E36M3 STR build

[fizzx]

The image links above should be fixed now.

Are there other forums where more of the top dawg autocrossers are active?

[justint5387]

We and most people run 245s on 17x9 with STX BRZ. But the BRZs are a lot lighter than a E36 M3, i would run a 255 on a M3.

[fizzx]

We and most people run 245s on 17x9 with STX BRZ. But the BRZs are a lot lighter than a E36 M3, i would run a 255 on a M3.

Thanks for the input.

[GG Emerican]

Very cool to see Type-Fs on a Euro car. Are they 5x120 or do you run adapters? Let me know if you ever decide to sell them!

[fizzx]

Very cool to see Type-Fs on a Euro car. Are they 5x120 or do you run adapters? Let me know if you ever decide to sell them!

I run 18mm spacers up front to clear the struts.

[matthugie]

I have been running 255's on 17x9 Apex Arc-8's. The rear fenders required a pretty good roll and the fronts took a 15mm spacer but that's all pretty normal for fitting wider stuff on these cars. I haven't tried 245's, but other than availability I don't see a reason to run them. It's not like 255's are pinched on a 9, and the RE-71 sidewall is so stiff that s2k guys in BS have successfully been running 255's on a 7.5.

[fizzx]

First "edit" to my new STR mule lol.
IMG_9374.jpg

Sending my old AST4100's off to be rebuilt next week.

[SLA]

Good luck this year! I'm in the same boat as you. I'm going from a STU Lite build to a very solid STR build.

I didn't see it on your list, but changing the steering wheel will be helpful if you're big like me and have issues getting comfortable in the car. It was a huge help for me getting the wheel another ~2 inches closer.

[fizzx]

Good luck this year! I'm in the same boat as you. I'm going from a STU Lite build to a very solid STR build.

I didn't see it on your list, but changing the steering wheel will be helpful if you're big like me and have issues getting comfortable in the car. It was a huge help for me getting the wheel another ~2 inches closer.

I've not had a need in 10+ years autoxing an E36 to need to change the wheel for seating position ... however, I do ponder if a smaller wheel would help me out on tighter courses where quicker steering would be helpful.

[matthugie]

The hard part about changing the steering wheel for STR is that you have to replicate the weight of the airbag, which on my scale was almost 5 lbs (8 lbs total for wheel and airbag). Finding a way to add that much weight back to the steering assembly isn't easy, and I haven't seen anyone come up with a real solution for it yet. That said, I very much prefer a smaller aftermarket wheel extended a bit. I have long legs so the extension lets me have a more comfortable leg position while still being close enough to the wheel.

[fizzx]

Any reasons to NOT do the typical fan delete mods w/o actually removing the fan? (colder spark plugs, lower temp tstat, etc)

[fizzx]

Any input on TRM vs EPIC tunes?

[Crustashio]

I like my epic tune. When my car still had the M50 manifold it dyno'd at 220whp. When I went back to the S52 manifold he retuned for free and it still pulls hard, but I haven't had it dyno'd again.

I just bought a stock 3.23 and ordered some 255/40/17 RE71s so it looks like I'll be giving STR a go this year.

[matthugie]

I had a TRM in my S52 E30 and I really liked it, but I doubt you could go wrong either way.

As an aside, for anyone running an aftermarket wheel David Whitener has come up with some steering wheel weights that match the standard Momo/NRG/etc. bolt pattern. Basically they work as a spacer but add weight in 0.5 to 1.0 lb increments depending on the diameter of the disc. He isn't really interested in producing/selling at this point, but if there's enough demand then he may. If anyone is interested in those let me know.

[fizzx]

I like my epic tune. When my car still had the M50 manifold it dyno'd at 220whp. When I went back to the S52 manifold he retuned for free and it still pulls hard, but I haven't had it dyno'd again.

I just bought a stock 3.23 and ordered some 255/40/17 RE71s so it looks like I'll be giving STR a go this year.

Did you just get the base tune or do the 1hr custom remote tune option initially?

[Crustashio]

Just a base tune, and that was still with stock headers/midsection and a catback.

[fizzx]

I've got a sharked dme from my other broken M3, but apparently there's some mojo required with the ews so it's not just a simple swap.

[Fair]

Pretty cool build thread started here. I was a bit worried when they moved the E36 M3 to STR but hey, its where it is so race it. I read the whole thread and noted a few things I could add... my response kind of got a bit long, sorry for that. I sectioned it out into 4 areas...

SHOCK QUESTIONS

If someone will rebuild the AST's then you're good, though $150 for a full set rebuild does seem a bit cheap. I agree, if you're not trying to win trophies at national events then MCS/JRZ/etc. is probably overkill.

Yea, most non-remote monotubes like an AST cost closer to $125-$150 per shock to rebuild. Same for MCS, JRZ, etc.



Adding remotes and hoses adds more time, thus more cost.

I thought the AST 4100's were the ones that needed constant rebuilds since they would blow seals quickly? That's something to take into account if you're planning to daily it and put mileage on it.

Well... that's not exactly what happens with an AST. A lot of AST's issues early on were reliability issues, but some of it was the customers were not used to the maintenance interval of a competition monotube. We had guys 8+ years later call and FREAK OUT because one shock had leaked - after 8 years of hard street and track use, in salted hell winters.



Not saying AST didn't have some reliability issues in some cases - they did - but the lower price point we helped them get to just put their shocks in the hands of people not accustomed to higher end shocks and their associated maintenance. The 3rd and 4th hand AST buyers can fall into this trap even worse - if the shocks are more than a few years old, they need to be rebuilt.



I haven't had much to do with this company's shocks since we stopped selling them in 2012, and we have had much better reliability with MCS monotubes over the past 6 years. I also don't like "blaming the customers", but in reality you should expect 2-3 seasons of use between rebuilds with any higher end monotube competition style damper, unless you have a crash or otherwise damage one. Always keep an eye out for hydraulic fluid, and if you see a leak get that damper rebuilt immediately. Driving around "for just a few days" without Nitrogen or low fluid levels will RUIN the internal parts. And no competition style monotube brand should be expected to go more than 5 years between rebuilds.



A performance twin tube shock doesn't last much longer either, for that matter. The difference is most people never KNOW when their twin tube dampers are blown (because they tend to leak internally, not externally). We inspect cars at our shop all the time and generally 1 or 2 shocks are blown on every car we check twin tube shocks on (two of the four Konis on the car above were blown when we inspected them - all too common).

https://youtu.be/xD2OYEWIzzM

We made the video above to show how to check for Nitrogen pressure in a monotube or twin tube shock. You have to pull the shock off the car, but otherwise its easy to check yourself. Nothing lasts forever, and the more complicated and expensive the shock, the more maintenance is usually needed.



Adding hoses and reservoirs and swivels adds failure points. Nature of the beast. Dampers matter A LOT though so if you cut costs in either buying lower end dampers or skimping on rebuild intervals you will pay the price in performance.

FENDER ROLLING

I would also second the wire wheel for the rear arches, I didn't have one at the beginning of the process and would not recommend a manual undertaking.

Agreed. Its a bitch of a job to get that goop out of the inner rear fender lips but you HAVE to do it to roll the rears for clearance with a 255mm tire (which you absolutely should use).

https://vorshlag.smugmug.com/Instruc...ender-rolling/

That gallery has some instructional pictures showing fender rolling (and more) on an E46, but the same technique applies to an E36.



The front E36/E46 fenders are easy to clearance. I have had better luck with a leather wrapped dolly and a plastic faced hammer... slowly massage the lip vertical and flat with the fender's inner face, working your way around.



The rear is the tough end to roll. Get the goop out then use heat on the paint and a roller + hammer/dolly to get the contours flatter.



There is no way to measure the fenders for "stock contours" so a rules challenge here is virtually unenforceable. Trust me - we had some people try at Nationals in STU and it went nowhere. We were running 18x10s in STU back in the day and we had to MOVE the fender contours a good bit to try to fit the class legal 285mm tire sizes...

HEADERS & EXHAUST



You had questions about shorty vs long tube headers. You definitely want to go long tube if you want to add any usable power. I talk about this in my most recent series of 3 posts on our E46 330 we run in NASA TTD, where I show dyno testing on stock, eBay headers and a custom long tube header we built (above).

TIRE SIZE - GO BIG

Currently pondering 245 vs 255 RE71's ...
Comment from a knowledgable facebook buddy:
"Tires: I'm not truly sure you'll gain much/anything with the 255 on a 9" wheel as the 245's are
only giving up .3" of tread width per tire,
but you gain a .4" shorter diameter tire,
and save 1lb of rotating mass per corner and get a sharper steering feedback.
Might be enough to outweigh the width, might not."
245's would certainly mean less fender rolling required. I ordered 245's last spring 'cause at the time the 255's were out of stock everywhere with no immediate relief in sight. Hmmmmm

I would respectfully disagree with your facebook buddy. We ran in STU with our E36 M3 for 2004-2006 on 245 and 255mm tires and definitely were faster on 255s. Wheelspin on the 245s would overheat the rear tires in a run much easier than the 255s - if you are making any real power. The 17x9.5" wheel and 255/40/17 setup above was our quickest STU setup - I got 2nd at Nats in 2006 and my wife got 1st in STU-L like that. On 17x9s with 255s I took 6th at Nats in 2005.



We kept getting faster the bigger we went on tire and wheel widths, but ran into a wall on the taller 18" tires and 10" wide wheels. STU allowed a max 285mm tire but we could never quite fit that on these E36 cars without blatantly moving the fenders a couple of inches. The 265/35/18 on the 18x10" setup shown above was rubbing like crazy, inside and out. We had to compromise ride height and alignments too much to make it worthwhile. If we could have CUT the fenders then yes the wider tires would have been faster (they always always are - you can never have too much tire!).



The 17x9" wheel and 255/40/17 tire is the limit of STR class, and one of the easiest to make work on an E36. Don't hobble the car with narrower wheels or tires than STR class allows.

Cheers,

[lowside67]

I would echo Terry's comments - in STX, the 128 is very tight on the front with a 255, but given that the car is so much heavier than the FRS/BRZ twins, it is essential to try to get the very largest tires on that you can get. The weight and gearing penalty is not relevant considering your car already makes a ton more torque than an S2k - it's weight-to-tire that you are most disadvantaged. Well, maybe not most, probably sweeping ability versus the superior S2k double-wishbone front suspension but I digress.

Weight is going to be your Achilles' heal in this car but fortunately there are some great areas to drop some. A light battery, a purpose-built 3" exhaust, precisely 25lb seat combos, etc are all individually small pieces but will add up to more than the sum of their parts.

It's going to be an uphill battle, but a fun car!

Best of luck,
Mark

[fizzx]

Thanks for the input Terry!
What brake pads are people using these days for autox? On my prior E36M3 I was running carbotech AX6's.

[Fair]

...it is essential to try to get the very largest tires on that you can get. The weight and gearing penalty is not relevant considering your car already makes a ton more torque than an S2k - it's weight-to-tire that you are most disadvantaged.

Mark hit the nail on the head, and the weight-to-tire width ratio is something we LOOK AT FIRST for any autocross car. It is THE most critical aspect of any autocross car, period.



We have been preaching the benefits of always RUNNING AS MUCH TIRE AS THE CLASS ALLOWS for autocross and road course cars for the last 15+ years. If I had a dollar for how many times I have heard "you'll NEVER get that wide tire up to temp!" I'd be a rich man.



I'll have to just live with the fact that we have proven those people wrong time and time and time again.



If running crazy wide tires works on a CSP car Miata with 150 hp, it damn sure is needed in a street tire classed car with more weight and power. I have not yet found a limit where running "too much tire width" becomes an issue.



And the MEMES don't lie...

Weight is going to be your Achilles' heal in this car but fortunately there are some great areas to drop some. A light battery, a purpose-built 3" exhaust, precisely 25lb seat combos, etc are all individually small pieces but will add up to more than the sum of their parts.

Yep, the other half of the weight-per-tire size equation always needs help, too. The lighter the car, the better it turns, stops and goes! Chase every pound, but hit the BIG stuff first like Mark pointed out:

• Battery
• Wheels
• Brakes
• Exhaust
• Seats
• Flywheel/clutch

Some of the weight loss targets are even amplified by being 1) unsprung mass and 2) rotational mass. Wheels and Brakes are all of those things!



We found 13.3 pounds rotational mass reduction in an aluminum flywheel + upgraded clutch in our E46 330, which is a "zero point mod" in NASA TTD. Now SCCA Street Touring legality is a different story...

Thanks for the input Terry!
What brake pads are people using these days for autox? On my prior E36M3 I was running carbotech AX6's.

Yep, its hard to go wrong with the Carbotech AX6 or G-LOC R6 pads for autocross use.



G-LOC pad compounds:
GS-1 = street only
R6 = autocross and light track use
R8 = light track use
R12 = heavier track use
R14 = endurance racing on light cars
R16 = aggressive track use
R18 = extreme track use

We have used more aggressive compounds on the G-LOC scale for autocross, but you have to make sure to arrive at the line with some heat in the pads when you bump up above the G-LOC R6 pad. The other thing is for street compound tires its easier to overpower the tire compound with a more aggressive brake compound. So it might make sense for a Hoosier clad autocross car to use an R8 or higher compound, but maybe not an ST category autocross car.



I ran an R16 on the Mustang above for autocross, mostly because it was what I used for Time Trial and I'm too lazy to swap. But with a 335/345 Hoosier A7 they worked GREAT - just had to drag the brakes to the starting line.

Cheers,

[fizzx]

Terry - with your rtab limiters, do you have to adjust for preload or can you just pop them in and go like poly?

255 RE71R's ordered. I was on the fence between those and the new rival 1.5's, but after hearing a number of autoxers this weekend not really raving about the 1.5's on heavier cars, decided on the 71's ... which I also ran last year. Of course now they're backordered.
My AST's were sent to Inertia Lab in Dallas last week so awaiting word back and crossing fingers that they'll be able to rebuild them.
The "new" STR M3/4/5 is currently at a local indy getting both rear wheel bearings replaced since one was completely trashed figured might as well just do both. Next up will be figuring out which bushings need immediate replacement and which can be done later in the season. Assuming the RTABs will for sure be 1st up.

IMG_0075 (1).jpg

[Kaizen81]

I've been using the PFC Z Rated and liked them a lot for autocross. Great bite and consistent. I used to have PBR Ultimates which had great initial bite and modulation, but would become inconsistent on 3+ runs.

For your reference, here my setup. I do relatively OK locally.

17x9 with 255/40R17 RE71R
JRZ RS1 (wish I had the cash for RS PROs or MCS Doubles)
Vorshlag Camber Plates
700F / 900R Springs (650F or even 600F might be even better)
Turner Front Bar / No Rear Bar
Poly RTAB FCAB
Vorshlag TM Mounts
Diffsonline Diff (Very important)
Borla Cat back
AFE Intake (just sounds so nice)
Lots of front camber (3.7++)
BimmerWorld Rear Lower Arm

Things I want:
- To drive better
- Double adjustable dampers (RS1 1way have limited adjustment)
- Sub Frame Bushings (noticeable and inconsistent movement in the back, I want to get on the throttle sooner and more confidently)
- Small Rear Bar (want some roll adjustability, if someone makes a bar with smaller than stock, I'm interested)
- Power/Headers/Tune (I don't see much benefit, low on my list and it's a Smog Check Year)

[SLA]

Thanks for the input Terry!
What brake pads are people using these days for autox? On my prior E36M3 I was running carbotech AX6's.

I'm running Hawk HP+s. they're a great AX pad if you can put up with the noise and dust. After 6 runs, my front wheels are completely covered in dust.

Terry, do any long tubes currently produced retain the air injection? I was lucky enough to score a BNIB & local set of Turner Shorties a few weeks ago. The install has been...fun.

[matthugie]

I've been using the PFC Z Rated and liked them a lot for autocross. Great bite and consistent. I used to have PBR Ultimates which had great initial bite and modulation, but would become inconsistent on 3+ runs.

For your reference, here my setup. I do relatively OK locally.

17x9 with 255/40R17 RE71R
JRZ RS1 (wish I had the cash for RS PROs or MCS Doubles)
Vorshlag Camber Plates
700F / 900R Springs (650F or even 600F might be even better)
Turner Front Bar / No Rear Bar
Poly RTAB FCAB
Vorshlag TM Mounts
Diffsonline Diff (Very important)
Borla Cat back
AFE Intake (just sounds so nice)
Lots of front camber (3.7++)
BimmerWorld Rear Lower Arm

Things I want:
- To drive better
- Double adjustable dampers (RS1 1way have limited adjustment)
- Sub Frame Bushings (noticeable and inconsistent movement in the back, I want to get on the throttle sooner and more confidently)
- Small Rear Bar (want some roll adjustability, if someone makes a bar with smaller than stock, I'm interested)
- Power/Headers/Tune (I don't see much benefit, low on my list and it's a Smog Check Year)

Out of curiosity, what diff options did you choose? I just did the 3 clutch upgrade on my E30 and loved it, but am curious if you chose the ramps and what difference that makes.

As for wanting a rear bar, you may be able to achieve similar results to what you're looking for with a spring change.