'88 325is M30 street car-->S54 -->S50 -->M54 Enduro Race car

[Jb325is]

Yeah, forgot to mention that. The spacer accounts for the thickness of one additional clutch/wear plate, and you machine for the 2nd.

[328ijunkie]

yeah total preload/stack height. Glad david helped yoiu.

[tinkerputzer]

So how did the diff work out at autocross?

[Jb325is]

Hard to tell, I only have Continental ST slicks for the car right now, and it was 45 degree with no sun. Never got them even remotely warm so I had zero grip and no confidence. I was also really disappointed with my driving after watching the video, I haven't done much autocrossing in the last two years. The car was not pushy though, which is what I was worried about with the diff. I also think the 3.23 is too tall, I was barely getting over the stock rev limiter

Here is a video

[tinkerputzer]

Nah man still looked pretty good. Don't get down over the first event with a new set up especially with those conditions and those tires. Reviewing video always makes it seem slower. The right tire is going to make a world of difference. I really wish i hadn't seen that video. Car sounds mean as hell and now i want s54 power.

How are you liking that brake set up aside from being boosterless?

[DER E30]

That looked FAST! Where I've ran we don't go that fast I don't think, Maybe the GT3s do but my m42 doesn't go that fast!

I keep going back and forth on LS vs s54 as my dream swap! THAT NOISE!!!

[Benjamin_Button]

That was slow to you? Is this with the old exhaust?

[LJ851]

I also think the 3.23 is too tall, I was barely getting over the stock rev limiter

I've got a 3.46 lsd on the shelf if you want to try it for research purposes.

[Jb325is]

The car was fast, but I was not. I was very familiar and comfortable with the car in it's previous configuration and I definitely do not have that feeling anymore. I was not able to get back to gas and carry and speed anywhere. Just need more seat time

The brakes are ok, still not confidence inspiring but they were better than I thought they would be. Especially for not being warm and having stock pads in the rear. I still need to make some bias changes when I get race pads in the back and mess with the pedal adjustment a little bit.

One thing that was very obvious in the video is I need a steering rack. The corrections that seem minor and don't really register as they are happening are pretty big on video. What is the best option on a rebuilt z3 1.9 rack? I can't see myself spending $500 on one from Rack Doctor, anyone have any suggestions?

Lorin, what diff is it? I have this thing all set up with the 4 clutch now, so it would be a PITA to change gears again. I might just try to work with this for a while. Hopefully with a remote tune from TTFS I can smooth out the power delivery, it's pretty peaky right now

[The Dark Side of Will]

The spacer is taken out of the bottom of the stack as well. Lower right in this pic.
https://flic.kr/p/pauWJZ

Cool. Thanks for the photo!

[Luke_M]

You can grab a new z3 1.9 rack from a company called aae. New, so no core needed which is nice. Mine is certainly quick. Approx 2.7 turns lock to lock just as advertised.

http://www.aaesteering.com/steering-racks/3111n-new-power-steering-rack.html

They only thing is mine felt to light at speed and super heavy when I was still. An alignment and tightening the preload on the rack fixed it. Rockauto used to carry them but not anymore.

[LJ851]

Lorin, what diff is it? I have this thing all set up with the 4 clutch now, so it would be a PITA to change gears again.

It's a stock LSD out of a 7 series with like 90k on it. I want to keep the diff, but you are welcome to borrow it to see if it is the ratio you would like to run.

Honestly, it sounds like you made so many changes to the car that it would probably be best to get used to all the new aspects with seat time first. What feels like the wrong ratio now might feel great in a few months.

[MX339]

^I concur. You even said it yourself that you're struggling to get on the power as early as you need to. I'd say a combination of better conditions, setup adjustments, and driving adjustments may prove the current gearing to be just fine.

[tinkerputzer]

One thing that was very obvious in the video is I need a steering rack. The corrections that seem minor and don't really register as they are happening are pretty big on video. What is the best option on a rebuilt z3 1.9 rack? I can't see myself spending $500 on one from Rack Doctor, anyone have any suggestions?

I noticed that too. I can't imagine autocrossing a stock rack anymore.

I didn't go with this one because i found it after the fact. May want to verify it's 2.7LTL.

http://m.ebay.com/itm/151076806130?nav=SEARCH&sbk=1

[eduTechnic]

Just get a z3 1.9 rack off eBay and rebuild it yourself if it even needs it. Mine was like 135 shipped from one of those bulk parts sellers and the guy even put the vin of the car it was from.