1987 E30 Coupe Rally Build

Sweet! Glad you got it sorted! It's amazing how much a fresh cap and rotor can wake up a car, huh?

In reply to AWSX1686 :

Seriously! Unfortunately our rallycross this weekend was canceled so our next one won't be until May. Plenty of time to make some changes to the car, which is nice, but I have a feeling I'll get a bit bored. I believe our local autocross season fires up sometime in April so maybe I'll take the e30 out for some laughs on pavement.

Pulled out my diff yesterday to swap with someone who has a 4.10 limited slip. Should be a nice upgrade in acceleration, and I doubt I'll need that extra top end. While I was down there, I realized this is probably a good time to pull the subframe and replace all the bushings. 

To those that have experience with e30's, rally, or both (I'm looking at you irish44j), what is the general consensus on bushings? Are stock-replacement rubber bushings the way to go for the extra compliance with rough roads, or should I go polyurethane for their durability?

I'm planning on replacing both subframe mount bushings and all of the trailing arm bushings. Depending on the condition of the diff bushing in the new diff, I may be replacing that as well, so inputs on all of those (and/or others) is welcomed. 

On the Merkur (strut front, trailing arm rear, so similar) I have the subframes solid mounted (steel), the differential solid mounted (steel), the suspension bushings are all polyurethane, and the motor and transmission mounts are rubber. Seems to work well but the polyurethane needs to be cleaned and greased every couple of events, and there is a great deal of NVH if that matters to you.

Now that it's starting to warm up, I am able to actually make progress in the garage and not be miserable. 

I pulled out the diff in preparation for a 4.10 (previously 3.73), so I figured this is a good time to go through and reinforce everything as well. Pulled out the trailing arms and subframe. Unfortunately no pictures of the subframe, but I reinforced the trailing arm mounts, diff mount, and swapped in some polyurethane subframe bushings. 

Then I moved onto the trailing arms. Bought some 1" DOM tubing and went to town. First I cleaned it up and added a brace for the shock mount:

Made sure to double check clearance to the CV and called it good enough:

With that done, I wanted to tie the two leading ends of the trailing arm together:

Added another plate (for welding practice if nothing else), and slapped in some new polyurethane bushings. Here's a comparison of stock vs. reinforced:

I'm hoping to get the other one done this week and start reassembling things. 

Took a fair amount of wrestling, but I managed to get the rear end of the car put back together! 

While I was already in there doing all the bushings and reinforcement, I swapped to a 4.10 limited slip (had a 3.73), and installed some H&R "OE Sport" springs. I really don't want to lower the car, so these are the closest I could find to stock (less than an inch drop), and had a stiffer spring rate than stock. 

I decided to slap the street tires onto the car and go for a quick drive to make sure nothing falls off, and the rear end seemed to stay together pretty well. You can sort of tell that the rear is slightly lower than the front:

Unfortunately, I found another electrical issue. The alternator I frankensteined together a few weeks ago doesn't seem to actually be charging. Might be time to pony up some cash and actually get a reman'd alternator. I want to double-check all the wiring first though.

While I wait for more parts to arrive, I decided to get rid of the factory sunroof. Saying goodbye to all of this:

And hello to a hole in the roof. This will get covered with a sheet of aluminum and a roof vent:

Note to self, go buy some more cutting discs:

As someone who recently did the same thing, good job on not totally botching up the rest of the roof. I rushed it way too much.

hint: if you have a beat-up spare e30 hood sitting around, cut out the middle for a roof patch panel. Since it already has a "profile" to it, it's very strong and stiff. I can stand on mine. :)

hint 2: when you put a patch panel in, use bolts or rivets so you can remove it if needed (i.e. for cage in future, or whatever). Having the thru-roof access is great for certain things, and if you weld on a new panel you'll lose that. 

If you plan to stage rally at some point, roof patch material has to be as strong as stock sheet metal, FYI. One of the main reasons I used OEM hood sheet metal. 

In reply to irish44j :

Unfortunately I don't have a spare hood, but I do plan on using rivets for exactly that reason. 

artur1808 said:

In reply to irish44j :

Unfortunately I don't have a spare hood, but I do plan on using rivets for exactly that reason. 

second note: I can't recall which, but one of the national rally organizations requires that ever xx number of inches you actually have a nut and bolt (vice a rivet), since rivets really aren't as strong. I would dig through NASA and ARA rules just to check if that's still a thing (it may or may not be, or it may be an old RA rule that doesn't exist any more). Mine is actually attached completely with little M5 bolts and locknuts all the way around (and using the little rubber-backed washers for good sealing). Way easier to remove than drilling out 20 rivets, also easier to make sure you get even tightness all the way around when you put sealant in. I had rivets initially and has a few leakage problems in heavy rain. Either way will work (especially for rallycross), but just throwing it out there as an option.

In reply to irish44j :

Interesting, I had never heard of such a rule. Sounds like I need to go re-read the rulebooks. Thanks for the tip!

ARA:

NASA:

Looks like both specify that they need to be fixed in the closed position and made of metal. I couldn't find any mention of what sort of fasteners you have to use. And I question how NASA would validate that the replacement panel is of equal or greater strength than the permanent roof...

Obviously if you replace your sunroof with tin foil you'll have a problem, but as long as it's made of metal and a reasonable thickness I cant imagine a scrutineer would somehow test the strength of the roof.

IE no Lexan, aluminum, rain gutters/window flashing etc. 

In reply to Crackers :

Lexan and rain gutters I can understand, but I feel that aluminum of substantial thickness should be fine.

For example: the OEM sheet metal is 20gauge steel (as far as I can tell from things I've found online), and I'm using 14 gauge aluminum. It's not steel, but it's twice the thickness of the original steel. Once the cage is in place, I find it hard to believe that the difference in sunroof panel materials will be meaningful in any sort of crash. However, I've been wrong plenty of times before, so I'm open to discussion if someone disagrees.

artur1808 said:

ARA:

 

NASA:

 

Looks like both specify that they need to be fixed in the closed position and made of metal. I couldn't find any mention of what sort of fasteners you have to use. And I question how NASA would validate that the replacement panel is of equal or greater strength than the permanent roof...

Obviously if you replace your sunroof with tin foil you'll have a problem, but as long as it's made of metal and a reasonable thickness I cant imagine a scrutineer would somehow test the strength of the roof.

probably true. I imagine the criteria is "if it's steel, it should be the same thickness as factory roof steel, and if it's aluminum, it would presumably be thicker than the factory steel.

Then again, old BMW steel is thicker than, for example, modern Subaru steel (source: I actually checked when I had both). 

In the end though, you never want to give a scrutineer and excuse to question anything. I'm of the opinion that if the rules state something, make sure you exceed that by enough margin that it's obvious to scrutineers that you meet that rule. Don't leave it up to their "personal judgement" since they all have different opinions about stuff, even stuff that isn't mentioned or explicitly stated in the rules of ARA or NASA or whatever. A lot of these guys are old-timers who may have done it under older organization rules (RA, SCCA, etc) and may get things mixed up (I've seen it happen). And telling an inspector "you're wrong" isn't a way to get in their good graces. And I know guys who are adversarial with scrutineers, and scrutineers definitely look at their cars more closely and find little dumb E36 M3 to gig them for. Bottom line is if you're at an event and the scrutineer says something isn't legal, it's a giant pain in the ass to change his mind (even if he's wrong) and could cost you your entry.  Don't give them an excuse, that's my advice. 

 At least at our level. If your name is Pastrana or Higgins, I suppose you go right to the edge of the rules to save that extra 10 ounces of weight for that extra 0.5 seconds in time or something lol. 

artur1808 said:

In reply to Crackers :

Lexan and rain gutters I can understand, but I feel that aluminum of substantial thickness should be fine.

For example: the OEM sheet metal is 20gauge steel (as far as I can tell from things I've found online), and I'm using 14 gauge aluminum. It's not steel, but it's twice the thickness of the original steel. Once the cage is in place, I find it hard to believe that the difference in sunroof panel materials will be meaningful in any sort of crash. However, I've been wrong plenty of times before, so I'm open to discussion if someone disagrees.

I wouldn't think that would be an issue. If you had 20ga aluminum, yes. If it's obviously strong, no. If it flexes less than the stock roof metal, you'll be fine. I even had two small angle aluminum braces under my original sunroof patch panel, just to make it stiffer. keep a safe margin with regard to the rules, and you'll be fine. 

In reply to irish44j :

Fair enough. And thankfully the ARA rulebook doesn't say anything about the strength, besides that it must be made of metal. I don't anticipate running many (if any) NASA events, so I think it'll be fine. 

artur1808 said:

In reply to irish44j :

Fair enough. And thankfully the ARA rulebook doesn't say anything about the strength, besides that it must be made of metal. I don't anticipate running many (if any) NASA events, so I think it'll be fine. 

at least here in the East, NASA tech is MUCH more lax than ARA. Marcel Ciascai is the NASA tech for most eastern events and he's pretty laid back if he's cool with you (especially if he logbooked your car, like he did ours lol). Some of the ARA guys can be much more picky :)

We have a roof again!

60+ rivets between the panel and vent. Plus an entire tube of RTV. I’m hopeful that it won’t have any leaks

nice, looks good. 

Unfortunately not a ton to report. Finished installing the H&R OE Sport springs and decided to try out a mild (1.25*) Camber plate for the front as well. 

I have officially registered for our next rallycross (may 4th) and decided to sign up for an autocross just for the hell of it at the end of April. I'm hoping to get the cooling system upgraded by then and finally figure out my driveline noise. 

After replacing the rear wheel bearings, axles, and diff, I'm left with driveshaft and transmission as my potential sources of noise/vibration. The center support bearing on the driveshaft looks new, but I replaced it anyway. If any of the other e30 owners on here have experience chasing driveline noise/vibration, I'm open to suggestions of things to look into. It is definitely speed dependent, so I'm thinking the driveshaft may not be balanced. Perhaps whoever replaced the CSB last didn't mark the orientation of the two driveshaft halves relative to one-another when disassembling? 

artur1808 said:

Unfortunately not a ton to report. Finished installing the H&R OE Sport springs and decided to try out a mild (1.25*) Camber plate for the front as well. 

 

I have officially registered for our next rallycross (may 4th) and decided to sign up for an autocross just for the hell of it at the end of April. I'm hoping to get the cooling system upgraded by then and finally figure out my driveline noise. 

After replacing the rear wheel bearings, axles, and diff, I'm left with driveshaft and transmission as my potential sources of noise/vibration. The center support bearing on the driveshaft looks new, but I replaced it anyway. If any of the other e30 owners on here have experience chasing driveline noise/vibration, I'm open to suggestions of things to look into. It is definitely speed dependent, so I'm thinking the driveshaft may not be balanced. Perhaps whoever replaced the CSB last didn't mark the orientation of the two driveshaft halves relative to one-another when disassembling? 

I'll be curious to hear what you think about more front camber. I had (still have, sitting on a shelf) the fixed front plates that added about that same amount. After one event I took them off because they didn't allow the wheel's outside edge to bite hard in soft surfaces, which resulted in understeer. I keep them around for track/autocross possibilities, but defintely didn't like them on soft surfaces. YMMV.

btw, easy enough to check the driveshaft. The P/O's marks are irrelevant - BMW put marks on each half (a white dot) that are the balance points. Align those dots and you should be in balance. Have you checked the U-joints?

In reply to irish44j :

Interesting about the camber plates. Did you run them at rallycross or stage rally? I'm wondering if decreasing tire pressure a little might help with that? I want to do some testing with different tire pressures on gravel tires.

I didn't notice any white dots but I'll have to get back under the car and check. U-joints seemed alright, no slop or significant resistance when I try to rotate them.