Given the potential of damage to the differential when oil temps go above 200F (especially using the 5.12 R&P), please share your setup for measuring and managing differential oil temperature.

Today, I run on a S1 R&P with OEM LSD and I don't measure diff oil temp; to mitigate temperatures, I use an S2 rear cover and a home made heat shield between the exhaust and the differential.

 

Simple 1/8" NPT tap into the cover would do. Or for those who have diff coolers and pumps you could install and inline AN fitting with a 1/8" NPT port or just use a cooler with a provision for a temp sending unit as well.

Dannobre has a diff cooler/pump setup, maybe he will chime in.

 

This is the second time ive read about the diff cooler. search brought up no results. care to point me in the right direction 9K?

edit: Or, is this a one off thing that im going to have to fab up myself?

 

Yes, this would be a custom setup.

 

If you are heavy tracking...you will likely find your Diff temp is closer to 300deg than 200.

To run a cooler...you need to figure out a few things....

1. Where are you going to put the pump and what type?
2. Where are you going to put the cooler
3. Plumbing....wiring for pumps and fans

I have put my coolers in the rear bumper behind where the license plate is. I built a block off plate that holds the license plate...and when I get to the track I uncover the coolers and fans and am good to go. ( I have 2 coolers...Tranny and Diff )
I put the pumps under the rear bumper cover behind the drivers wheel..there is a flat spot there that works well

You need to alter the rear cover on the diff...you can use the fill hole for the return ( I think the fittings are -18 ORB like the oil cooler fittings in the front..but check..it's been a while since I did this) and the drain hole for the pump feed...but you need to add another fill hole so that you can get the level correct. I just tig welded a flat boss and added a 1/8NPT fitting beside the original fill hole and tapped it for a plug. That way you fill the diff with the pump running until it drips out the new fill hole. If you make the hole a bit bigger...and go to a 1/4 NPT it makes it easier to fill...just harder to find a spot for it to fit

I used a diaphragm style pump....they last a long time and aren't quite as noisy as a gear pump...the only issue is that you have to make sure they turn on before the oil gets hot. Most have a max temp of 265deg or so...and if the diff gets hotter than that before you turn it on...the pump head will melt ( ask me how I know )

I have coolers with a fan and 180deg thermostat built in....funny story..I wired it all up and went to the track the first time and everything worked great...I came into the pits after a cool down lap...expecting the fans to be on still...no go. They were off. I though I wired them wrong...so I pulled the bumper off to have a look...everything looked correct...so I went back out.....same thing..came into the pits and they were off. I finally thought to look at the temp gauge and noticed that the temps were below 180 DUH....took a heat gun and warmed up the temp sensor and things came on correctly....just a brain fart...and a system that keeps things cooler than I expected

I don't have any pictures currently...but I likely will be at the shop on Sat and I could throw a couple up or to your email

 

legal mod for ttd/ptd?

Posted From RX8Club.com Android App

 

I snagged some pics of yours for future reference the last time you posted them. Hope you don't mind.

 

LOL...no worries....I just don't have time to find them again right now

Trunk looks empty in that picture...I have a huge dry sump tank in there now..and the surge tank for the fuel system

 

Cool. You posted these a while back, along with pics of your front cooler setup and ducting.

 

Diff and transmission coolers are free mods for NASA PT/TT. However, modifying the rear bumper Will probably mean additional points.

 

Thanks Dan!

 

There's a beefed up aluminum reinforcing diff cover with extra capacity sump and an oil cooler threaded return hole for about $300 from Revo-tune in Japan

I don't think you need a bumper cutout. Dan reported that his fans were not even coming on using a 180*F thermostat.



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Does most of the heat in the rear diff come from the actual mechanical workings of the diff, or does it happen from heat soak from the exhaust? I've got DEI exhaust wrap around the exhaust when it goes past the diff.

 

I would say it would be all due to friction in the diff.

 

They come on when driving hard...but we're off by the time I finished a cool down lap... I think you could easily mount them under the rear cover with no cutout. .the fan would provide enough airflow. You could also mount them in the trunk.....and blow the exhaust out the vents into the wheel wells

 

Plus he does't have 500+ hp churning thru it ...

 

It got plenty hot with the stock motor......I had to do the cooler before I did the REW swap

I actually didn't notice more heat with the increased HP...the coolers didn't hiccup at all

 

Maybe you need wheels/tires with more grip?

 

https://www.rx8club.com/rx-8-racing-...2/#post4659357

 

Any idea where one might purchase this? I can't seem to find it.

 

||| Revolution :: Catalogue - ????????

 

Yes

This part isn't listed on their site but I'm pretty sure that either RHDJapan or Japanparts is where you can request pricing/order it from


.

 

is there anything better than redline 75w-90 for the rear diff on the tracked S2?

 

I used that for a long time. Last few times I have gone to the 75W140...it gets a workout

 

especially for the temps most people are reporting