. If you only run 30 minutes a day in 80 degree whether, don't worry about it. If you want to run hard for 2 hours in 90+ degrees, get the cooler. I live in Dallas and like to drive a couple hours a day; went for bigger radiator, oil cooler, tranny cooler and diff cooler (had crazy high temps when I went out before getting the coolers).

0Randy@DRM

On a bone stock car we have measured hotter temps in the diff then the trans (track dependent). The trans is a bunch of gears. The diff transfers the power 90 degrees and also has a limited slip (friction). The trans holds 4.1 quarts of fluid and the diff is a tick under 2.

Doing both is ideal if you want something that you can drive without worrying about temps.

Randy

RX-Ben

I thought the Quaifes ran significantly warmer than stock b/c of the additional gears?

Apocolipse

Fluids, fluids, fluids

Call up redline and find some good stuff that will take the temps...may have to change more often but less $ than a cooler.

joenationwide

I have heard the same that Randy@DRM was hinting at. That the diff overheats and causes the trans to overheat. Control the diff temp and you control the trans temp. Therefore, this theory suggests diff cooler is most important.

Paul Schmidt

I'm building mine now. I'm useing a 13 row Setrab for the differential and a 16 row for the transmission. I have a 10 inch Spal fan (Pulls) that will vent out the rear plate. All sealed with naca ducting. I'm basically building a speaker box out of some thick aluminum sheet metal. It will bolt up to the back of the rear tub and exit out the rear plate. Also useing the LG drysump pump.

Something like this.






Something like Jame's car.

Apocolipse

Watch the angle of attack on that diffuser. You are going to run into issues with turbulence and pressure differentials where that naca duct is. Have you done pressure tests to compare that area vs the rear of the car?

Paul Schmidt

That's not my car. I should have stated that. I'm useing these pictures that I've found overtime to help me on my build.

Apocolipse

Ah yes that is fair, no worries. Added some pointers for you then haha

trj3

Glad to see this thread. I tracked my stock 2001 c5 z06 last weekend. DE. Advanced group. I saw oil 286, Water 236 and got high trans temp warning twice. The high trans temp came on both times at about the 45-50 min mark. Running at VIR. I have an engine oil cooler to put on but may need more. This will be our play car and will see back to back 20 -30 min sessions 3x/day at events. I dont want to spent 1200 to do both the tranny and diff coolers but if thats the only solution.......

Any solid suggestions appreciated.

Apocolipse

http://www.redlineoil.com/Products.aspx?pcid=8



Not recommended for DD tho...

Go with one of these for DD

http://www.redlineoil.com/Products.aspx?pcid=4

Zeoohsix

I ran into temp issues at CMP and VIR with the oil temps and trans temp. I didn't realize it at the time but I had really been cooking the rear as well, the fluid was dark and smelled very burnt after just 2 track days. I was running in the Novice class at the time so I would expect that others run their cars much harder than me. I bought all 3 coolers (oil, trans, and diff) from DRM and put them all in. Everything stays very nice and cool now. I figured it was cheap insurance for a car I want to run as hard as I feel like without worry about temps. I would spend the cash again for the peice of mind alone.

crease-guard

I wrestled with this same problem for 2 years. I now run coolant temps no hotter that 210 on 100+ heat days by making the C5Z a true front breather with a custom nose and ducting from that opening to the radiator. ALL the air coming in the front passed through the radiator and that is the single best thing you can do to keep these cars cool.

I still have oil temps in the 260s and 270s on 100+ days but in the low 250s on cooler days. A dry sump and bigger cooler would solve this issue.

I have both trans and diff cooler with fairly small radiators and electric fans and pumps and have never gotten an overheat warning.

You can't have too much cooling. With that said, I've only missed one weekend in 2.5 years and that was due to an oil leak.

redtopz

Thanks Randy. I ran my T1 car for a year with only a diff cooler and found that while racing on tracks that required 2nd gear my tranny would overheat. That's when I installed your tranny cooler and never had another problem.

You might be right, I've heard conflicting reports and I've never personally measured diff temps. I thought the friction from gears in the torsen would be less than friction from the clutch packs and thus produce less heat. But that's just my theory and what I've read in a few places. Other sources say the torsens run hotter, so I'm not sure. All I know for sure is that my current setup seems to work very well. And I'm using Royal Purple fluids.