Aftermarket Diff Cooler on Z06 Differential
Thread Starter
Racer
Joined: Aug 2011
Posts: 466
Likes: 25
From: Charleston South Carolina
Aftermarket Diff Cooler on Z06 Differential
I am swapping a Z06 differential into my 05 Base Model and have been researching options for the differential cooler and came across these 2 setups. Anyone on here running these setups or something similar? If so, how much of a temp decrease have you seen?
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
Smart swap, the 05 diff's crack open often
The stocker relies on the trans fluid to keep cool, I've done a few C6Z trans/diff into C5 conversions, but often times remove the aft cover and ditch the pump on the C6Z diff
The stocker relies on the trans fluid to keep cool, I've done a few C6Z trans/diff into C5 conversions, but often times remove the aft cover and ditch the pump on the C6Z diff
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 265
From: St. Louis, MO
St. Jude Donor '08
I have a diff temp gauge in my Vette so I can tell you that the stock diff runs hot - on the highway it'll get up to 250, but not above. Not a big deal. On the drag strip it doesn't get up to measurable temp. On the road course it will get up to 280 after 20 minutes which was my signal to get off the track, I didn't want to push the fluid past 280 or so.
So if you road course, the diff cooler is a great idea. If you don't, it's not really needed.
BTW the diff fill and drain are an odd metric size that is impossible to find as an adaptor for the temp sensor. If you want a temp sensor, first, use an oil temp gauge which goes up to 300 degrees, then, buy a magnetic diff plug from a forum vendor like Ecklers, drill out the center and tap it for the 1/4" pipe thread that the sensor is (double check that measurement on the sensor, that's from memory).
So if you road course, the diff cooler is a great idea. If you don't, it's not really needed.
BTW the diff fill and drain are an odd metric size that is impossible to find as an adaptor for the temp sensor. If you want a temp sensor, first, use an oil temp gauge which goes up to 300 degrees, then, buy a magnetic diff plug from a forum vendor like Ecklers, drill out the center and tap it for the 1/4" pipe thread that the sensor is (double check that measurement on the sensor, that's from memory).
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 265
From: St. Louis, MO
St. Jude Donor '08
Frankly 20 minutes is about all brake pads..or you...are going to want to do anyway most likely!
I do HIGHLY recommend a trans temp and diff temp sensor. I use one gauge in my pod for both, with the inputs switched via a double throw toggle switch mounted on the A pillar next to the gauge. Unlike the diff, the tranny drain or fill is a common size and the adaptors that come with the electric gauge will work fine. The factory z51 trans cooler does a great job, never rising above 240 or so. Same with the factory z51 oil cooler.
Two buddies didn't have a trans temp gauge or cooler in their C5 Z's and both cooked their transmissions on a hot day at Sebring. The got the "hot trans temp" warning on the Dic but it was too late - the syncro rings cook and then your trans won't shift worth a darn ever again, you need a rebuild.
Good luck on the road course...next mod should be R rated tires. And of course brake fluid swapped before every event. R tires are NIGHT and DAY. I won't ever bother running street tires again, it's like ice skating in sneakers. Just no fun.
Melting Slicks
Joined: Jul 2010
Posts: 3,001
Likes: 243
From: Surprise, Az
I have a trans cooler, actually just replaced the radiator with a HD DeWitts with integrated engine and trans coolers. The engine oil is now remains within limits (260) but the transmission is up around 230 so would like to bring it down below 200. Our hpde's can run between 20 and 30 minutes, depends on who is running it so additional cooling will be well appreciated.
In the above pictures, I think pic #2 will be least effective of the two. I would really like to know how pic #1 is working out. The alternative to these options may be to go with the T-1 version for the C-5 Z's, the problem there is losing one of the rear brake ducts unless I can fit the heat exchanger into the rear diffuser, removing the reverse lights and installing screens.
The track we run at out here (The Ridge Motorsports park, it can be googled) has 16 turns so on a hot day the diff is probably getting pretty warm, a cooler will help give balance to the situation.
I like the suggestion of adding a differential temp sensor to help keep tabs on what is going on back there.
I'm not on R-Compounds yet, those create another set of problems I'm not ready to deal with yet, like better brakes and oil starvation issues so i'll ice skate in sneakers for awhile yet. LOL.
In the above pictures, I think pic #2 will be least effective of the two. I would really like to know how pic #1 is working out. The alternative to these options may be to go with the T-1 version for the C-5 Z's, the problem there is losing one of the rear brake ducts unless I can fit the heat exchanger into the rear diffuser, removing the reverse lights and installing screens.
The track we run at out here (The Ridge Motorsports park, it can be googled) has 16 turns so on a hot day the diff is probably getting pretty warm, a cooler will help give balance to the situation.
I like the suggestion of adding a differential temp sensor to help keep tabs on what is going on back there.
I'm not on R-Compounds yet, those create another set of problems I'm not ready to deal with yet, like better brakes and oil starvation issues so i'll ice skate in sneakers for awhile yet. LOL.
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Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 265
From: St. Louis, MO
St. Jude Donor '08
I have a trans cooler, actually just replaced the radiator with a HD DeWitts with integrated engine and trans coolers. The engine oil is now remains within limits (260) but the transmission is up around 230 so would like to bring it down below 200. Our hpde's can run between 20 and 30 minutes, depends on who is running it so additional cooling will be well appreciated.
In the above pictures, I think pic #2 will be least effective of the two. I would really like to know how pic #1 is working out. The alternative to these options may be to go with the T-1 version for the C-5 Z's, the problem there is losing one of the rear brake ducts unless I can fit the heat exchanger into the rear diffuser, removing the reverse lights and installing screens.
The track we run at out here (The Ridge Motorsports park, it can be googled) has 16 turns so on a hot day the diff is probably getting pretty warm, a cooler will help give balance to the situation.
I like the suggestion of adding a differential temp sensor to help keep tabs on what is going on back there.
I'm not on R-Compounds yet, those create another set of problems I'm not ready to deal with yet, like better brakes and oil starvation issues so i'll ice skate in sneakers for awhile yet. LOL.
In the above pictures, I think pic #2 will be least effective of the two. I would really like to know how pic #1 is working out. The alternative to these options may be to go with the T-1 version for the C-5 Z's, the problem there is losing one of the rear brake ducts unless I can fit the heat exchanger into the rear diffuser, removing the reverse lights and installing screens.
The track we run at out here (The Ridge Motorsports park, it can be googled) has 16 turns so on a hot day the diff is probably getting pretty warm, a cooler will help give balance to the situation.
I like the suggestion of adding a differential temp sensor to help keep tabs on what is going on back there.
I'm not on R-Compounds yet, those create another set of problems I'm not ready to deal with yet, like better brakes and oil starvation issues so i'll ice skate in sneakers for awhile yet. LOL.
If I was in your shoes, knowing what I know from a few years of doing this, I would just install a diff gauge and keep my eye on it and loop the pump for now. Since you have stock 3.42 gears you might not need a cooler.
And I would buy some R rated tires! It is SO MUCH more fun and you aren't burning up your expensive street tires.
Trust me you won't be disappointed. You don't need new brake pads for R tires. Your stock brake pads will pull your fillings out when you give them something sticky to work with.
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
I have a diff temp gauge in my Vette so I can tell you that the stock diff runs hot - on the highway it'll get up to 250, but not above. Not a big deal. On the drag strip it doesn't get up to measurable temp. On the road course it will get up to 280 after 20 minutes which was my signal to get off the track, I didn't want to push the fluid past 280 or so.
So if you road course, the diff cooler is a great idea. If you don't, it's not really needed.
BTW the diff fill and drain are an odd metric size that is impossible to find as an adaptor for the temp sensor. If you want a temp sensor, first, use an oil temp gauge which goes up to 300 degrees, then, buy a magnetic diff plug from a forum vendor like Ecklers, drill out the center and tap it for the 1/4" pipe thread that the sensor is (double check that measurement on the sensor, that's from memory).
So if you road course, the diff cooler is a great idea. If you don't, it's not really needed.
BTW the diff fill and drain are an odd metric size that is impossible to find as an adaptor for the temp sensor. If you want a temp sensor, first, use an oil temp gauge which goes up to 300 degrees, then, buy a magnetic diff plug from a forum vendor like Ecklers, drill out the center and tap it for the 1/4" pipe thread that the sensor is (double check that measurement on the sensor, that's from memory).
Thanks
Drifting
Joined: May 2010
Posts: 1,274
Likes: 75
From: Fairfield County, CT
[QUOTE=mikeCsix;1584618982]I have a trans cooler, actually just replaced the radiator with a HD DeWitts with integrated engine and trans coolers. The engine oil is now remains within limits (260) but the transmission is up around 230 so would like to bring it down below 200. Our hpde's can run between 20 and 30 minutes, depends on who is running it so additional cooling will be well appreciated.
Below 200 is very likely unattainable. Even in 55* with 2 days experience my tranny was at 210*. Now with your same DeWitts, 25 days and a B&M cooler with a fan, I average 250*. On days with the ambient in the 90's, I have to back off @ 268 twelve to fifteen minutes in. IMHO, 230 is not bad at all. Sure 215 or so would be great but that's unrealistic on the track no matter what tire you're running.
That said, coolers for the diff and trans are virtually a necessity for regularly tracked cars. Good luck.
Below 200 is very likely unattainable. Even in 55* with 2 days experience my tranny was at 210*. Now with your same DeWitts, 25 days and a B&M cooler with a fan, I average 250*. On days with the ambient in the 90's, I have to back off @ 268 twelve to fifteen minutes in. IMHO, 230 is not bad at all. Sure 215 or so would be great but that's unrealistic on the track no matter what tire you're running.
That said, coolers for the diff and trans are virtually a necessity for regularly tracked cars. Good luck.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 265
From: St. Louis, MO
St. Jude Donor '08
Good question, but no, I've had 3.90's or 4.10'a since I installed the gauge. I suspect 3.42's may run a little cooler but have not proven it.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
The Z51 cars that were sold in Europe had a diff cooler. Must be a reason GM spent the money. When I build my Quaife with 3:73 gears, I used a European left side cover and a ZR1 pump.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Melting Slicks
Joined: Jul 2010
Posts: 3,001
Likes: 243
From: Surprise, Az
timd38, thanks for taking the time to post the photo and TKOGTO, thank you for the comments, they really help with perspective. I have a friend that has a GT-R, we run at the same road courses, his transmission stays less than 200 degrees, hence my targets stated above. The solution may be two fold, one is to incorporate the Z07/ZR1 cooler above which uses cooled transmission fluid to cool the differential in the heat exchanger block, the other would be to add an external heat exchanger placed in front of the radiator to help further cool the transmission fluid before it makes its way back to the differential cooler. I also like the picture in post #1 as it appears to be compact, unobtrusive and doesn't add to the heat load on the radiator. The problem is how effective is it?
I've been trying to find part numbers for the Z- coolers online at GMPartsHouse but can't find any pictures or references other than to the "axle-cooler" options for the various differential options. Anyone have an idea where I might find part numbers?
I've been trying to find part numbers for the Z- coolers online at GMPartsHouse but can't find any pictures or references other than to the "axle-cooler" options for the various differential options. Anyone have an idea where I might find part numbers?
Track Junky
Joined: Jun 2007
Posts: 4,075
Likes: 36
From: Orlando Area
Tech Contributor
I just installed the DRM cooler on my C5Z track only car. The reason for it was a blown diff due to overheating the fluid. It melted the speed sensor, sprayed fluid all over and just went south from there. Sent the diff to DTE and they said the fluid got to over 800F based on their inspections! I bet when half the fluid sprayed out, things went to h3ll in a hand basket quickly.
Hoping not to duplicate that again...
Normal temps get up to about 280F on the road course and I hear the cooler will drop 30F or more. Hope that helps.
Hoping not to duplicate that again...
Normal temps get up to about 280F on the road course and I hear the cooler will drop 30F or more. Hope that helps.
Advanced
Joined: Sep 2005
Posts: 92
Likes: 5
Old thread, maybe help new owners. I replaced one diff and am just now installing the DRM cooler. Myself and many others heard that tranny cooler was all that was needed to cool the diff by conduction, since it is a transaxle system. BS. Have to say, tho, that it worked for about 15 years of tracking maybe 8-12 days a year for those 15 years. Now, not taking any chances. it is a challenging fab, but there's threads here with pics, many thanks to AHJ in Virginia for photos. Yuge help! Also, Randy at DRM super helpful.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Old thread, maybe help new owners. I replaced one diff and am just now installing the DRM cooler. Myself and many others heard that tranny cooler was all that was needed to cool the diff by conduction, since it is a transaxle system. BS. Have to say, tho, that it worked for about 15 years of tracking maybe 8-12 days a year for those 15 years. Now, not taking any chances. it is a challenging fab, but there's threads here with pics, many thanks to AHJ in Virginia for photos. Yuge help! Also, Randy at DRM super helpful.
