If you could go back and mod your suspension differently...

[b1aze]

Where would you start and what WOULDNT you do?

I had an epiphany the other day that modding my 135i for power, while fun, its counter productive if i want to be at all competitive in AutoX with BMWCCA. If i can hardly control the car's rear end on stock tune with 265 Star Specs in the rear, another 50hp or more is useless.

So i want to go with suspension modding for now.

The car is a daily driver that sees almost 100miles of highway driving a day I dont dislike the comfort now, i wouldnt want it significantly harsher but wouldnt mind a bit firmer in the corners. I would like adjustable dampers to at least be able to toy with them on track/autox days but its not necessary by any means. I will be looking for a means to dial in a bit more front camber.

If you could go back and change what you have done to your suspension knowing what you know now about it, what would your mod-list and order of mods be? Be specific and have reasons why if you can.

My current most sensible plan now would be:
E9x M3 FSB+bushings
M3 subframe bushings
Spring/Strut combo (adjustable dampening options??)
Camber plates (static or dynamic. Not sure which i would rather yet)

Would M3 control arms be worthwhile if i can get the camber i need out of my plates?

I already have ER full brakeline kit ready to go to help a little with left-foot braking pedal feel. Once i chew through these oem pads, ill upgrade to something a little more suitable if i actually find the stock ones to fade too much, but i have read the brake piston cracking thread and it didnt make me warm and fuzzy about going with a non-oem pad.

I am relatively green to suspension but it seems relatively straightforward.

Thanks in advance for any insight into brands/models/thought processes to modding for a good DD but competitive AutoX setup.

Derek

[Focusedintntions]

I think i would follow the same route I took more or less.

-Wheels and tires
-kw v2's with vorschlag camber plates
-m3 lca's

The only thing I did different in real life is I added the m3 fsb 1st. I don't think i should have done this b/c while it did get rid of some of the front end body roll, it also added greatly to the understeer issue the car has. Once the rest of the suspension is there it can all be adjusted to help dial it out. But if you're doing one thing at a time, it'd be the last thing I'd do again.

[pixelblue]

I echo what Focus said plus I add the sub frame bushings and go with Dinan's static camber plates instead of the Vorshlag adjustables. depending on how ocd you are about noise the Vorshlag's tend to be a bit noisy. something I had to live with and could really do without and the small difference in max camber advantage through the Vorshlag's is not that significance to exclude Dinan's as a viable option (2.7 vs 3.0). btw I am not endorsing KW's perse. that all depends on your budget

[ilikebmxbikes]

I would have done M3 rear subframe bushings in my first batch of suspension mods. I waited too long to do the rear subframe bushings.

[MLSavage]

Great timing Derek, I was thinking of creating a similar thread as I am starting from stock and I'm fortunate enough that I get to learn from everyone else's mistakes

[Tk423]

Originally Posted by MLSavage

Great timing Derek, I was thinking of creating a similar thread as I am starting from stock and I'm fortunate enough that I get to learn from everyone else's mistakes

Same here....looking forward to learning some more from other's experiences!

[Eyeman]

Pick your wheels then find a good shop!

My mods are listed below pretty much in the order I added them. I'm pretty happy with my suspension but I do plan to add the M3 subframe bushings next time I need some work. I also plan some slight brake mods as the stock parts wear out. I don't plan to track or Auto-x my car, partly because as you mentioned, these cars are traction challenged.

The main thing suspension wise that has been annoying for me has really been more related to getting heights, alignments, installations, etc right. I went with a less specialized installer initially and had a rattle that I thought was my strut bar. By the time I figured out it was improper strut installation I had some damage and had to replace one of the struts.

I've really struggled getting my front alignment correct. My steering has never pulled but I've chewed up a few sets of front tires. Also after switching tire brands a few times I now wish my front suspension was a little higher and the rear a little lower. But then again they made that worse when I had a corner balance.

Try to pick out what wheels and tires you plan to stick with first. Then try to find a shop that regularly works with track cars, etc, can do corner balancing and alignment themselves if possible, and make sure they know what you want.

The M3 front control arms and bushings are worth it to me and I don't track my car, for sure I'd get them if I autocrossed. By FSB I assume you are talking about a front strut tower bar, I can't really say that my bar helped. You didn't mention anti-roll bars, for sure I'd add them if I autocrossed.

[b1aze]

FSB is Front Sway Bar.

Thanks for the thoughts guys. I have the local alignment shop that most people in the CCA go to for autox alignments. I might have to go pick his brain. See if he has any suggestions.

[BMW86]

I'd ditch those tyres and get MPSS or RE-11. Tyres make a huge difference.

[b1aze]

Mpss is my tire choice this year. 235/265 on CS7s.

[fboutlaw]

Originally Posted by b1aze

Where would you start and what WOULDNT you do?

1. Check the rating system with your local BMWCCA chapter. Pick a class and don't modify past that.
2. Check if any mods are not regulated by the points system
- M3 wishbones
- M3 control arms
- M3 subframe mounts
- M3 Rear upper links
- Modified CDV
- Brakes (BBK or some HPS pads)
My chapter doesn't regulate those things and you can get some big gains quickly.
3. Remove the power mods. You don't need them for AutoX and they likely add points.
4. 4pt racing harness (makes a HUGE difference)
5. Camera system that you can play back between runs (you'll see the track 10x for each run), I use a contourHD in car and swap the memory stick into an iPad with the iPod camera connection kit. Import the video. Pop the memory stick back in the camera.
6. Get an aggressive alignment by a professional.
7. Tire / Wheel combo. (likely adds points)
- Apex Arc-8's
- DSS2, RE-11's, AD08's, 888's, get something super grippy in the summer tire category
- Go 245F, 275R
8. If you're still not where you want to be and can spare points to be in a low category. List is in order of priority
- a. Front Sway Bar (E92)
- b. Adjustable camber plates (Vorshlag)
- c. Stiff springs (~500lb/in front, ~700lb/in rear)
- d. Adjustable shocks or coil-overs
- e. LSD (Quaife or clutch type)
- e+. Dinan rear sway bar (M3 is too stiff)

That's about it on my list. Stick with "free" mods as much as possible. Running in a lower category in 2010, I consistently placed top 3 with some wins, and now running in the top class with my chapter I consistently place 4+. I went the extreme route and added things with high point values rather than "value" mods which increase handling + feel, which is what I wish I had done.

[b1aze]

Thanks FBoutlaw.

I did do some of that work and unfortunately, the 135i 6mt comes in at ~12pts below a maxed out Class C car in my chapter. It is quite easy to pick up 12pts with a wheel width and tire width increase and some camber alone, nevermind adding coilovers (8points) and sway bar (2 pts).

At this point, i think this will be my current list of things to do:
Alufelgen CS7s staggered in 1series offsets
235/40/18 and 265/35/18 Michelin Pilot Super Sports
ER Full brakeline kit and Motul fluid
MAYBE pads if i can justify it after feeling out my LFB skills on course. I find the stock pad to bite FAR to quickly when i LFB just for kicks.

I will use this setup on stock Sport suspension with a proper alignment for the first AutoX school 4/14 and probably the first event 4/28 and go from there. If i find things that just feel "wrong" to me, i will see what i can do and what it costs to remedy it. Some of it may still be getting comfortable with the car itself and some may be curable if i throw money at it.

I also have to contact my local autox registrar and see what some of the grey areas in the Inspection and Modification form. It has some pretty general check boxes that arent overly descriptive, but hold some pretty hefty point additions.

If i keep my wheel/tire sizes the same as i currently have planned, I could theoretically squeeze in the following under the cap:
Wheels/Tires
Spring/Strut combo
1* added camber (not sure if the added camber from a drop is counted or if just a camber plate that adds X* of camber is counted).
MAYBE a FSB, but thats putting me within .5 points of Class B

[Eyeman]

That's cool, your hobby will help regulate your mods. Sounds like you have it planned out well.

I plan to go to Michelin PSS with my next tire upgrade. I'm worried that I'll not be able to fit 225/35/19fr or 255/30/19r. I think I might need to slightly raise my front suspension and maybe add a little rear camber since PSS's run much wider than the Nittos and Toyos that I'm currently using. I'd bet the same would happen to you if you run the sizes you mention and then decide to lower your car.

[b1aze]

Luckily with lowering the car you pick up a bit of camber naturally. Worst case is I have to roll the fender a tad, nothing that has never been done before.

[pixelblue]

Originally Posted by b1aze

Luckily with lowering the car you pick up a bit of camber naturally. Worst case is I have to roll the fender a tad, nothing that has never been done before.

no camber change on macpherson strut equipped cars when lowered

[b1aze]

Originally Posted by pixelblue

no camber change on macpherson strut equipped cars when lowered

Ah shit thats right. At least in the rear. Fronts pick up a little, no?

[1Pirate]

I'm actually very satisfied with my suspension mods and the order in which I did them. I guess I did enough research before beginning the process that I had a good game plan.

Here is a link to my suspension mod thread with the details of my set up.

http://www.1addicts.com/forums/showthread.php?t=636984

[pkimM3r]

Originally Posted by Eyeman

Pick your wheels then find a good shop!

My mods are listed below pretty much in the order I added them. I'm pretty happy with my suspension but I do plan to add the M3 subframe bushings next time I need some work. I also plan some slight brake mods as the stock parts wear out. I don't plan to track or Auto-x my car, partly because as you mentioned, these cars are traction challenged.

The main thing suspension wise that has been annoying for me has really been more related to getting heights, alignments, installations, etc right. I went with a less specialized installer initially and had a rattle that I thought was my strut bar. By the time I figured out it was improper strut installation I had some damage and had to replace one of the struts.

I've really struggled getting my front alignment correct. My steering has never pulled but I've chewed up a few sets of front tires. Also after switching tire brands a few times I now wish my front suspension was a little higher and the rear a little lower. But then again they made that worse when I had a corner balance.

Try to pick out what wheels and tires you plan to stick with first. Then try to find a shop that regularly works with track cars, etc, can do corner balancing and alignment themselves if possible, and make sure they know what you want.

The M3 front control arms and bushings are worth it to me and I don't track my car, for sure I'd get them if I autocrossed. By FSB I assume you are talking about a front strut tower bar, I can't really say that my bar helped. You didn't mention anti-roll bars, for sure I'd add them if I autocrossed.

Op is asking advice for performance mods. Not for looks lol.

[pkimM3r]

Originally Posted by BMW86

I'd ditch those tyres and get MPSS or RE-11. Tyres make a huge difference.

Starspecs?! Pss are great for dual purpose but get greasy.