e90 330i DD & DST Autocross Setup

[dpspeed]

So, I bought a 2006 BMW 330i with a 6 speed that wasn't running, had a buddy drop a used 80k mile 3.0 N52 in it and it roared back to life! Previous owner's son had the mickey mouse flange break off and kept driving until it locked up. While in there, we did all the normal maintenance stuff that is easy while the engine is out of the car.

My daughter takes drivers ed next month and gets her permit in March. The plan is for this to be her first car! 6 SPEED!

Anyway, here' how the car sits currently!

Current mods
- Eibach pro springs
- newish sachs shocks (not bad actually)
- LSD
- new motor & transmission mounts
- 300 tw tires (Conti Extremes) 245/40R18 (still have lots of life)
- Konig Ampliform 18x8.5 wheels (need to check offset) (these will be autocross wheels)
- wheel spacers front and rear (not sure what mm)
- Found some cheap 325 16" wheels for her to drive around on...

Before I get into my questions, I want to state that I'm not interested in turning this into a nationally competitive DST autocross machine. It needs to be a comfy daily driver for my daughter that isn't going to bite her as a new driver. My plan is to stay with the Eibach springs and maybe do something like a Koni Yellow shocks. There are a few 86s that run in DST locally (North Carolina) with me and I'd love to be competitive with them. They aren't nationally competitive cars/drivers (at least not with Triad Sports Car Club).

The car has a TON of grip and generally likes to turn, but obviously without negative camber and a performance alignment, there so much left on the table.

Here's sort of my vision for the car.

- Vorshlag camber plates (next mod) & alignment (to mark the plates for dd/autocross)
- 200 treadwear tires
- ECS tuning valved muffler kit (I can't hear the car when on course)
- intake
- tune (maybe)
- koni yellows
- adjustable rear swaybar
- maybe front swaybar, but got to get ride of understeer first
- M3 front control arms

Camber Plates & Adjustable rear swaybar
Current feel of the car. I was pretty surprised at how well the car handled with springs & decent rubber (not autocross 200 tw rubber). The car does really well at the limit and is pretty solid in slaloms and the rear sticks really well. It suffers from understeer - not Mustang level understeer, but you can really feel it limiting the speed because it just starts to push. 3* of negative camber will help a ton! I'm also thinking about an adjustable rear sway bar.

Once I tackle these 2 mods, I will probably look at tires next since I've got the Konigs and they probably won't live on the car until my daughter proves that she doesn't hit curbs. haha

This is where my biggest question lies.

Can I run 255/40R18's with STOCK style springs without much fuss? I already have some spacers and I need to pull a wheel off to see what offset they are, but is there a recipe for 255/40R18s on a 18x8.5 wheel? If so, that's probably my plan, if not, I will probably just stay with 245s to keep things simple.

I haven't autocrossed in about 5 years and I think if I get back in practice, I can get within about 1-2 seconds of the fastest car/driver as is, so I am probably looking for around 1 second of mods if that makes sense. I lost by about .600 Sunday to a BRZ. A nationally competitive BRZ is probably 3-4 seconds ahead of me. For reference, I was about 6 seconds off FTD last weekend and about 3.8 seconds last month.

I am looking for some guidance on mild mods that will get me into a respectable position to battle for DST wins in NC an maybe even do one of the national events in Charlotte or Bristol - and be respectable.

Also do you have any suggestion on what kind of alignment I should run for daily driving and autocross?

Thanks!

[Fair!]

David,

Well that is a good list of wants and desires, and we can help reach those goals, if you follow our advice.



One thing we won't do is ever encourage anyone to use twin tube Konis and lowering springs. There are many problems with that formula, but mostly the fact that all OEM style lowering springs are just too soft to deal with the loads that modern tires can put through a suspension, and then you end up with a floppy fish like this:



For autocross this leads to massive roll, dive, squat and heave. It is easy to blaming the image above on "being a Mustang" but my buddy Sean's E46 ZHP was no different, as shown below.



Even the "adjustable" Konis could not control that sloppy handling. Konis are just... junk. I don't understand why anyone buys them for any sort of competition. It boggles my mind! That kind of body roll turns my stomach, and it wrecks suspension geometry and ruins tires - even with lots of static negative camber added.



The E90 335i above was prepped to what would be Street Touring rules nowadays, and I drove that at an autocross after we installed AST coilovers in this car in 2008. With only an 8.5" wide wheel I won the class and missed setting FTD by .04 seconds, in a sedan with a child seat in the back he drove to the event. Beat real "race cars" that were probably on Konis, ha!

That's the difference "real" spring rates and "real" coilovers make. Winning, or not.



We have a number of coilover kits available for the E90 chassis, and I get that putting MCS dampers on a daily for your daughter makes no sense. But you do autocross the car, keep track of your times, and for the same amount of labor you could install an Ohlins R&T kit or even the more affordable H&R monotube kit.



The H&R kit comes with these tapered springs that work with the OEM top mounts, but of course you can get them with our camber plates and we pre-assemble the kit as shown above. These have more spring rate than any lowering spring could ever hope to PLUS they give you 4 corner ride height adjustment.



The best part about these H&R kits is that we can change the springs to make it even spicier, for not much more $. If you do this up front we call it the "Track Pro" version, and the camber plates are even less expensive, since the front goes to a proper coilover spring diameter and that lowers the camber plate cost over the OEM perch versions of our plates.



Anyway, going the H&R route over an old school, sloppy, twin tube like the Koni is a huge improvement that is hard to overstate. We really like these, and unlike the old Bilstein PSS series, we can actually get these. This E90 set is in stock at our warehouse supplier and we can have them here, assembled with our E90 camber plates, within "ones of days". It will transform the car and exceed the performance of that Koni + lowering spring setup hugely.



Wheels and tires are almost as important as the dampers and spring rates, to be honest. Running a 8.5" wheel is easy, but that's not really enough to support a 255mm tire. We tested a number of wheels back in 2007-08 when these cars were coming out and the 9" wide wheel fits under stock fenders with some camber. The rear of the E90 can fit an 18x10" and 305mm tire, but I hate running that much wheel stagger.



Wheel options in 17x9 or 18x9" are available from Apex Wheels. I'd be weary of the 18x9.5" fitments up front, but maybe they have found a way? I don't know the wheel width maximum in your class, but get the widest they allow and that will fit under stock fenders. I know a 9" and 255mm fits, but only just. If you are worried about your daughter curbing these, just swap them on before an autocross and keep the 200TW tires from cycling out with needless heat cycles.



Once you have proper dampers, spring rates, alignment, and wheels.... tires are EVERYTHING. The 200Tw league is huge and you can go from "fun casual autocross guy" with something long wearing like a Falken RT-660 to the "I want to win local events" with a serious 200TW compound like the Yokehama A052 or Bridgestone RE-71RZ.



If you care about lap times or autocross placing, keeping the fastest and freshest set of tires on your car becomes the MAIN priority. The difference between an RT-660 to an A052 is roughly 2 seconds on a 60 sec autocross course and even more on a 1.5 mile road course. I have data to back up that claim. And this advice is the most ignored by people chasing trophies... they will buy a million useless doo-dads before JUST KEEPING FRESH AND FAST TIRES ON THEIR CAR. Not daily driving on your 200TW tires is so important, too.

Let's look at your list:

1 Vorshlag camber plates (next mod) & alignment (to mark the plates for dd/autocross)
2 200 treadwear tires
3 ECS tuning valved muffler kit (I can't hear the car when on course)
4 intake
5 tune (maybe)
6 koni yellows
7 adjustable rear swaybar
8 maybe front swaybar, but got to get ride of understeer first
9 M3 front control arms

Of the list above I think items 1, 2, and 8 are worthwhile. The rest is just window dressing, which won't really fix anything. Well a bigger front swaybar will probably reduce roll enough to affect understeer, but not nearly as much as proper spring rates and "real" monotube dampers.



We used to sell a lot of these E92 M3 rear control arm conversion kits to non-M E9X/E8X customers. This solves a lot of problems with the rear shocks, as it has provisions for a lower shock "eye" vs the weird "double pin" dampers made for the non-M cars. It also gives you a lot more rear camber adjustment, which helps.

Exhaust won't help. The CAI and tune won't help. Fixing that push is down to shocks / springs / alignment. Maybe the front bar, maybe. As for alignments...



This is a similar McStrut car with an alignment I like to recommend to track and autocross folks. Camber of -3.0 to -3.5 deg up front and about .75 deg less in the rear. No front toe, and a hair of rear toe in (.29 deg total). That's good. Leave the caster where we set the plates and you are golden.



Anyway, I hope that helps. Most casual autocrossers won't listen to any of this advice, because they tend to not spend money on good parts. Instead they usually go with the "tried and terrible" Konis and crappy tires. And they will lose to a decent driver with real springs / dampers / tires, every time.



If people want to get serious, they should call us. We've built championship winning Street Touring cars many times. We can keep them livable on the street, too.

Cheers!

Fair @ Vorshlag