has anyone done rear diff oil analysis to actually see what the wear numbers look like for one fluid vs another?

 

well if you're going to ask, might as well shoot for the sky ...

 

So I ordered that Revolution Extra Capacity Rear Differential Cover from RHD Japan.

I think something must be wrong with their site as there price on this part is currently like $14 at current exchange rates. I went ahead and ordered it... we'll see what happens.

Here is the link to the part at RHD Japan:

Revolution Extra Capacity Diff Cover - SE3P - RHDJapan

 

As I mentioned, I used a S2 diff cover. I think it took a bit more oil than the S1 but it could very well be placebo effect. The S2 cover does have more cooling fins than the S1.

 

Hell of a deal considering it lists for $290 in Japan, probably should have kept that under your hat because if they suddenly get a dozen orders somebody will wonder wtf is going on

 

I just got my diff oil analysis back. 2 yrs, 19 track days and 26500 miles on Amsoil 75W/90 severe gear oil in a 2010 (S2). I was pleasantly surprised as wear appears to be completely normal!

Going to send my gearbox oil in next. I'm not expecting that to look so good as it was more grey than black after the same amount of abuse.

 

hm interesting note about the heat, so good syn diff oil will handle S2 diff heat just fine even with heavy track use..good to know!

I just flushed my S2 diff, car(new to me) only has 28K of probably gentle street driving. I put in 50/50 mix of Redline lightweight shockproof and their 75w-90 gear oil.

 

 

Yeah... the ended up cancelling the order and saying their website had an error! HAHA!


Guess I'll have to reorder once they fix it.

 

Don't hold your breath

 

I don't know about a capacity change in putting an S2 cover on an S1 diff, but I can tell you that my S2 diff holds almost exactly 1.5 quarts.

My strategy for my diff and trans is to use Redline 75W90 and MT90, respectively, and change them once per year. Both looked good last June after a year and 11 track days. I will probably send them to Blackstone this June for analysis out of curiosity.

 

The owners manual lists both s1 and s2 differential oil capacity as 1.4 quarts. I used closer to 2 quarts both times I changed my s2 diff oil though. Some wastage, but still seems like more than 1.4 quarts went in with the car level.

 

You must have had a lot of wastage but it is really right around 1.5 quarts.

 

Rx8performanc.com has a cooling device in the front under panel that you can buy. They claim it can be used for many things like a transmission cooler or a differential cooler. I hope this info is beneficial to somebody. Me not having my 2nd 8 yet, I have research nearly every performance website there is to find. I wonder if anyone else is a rx-8 junkie like me. :/

 

ok then ....

 

Is this something I need to be concerned about when running a mostly stock vehicle on HPDEs?

Without installing a diff temp gauge, is there a way to figure out at what point this is something I need to be concerned about? I've done many HPDEs on my 8, but haven't even thought about my diff temps... realistically, I just take the car out and go - so long as nothing pops up on the dashboard, I figure I'm ok, haha.

 

Stock diff...and stock power you will likely be OK. I would change the oil at least every year if you are doing that

 

I agree with Dan. You'll be fine at stock power, but it is prudent to change the diff oil yearly with high quality synthetic gear oil. I use and like Redline 75W90 as noted above. I actually just changed it last weekend after 14 track days, and it looked very good. I forgot to take a sample, so there will be no UOA report this year.

 

Yep, see my UOA in post #31 Diff seems to hold up well (on an s2 at least). Gearbox is another story. There was a lot of metal in my transmission fluid after the same duration.

 

That kind of makes sense, a lot more moving parts in the tranny. With good syn fluid both should be good for 2 seasons at least....

 

Surprisingly a lot of the tranny heat comes from having the exhaust pipe traveling right beside it

 

^^which is why it's not a good idea to angle your exhaust over towards it, some people still don't get it

synthetic fluid only goes so far, have a 3rd gear synchro pic on here somewhere from the past with what looks like burn-on all over the surface and it had cracked & broken, all that went away when I changed the piping to stay away and then bend it over at the end of the tunnel




.

 

Has anyone done any write up on a differential cooler install? It's time for me to do it. Would just be nice if someone else has done the homework on fitting sizes/thread that kind of thing.

Search is not working too well...

 

how much does the catless midpipe reduce EGT/exhaust and transmission temps?

 

it doesn't really