High spring rates

[Herb]

I'll start of saying that I am not as versed as you all, but would like to contribue from my experience/progression. '90 325i 2dr s52/260getrag 3.73lsd

Setup (autoX / trackday) - Starting point: gc 475lbs f, 625lbs r, no camber plates, stock sways and worn hardware, bilstien sports, rota slipstreams 225/15 es100s. Autox for about a year on this setup.

Read about rear sway removal, gave it a shot - noticed immediately that the rear felt more planted and predictable. About 3months on this on both es100s and v710s.

Current setup - new oem front sway bar bushings, m3 sway end links, rear shocks changed to koni sa one click off full hard, bmp poly rsm's, tires permanently changed to 225/15 v710s. OH MY GOD, the difference is night and day. Car feels glued to the ground, the rear is even more predictable. A friend co-drove my car on track day, so I got the chance to see how it acted, I plan to go up 50-100lbs f&r in rates, koni's for the front, and camber plates in front (I'm solid ajustable subframe in the rear). I believe that will take care of the minimal squat, dive, and roll that I saw/felt.
Herbert

[Jean]

Herb, yeah, the way dot-r tires transform ANY car is nothing short of amazing... grip grip grip, ohshitnogrip... ;)

So I also made a thread in the track section on bimmerforums, and someone is suggesting at least 700front, and 1000rear.



This will be fun hehe :)

[Herb]

I was considering 650#F/800#R, but after watching my car handle I think it will be overkill (for me). Keep us posted though.
Herbert

[DSP74]

Herb, yeah, the way dot-r tires transform ANY car is nothing short of amazing... grip grip grip, ohshitnogrip... ;)

So I also made a thread in the track section on bimmerforums, and someone is suggesting at least 700front, and 1000rear.



This will be fun hehe :)

Yeah and the west coast guys in ESP were using 1000lb plus front springs and 250lb rear springs. Guess what. They got handled by a car that had 550's and 150's

To each his own. I know what way I'm going.

[Jean]

Yeah and the west coast guys in ESP were using 1000lb plus front springs and 250lb rear springs. Guess what. They got handled by a car that had 550's and 150's

To each his own. I know what way I'm going.

1000f/250r seems like a crazy combo?? and so is 550/150

[DSP74]

Those are with strait axle cars with a MUCH better motion ratio. And strait axle. And a higher roll center. And much bigger rear bars. 22mm hollow, or 19-21 solid

[nando]

Yeah and the west coast guys in ESP were using 1000lb plus front springs and 250lb rear springs. Guess what. They got handled by a car that had 550's and 150's

To each his own. I know what way I'm going.

I know what you're trying to say, but that car obviously wasn't an E30 so it will react differently to spring rates.

I think I could have gone a little stiffer than what I have now (600/700), but it worked out pretty well. I'm still on stock sways but that's about all that's left of the original suspension.

[DSP74]

I know what you're trying to say, but that car obviously wasn't an E30 so it will react differently to spring rates.

I think I could have gone a little stiffer than what I have now (600/700), but it worked out pretty well. I'm still on stock sways but that's about all that's left of the original suspension.

Obviously different cars sure. Same principal. Everyone wants to be on god awefull stiff springs, and the softer sprung car works better, but doesn't "feel like a go kart".


Why would anyone want to go stiffer, that was on a stock sway bar? Just a question...What exactly would be the reason to go stiffer?

[Jean]

Obviously different cars sure. Same principal. Everyone wants to be on god awefull stiff springs, and the softer sprung car works better, but doesn't "feel like a go kart".


Why would anyone want to go stiffer, that was on a stock sway bar? Just a question...What exactly would be the reason to go stiffer?

Ahh, different cars ok that makes more sense.

There are as you know two camps, stiff rates or not so stiff rates and big sway bars. I am not going to be running stock sway, but I am trying to compensate for the new car being heavier and being on sticker / wider tires to control it's roll.

Plus, each driver has a difference preference, so we'll see how it works :)

[nando]

Obviously different cars sure. Same principal. Everyone wants to be on god awefull stiff springs, and the softer sprung car works better, but doesn't "feel like a go kart".


Why would anyone want to go stiffer, that was on a stock sway bar? Just a question...What exactly would be the reason to go stiffer?

I'm going to do both, but I didn't want to change two variables at the same time. my car is a little different anyway, I'm going to use a 19mm rear adjustable and stock front.

and I agree that a stiffer car isn't neccesarily better - but that doesn't mean that a particular rate of say, 450/750 is too stiff and softer would work better. It might, but it might not - it depends on the conditions and driver.

[joshh]

One thing I've learned is you have to do what works for you. Taking advice from people is a great idea but pick and choose who and what they are saying.
A good friend of mine ended up doing exactly the opposite of what everyone told him and he's doing pretty damned well that way.
You have to make the car fit your driving style to some degree.
Playing with springs is great because there's always someone waiting for the spring you just pulled off your car.

[DSP74]

most importantly you have to listen to folks who are at 10/10ths. I'll admit that isn't me.
But keep that in mind. We aren't shooting for 8/10ths. Or 9/10ths. But 10/10ths.
So unless Alex comes in here shouting I use this and that, for us,
or Shields, or Sias says I use this and that, for the E36 it all has to be taken with a grain of salt......

Again I'm not that person.....And I don't think anyone here is....Which is why you will have to experiment.

[rsafier]

Well the other thing is those going 10/10th have spent a lot of time and money to figure out what does work. Tends to make full disclosure not nearly as likely :) I have never found completely straight anwsers out of any national level driver's when you ask about setup. Nothing wrong with that, if I had a hot setup that works I wouldn't be giving it out either to keep my advantage.

[Jean]

Yep, takes a lot of R&D and trial and error as well. A friend of mine is a very good/consistent driver who is 1 or 2nd in SM at the local and SFR in two different cars, and in top 20 pax. I've been picking his brain on the setup, even though our cars are very different, he gets to drive mine to show me how much faster the car can still go LOL.

[rwh11385]

Too stiff rates don't do you any good, but I'm not complaining about your decision.

300# were surely way too soft, but the cars wasn't very slow on the track either. For shopping cart dodging, who knows - just buy a 550, 600, 650, 700, 800, 900 and swap them in and out. obviously rears are a lot easier