I just re-stacked my rear differential. I'm going to fill it with Mitsubishi gear oil for the first 500 miles + 1 event and then replace the fluid.

Has anyone experimented with Redline 75W140 NS for more lockup? I've read a few reports of increased lockup, along with increased chatter, from the NS fluid. I would probably add some small amount of Redline friction modifier to keep the wear and noise in check.

Either way I'm looking forward to trying out the new diff setup.

 

You won't be disappointed with the rear diff. It's like going from a WRX to an STi

That said - it may also cause you to reconfigure your suspension a lot.

 

I'm interested in this as well,. read somewhere on here about it somewhere, not sure if it was redline, but same effect.

 

I used it with my 12plate. It made a ton of noise, enough that I drained it and switched to diaqueen real quick. It may have had more lockup, but its hard to tell with the 12plate because to me it has a little too much lockup.

We end up having to run a bunch of toe in to keep the back end behind us on corner exit.

 

After restacking the differential and driving on it briefly, I'm not even considering the Redline NS fluid. Actually I've had the differential apart twice now. The static lockup is significantly higher than I expected or the service manual indicates is reasonable, so I assumed I had somehow accidentally installed a spring plate wrong. Everything looked fine when I tore it down again and carefully inspected it, so I'm assuming I just need to break it in a bit. I used the exact same plates, but in a different order, so the stack thickness couldn't have changed appreciably unless I really screwed something up or introduced enough foreign dirt/dust in to the stack to change the thickness. I was careful to dip each plate in gear oil first as the service manual indicated, so that seems unlikely.



It did calm down quite a bit after putting a few miles on it, so maybe I'm just being too paranoid here.

When I first backed out of the driveway, I was moving very slowly with the windows down to listen for any unusual noises. I heard a muffled *CRUNCH* sound at one point and came to a complete stop. I tried moving the car a few inches forward and heard the crunch again. My heart sank, and I started calculating how much it was going to cost me to get this diff serviced. Then I got out of the car and noticed I had just run over a gigantic, crunchy pine cone.

 

Make sure you drive figure eights to break it in. Driving down a road doesn't really cause the clutch plates to slip much because both rear wheels are at the same speed.

Also, I use nothing but Diaqueen LSD in the rear.

 

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lol!

 

Jimmy (Jim3142) and I bought a set of BFGs and tried them out for the first time yesterday. We haven't yet done a comparison with the 'stones, but as compared to the Z2 Star Specs the car had before, these are leaps and bounds ahead. They have much more lateral grip, even out of the box as stickers (save for the first couple turns). For some reason it didn't seem like there was as much longitudinal grip, however. With one event under our belt, I don't have a whole lot to report yet. We were running the 245/40/17s mounted on 17x9.5. Hopefully I'll be able to order a set of Bridgestones next month so we can do some back to back testing. The car should also have my JRZs and some stiffer springs on it at that time too. Also...man it feels great to be back in an Evo.





Here are some photos for comparison:

245/40/17 Rival S on 17x9.5 vs. 245/40/17 Z2SS on 17x9



Some pics of the front tire wear. Also, the rears picked up a fair amount of OPR at a site that doesn't normally have that issue. It seems like the center block is tapering toward the outside, and has already tapered down to the wear bar.




That's the right front, and the course was counterclockwise and very heavy on left-hand turns. I'm really hoping that these tires are a little more durable than the 10 runs we put on them appear to show. We may need to play around with the pressures some too. We just kind of threw a guess at it that seemed to work. It's also worthwhile to note that the car is probably pretty undersprung, so once we take care of that, hopefully we'll see better results.

 

I have no specific experience with the Rival S tires, but the Dunlops (until the release of the RE71R) had been the class of the field in longitudinal grip. I struggled a bit with the original Rivals, especially under braking as the lack of straight line grip would upset the ABS until I got brake pads with less initial bite. It had never been an issue on the Dunlops.


The OPR may actually be graining on your tires, rather than pickup. I got a bunch of that on my RE71Rs as well, the newer tire compounds are pretty soft, and supposedly benefit from a heat cycle before driving aggressively on them else you get that tearing of the surface of the rubber.


Also, with the original Rivals wore through the first 4/32 or so of tread really quickly. They stayed at 2-3/32 for significantly longer and the grip didn't really drop off until they corded.


-Bryan


Disclaimer: YMMV, I'm usually wrong about everything.

 

Thanks for your insights, Bryan

I think during our first few runs, Rich and I were still getting used to the lack of longitudinal grip (compared to the Dunlops) in terms of braking, but we realized that we didn't have to slow down as much on the Rival S because they had so much more lateral grip, so we could carry more speed into turns. Pretty worthwhile tradeoff in my opinion

 

I had the same experience with the initial few 32nds wearing relatively quickly but the last few 32nds feeling like they were going to last forever. They didn't feel like they had dropped off, but I went significantly faster when I switched to newer tires. I was left with the impression that they did drop off gradually, but the drop off was very subtle. Also I daily drove mine, for what it's worth. And as always, it's hard to say if my impressions match reality or if it's all in my head.

 

Isn't AWD STU limited to 9" wide rims or has that recently changed?

 

Wheel width has been unrestricted in STU since its inception

 

I should have been more clear. They didn't "fall off the cliff", they didn't have peak grip by the end, but they didn't stop gripping like Dunlops, Hankooks, etc.


I think they were a little peakier than new tires too at the end, but I didn't throw a new set on after my Rivals corded out.



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