Stiffest front sway bar??

[bensonae]

What is the stiffest and largest front sway bar for an 05 leg gt 5 spd?

[Val]

Granted there's not much info in your post, I can't see why you would want a stiffer front sway bar, which would increase understeering.

[chucktoo]

Cusco 23mm front and 21mm rear works real well.

[Guest turboman]

As was said, a stiffer front bar just increases understeer (front tires squealing and straight off the corner).

 

You might want to use stiffer bushings and stronger end links to tighten it up a little. And get as much negative camber as you can on the front.

[racerdave]

Ah, grasshoppers... but less roll up front means less dynamic (positive) camber change. So it is not all it appears to be.

[Xenonk]

Granted there's not much info in your post, I can't see why you would want a stiffer front sway bar, which would increase understeering.

 

Not if you know how to drive the car. Understeering happens the most when the driver is doing too much steering input in combination with excessive speed that exceeds the tire grip limits. I've been talking to a lot of Solo2 Stock class drivers about larger Front Sway bars helping out on initial turn-ins to keep the front end level and less corner-pitching. With this note, when going into a turn, instead of the outside front wheel doing all the grip work, the larger sway bar will help transfer some of the load from the outside front tire to the inside front, giving you more grip on the front end initially (1 tire grip vs 2 tires grip). Most people say it produces understeer is because they are overloading BOTH of the tire's grip by either over-braking or adding too much steering input.

 

From what I know, I am running Cusco Vacanza 23mm solid front sway bar on my 5sp Sedan GT.

 

Keefe

[firedawgs]

The problem is with the rear swaybar. Why would you want to change the front swaybar? You will increase the understeer changing the front.

[bensonae]

i am getting the 23mm cusco front as it is the stiffest it would appear currently avail. for our car. xenonk is correct about the addiitonal grip and driver pushing a car to understeer. plus that bar w/ a whiteline rear bar on the stiffest setting should make it more neutral.

[racerdave]

We also have a strut front suspension, which has a very poor camber curve as body roll increase in comparison to a dual-wishbone setup. That's one of the reasons the older Hondas handled so well stock... like the last-gen Prelude.

 

But with a strut-type suspension with a more limited camber curve, less roll actually helps limit the outside tire from going more to positive camber in a corner... which, surprise, helps cornering speeds.

 

Some of the original 16v GTIs and Sciroccos -- when autocrossing in stock form -- actually ran monster front bars to *reduce* understeer. The reason was that it kept the outside front's contact patch in better contact with the road.

 

So don't just think that the overly broad generalization of "more front bar = more understeer." It's not *always* the case...

[Guest turboman]

We also have a strut front suspension, which has a very poor camber curve as body roll increase in comparison to a dual-wishbone setup. That's one of the reasons the older Hondas handled so well stock... like the last-gen Prelude.

 

But with a strut-type suspension with a more limited camber curve, less roll actually helps limit the outside tire from going more to positive camber in a corner... which, surprise, helps cornering speeds.

 

Some of the original 16v GTIs and Sciroccos -- when autocrossing in stock form -- actually ran monster front bars to *reduce* understeer. The reason was that it kept the outside front's contact patch in better contact with the road.

 

So don't just think that the overly broad generalization of "more front bar = more understeer." It's not *always* the case...

 

 

Speaking of Sciroccos, I ran one in Solo2 in '75 and a Rabbit in '76 (I took SCCA Central Division championship w/Rabbit). At that time nobody sold heavy sway bars, it may have changed in following years. These 2 cars had virtually no weight on the rear wheels. The inside rear wheel would lift 6" in a tight turn. You could literally take off one rear tire/wheel and it would stay up in the air by itself. So any swaybar characteristics applied to these cars has no bearing on a normal car.

 

The best way to increase turn in sensitivity on a macpherson strut is to run as much negative camber as you can get (helps keep the heavily loaded outside front tire more vertical), ideally along with toe OUT. The toe OUT will make the car difficult to drive on the street as the tires will follow every bump on the road.

It's feasible to readjust toe at the event when you're changing tires.

[Guest turboman]

For a good autocross suspension alignment reference source use "dogpile" as the search engine and enter "toe-in, autocross". Haven't had a chance to go through all the items but it looks interesting.

 

Question I would like answered and never have is...what is the effect of the drivers weight on suspension alignment? On a McPherson there probably is not that much effect, but if there are upper and lower a-arms I wonder...

 

There aren't many alignment shops that will let you sit in the seat while they align it. Most shops nowdays don't even like customers in the service area, supposedly for insurance reasons (?). But you see outside vendors from Snap-on and Matco and Speedi-clean walking around the area all the time.

[Jay]

Yukon,

 

I'm running the 23 mm front 21 mm rear Cusco setup. It is very balanced and I'm quite happy with the results. Xenonk runs the same setup, except he was able to get the adjustable (21 mm) Vacanza version for the rear. (Evidently Cusco has decided it will not import the Vacanza brand to the US. The Cusco sways are identical to the Vacanzas up front, but don't have the two bolt positions for adjustment the Vacanza's have in the back and have a slightly different bend geometry at the end points.) I installed mine on Xenonk's advice.

 

I do wish the front bar was a little more stout to improve turn in, but overall, it's a very good setup.

[Guest turboman]

Jay. If want more responsive turn in, have the front toe set at 1/8 to 3/16 toe OUT. It will make the car a little "darty" on the street but the faster steering ratio on the GT should make it correctable.

 

Another trick is to run the rears ALSO at about 1/8" toe OUT. Makes the rear want to come around more with trailing throttle.

 

And run at least 45-50 lbs in the front tires. This pressure is for SOLO days only. By the way a STIFFER front bar INCREASES understeer, not quicker turn in. Heavier rear bar makes the tail come around easier (oversteer).

[yukonm]

I would agree with turboman - I'm not sure a stiffer front bar will help with turn-in. With a stiffer front/softer rear, the front outside tire would take more load at initial turn-in, which I would think would increase its tendency to slide. In comparision, I would think that with a soft front/stiff rear setup, the initial turn-in would result in some initial body roll, transferring load to the rear outside tire. The load on the outside front tire would be reduced and be more distributed over time because it would share work with the inside front tire (less body roll resistance from front end) and the outside rear wheel (more roll resistance from rear end).

[Xenonk]

Actually, it does by keeping the more level and sharing as much of the grip in front tires using TWO tires instead of nose diving into ONE tire (the area of contact patch is greater with 2 than 1).. of course, over-driving the car can also result of lifting the inside front, making the front sway useless. If you are lifting the inside wheel, you might want to look at upgrading springs to take in the duty to be able to support all the force of the ENTIRE front end of the car on ONE front corner.

 

Keefe

[Guest turboman]

Respectfully to all, but.. you are overlooking the effects of "toe" setting. At the Nationals there are drivers that run as much as 1/4" toe out on the front (slightly less toe out on the rear) if it's a tight course and an abrasive concrete surface.

 

Since castor is not ajustable in stock classes (no camber plates) "toe" is even more important than camber. And neg. camber is critical. I never fully appreciated "toe" when I last went to the Nationals (way back in the '70's). But this year will be different. Got five of the new Azenis RT-615 (613?) ordered. Ran (the earlier Azenis) on the street and at solos on my WRX. Fabulous tires and year long wear.

 

This much toe (1/4") is not a street alignment. The car will follow every bump and dip in the road. And it'll greatly shorten tire life. If you drive to an event you can drive home with it and reset it in the garage. Easy to do once you've done it. And the tie rod threads can be marked with paint.

 

Read every copy you can get hold of (bi-monthly mag) "Grassroots Motorsports" and how they set up their project cars. Especially the issue on the WRX.