Dave-gerous E21

[Simon S]

so much win in this thread !

Fucking love it.

Thanks for sharing.

[pureaudio]

Love this car so much, keep it up.

[hi its me alec]

One of my favorite projects on here, I loved the dinosaur. You should get some videos up sooner or later

[sandlock]

great 2nd save man. there's something to be said about trials along the way.

[LJ851]

Did you have a professional drive line shop make your first driveshaft ? There is a reason bmw uses 2 piece shafts, there is no way you could spin a shaft that long and thin !! Im glad you escaped injury last time , are you sure that your new shaft can spin the required rpm for top speed ? I talked to several high performance driveline shops when i was considering a 1 piece shaft for my 2002 project and 1/3 of them said they would not build me one and rest said it would need to be 3.5 or ideally 4.0 inch in diam. to turn 6500-7000 revs. I believe there are formulas for this purpose (rpm vs length) and id hate to see this happen to you again. good luck !

[CHIF8008]

just saw this. man i love the car and your truck. i swear just looking through this makes me think that your part of my family. right on the money with what and how my fam dose things.

sucks to hear about the crash- but happy to see her rolling again. Props

[Dave-ger]

thanks dudes! I'm really excited about having it fixed, but I can't really drive it too well with all the snow there is around here right now.. oh well. having a cold blooded rotary, bald front tires, and no defroster at all will do that to you.


LJ, on page 10 you can see the stuff about the drive line. the original drive line I was running was home made and it was a bit smaller than 2.5". a professional drive line shop told me to just make one kind of like that after seeing my mock up drive line and not being able to help because of the complications with the BMW yoke at the back end. after the crash, I was considering something like a 240sx rear sub frame so I could run a diff that bolts to a more conventional flanged yoke, but I came up with the idea for the adapter. the different drive line shop I went to this time said that the RX7 yokes that I planned to use this time around front and back ran the 2.5" tube that was simply too small for the length I needed, and that could cause it to whip and kink... like my old drive line did... so he upped it to 3" with the dodge slip yoke setup and the adapter ring on the RX7 yoke. The distance is also shorter between the trans and the diff than factory cause the output on the RX7 tranny is further back than the stock one. hopefully that answers your questions, and yes, I did learn why some cars and trucks have carrier bearings the hard way... I don't intend on doing that again. the fact that my old drive line was not balanced at all probably didn't help either.

I can't be too upset with the drive line shop that suggested I just make a drive line all ghetto like, cause I'm the one who did it. Also, I can't beat myself up too much, because nobody ever told me anything about the drive line diameter being such a big deal, they just told me about the fact that it was out of balance. I'm pretty sure the balance issue had little effect on the outcome. I could be wrong though. I shouldn't be having that problem ever again for two reasons: I don't plan to go that fast again, nor did I know I was going so fast, and I now have a legit drive line.

[LJ851]

How long is your shaft ? heh heh. I will see if i can find that formula for diameter vs revs. Also , the lighter the shaft is the smaller it can be. 3 inch is way better than what you had before, it would be nice to know the max safe speed of this new shaft.

[Dave-ger]

ha, sounds like a very personal question!


but if I remember right, it was 55" and some fraction of an inch in addition. I wish I remembered the exact length. that was the distance from the output seal on the transmission to the adapter flange at the diff. there is about 3/4" of slip shaft showing out of the output shaft just as the drive line guy recommended. I'm pretty sure the diameter is going to be okay, but it would be cool to know that formula. The guy at the drive line shop wasn't going to let anything he didn't think was completely safe leave his shop; I'm glad he had that attitude.

[Lof8]

Damn! I'm not sure how I've missed this for so long. Great work and very cool cars!

[LJ851]

OK, i found a calculator but it wants to know tubing wall thickness and u joint center to u joint center. Do you have these specs ?

[Yonkers320is]

looking good, I missing my e21 now. You should post in the e21 section of bimmerforums. Great bunch of e21 owners, and a lot are from Oregon too.
kind of way late posting, but if anyone else is considering doing something similart to another e21, you can cut the front strut housing and use MK1 rabbit inserts, and if you use Bilstein HD rears you can lower the rear almost 2 1/2 inches......

[Dave-ger]

looking good, I missing my e21 now. You should post in the e21 section of bimmerforums. Great bunch of e21 owners, and a lot are from Oregon too.
kind of way late posting, but if anyone else is considering doing something similart to another e21, you can cut the front strut housing and use MK1 rabbit inserts, and if you use Bilstein HD rears you can lower the rear almost 2 1/2 inches......

I tried posting on bimmerforums and it wouldn't let me, it was weird. whatevs I guess.

and I do wish I would have used mk1 struts instead of the MR2 ones. I had to grind down the MR2 struts so they'd fit in my strut mounts... oh well. I can always just switch to rabbit struts when I need new ones some day. Also, you won't gain anything with shorter struts on E21's without modifying the sub frame like I did, you'll bind the control arms on it at about the same time you'll bottom out your stock struts.



LJ, I don't have those specs right now. hopefully I'll remember to get that measurement when I have my car on jack stands the next time. if I can find my reciept, I'm sure I can find the tubing wall thickness. I passed my friend that was going 85 fast enough that he said I came out of nowhere right before my old drive line kinked, so I'm sure that was over 100 MPH. I don't plan on ever driving that fast again, so I should be fine... I also didn't ever intend on passing someone who was going over 80. he sped up right before I went to pass him and I wasn't paying attention to my speed... sometimes you have to learn the hard way. anyways, since I'll probably never drive that fast again, at least in this car, I should be fine.

[Dave-ger]

so, I just wanted to share how much I regret buying an RCI fuel cell. it doesn't seal so well around the cap assembly or sending unit. the sending unit turns out to be held on with sheet metal screws, not bolts like I thought, and they are barely snug, and won't tighten any more...

oh, and here's the fuel cap assembly gasket I replaced with a hand cut one today:



RCI sucks.

I'm going to try to get my money back.

[imprttuner88]

So much win and trial and error in the thread. I absolutely love it.

Hopefully RCI makes good on their product, would hate to see a fuel tank slow you down!