help me plan upgrades for autox

[tuj]

Hi fellow 1er's!

Please help me plan some upgrades for my 2013 135i for autox mainly but also occasional track days. I am not sure what class I want to run in yet, but I am thinking one of the street-tire classes.

Here's what I am thinking:

1. Wheels and tires. Not sure what is the optimal setup. I have seen some people running square setups and others staggered. Also, what about wheel size, is the slight gear reduction and cheaper cost of 17" worth it over 18"? What street tires are people running for max performance?

2. Front sway. Going to get the M3 'vert sway.

3. M3 front control arms.

4. M3 rear subframe bushings.

5. Dinan Torsen LSD.

6. Dinan Stage 2 tune, including Dinan upgraded IC and oil cooler.

7. Coil-overs, not sure which ones.

8. Autox alignment once all parts are installed.

Anything else you would add? Anything you would not do? Am I missing anything in the street class rules for 2014 that would preclude any of these modifications?

Just for perspective, I'm coming from campaigning an RX-8 in B-stock and a Miata in E-stock. So I'm used to driving on true R-compounds. I've done two Evo schools and placed 2nd in my class in regional competition a few years ago when I was actively competing.

Would really appreciate everyone's feedback/thoughts/suggestions!

[Ginger_Extract]

I was going to say "The Driver", but I feel like you've got a solid start on that part. If you want to be competitive, pick a class, and mod to meet it's requirements/allowances. I think the 135i could do well in STU locally. It will still get its nuts stomped on by the Evos, but at least it would put up a fight before ending in the fetal position.
It looks like you have a '12 MX-5 to play with as well, ever consider STR?

[tuj]

Would the '12 MX-5 in STR be more competitive than a 135i in STU? Kind of sounds like it... Those SCCA buggers always were trying to give us poor Miata guys a place to play... I don't know...I've never seriously autox a car with some actual torque like the 135, so I was thinking it might be a fun exercise. 400hp/400tq at ~2000rpms....hmmm, just sucks we have to go up against the 4wd baddies. I have driven an Evo9 on course and I was amazed at how easy it was to drive fast.

On the downside, the MX-5 is a power retractable hard-top version, so that ends up adding something like 40lbs over the cloth top version.

Its been a while for me re: the regulations and I've heard talk of dramatic changes to the Stock classes (ie. no more r-compounds, is that true?). Anyway, I've bought enough V710's....great tire, but has a narrow operating window for tread temps.

[Clovef]

I am not sure as it could have changed in the last few years but I don't think you would be eligible for STU with the Dinan tune. If I remember right you can adjust timing and fuel but not boost. With the tune you would be in SM. Either way you will probably want camber plates. The M3 front control arms will get you a little and removing an alignment pin with get you a bit more but not enough that you won't eat up the edges of tires AutoX. If you plan on changing out your wheels and tires when you go you may want to consider getting wheel stud conversions added.

[tuj]

SM is where the corvettes play, no?

[Bimmer-Bob]

Originally Posted by Clovef

I am not sure as it could have changed in the last few years but I don't think you would be eligible for STU with the Dinan tune. If I remember right you can adjust timing and fuel but not boost. With the tune you would be in SM. Either way you will probably want camber plates. The M3 front control arms will get you a little and removing an alignment pin with get you a bit more but not enough that you won't eat up the edges of tires AutoX. If you plan on changing out your wheels and tires when you go you may want to consider getting wheel stud conversions added.

FYI, I seem to recall that a tune is allowable, provided the boost is under a certain amount. OP may want to double-check the rules just to be sure.

[Kgolf31]

Originally Posted by tuj

Hi fellow 1er's!

Please help me plan some upgrades for my 2013 135i for autox mainly but also occasional track days. I am not sure what class I want to run in yet, but I am thinking one of the street-tire classes.

Here's what I am thinking:

1. Wheels and tires. Not sure what is the optimal setup. I have seen some people running square setups and others staggered. Also, what about wheel size, is the slight gear reduction and cheaper cost of 17" worth it over 18"? What street tires are people running for max performance?

2. Front sway. Going to get the M3 'vert sway.

3. M3 front control arms.

4. M3 rear subframe bushings.

5. Dinan Torsen LSD.

6. Dinan Stage 2 tune, including Dinan upgraded IC and oil cooler.

7. Coil-overs, not sure which ones.

8. Autox alignment once all parts are installed.

Anything else you would add? Anything you would not do? Am I missing anything in the street class rules for 2014 that would preclude any of these modifications?

Just for perspective, I'm coming from campaigning an RX-8 in B-stock and a Miata in E-stock. So I'm used to driving on true R-compounds. I've done two Evo schools and placed 2nd in my class in regional competition a few years ago when I was actively competing.

Would really appreciate everyone's feedback/thoughts/suggestions!

Hate to break it to you, but the 135 isn't that competitive how it is classed.

Here is what you can run:

Stock/Street Class - Allowed modifications:
Sway Bar (Either Front or Rear)
Brake Pads
Exhaust from cat-back
Wheels that are same offset +-5mm and a diameter that is +-1" from OEM spec.
Shocks, but must maintain OEM springs

The rules for STU are a bit more complex, so you should consult with the SCCA rules (just google 2014 SCCA SOLO II rules)

If you can squeeze 17"s, run them. They offer lower weight, which is lower moment of inertia which equals quicker acceleration. For street tires, Hankook RS3s, Dunlop ZIIs or BFG Rivals are the go to tires for autocross.

Currently, the mod list you have (if you were to run STU) there are a couple illegal modifications.

#3 - Control arms must be OEM
#6 - See below for more information

Originally Posted by Bimmer-Bob

FYI, I seem to recall that a tune is allowable, provided the boost is under a certain amount. OP may want to double-check the rules just to be sure.

Kinda yes/no...however the way you wrote it is wrong.

You can do modifications to the car (aka downpipe, exhaust...etc) and because of those modifications, there will be an increase in boost.

You can tune the car to effectively utilize this boost, however a tune that increases a boost is illegal.

Make sense?

PS - As of now, 2014 there is still a racing compound stock class for each class. In 2015 it will all change to street, and only Super Stock will have a R Compound stock class