^^Excellent post!

 

Wait 'til you get him on the phone!! Jon is chock full of all kinds of interesting stuff. He also puts out some solid product to boot.

 

Whoa.

Had this upgrade while getting TRE's Stage 4 TC. Due to the lengthy break-in of the TC, I've been really nice to the car and not driving it hard at all.

Leaving MOD I took the turn onto the entrance ramp with some healthy throttle input. I was a bit worried since I have the Progress rear sway and hadn't felt this rear diff yet, so the throttle was NOT mashed.

Whoa. Like I said above. She snaps around!

After 67,000 miles I'm damn used to some push up front and it's GONE. Now I'm much more concerned about oversteer.

I've not driven a rear wheel drive in hundreds of thousands of miles and many years. I've NEVER driven one at an autocross. This is completely new to me.

I'm looking forward to getting the TC more broken in (I know, I know, I can turn the car agressively, just not launch the thing agressively, but one leads too easily to the other) so I can have some opportunity to start adapting.

I'm wondering if now's the time to put a front sway on?

How're folks adapting their setups to the new turning prowess?

THANKS JON & TRE!!!

 

I would try more rear camber and a front roll center correction kit if you don't already have one before a big front bar. A big front bar will lift the inside front tire, bringing the push back. While the car will feel more balanced, it won't be as fast. Keep improving the rear with more camber, lower tire pressure, and less rear bar if necessary. You can also add friction modifier to the rear diff to continuously lighten the lock relative to how much you add, up to a point. When you refill with gear oil without modifier, it will be back to full lock. You may need to soften the rear springs as well.

 

Front roll center kit is in the box, waiting. Thanks. Good stuff!

 

some really great information in this thread.

To Jon or others who might know. What other bushings would you recommend for complimenting this diff if any at all? I, like others was thinking of getting a larger rear sway but this definitely appears to be a better option. I currently run -1.5 camber with .05* of toe in the rear and my car plows like crazy on autox. I really like the alignment but i need something to get me to rotate better. If/when i do this i wouldn't mind doing some bushings to really help compliment the max-lock.

 

Personally, I would recommend the use of a polyurethane bushing. They are durable, and offer some give that Aluminum bushing can't. There is a reason why you don't solid mount certain items and to do so can cause potential stress that can lead to fractures and or cracks.

Not only that but polyurethane bushing are so much more quiet. When the rear differential is solid mounted to the floor it transmits all that road noise into the car.

I installed a set of the rear differential bushings from WORKS on an EVO that had solid metal bushings and the car was so much quieter.

 

Do you think there is a need to do poly bushings over the stock ones? Is the improvement worth it i should say?

I may have a couple local guys interested so hopefully i will have a few orders coming your way this winter.

 

I'm currently running the Energy Suspension Poly U bushings in my factory rear mustache bar and in my rear side diff carrier...

If I upgraded to the Buschur mustache bar along with the Buschur aluminum side diff supports, will this be more prone to cracks/stress???

 

I'm sure it'll be fine but there are reasons that items should not be solid mounted and in the case of the differential housing it's up to you but in mine it'll be supported on the polyurethane.

 

I would really like to save the extra 18 lbs in the rear with the BR stuff, but I know there are trade offs.... I do plan to drag my car, and want the parts to hold up for sure. I would not want to end up cracking parts and breaking brackets if in the end that will happen.....

In this case I need to find a good balance of everything, and who knows, maybe I already have it.

 

No no no.... no worries guy. I'm not trying to scare you or anything. It's a good product.

 

The BR or AMS mustache bar replacement and the BR side mounts together does NOT save 18#. It will be more around 11-12#. . .

I've had the rear diff solid mounted and will tell you that you will NEVER want to drive you car any long distances without ear plugs. This modification is the #1 culprit for turning my street/race car into a full race car. But, I also don't have rear seats or trunk carpet, which will muffle the diff noise quite a bit. . .

Would I do it again - hells yeah!! But I have other cars to drive to work . . .

As for the TRE diff mod - I consider it a must have for any EVO race car, whether it be drag, autoX, road race, or drift (not many of those out there) . . .

 

Thank you Evolutionary for the very informative and insightful post. You have mentioned things that are important to me.... and I think that since my car is mainly a street/highway car, I'll just leave the rear the way it is with the ES Poly-U bushings... as for losing the 10-12 lbs, I can deal with it.

Now back on topic, I should look into the TRE rear diff.....

 

For the DIY guys, the bushings are a pain to press out. I was able to press out all but one (long story). Bottom line, get a decent press. It is possible to torch them out but it is a smokey and messy process.