Das Beast: My E30 track / street build

[ForcedFirebird]

The only snag about putting the bolts inboard is you have to pull the sub frame to remove a trailing arm. I leave the nut on the outside and use a "S" shaped starter wrench to tighten them.

[Digitalwave]

Impossible to fall out, but it can still loosen.

[zwill23]

Ahh okay, awesome! That's seems much more robust than the eccentric bolt method, carry on!

[dvallis]

We actually re-bored the frame, replaced the bushings and run a tight tolerance non-eccentric bolt. We measured the camber as about 1.5 degree fixed if I recall, with a slight toe in. See way back around page 35. It was secured with a nylon lock nut but still fell out. We're further upgrading to a shank drilled bolt like this, with cotter pin and nylon lock nut. Impossible for that to fall out.

[zwill23]

Community poll. Guess what this is and what's missing.



We caught it before anything bad happened. Will replace all 4 with aircraft grade shank drilled bolts & cotter pins.

Always nut & bolt your track toys.

Those outer eccentric bolts are a pain in the ass to keep tight, a few of us in the Austin area have had issues with the bolts coming loose and requiring a re-alignment.

I needed to go back to Soulspeed for an alignment twice before getting it right. I recommend jacking the car up and ensuring the nut is tight yourself after having the alignment done, the bolt orientation is also important to ensure tightness. The nut should face toward the center of the car, and the eccentric bolt head to the outside of the car, that way you can really crank on it to get it tight.

[dvallis]

Community poll. Guess what this is and what's missing.



We caught it before anything bad happened. Will replace all 4 with aircraft grade shank drilled bolts & cotter pins.

Always nut & bolt your track toys.

[dvallis]

Well fuck. Imgur was hacked and they put a fake email address in my account. I caught it in time and changed my password. Suggest anyone using Imgur does the same

[dvallis]

I'm running a 3" mandrel bent downpipe and 3" exhaust all the way back. T4 0.58 housing looked well matched to it., Data says the M20 really likes it CFM-wise.

[SLEEPYDUB]

Happens more than you'd think. It's very common for people to have the "bigger is better" thinking, and it may not always be true. Header/exhaust sizing one that often over-shot.

I mean I get that, but from what I've seen especially on M20's, they need as little exhaust back pressure as possible, and the 0.58 I assume would choke it down

[Elysian]

Look forward to seeing this thing on the other side of the pandemic

[ForcedFirebird]

This seems counter intuitive

Happens more than you'd think. It's very common for people to have the "bigger is better" thinking, and it may not always be true. Header/exhaust sizing one that often over-shot.

[dvallis]

Was the difference between the housings? T3 0.84ar and a T4 0.58? Or were they both T4?

They were both T4. The 0.84 was divided, 0.58 is single. Look back a few pages for comparison pics. My best guess on why more power is the 0.58 is optimally sized for the M20 head CFM. We probably didn't have enough exhaust gas flow to fill the bigger housing properly and drive the wheel to max efficiency.

Definitely go 0.58

[SLEEPYDUB]

Was the difference between the housings? T3 0.84ar and a T4 0.58? Or were they both T4?
I do expect a smaller housing to make power sooner, but I do not expect it to make more peak power. This seems counter intuitive, but if this is correct, I may be sourcing a T4 0.58 for my 6266 instead of the 0.81

[Digitalwave]

P.S. what's with blocking out your eyes? Are you a top secret government operative?

[ForcedFirebird]

Nice! That 10psi "curve" looks like a tabletop. That's exactly right for a road racing car. :)