E36 M3 RallyCross build!

Hey there GRM, I'm a long time lurker, but this is probably my first real thread. I've been loving E36 M3s since high school (10+ years ago), but it wasn't until my E28 rallycross car (build thread) got rear ended by a tractor trailer that I finally had a good opportunity to pick one up.

RIP E28, you were loved.

Except I wouldn't be building it for auto-x/track like I imagined, but rather for rallycross! It turns out that one of the guys in my class at Solo happened to be selling a silver 98 M3/4/5, and he was only asking $4,000! I wanted the sedan because it's much easier to get wheels into the back seat, and silver is pretty cool, so it really got my attention.

Here's the seller's description, "it's a pretty nice car, but it's got high miles (220k) and burns some oil.....it's got bilsteins, hawk brakes, brand new TR motorsports rims (tires are shot), UUC short shift kit, aluminum flywheel, newer clutch, aluminum radiator, new overflow tank, Dinan strut tower brace, projector Depo headlights with HID, M50 manifold, Conforti intake, cat back, AC Schnitzer pedals, new driveshaft & guibo, etc. it has a couple tiny bubbles on the rear fender lip and a spot on the roof that could use a respray."

A page of maintenance history for his two years of ownership showed things like coolant, trans and diff fluids, oil temp gauge, clutch delay valve and spring, rear ABS sensors, reman starter, new/used front door panels, thermostat, shifter linkage rebuilt, CCV done, replaced all dead bulbs in OBC, power steering hoses, all dead bulbs in instrument cluster, oil filter housing gasket, exhaust gaskets, O2 sensor, coolant level sensor and connector, CSB to go along with the new driveshaft, and much more.

I had test driven a water damaged E36 M3 and a super beat E36 328i, but both were disappointing. When I drove this M3, it felt more like my buddy's auto-x prepped M3, and I loved it! The motor pulled hard from 1500 to 6500, the shifter felt pretty good for a BMW, the exhaust had a nice note but wasn't too loud, and the steering was so tight that I had to have it. A thorough inspection with the car on his full size lift revealed minimal rust and minimal fluid leaks. A week later it was in front of my house, and I've been feverishly planning my build ever since. But before I get all serious, here are some pics!

The E36 M3 has many strengths, but it also has some weaknesses that will need to be addressed if this is going to make it through an entire rallycross season without a catastrophic failure. I will be heading right back to Mod Rear (MR) which is the top of the three RWD classes, and is unlimited in terms of modifications.

Here are some of the normal things I'm planning on doing to get the car ready for MR:

-Remove most of the interior, and put in old Recaros

-Sunroof delete to eliminate potential leaks and to remove weight from roof

-Beefy skid plate and bracing

-Mud flaps

And then there are the things I have to do because I got an M3 instead of a non-M E36:

-Downsize front brakes to be able to clear 15" wheels (328 brakes?)

-Find a way to raise the suspension to non-M height (custom coilovers?)

-Put on a non-M font bumper

-Replace stupid M-mirrors with normal ones that I can actually use

And then there are the things I have to do because it's a high-mileage E36 instead of the default E30:

-Reinforce the front subframe, front strut towers, swaybar tabs, rear shock towers, and rear trailing arms

-Loctite the oil pump nut

-Keep a close eye on the cooling system

-Add a quart of oil every 500 miles!

Oh, and WTF was BMW thinking by removing the tilt from the steering wheel with these cars? How was that acceptable in the 90s? I'm going to have to retrofit in one from an earlier E36 because the wheel is set up way too high.

I'm planning on replacing every bushing on the car, and right now I'm leaning towards doing pretty much everything with OEM or better rubber instead of poly or delrin. Certain purple poly bushings don't have a great reputation for durability, and after having delrin on my street car before, I'm pretty sure I don't want it anywhere near a car that's going to be pounding through rough gravel! I feel like that give in the rubber is going to save the sheet metal stress and also make the car a little more forgiving on the rough stuff. What do you guys think? I'm also thinking of setting my spring rate (for coilovers) at 250/350. I know there aren't many other rallycrossers here, but if anyone has any suggestions to make the car better, let me know!

This is a copy/paste job from my original post on Bimmerforums, and apparently GRM doesn't like [URL] coding around pictures (the IMG choice on Photobucket) like other forums do. And why do my paragraph breaks not work? What's the deal with that?

Nice buy! I'm on the verge of picking up an e36 M myself and already bought the non-M mirrors to put on a car I do not even own yet. Those M mirrors are so stupid! tiny and don't fit the lines of the car at all! Good luck on the build. A guy local to me used to rallycross an e36 M and let me co-drive at an event. It was lots of fun!

I'll only subscribe to this build if the milk crate gets built into the e36 too.. Oh wait.

Seriously, dibs on the stock seats. Talk more on new years day.

bluej wrote: I'll only subscribe to this build if the milk crate gets built into the e36 too.. Oh wait. Seriously, dibs on the stock seats. Talk more on new years day.

Consider the seats yours! I'm working on a way to make the milk crate an integral part of the structure of the car, don't you worry.

bluej wrote: I'll only subscribe to this build if the milk crate gets built into the e36 too.. Oh wait. Seriously, dibs on the stock seats. Talk more on new years day.

btw, my old harness is yours (Josh)....happy birthday.

I already told him it needs a milk crate.

Cool build. As soon as I saw the title I was thinking, "I wonder if he's going to keep the M3 bumper on there - that would get ripped off right-quick..." but I see you've got that covered.

And I can't help but chuckle at all of the plain-Jane E36's I've seen "converted" to look like an M3. And here you want to go and do the opposite. Put a 318i badge on it and really mess with them.

95maxrider wrote: This is a copy/paste job from my original post on Bimmerforums, and apparently GRM doesn't like [URL] coding around pictures (the IMG choice on Photobucket) like other forums do. And why do my paragraph breaks not work? What's the deal with that?

When you write your original post on bimmerforums use the [IMG] [/IMG] brackets with the direct link from photobucket (not the URL coding). Then copy it BEFORE you post it there. Paste it here....your photos and paragraph breaks should come out fine. That's the way I do it.

Ian F wrote: Cool build. As soon as I saw the title I was thinking, "I wonder if he's going to keep the M3 bumper on there - that would get ripped off right-quick..." but I see you've got that covered. And I can't help but chuckle at all of the plain-Jane E36's I've seen "converted" to look like an M3. And here you want to go and do the opposite. Put a 318i badge on it and really mess with them.

Yeah, I've been contemplating the 318i badge already, seems like a good idea!

Does anyone know if there's a way to get notified/emailed when a thread here gets bumped? I can't find anything in settings....

Click the heart icon at the bottom of the page. It'll add it to your favs

95maxrider wrote:

Ian F wrote: Cool build. As soon as I saw the title I was thinking, "I wonder if he's going to keep the M3 bumper on there - that would get ripped off right-quick..." but I see you've got that covered. And I can't help but chuckle at all of the plain-Jane E36's I've seen "converted" to look like an M3. And here you want to go and do the opposite. Put a 318i badge on it and really mess with them.

Yeah, I've been contemplating the 318i badge already, seems like a good idea! Does anyone know if there's a way to get notified/emailed when a thread here gets bumped? I can't find anything in settings....

Those of us with real 318s will disallow that course of action :)

Unless you give me the M3 badge, lol.

irish44j wrote: Those of us with real 318s will disallow that course of action :) Unless you give me the M3 badge, lol.

Done.

Well I am 100% excited.

Ok guys, I need some input. I'm planning on replacing every bushing in the car, and I have been thinking that OEM rubber (or better, where available) was going to be the way to go, instead of poly. I might be able to get a discount on Powerflex poly bushings, so I'm reconsidering my opinion. What do you guys think; is OEM rubber going to isolate the body shell/suspension mounting points from the roughness of rally-x and keep the car more planted, or will the reduced deflection that comes with poly bushings actually do a better job by keeping arms moving in their intended direction? Are there certain parts of the car (diff mounts vs. control arms, for example) where I would really want one type over the other? I'm pretty sure I'm going with upgraded rubber engine and trans mounts, because I just don't see any benefit in rally-x from having super stiff poly in those places.

you're planning to do a custom coilovers? ooh gotta see that

After doing some research, I came across this thread, and I believe I have now made up my mind in regards to at least the subframe and diff bushings. The theory seems to be that you want the subframe to be as stiff as possible so the suspension has a solid point to attach to that won't move around. My E28 had its subframe welded to the chassis, and new M cars also have a solid mount/connection, so it doesn't seem like aluminum subframe mounts are too crazy for even a street driven car. I have yet to read a review where someone said there is a substantial NVH increase from aluminum subframe bushings. Where the NVH really comes into play are the diff bushings. Another thing to consider is having to replace bushings/tighten the subframe up again after installing bushings. It now seems as if OEM bushings just allow too much movement, and over time will wear down and possibly allow the metal to rip. The PF bushings need all sorts of extra R&D to work properly, given the extra washers and bolts necessary to install them properly. The AKG poly bushings appear to have deformation problems, where people were finding they needed to re-torque the subframe bolts multiple times after installing the AKG bushings, which isn't confidence inspiring. That leaves aluminum. As for the diff, I'm thinking AKG 75D poly. Motor mounts will be Bimmerworld rubber, and trans mounts will be Rogue Engineering rubber. RTAB will also be rubber for sure, but I'm unsure about the front LCAs. Thoughts or comments?

UHMW. They are solid, but actually do give you a small level of NVH isolation. I use them in the subframe and diff mount. I've never been a fan of aluminum directly in a press-fit application with a steel collar, personally. Aluminum in direct contact with bare steel can result in galvanic corrosion (unless you use an anode/electrode, which you really can't in this aplication) UHMW doesn't deform or wear like poly does.

Also saves you some cash (and if you drop my name, maybe you'll save a bit more, IDK...)

http://www.condorspeedshop.com/collections/e36-suspension/products/e36-solid-rear-subframe-bushings-e36-e36-m3

http://www.condorspeedshop.com/collections/e36-suspension/products/e36-solid-differential-bushings-e36-e36-m3

CABs I currently have OEM M3 rubber, but if I ever replace them I'll use UHMV there as well.

Engine/trans mounts I'd stick with rubber or a softer poly.

EDIT: btw, my solid UHMW diff bushings resulted in little to no additional NVH.

Well there are a few updates, but nothing too important yet.

First up, I had to get the E28 to Patrick's house to begin the disassembly, as he will be taking the motor/trans/diff out of it for his E30 vert. Josh was kind enough to lend a hand and a trailer.

Patrick wanted the 17x8.5 Tire Rack wheels that came on the M3, so we took them off and put them on his E36 vert. Yes, he has two verts, and yes, they look very sinister on his black car (not shown).

In doing so, we found out why the M3 had a steering wheel shimmy on the highway. This is not what wheel spacers are supposed to look like! My 12mm spacers are on the right:

Seriously, WTF is this?? My faith in the previous owner has been officially shaken. I didn't think he would let something like this slide on one of his cars. With them taken off the car obviously drives much smoother.

While we were at it, we test fitted my rally wheels on Patrick's 328 front brakes. Success!!

Unfortunately, the rally wheels (Style 46, 15x6.5, +42) didn't clear the M3 rear brakes :( More investigation is needed....

In the mean time, we installed my old Style 4 wheels (16x8, +23), and they looked awesome!

Unfortunately, a short test drive revealed pretty bad rubbing in the rear on the fenders, so Patrick's Style 30 wheels had to go on the back, and needed a 5mm spacer to clear the calipers.

The new meets the old:

While taking the mud flaps off the E28 I found evidence that the PS rear tire made contact with the body during the accident:

Wild stuff, right?

Now for something even more boring: lubricating hinges. I can't get enough of this Permatex silicone spray lubricant I bought a while ago, so I decided to hit all the hinges and latches in the M3's doors.

Hooray, smooth doors!

Yeah, that's it for now. Stay tuned!

I'd love to talk about buying a few things if you end up not needing them.

I also am trying desperately to diagnose a problem that just came up after a previous alternator overcharged my system: cruise control and all the obc functions related to speed stopped working. I would love to just try a known working gauge cluster as apparently they might be the culprit. My gauges all read good but apparently the cluster sends speed info out and maybe this is my issue.

Anyway, please email me username at yahoo if you'd like to talk about selling or loaning!

And about the project - eager to see what else you find as you build it.

jfryjfry wrote: I'd love to talk about buying a few things if you end up not needing them. I also am trying desperately to diagnose a problem that just came up after a previous alternator overcharged my system: cruise control and all the obc functions related to speed stopped working. I would love to just try a known working gauge cluster as apparently they might be the culprit. My gauges all read good but apparently the cluster sends speed info out and maybe this is my issue. Anyway, please email me username at yahoo if you'd like to talk about selling or loaning! And about the project - eager to see what else you find as you build it.

Are you talking about buying parts off the E28? Some have already been sold, others are spoken for. What are you looking for? When the accident happened the gauge cluster went black, and I have no way of knowing if it works anymore, but you're welcome to it.

Sorry, not clear: the e36 is what I'd love some parts from. And knowing you'd need the gauges, f your cruise control works, I'd love to pay a test fee and shipping both was to borrow it if/when the car will be down for a bit while working on it.

Feel free to email: My username at yahoo

Thanks!

And I just noticed the buggered up wheel spacers.... Wowzers! What a mess

Finally, a real update!

I ordered the S2R Tuning fiberglass sunroof delete panel a while ago to shed the ~32 pounds of sunroof crap from my roof, but I didn't get around to opening the box until I had already removed the sunroof from the car. Low and behold, a beautiful carbon fiber delete panel greeted me instead of a fiberglass one! I called up Alex and he said it was a mistake but that I could keep it, so I happily accepted and got busy finishing the install.

While disassembling the interior, I found evidence on the top of the passenger side B pillar of some rather serious (I imagine) prior damage:

The paint on the roof above this area is cracking and peeling, and it looks like the roof was poorly resprayed at some point. I had initially thought the messed up roof was just the result of poor repairs resulting from hail damage, but this B pillar makes me suspect the car suffered far more serious damage. Oh well, nothing I can do about it now!

Before:

After:

You have to remove the weatherstripping from the sunroof or else the new panel won't fit:

So I used my handy plastic scraper thingy and it came off pretty easily:

The sides of the delete panel needed a bit of sanding/filing so they didn't rub against the inside of the car. It's possible Alex sent me a panel for a coupe instead of one for a sedan, but no matter.

The delete panel uses the stock holes for the sunroof on three sides, but you have to drill 4 new holes on the back section. Rather than trying to find the correct length of self tapping screws that wouldn't hit the outer skin, I just figured out that the stock bolts are M5x0.8, tapped four new holes, and reused the stock bolts. I did use three spacers on each of the rear bolts to again make sure they didn't hit the outer skin.

After a test fit the panel a few times and was comfortable with fitment, I opened up the super-serious 3M windshield adhesive.

Quite a few people have had good results just sealing up the panel with silicone/RTV, but I wanted something a little more durable.

I put a 1/4" bead around the bottom lip of the panel and shoved it up into place. I then put down more from the top to ensure a leak-free seal. I shouldn't have removed all my tape on the top, because the end result is pretty ugly, but at least I know it will never leak!

I opted to not reinstall my headliner as it was being held in place by staples, but this meant I didn't have a way to secure my dome light. After blowing out a fuse when the back of the exposed dome housing touched the roof metal, I got a little creative in how I attached the dome light back to the car. First up, I had to make sure no metal touched any other metal, so electrical tape to the rescue:

I considered an elaborate network of zip ties to secure it in place, but realized they would probably not survive the rigors of rally-x, so I broke out the double sided tape and some gray RTV.

Boom! Let there be light. Well, you know, when it's turned on.

Next up was replacing the rubber surround for the rear windshield. It's common for the corners to break off and let all sorts of crap get down in the groove, and since a new seal is only $25, I figured I might as well get it cleaned up and "sealed" before I start playing in the dirt. I have a sneaking suspicion that there is a water leak somewhere in the car, as there seems to be way too much condensation inside the car after it rains, so this was also a minor attempt to fix that, even though it really provides no seal from water (the windshield is sealed with that 3M crap).

The grooves/drains were pretty filthy, so I wanted to clean them up before installing the new one.

All cleaned up!

And installed!

It probably did nothing to help with the water, but at least it looks better!

Then I decided I should probably gut the trunk and see what I'm going to be dealing with. Naturally, it was pretty disgusting:

WTF is this, and why is it only on one side (the rust, not the weird markings)

And is it me, or does it look like the area where the hoses come into the car is damaged?

All clean!

New parts are starting to arrive too. First up was a Thayer Motorsports rebuilt 3.38 diff with the 3 clutch pack upgrade. It's got about 2,000 miles on it after the full rebuild (seals, bearings, clutch packs, etc) and I got it for a nice deal. When jacking the car up at Patrick's house a while ago we noticed that we could spin one of the rear wheels in the air while the other was on the ground, which sounds like dead clutch packs. This can't be installed soon enough!

And then I scored a new/used set of Yokohoma Advan rally tires for cheap!

Slowly but surely things are coming together. That better speed up soon though, because I've got less than 2 months to completely redo every suspension piece on the car before the first race. It's going to get crazy very soon!

look at you mr. fancy pants

carbon fiber on a rallycross car....HERESY!

well at least you did the sealant ugly so nobody thinks you're going for looks, lol.

Ok, I could use some input on which weight diff fluid to use on the car. 75W90 is recommended in the manual, but it seems as if many E36 owners prefer 75W140 because it supposedly provides better protection when the diff is real hot. Given how cold it can be in Frostburg for the first/last races of the season (20 isn't unheard of), I was thinking the lighter 75W90 might be the better option. Then I thought that I'm also going to auto-x the car in the DC summer with temps above 90, in which case the 75W140 might be the better option. Does anyone think it would be worth swapping to the heavier fluid when the summer starts and swap back when fall comes around, or will the regular 75W90 provide enough protection for summer auto-x in DC? What about a track day in DC summer, would that warrant the 75W140? I'm leaning towards the Redline GL5 for the diff and Redline D4 ATF for the manual trans. What are people's thoughts on all of this?

I don't have input on the diff fluid, but have you decided if you're going to WMWR?

by "hot" they mean "on the track for extended periods." Your diff isn't going to have heat problems on short autocross runs, regardless of the temps at autocross.

FWIW I use Royal Purple in the diff.

And yes, need to know what your and Josh's plans are for WMWR (or not).