What size Ground Control anti roll bars?

[CoMZ302]

I'm running 550/750 on 24mm 325i front bar attached to strut and stock 19mm rear bar. I'll most likely be going up to 750/900 and adjustable bars to limit roll/camber loss at the end of the year for next year.

This setup with my alignment has some understeer dialed into it, sometimes too much.

Here is a good video of how it performs on track.

Yep. That's a good handling car.

I'll try and remember to turn on my camera for High Plains in a couple weeks. I don't like the track very much, and with a bunch of 180s you won't really be able to tell much about handling.

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I ordered the Medium F/Small R, figured I would start small and if I run out of adjustment will order the next size up.

You will like it. Start with the bars in the middle setting, both ends.

If you run out of rear adjustment, go all the way to the 'large' rear bar. The Small and medium rear bars have a ton of overlap.

[jakermac]

If you run out of rear adjustment, go all the way to the 'large' rear bar. The Small and medium rear bars have a ton of overlap.

I thought we already determined that there is no medium rear bar. Only large and small.

[CoMZ302]

According to their website, there are only small and large *rear* bars. According to them, there is a medium rear you can call and order...

Forgot to mention that!

[Inflame]

Awesome driving Inflame! What strut shocks are you running?

Stace SS+ custom valved to my rates. I'll be running the same equipment with my new spring rates, but rebuilt/revalved.

Yep. That's a good handling car.

Thanks!

She performs really well on NT01's, but not too well with the Maxxis RC1's - Have had a horrible time on these tires.

[CoMZ302]

I'm running 550/650 on 24mm 325i front bar attached to strut and stock 19mm rear bar. I'll most likely be going up to 750/900 and adjustable bars to limit roll/camber loss at the end of the year for next year.

Just as a follow up: I went from 650/800 to 750/900 this weekend and hated it. Mich much slower for me anyway. Of course everything works together and maybe my combination of alignment and bars didn't match the springs. But raw testing I was dramatically slower and hated it. I'm thinking 600/700 or /750 is probably where i will land, then mess with the bars and shocks.

If you have stiffer springs and like them - good for you. I did not. This is not an indictment of stiff setups.

[TXBDan]

Just as a follow up: I went from 650/800 to 750/900 this weekend and hated it. Mich much slower for me anyway. Of course everything works together and maybe my combination of alignment and bars didn't match the springs. But raw testing I was dramatically slower and hated it. I'm thinking 600/700 or /750 is probably where i will land, then mess with the bars and shocks.

If you have stiffer springs and like them - good for you. I did not. This is not an indictment of stiff setups.

What shocks are you running with them? That's a big factor.

[CoMZ302]

What shocks are you running with them? That's a big factor.

MCS double remotes from BimmerWorld. They suggested 800/900 springs with these shocks.

I am starting to think the 328 is different enough that it warrants different setup. For example, I'm getting only 6* caster and I know people are running 8-9 on E36 M3s.

Anyway same tires, same track, same weekend - 3 seconds slower.

[jakermac]

What was the undesirable behavior that made you slower?

[CoMZ302]

What was the undesirable behavior that made you slower?

Much lower grip by the data. Nervous and difficult to drive. Won't take a set in the turn. Won't allow power application.

I don't have video of the softer springs but the difference was dramatic.

[jakermac]

I'm no road racer, but I think the rear spring rate in combination with your rear sway bar was the culprit. It's a shame you didn't try those rates with no rear bar, or the bar disconnected. I think you would have liked it.

[CoMZ302]

It was so pushy - I tried going down in front bar, and actually added one notch of rear bar - and it certainly was worse. This car confuses me!

I ran 550/700 on my MRoadster and thought it was really good but not great. That's where I'm going next.

Well that and trying to figure out what caster to run.

[jakermac]

Mine is currently mid-corner to exit pushy. Turn in is great. I'm going to try more front bar to help the push. How much front camber are you running? I'm at 4 degrees.

[aeronaut]

I helped my mid-corner-to-exit push a lot by softening the front bar. Now with power, the car is neutral to oversteer on many turn exits.
E36 M3, TCK SAs, 550/650 springs, Toyo RRs, ~3.5 neg camber front, ~2.5 neg camber rear.

[CoMZ302]

Mine is currently mid-corner to exit pushy. Turn in is great. I'm going to try more front bar to help the push. How much front camber are you running? I'm at 4 degrees.

Since we both have 328s... How much caster can you get?

3.5 front camber. Maybe 328s need more static camber to make up for less caster.

[CoMZ302]

I helped my mid-corner-to-exit push a lot by softening the front bar. Now with power, the car is neutral to oversteer on many turn exits.
E36 M3, TCK SAs, 550/650 springs, Toyo RRs, ~3.5 neg camber front, ~2.5 neg camber rear.

Those spring rates sure are looking good
..

What bar do you have and what change did you make?

[jakermac]

Since we both have 328s... How much caster can you get?

3.5 front camber. Maybe 328s need more static camber to make up for less caster.

325 here, but I actually reduced caster from about 6.5 down to 5 degrees to combat weight jacking.

[CoMZ302]

325 here, but I actually reduced caster from about 6.5 down to 5 degrees to combat weight jacking.

Interesting. You also can't get both 4 degrees camber and 6.5 caster at the same time on my car any way

[TXBDan]

325/328s have the same geometry as a '95 M3, right? The chassis are all the same, the difference comes from stock strut mounts, lower control arms, lower control arm mounts/bushings and the spindles.

What combination of LCAs, LCABs, and spindles are you running?

https://www.bimmerforums.com/forum/s...E36-M3-spindle

In my '97 M3 I'm running '95 M3 style Myle HD LCAs (lose some castor), offset LCABs (gain castor back), '96+ spindles, and i get 6.5ish degrees of castor. I haven't tried to get more than -3.5deg of camber, but i can get that no prob.

[aeronaut]

Those spring rates sure are looking good
..

What bar do you have and what change did you make?

Front; UUC. Rear, OEM.
I changed front from full stiff to full soft. I was hoping to get less neutral/mid-turn understeer. It didn't seem to change that any. But it's definately easier to get the backend out with power. More funnnner!

FYI, my caster is ~7.5deg (I'm running GC street camber plates, which allow just a touch of castor adj)

[CoMZ302]

325/328s have the same geometry as a '95 M3, right? The chassis are all the same, the difference comes from stock strut mounts, lower control arms, lower control arm mounts/bushings and the spindles.

What combination of LCAs, LCABs, and spindles are you running?

https://www.bimmerforums.com/forum/s...E36-M3-spindle

In my '97 M3 I'm running '95 M3 style Myle HD LCAs (lose some castor), offset LCABs (gain castor back), '96+ spindles, and i get 6.5ish degrees of castor. I haven't tried to get more than -3.5deg of camber, but i can get that no prob.

I honestly don't think they're all the same, are they? I know the lower control arms are different (much different outer balljoint) but I don't know if the lengths or widths or other aspects differ.

Here's what I'm running
GC upper plates - oriented between max camber and caster
98 328 spindles
98 328 control arms, but with GC rollcenter correction - oriented to move the bottom of the shock outwards as far as possible.
GC offset lolipop bushings, rotated so the rear of the control arm is pointed as far outward as possible.

I can get only 6* of caster with this setup - with my M Roadster I can get 7.5 or more IIRC.

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Front; UUC. Rear, OEM.
I changed front from full stiff to full soft. I was hoping to get less neutral/mid-turn understeer. It didn't seem to change that any. But it's definately easier to get the backend out with power. More funnnner!

Awesome thanks for the info.

FYI, my caster is ~7.5deg (I'm running GC street camber plates, which allow just a touch of castor adj)

I wonder why I can get only 6.5??? I even have the offset lollipop bushings.

[TXBDan]

I think you're overly fixated on castor. We're all within a degree of each other, i don't think it makes much difference. We don't turn the wheel enough on track for significant difference in camber gain, it's more of a feel/weight/stability thing. It certainly isn't the major setup issue you're chasing.

What are your ride heights?

[CoMZ302]

Well, maybe so. There's a lot of 180s on the tracks around here, and the car feels good then washes out on all of them. Medium- to high-speed corners it's great.

I have flares so I'm not sure how to measure the ride heights. I can measure at the jacking/towing points tonight if that helps.

28July1gp5_10.jpg

Here's a pic of some mild understeer from the weekend. This is decreasing radius, off camber, mo-fo of a turn.

To me, it looks like the car just isn't working. Like the front's way too stiff. Those are only 650lb springs, but the car weight only 2500lbs plus me.

[TXBDan]

I don't know. Have you worked with whoever sold you the MCSs? They should be able to give you some baseline setup info. Bimmerworld for example will give you a full spec sheet with alignment specs, ride heights, shock settings, etc.

[CoMZ302]

I don't know. Have you worked with whoever sold you the MCSs? They should be able to give you some baseline setup info. Bimmerworld for example will give you a full spec sheet with alignment specs, ride heights, shock settings, etc.

Phil at BW has been pretty helpful - I bought them through him. I have (presumably) James Clay's setup instructions, which call for 800/900 springs and specify camber/toe settings, as well as baseline shock settings for dry and wet. They don't have caster settings, but I was told yesterday I want 7-9* and 8 is preferable (again, that's not on the sheets). They also don't specify sway bars until you ask, and luckily I happen to use one of the setups they suggest (medium GC front and rear).

These blanket setup suggestions rarely work for me. A 3100lb M3 needs more spring than a 2500lb gutted 328. A car with a stock motor can get away with more rear spring than one with +100hp.

I did really well at the Solo2 nationals (15 years ago) on 550/700 springs (I know it's not the same car). That M Roadster weighed 250lbs more than this car. "Just Because" I was road racing, I randomly added 100lbs to that setup and started there (650/800). The new car was so-so, but not great, until I moved the front bar to medium and the rear bar up one notch from full soft. At that point it was pretty good but I still wanted more.

This past weekend, on BW's advice, I went up to 750/900, which is pretty much what they suggested (and a common setup). Same car, same track, same tires, same weekend - 3 seconds slower. I have race results and data. The car just skates around and is not something I like driving. One end or the other is doing all the work - the car doesn't carve or take a set. It just starts washing out way before it should.

At this point, I need to test front rates of 550/600 and rears of 650/700/750 and see what combination I like. If I don't like any of them, then I guessed perfectly at 650/800 (unlikely). My new guess is 600/700 or 600/750 is going to be fantastic.

I'm going to the Heartland SCCA Majors Aug 1st, and will run the test day before and decide all this stuff.

I've never seen 100lbs turn a car from pretty good to awful before. That's just not enough difference - so I'm suspecting something else is afoot.... thus all the Caster questions since mine is way less than I expect (and have been told to run, and ran on my other car).