[stressdoc]

I think that the M-sport and I believe the Performance suspension w/springs lowers ride height another 5mm from sports (1.5cm from standard).

[seccsc]

Originally Posted by Orb

The stock spring +Koni FSD + H&R sway bars are an awesome setup. It really is winner setup and the car gracefully under steers when pushed to limits. The ride quality is just better than anything you can get so great for street setup and does well for occasion track day.

My opinion on sway bars is that this car can never ever be fixed properly without sway basing correction and 92% / 7 % biasing doesn’t cut. Cars that are setup neutral tend have the sway bar biasing around 68% to 80% for the front. You can at some point do it with very stiff springs but you end with less traction and a lot of negative front camber. I never experienced any snap over steer with this car with H&R sway bars. I had the rear come out more that a few time but always recoverable even under some scary circumstances.

The Hotchkis sway bars will achieve less roll but it is at cost so it will work for some but no other. This setup is a better comprises with no LSD unless you’re on bumpy roads often. Not having LSD is major handling compromise by itself.

There is several ways to setup a car but most setup has just as many negatives as they do positives. The only way to get neutral handling with this is to fix it with both springs and sway bars.

BTW, if you think the way to setup car is what have been said here then checkout KW 1 series test car at 1addicts with a big KW rear sway bar on the rear with a matching front (aka H&R sizes).

Orb

Thanks, Orb. I'll check it out.

[Mr. 5]

I just drove the rear of my car on ramps.
You guys aren't kidding! This installtion looks like a complete PITA!
I saw the installation pictures for the 135 though and I was hoping that someone could just give some pointers to go along with these pics.
I see how dropping the rear subframe will help, but are we going to need a jack to jack it up afterwards?
Is the rear frame going to be completely dropped or should we just loosen the bolts to where they're still attached?

http://www.eurotuner.com/techarticle.../photo_08.html

[Quisp]

I went with the Hotchkis Sway bars front and rear, also the Koni FSD and Eibach Pro Kit and I am very happy with it. I had it all installed at once so I cant really say how much each compnoent added to the handling, but from what i have read it seems the sawy bars help handling more than shocks and srpings, which do more for the ride. That is not to say the shocks and springs dont do anything for handling, they help a lot. I chose the Hotchkis because they were lighter and I read that the H&R was better suited for harder driving than I usually do. I also saw something about the iside wheel coming up in very aggressive turns.
The hotchkis are not adjustable though. As for the install, it looked like a pain in the ass and I left that up to a local garage that works on a lot of BMWs.
The setup i got is very nice for me. I like to drive the country roads and truns fast and hard, but i dont track. I also wanted a comfortable ride as it is my daily driver. I was able to get a good balance with this and it actually rides better than stock. A lot less understeer and body roll plus the car feels much more grounded. To me it used to drive like it was skimming the surface of the road and not really planted. Now it feels planted and gives more confidence when i drive it.
The car holds straight lines better at highway speeds. Less steering correction needed, not as twitchy.
Where i used to feel every seam and crack in the highway I dont anymore. The bumps diminish but the dips are a bit more exagerated. The bumpy turns are better than stock but the car still skips a bit if the turn is especially bumpy and I am going a bit faster. There is barely any front end plow or dive from the front end when I am in a changing radius turn and have to tighten it in the middle. Prior the car would feel like the nose was going to the ground and then the front tires would start to come loose.
I realize I am a bit late with this info but I hope it helps.

[Ray]

Originally Posted by Mr. 5

I see how dropping the rear subframe will help, but are we going to need a jack to jack it up afterwards?
Is the rear frame going to be completely dropped or should we just loosen the bolts to where they're still attached?

You will need jack to raise the sub-frame back to it's original position. The 6-8 bolts are removed completely to allow sufficient clearance.

Use a jack to hold the sub-frame after lowering it

[Mr. 5]

I installed the 14mm sway bar, and I now know what Leftcoastman is talking about. I rounded a corner, hit the gas, and my tires were more likely to spin.
I'm not complaining though. I really like the feel and I think that it's the perfect size for the regular 335s.

I'm glad I didn't go with the 15mm XI sway because if I can feel the tires spinning a bit with this one, I could just imagine what would have happened with the 15mm.

For those who are thinking about the M3 20mm bar, I would highly encourage you not to get it, unless you like going through tires really fast and doing 180s around corners. That is, if you drive spirited like myself.
Do not start comparing our suspension with the M3's suspension because it is completely different. Yes, the M3 has a 20mm sway that is fit for the M3's suspension.

[Mr. 5]

Since the sickness still lingers in my head, now I'm thinking about trying the front H&R sway to go along with the stiffer 14mm rear sway.

Any comments...good decision...bad?

[Chowbow]

Mr. 5, did you DIY the rear sway install? I'm thinking of tackling it one of these days if I ever decide to go with sway bars.

[Mr. 5]

Originally Posted by Chowbow

Mr. 5, did you DIY the rear sway install? I'm thinking of tackling it one of these days if I ever decide to go with sway bars.

I did. It was one of the hardest things that I've done.
A DP installation is so much easier!

I had access to a lift, and it was still a pain.
I used the lift, floor jack, subframe jack/brace.

I was sore for 2 days afterwards.

[Chowbow]

OK, so I won't DIY it. :P

[Mr. 5]

OK guys,
I've added another variable into the mix.
I ordered the front Hotchkis bar to go along with my 14mm rear M sport bar.

Since Orb was kind enough to post about the different percentages, I'd like to add my setup to the mix.
I'm going to have the following:

Front
Hotchkis-31.75 mm: 75961 mm^4

Rear
M-sport-14.0 mm: 3771 mm^4

Front/Rear Biasing

Hotchkis front + M sport rear: 95% / 5%

I'll let you guys know about how this setup feels.

Originally Posted by Orb

...
Here is the polar moment of inertia calculation for all other bars:

Front:

• Hotchkis-31.75 mm: 75961 mm^4
• Dinan-28.0 mm: 60343 mm^4
• H&R-27.0 mm: 52174 mm^4
• UUC-27.0 mm: 52174 mm^4
• Stock-26.7 mm: 39310 mm^4

Rear:

• H&R-20.0 mm: 15707 mm^4
• UUC-19.0 mm: 12794 mm^4
• Hotchkis-16.0 mm: 6433 mm^4
• Dinan-15.0 mm: 4970 mm^4
• M-sport-14.0 mm: 3771 mm^4
• Stock-13.0 mm: 2803 mm^4


Front/Rear biasing:

• Stock: 93% / 7%
• H&R: 70% / 30%
• UUC: 75% / 25%
• Hotchkis: 92% / 8%
• Dinan: 92% / 8%
• Stock front + H&R rear: 60% / 40% (Leftcostman….yikes!!!)
• Stock front + Hotchkis rear: 83% / 17%
• Stock front + M-sport rear: 90.5% / 9.5%
• Stock front + Dinan rear: 87.5% / 12.5%

Orb

[Chowbow]

I'm wondering... if you were going to add a front sway bar anyway, maybe it wouldn't have been a bad idea to just go with a matching Hotchkis set? I know that Hotchkis actually tested their setups to some extent at autoXs and didn't just pick some arbitrary diameters and threw them onto market.

[Mr. 5]

Originally Posted by Chowbow

I'm wondering... if you were going to add a front sway bar anyway, maybe it wouldn't have been a bad idea to just go with a matching Hotchkis set? I know that Hotchkis actually tested their setups to some extent at autoXs and didn't just pick some arbitrary diameters and threw them onto market.

I know-I know.
I can easily say that I think I screwed up, but I will tell for sure after I do the install.
If you look earlier in the thread, I was looking at installing the set but there was worry about the improper balance, bla bla.
I was also worried about installing a rear sway bar that was too stiff, so I stuck with the M sport.
I didn't want to be loosing the rear end around the corners which is what a thick rear sway will make you do.
Although I agree with you, it looks like H&R just came up with some "arbitrary diameters and threw them onto market."
The reason why I say this is because the rear bar just seems to be way too thick for this car, especially when comparing to the front H&R bar.

[Gen_E92]

but why would you want even more front biasing than stock? BMW already set up all the non-M cars to have a natural understeer for safety purpose...

[Mr. 5]

But when you are talking about the M3 biasing, this is just fun facts.
It's been stated that a bias like that with our cars will be a nightmare.

Originally Posted by Orb

This is additional information on bars that will fit e90/e92. I correct the information from the 3rd party for the front stock sway bars as it included paint so it was wrong.


Polar moment of inertia calculation:

Front:

Stock 335i-26.5 mm: 36951 mm^4 (hollow - 4mm thick)
E92 M3-26.5 mm: 36951 mm^4 (hollow - 4 mm thick)

Rear:

E92 M3- 22.3 mm: 18898 mm^4 (hollow – 3.5 mm thick)


Front/Rear biasing:

E92 M3: 51% / 49%

[T7R_Sky]

So which shock do you think will work best with ZSP springs and some H&R Sways? The Perf. Suspension shocks or the Koni FSD's??

[LaYzEe]

Originally Posted by Mr. 5

OK guys,
I've added another variable into the mix.
I ordered the front Hotchkis bar to go along with my 14mm rear M sport bar.

Since Orb was kind enough to post about the different percentages, I'd like to add my setup to the mix.
I'm going to have the following:

Front
Hotchkis-31.75 mm: 75961 mm^4

Rear
M-sport-14.0 mm: 3771 mm^4

Front/Rear Biasing

Hotchkis front + M sport rear: 95% / 5%

I'll let you guys know about how this setup feels.

Mr. 5, did ur front Hotchkis bar arrive yet?

Im still deciding if i should just stick with the 14 mm M rear sway or buy the Hotchkis set

[Panzerleder]

Very interesting discussion. However, one important item missing is any discussion of alignment after messing with the suspension. Could any of you who have had suspension work done comment on whether you had a subsequent alignment, the specs chosen, and how you like it?

[Chowbow]

Dropping the rear subframe would definitely require an alignment IMO.

[I335]

If this question should be a new thread, just let me know and I'll do that, but for now, I guess I'll start here within this very informative thread...

There's a lot of talk about sway bar replacement causing rear inside wheel lift (and resulting spin & less traction) on hard corners, and I can understand and appreciate this. My question is, how hard a corner do you need to take for this lift to occur? Are we talking track speeds or just about every corner taken on the street? The reason I ask is because I simply want flatter cornering at normal to fairly spirited street driving speeds. I'll never track my car so I'm not talking about taking corners close to the limit. If I get a set of popular aftermarket sway bars like H&R, UUC, Hotchkis, etc., will I also experience the inside lift problem in spirited street driving situations? Or is this only an issue in 9/10's corners? THX!

[Gen_E92]

Originally Posted by I335

If this question should be a new thread, just let me know and I'll do that, but for now, I guess I'll start here within this very informative thread...

There's a lot of talk about sway bar replacement causing rear inside wheel lift (and resulting spin & less traction) on hard corners, and I can understand and appreciate this. My question is, how hard a corner do you need to take for this lift to occur? Are we talking track speeds or just about every corner taken on the street? The reason I ask is because I simply want flatter cornering at normal to fairly spirited street driving speeds. I'll never track my car so I'm not talking about taking corners close to the limit. If I get a set of popular aftermarket sway bars like H&R, UUC, Hotchkis, etc., will I also experience the inside lift problem in spirited street driving situations? Or is this only an issue in 9/10's corners? THX!

Definitely only from track speeds from my experience.

[I335]

Originally Posted by Gen_E92

Definitely only from track speeds from my experience.

Thanks. So what's been your experience with the H&Rs?