Sway Bar Summary

Dave Bell · 10-15-2002, 04:20 PM

Can someone with suspension tuning experience generate a table of useful/typical combinaltions of sway bars and spring rates that produce roughly neutral steering? Starting with stock component numbers

Table might include

- Front Torsion Bar Size
- Front Sway Bar Size
- Rear Spring Rate
- Rear Sway Bar Size
- Comments on shock settings
- Comments on resulting ride

Assuming no radical mods to car weight, engine, wheels and tires?

This would be great reference info.... good starting point for those considering 914 suspension mods.
______________

Second question... is there in general any handling disadvantage to using progressive springs on the rear?

Thanks guys,

- Dave

Brad Roberts · 10-15-2002, 10:52 PM

Dave,

I would post everything you asked for... but then people wouldnt pay me to do it for them.

There will be certain items you wont get from me.

This coming from a person who will drive a 914 on the street with 26mm front torsion bars and 280 rate rear springs and 31mm sway bar.

B

odie · 10-16-2002, 11:51 AM

what a dick...

Automotion used to have such a table in their catalog...what torsion bars, springs, sway bars, etc will do what to the car.

I've got 22mm front torion bars, 180# rear springs, front poly bushings, 195/60 Dunlops, no sway bars...it rides and handles fine to me. Maybe a little hard but this ain't no Honda. But I've never had it on a track or really tried to evaluate/compare how it handles. It's been mostly an idle project. I was planning a V-8 conversion years ago...

I've got a 7/8" front sway bar and 3/4" rear bar still waiting to go in...someday.

Brad Roberts · 03:15 PM

Ahh come on.. most people call me AS_HOLE.

I actually know Dave Bell and HE knows that I would tell him if he asked me OFFLINE.

Humm.. "Dick" I'll have to think about that name.

B

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The thing is, Odie, that the experience to say what does and does not work does not come cheap. You gotta go and burn up a bunch of tires, at the very least. (Usually you wind up breaking things, too.) It's a little much to ask a pro to give away the info that they've sweated and spent money learning for free.

An amateur like me, however, doesn't feel so constrained. But some of what I've learned was by reading things like the AM catalog, which was very much a "one size fits all" kind of thing, and did not take into account things like tires, alignment, engine size, weight of car, driving style, etc.

My impressions of how my cars have handled:

Stock 1.8 with stock suspension, no sway bars, and hard-compound street tires: Neutral, pretty decent.

Stock 2.0 with stock suspension including stock front and rear sway bars, and hard-compound street tires: Neutral, maybe a tiny bit tailhappy at times, but enjoyable.

Stock 2.0 with stock suspension and stock front sway bar but no rear sway bar, and hard-compound street tires: Fairly neutral, but tending toward understeer a tiny bit more than I liked at the time.

Stock 2.0 with stock front torsion bars, 140# rear springs, 19mm Weltmeister front bar, stock rear sway bar: Oversteer!! Pretty massively! Could not dial out the oversteer with the sway bar, with Koni adjustable shocks all the way around (full stiff front, full soft rear still gave oversteer), and even monkeying with tire pressures.

Stock 2.0 with stock front torsion bars, 140# rear springs, 19mm Weltmesiter front sway bar, no rear sway bar: Aaaah, there it is! Neutral, but very definitely tunable with the sway bar and shock adjustments.

There are other setups that people have told me about, but those aren't cars I have set up or driven more than once or twice.

--DD

odie · 10-16-2002, 02:32 PM

I thought a forum was to promote the free-flow of ideas and information amongst people of similar interests...

Brad Roberts · 10-16-2002, 03:18 PM

So.. Odie..

Check back in the archives and do a search on my name and see how much "free flowing" information I have "puked" up on this board and every other board for the last 4 years.

Relax man.. this isnt church and nobody gets paid to answer questions here.

B

Zeke · 10-16-2002, 04:30 PM

Quote:

Originally posted by odie
I thought a forum was to promote the free-flow of ideas and information amongst people of similar interests...

It is, but there is a big difference between common knowledge shared and proprietary information learned the hard way like Dave says. Where Brad went wrong is even allowing that he knows. So I guess if you're not going to answer the question, don't tease. Throw him a bone, Brad. The stuff you do is so radical it wouldn't mean anything anyway.

Ron Meier · 10-16-2002, 04:42 PM

Search or buy a book on suspension tuning. It will have all the formulas for calculating bar diameter, arm length, etc.

But - you must know corner weights, suspension travel loaded in a corner (based on spring you are using), unsprung weights, sprung weight, and several other things that require DINERO to obtain.

Pay Brad, it's cheaper in the long run (and he won't post his a_s again).

Brad Roberts · 10-16-2002, 04:57 PM

Dont make me post my ass... LOL

Your guy's are a hoot.

The secrets are in the alignments... and that changes for every track we run.

B

odie · 10-16-2002, 07:00 PM

If a guy is in business or competing for money, fine keep your secrets. You earned them. But if someone asks a legitimate tech question, either help him out or keep quiet. Don't play"I gotta secret", which is how I viewed it. If you know Dave Bell and were just pulling his leg, I'm sorry. It just struck me the wrong way.

Remember, junior guys are gonna be looking up to you. There are a lot of novice 914ers out there who might reconsider asking questions. the only stupid question is the one not asked. I'm on a lot of other tech forums...Fieros, Harleys, YJs, Z-cars, Volvo, sailboats. Help each other always.

remember guys, Porsche abandoned the 914 years ago. no one is ever gonna help us but each other and a very few suppliers such as Pelican.

sorry if I'm long winded

Brad Roberts · 10-16-2002, 07:22 PM

I was floored (Dick comment) people in the shop tonight where razzing me about a fellow TEXAN giving me crap..LOL

I'll build a web page one day on my website that explains each and every change and how each one effects the car.

A lot of this stuff is second nature to me and is easier to explain in person than it is on a BBS board.

I'm sure if I hurt Daves feelings.. he would have blasted back at me.

I forget to put the smilies and the ha ha's in every once in awhile. Most people know me and know my stupid attemps at humor.

B

Zeke · 10-16-2002, 08:39 PM

Odie, ever thought of entering the seminary? You preach pretty good.

I don't think Brad is your type. I really don't think you're gonna change him.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Now, I'm just trying to figure out if that animated GIF is a comment on what B's "type" is or not...

--DD

odie · 10-17-2002, 07:50 AM

hey, I'm no saint...

campbellcj · 10-17-2002, 08:39 AM

Quote:

Originally posted by Dave at Pelican Parts
Stock 2.0 with stock front torsion bars, 140# rear springs, 19mm Weltmeister front bar, stock rear sway bar: Oversteer!! Pretty massively! Could not dial out the oversteer with the sway bar, with Koni adjustable shocks all the way around (full stiff front, full soft rear still gave oversteer), and even monkeying with tire pressures.

Hmmm...I know there is some subjectivity in this understeer/oversteer stuff, but that's the exact setup I had on my Ravenna car and it always felt quite neutral to me. Definitely not spin-happy or "sketchy" feeling, even at 100+ mph on the track. The car also didn't have enough torque to where the rear bar caused inside-wheel traction issues. My new 2.4 car definitely does, and I had to pull the rear bar off immediately - the car was virtually uncontrollable exiting tight corners with it hooked up.