Driving questions? Setup questions?

[J Tyler]

Originally Posted by pkcormier

Jeff, if you had $2,500 to spend to make a stock 135i more track worthy, would you get coilovers or a LSD?

Coilovers! All day every day.


The rest of you -- So sorry for not getting back promptly, I have been extremely busy lately!! I check this thread when I can but usually don't have time for a long reply. I finally have a day off this Sunday so hopefully I will have some time to write up thoughtful relpies then!

[pkcormier]

Thanks again.

[J Tyler]

Originally Posted by akak1997

I've installed the Hotchkis front bar, it does reduce body roll a lot and the car is more composed when cornering. However, one weird thing I notice is when I go thru speed bumps, the rear seems more bouncy than the front. I'm not sure if it behaves like this stock, maybe I'm just didn't pay attention before. When I go over speed bumps, the front will settle after maybe 1 oscillation where the rear takes 2-3 oscillations before it settles.
I want to know if anyone notice this rear bounciness after a front only sway bar upgrade.

That's weird... sounds like the bar is not installed with zero preload at your static ride height. Meaning, for whatever reason, your bar has some load on it at static ride height.

As you know, during symmetrical up-and-down suspension movement, the bars do nothing (unless they have some load on them from not being installed correctly). I would try getting some adjustable sway bar endlinks, get any swaybar preload out, and then see how things are.

Originally Posted by lib

There's a 2-day open autocross practice event this weekend and I'm planning to spent part of the time playing with the various modes out of curiosity.

Are there any specific experiments you'd like me to try with DTC/DSC?

Currently I'm planning to compare all 3 modes; when entering a corner too fast, in a long sweeping corner, in a slalom (but I suck in slaloms ) and accelerating early out of a slow corner.

See below...

Originally Posted by white911

jeff,

As you may recall I mentioned that I had quite a bit of time to experiment on different skid pads. We are putting on an event at the Shenandoah Circuit this weekend and I have set up the skid pad for instructor training for the whole weekend. Time permitting - I will continue to refine my testing of the different modes which were covered in an earlier report.

If you don't mind please describe an effective E-LSD test --

Well.......hmm. Like I've said previously in this thread, with DSC+DTC off, I have not felt any kind of electronic intervention other than ABS. And I think if anyone is going to feel it, it's me.

But, to give you something to try: Since you have a skidpad, try getting the car near/at it's grip limit around the pad so that you are at constant throttle and constant steering. Then, abruptly lift off-throttle, turn in towards the center of the skidpad a little bit (maybe a 45* change on the steering wheel), and then abruptly go to full throttle and pay attention to the feel of the rear end of the car.

Originally Posted by philaf_666

I've noticed the exact same thing after installing the Hotchkis front sway.

At that time, I had the KW v2 set at max and the m3 front tension rods and wishbones.

I realized that the front of the car was now too stiff overall for the rear so I installed the UCC rear sway, m3 rear bushing and 700lbs swift spring in the rear only and the car is now really well balanced.

I do noticed the one wheel spin getting out of a tight corner, but since I'm not tracking the car, it's not a big thing for me. The rear sway is set at stiff so I might try the soft setting to see if it helps. That's the problem with open diff!

If installed correctly (i.e., with zero preload), the bars shouldn't affect front and rear ride rates at all. And therefore shouldn't cause what you guys are describing.

[J Tyler]

Originally Posted by Jcrewsn

I have a week old stock 2009 135i with a little over 500 miles on it. Maybe when I've completed the break-in I'll let you take her out to figure the e-diff situation... I'll be in Tustin until August so PM me if your interested.

Sure! If you are willing to lose a little bit of your rear tire tread. This would be very useful for all of us and would easily answer all these questions. I'm in Irvine btw.

[white911]

Originally Posted by J Tyler

Well.......hmm. Like I've said previously in this thread, with DSC+DTC off, I have not felt any kind of electronic intervention other than ABS. And I think if anyone is going to feel it, it's me.

But, to give you something to try: Since you have a skidpad, try getting the car near/at it's grip limit around the pad so that you are at constant throttle and constant steering. Then, abruptly lift off-throttle, turn in towards the center of the skidpad a little bit (maybe a 45* change on the steering wheel), and then abruptly go to full throttle and pay attention to the feel of the rear end of the car.

Sorry the test was this past weekend. -- Perhaps you will be able to feel it better then anyone and I appreciate the help. While I obviously don't have as much experience as you, I have quite a bit of experience myself with over 300 track days and a bit of experience working with past and current pro-drivers. (PM sent) I was not able to exactly try your test; but, I did try my own again. Between running the event this weekend, I was able to get about an hour to myself on the skid pad.

The car is very easy to induce either trailing throttle over-steer particularly when transitioning from an understeering condition or power on over-steer. We teach that to students. It was easier to hold a high yaw rate on the skid pad, then to hold at 10-15 degrees. unfortunately the skid pad was not level so it requires some work to drive it with the tail out. I was able to hold high yaw rate with out the power cutting, and with the tires spinning. At that point I was concentrating more on balancing throttle (high power setting, second gear) and steering because the skid pad is not level (camber changes). I did try another test which caused the E-LSD to definitely work. Accelerated hard across drying area with low yaw I felt a few pulses from the back when I hit the wet area again, right wheel hit it first, then both wheels on dry, then right wheel on wet, then both on wet. Obviously happened quicker then I can describe it.

Half way to the track, I realized I had left my digital IR pyrometer at home and it would have been helpful to take rotor temps. (After coming off the skid pad, the rears are ever so slightly blued -- certainly not like when coming off the track.) Next test will be July, so maybe we can work on something with more granularity.

[philaf_666]

If installed correctly (i.e., with zero preload), the bars shouldn't affect front and rear ride rates at all. And therefore shouldn't cause what you guys are describing.

The bar is definitely well installed. Of course, we're not talking in straight line, but during hard cornering.

Before I had the front sway installed, there was a lot of body roll.

After the install, the front of the car felt flat and stiff but the rear end felt like it was bouncier than before. Actually, it might only be a feeling due to the front being more flat and stiff, but it really felt like the rear was going from side to side more than before while hard cornering.

After installing the rear M3 subframe bushings, rear sway and stiffer springs in the rear, that feeling is gone. Since all was installed at the same time, I'm not sure what cause that feeling to go.

So my understanding is that if you play with the front of the car, you also need to adjust the rear accordingly.

[J Tyler]

Originally Posted by philaf_666

The bar is definitely well installed. Of course, we're not talking in straight line, but during hard cornering.

Before I had the front sway installed, there was a lot of body roll.

After the install, the front of the car felt flat and stiff but the rear end felt like it was bouncier than before. Actually, it might only be a feeling due to the front being more flat and stiff, but it really felt like the rear was going from side to side more than before while hard cornering.

After installing the rear M3 subframe bushings, rear sway and stiffer springs in the rear, that feeling is gone. Since all was installed at the same time, I'm not sure what cause that feeling to go.

So my understanding is that if you play with the front of the car, you also need to adjust the rear accordingly.

Ah my bad; I thought you were talking about the rear feeling "bouncy" after going over a speed bump! And I was saying that the bars shouldn't affect that.

What you just described is correct. My bad.

[pkcormier]

Jeff, what toe settings do you use on the Berk 135i front and rear?

[kc_skyrider]

First let me thank you for sharing your experience for people like myself who only know enough to get in trouble. I just started a thread to get some opinions for drifting a 135i. My first question is do they have a good LSD available for the 6MT yet? Even if I have to do a little welding I don't mind. Next what suspension mods would you suggest to drift this car? I will have it on the street alot and also to some tracks. but I have a lift so I don't mind making major changes to suspension for a day of themed driving. (plus I love to work on this thing)

[J Tyler]

Originally Posted by pkcormier

Jeff, what toe settings do you use on the Berk 135i front and rear?

Hey PK, sorry for the late reply! Been busy (not a bad thing).


On the front they run ~1/16" total toe out = 1/32" out each side

On the rear they run 3/16" total toe in = 3/32" in each side

As much camber as they can get all around, which is about -2.4*F and -2.0*R

[J Tyler]

Originally Posted by kc_skyrider

First let me thank you for sharing your experience for people like myself who only know enough to get in trouble. I just started a thread to get some opinions for drifting a 135i. My first question is do they have a good LSD available for the 6MT yet? Even if I have to do a little welding I don't mind. Next what suspension mods would you suggest to drift this car? I will have it on the street alot and also to some tracks. but I have a lift so I don't mind making major changes to suspension for a day of themed driving. (plus I love to work on this thing)

1) Yes, search for HP Autowerks on this forum. Talk to Harold there. He sells and installs a very nice Quaife unit which is a perfect compromise between street and track duties.

2) KW V2 or V3 coilovers + front camber plates + non-staggered wheels/tires. If you want to go overkill, add an aftermarket rear sway bar. The KW's are an excellent compromise between street and track duty. They are a bit stiffer than a typica ///M suspension, but not by a whole lot. And for the love of god, save the drifting for an open track day! Please!


Hope that helps everyone. Whats new with your cars? Has anyone tried the mods or setup suggestions we've talked about?

Not too much is new with me. I have a fun summer job and am working a lot. Tomorrow I have the privilege of testing the HP Autowerks 335i at CA Speedway; definitely looking forward to that. I also spent a large portion of my semester/summer working on this at CSUN:

440lbs, 100+hp, 6-speed pneumatic paddle-shift with no-lift-shift... and no seat!

[vasracer]

cool, I will be there at cal speedway with speedventures, so I will try to say hi. I will be trying out the 135i with the dinan suspension with stock tires, I tracked there bone stock in may with bmwcca and had a ball. Now I have the stage 3 (springs, shocks, sways, camber plates), so hopefully it'll be fun. I am trying to chew up the tires, so I can get the fender flares and then get a square setup and hope the wife doesn't notice.

I will be in the red and green groups so please don't blow the doors off my car too badly when flying by...thx

[tkbr0wn]

Jeff, I just read the entire thread and this is very helpful. Ive had my 135 for a year now and I just ordered the KW V2's.

I recently switched from the run flats to so non run flats and the suspension seemed to get much more floaty. That combined with Oktoberfest coming up and me wanting to try some of the driving schools prompted me to go ahead and order the KW's.

Here are my questions.

1. I am planning on doing the suspension install myself. Im pretty handy and I have all the tools, but Ive never done something like this before. (other than installing a leveling kit on a truck a couple of years ago) Is it pretty doable in a day? Is it something I should even be considering?

2. I see lots of posts mentioning the camber plates. Is this something I should really do if I am going to be on the track maybe 3-4 times a year?

3. Should I go ahead and do a front swaybar while I have everything apart? Hotckis? Other suggestions?

Thanks,

Kenny

[J Tyler]

Originally Posted by vasracer

cool, I will be there at cal speedway with speedventures, so I will try to say hi. I will be trying out the 135i with the dinan suspension with stock tires, I tracked there bone stock in may with bmwcca and had a ball. Now I have the stage 3 (springs, shocks, sways, camber plates), so hopefully it'll be fun. I am trying to chew up the tires, so I can get the fender flares and then get a square setup and hope the wife doesn't notice.

I will be in the red and green groups so please don't blow the doors off my car too badly when flying by...thx

Nice meeting you, sir. Sorry I did not get the chance to blow your doors off.....was busy doing that to Corvettes.....

That 335i was awesome. Hope you had a good day and get home safely.

Originally Posted by tkbr0wn

Jeff, I just read the entire thread and this is very helpful. Ive had my 135 for a year now and I just ordered the KW V2's.

I recently switched from the run flats to so non run flats and the suspension seemed to get much more floaty. That combined with Oktoberfest coming up and me wanting to try some of the driving schools prompted me to go ahead and order the KW's.

Here are my questions.

1. I am planning on doing the suspension install myself. Im pretty handy and I have all the tools, but Ive never done something like this before. (other than installing a leveling kit on a truck a couple of years ago) Is it pretty doable in a day? Is it something I should even be considering?

2. I see lots of posts mentioning the camber plates. Is this something I should really do if I am going to be on the track maybe 3-4 times a year?

3. Should I go ahead and do a front swaybar while I have everything apart? Hotckis? Other suggestions?

Thanks,

Kenny

1) Yes, it's not too hard to do. I am no mechanic and I can do it. An extra person to help you will make things a lot easier. You may also have to rent/borrow a spring compressor from Kragen (its like $10).

2) I sure think so. Lack of front camber is by far the biggest problem with strut-type suspensions... and to really make the coilovers worthwhile, you need camber! Without them, the car will understeer pretty badly.

3) If you have to choose between the two, I'd recommend camber plates over a sway bar. But, if you have the budget for a sway bar, I thought the H&R solid front bar matched up very well with the kit KW spring rates. (I recommend keeping the rear bar stock unless you enjoy sideways motoring.)

[tkbr0wn]

Thanks for the help. Any opinions which camber plates I should be considering? Best bang for the buck?


Edit.....

I think I have decided on the Vorshlags. I was ready to order but I need to know what spring perch to order. I was guessing the 60mm perch's but wanted to make sure before I order them. I guess I will call tomorrow.

Thanks again for all the help.

[WhiteOne]

If I replace my stock front springs with custom made 210lb/in. springs will it improve the balance of my otherwise stock 135i?

[pkcormier]

Jeff - thanks for the settings. I'll try those next month. As for negative camber front, I have made a few modifications to get -3.2 drivers side and -3.6 passenger side. As you know, since the strut tower hole is so small, you can only slide the Vorshlag plates over so much before the top nut hits the flang. Well I took my dremel tool and lengthened the slide hole where the strut mounts and cut a notch in the shock tower to allow the strut top nut to more more inboard. Combine that with the M3 lower arms and we are now in -3+ degree territory.

Originally Posted by J Tyler

Hey PK, sorry for the late reply! Been busy (not a bad thing).


On the front they run ~1/16" total toe out = 1/32" out each side

On the rear they run 3/16" total toe in = 3/32" in each side

As much camber as they can get all around, which is about -2.4*F and -2.0*R

[HP Autosport]

Originally Posted by tkbr0wn

Thanks for the help. Any opinions which camber plates I should be considering? Best bang for the buck?


Edit.....

I think I have decided on the Vorshlags. I was ready to order but I need to know what spring perch to order. I was guessing the 60mm perch's but wanted to make sure before I order them. I guess I will call tomorrow.

Thanks again for all the help.

Vorshlag

[tkbr0wn]

Thanks, HP. I just sent you a PM.

[J Tyler]

Originally Posted by WhiteOne

If I replace my stock front springs with custom made 210lb/in. springs will it improve the balance of my otherwise stock 135i?

Personally I wouldn't go changing spring rate unless I was going to change the dampers as well (since the spring & damper are supposed to work together in harmony, and they have a big affect on the behavior of the car). If you change only the spring rate, then the damper rate is not matched up properly and things get weird.

Also, I would guess that 210lbs/in is softer than the stock spring rate. It's definitely too soft for any kind of 'sporty' application.

If you *have* to do only springs, I'd go with something that's been pre-tested like an H&R spring kit. At least then you know they won't bottom out / coil bind / be way too soft / be way too stiff.

[HP Autosport]

Originally Posted by J Tyler

Also, I would guess that 210lbs/in is softer than the stock spring rate. It's definitely too soft for any kind of 'sporty' application.

The oem front spring has a rate of 120 lb/in

[J Tyler]

Originally Posted by HP Autowerks

The oem front spring has a rate of 120 lb/in

Wow. That puts it at about 106lb/in wheel rate = 212lb/in front ride rate... that's soft!