Dwane

Has anyone tried the H&R 26mm rear swaybar?
I have a C4 and was thinking about this bar...
Any/All suggestions welcomed!
thanks guys
dwane

ilko

Holy oversteering batman! 26mm, that's an inch thick!!

joey bagadonuts

It's difficult to say if it's a good or bad idea without a little more information.

- What suspension is currently on your car?
- What tires (brand/model/sizes) and wheels do you run?
- What tires pressures?
- What are your alignment specs?
- Under what conditions do you drive your car? Street only? Track? Sunny? Wet?
- How does your car currently handle?
- What is it that you hope the sway bar will do for your car's handling?

Dwane

-H&R/Bilstein
-225front/255rear
-36psi fr/bk
-not sure I told the guy to align a little aggresive
-mostly street, 3 de's a year
I want to reduce understeer....yet I don't want to introduce oversteer!
thanks
IT'S a C4!!!

FotoVeloce

Actually, I ran a big TRG only on the rear of my C2 and it became VERY neutral.

In fact I still have the matching front TRG still in my shop, even though the 964 has been sold. The TRG was pretty big, (22mm) but not that big! The front I have is a monster bar (25mm according to the website)

joey bagadonuts

Sounds like you have the right idea, Dwane. Fine tune with a sway bar--but without turning your ride into a tail happy sled.

That 26mm bar from H&R might be a bit too stiff. I've done some rough calculations using the following formula: Sway bar spring rate = K x {D4 / (L x A2)} where K = 1,178,000 (constant for steel), D = bar diameter, L = bar length and A = arm length. The numbers are exponents, e.g. A2 = arm length squared.

My calculations produced the following spring rates for various rear sway bars set at the middle position:

19mm 236 lbs/in
22mm 424 lbs/in
26mm 827 lbs/in

My suggestion is that you start with a 22mm rear bar and see if that doesn't solve the problem. The real culprit in your set up are your spring rates. Like most aftermarket spring sets, the H&R's feature rates which are similar front and rear. Many racing 911's use springs which differ by 200 lbs, e.g. 600/800 lbs/in front and rear. The relatively soft front springs is what gives these cars better turn in.

Mark in Baltimore

I think a 26mm rear bar is way too big for a 911. I have a TRG bar (22mm) in the rear and it's too big (I'm at the softest setting and no longer have any more adjustment. The next hole is too stiff).

I believe you want to run the lightest bars possible.

joey bagadonuts

Agreed. The right solution is to find a lighter front bar but there aren't a whole lot of options.

Remind me, Mark, what spring rates do you use with your Motons?

Dwane

So Joey, What are my options?
-Combine springs(greens front/reds rear)
-Softer front bar/stiffer rear (Who makes the bars?)
HELP

joey bagadonuts

The TRG (The Racer's Group) 22mm rear sway bar should be fine and you can probably get everything you need from SmartRacing.
I ran the TRG 25mm front along with the 22mm rear on my C4. With RS Coilovers (300/500 progressive springs) it was pretty neutral.

Start there, Dwane, and then see if you need to make additional tweaks.

forklift

A few thoughts from my backwards spring world.

I ran 750/900 spring rates w/ my double JRZs and RS sways (22/19?, can't remember)....and have OS I coudn't dial out no matter what combination of sway and shock setting (I realize sways for mid-corner, shocks for entry/exit).

So...the drastic action was to go 900/750 with the springs (reversed)....and you guessed it US. However, I can dial it out (mostly) with the sways on full soft / full hard. Actually the car feels GREAT with this set up.

But....I am really out of adjustment if I get on a tighter track, so I mentioned to my shop going w/ something like 800/750...and they said to try a bigger rear bar instead.

A few weeks later at a suspension seminar at TPC I asked Mike Levitas (pro driver and owner of a very fast 964T) about my quandry and he agreed to put a bigger rear sway bar on the rear and to leave the springs alone. I remembered his exact words, "you can't get enough bar for the rear of a 964."

So.....still not sure what to do, but am thinking about buying a TPC, TRG, or H&R sway, probably TPC if priced ok since Mike took the time to help me....or taking Mark's advice and just leaving well alone.

Btw, it was pointed out to me that 997 Cups come w/ matching spring rates from the factory, front and rear are the same spring rate....although I know not a direct comparison to a 964, I thought it was worth noting.

Larry Herman

Jim, I have to respectfully disagree with Mike L, with Chris Cervelli backing me up. My car is setup by Chris with RS bars and it certainly does not need a stiffer rear sway bar. If your spring rates are properly stiff enough, and I am not an advocate of your reverse setup, then the purpose of sway bars is for some added roll resistance and tuning the balance. If you have to run some crazy large bar, then your spring rates are not right.

That being said, there are some cars that have very different setups that go quite fast. The ultimate difference is that some "fast" setups are very easy to drive right up to the limit, and others are not.

Mark in Baltimore

Hey Joe,

It's either 1400/1700 or 400/700; can't remember.

Just messin' with you. I have a fairly soft set up, 700/900. It's not Cervelli-hard, but, dammit, it feels great for my relatively low skill level.

Man, Evans' set up is just fine. I implore you, for the love of God, do not let him get any faster.

forklift

Thanks Larry. After putting much thought into this I agree that my answer lies in the springs, so when the time ($) is right I think I will move the front springs down to 800 from 900. I would move the rear springs up, but since I don't have a trailer, I think I will go a little softer. I-95 is hell to VIR. But as I mentioned, I will probably leave it be for a little while. I plan on coming out to Summit next weekend to visit you, Chris and Bob. Looking forward to a good/cold weekend there starting tomorrow.

Mark! LMAO, thanks, but you won't see me racing for another year at least...but hopefully before 2040, lol. Get your *** to Summit tomorrow!