Mark R. Jahnke asks:
> I have heard several people talking about putting smaller sway bars on the
> front of their cars. What does a smaller sway bar do? What is the
> advantage of going smaller.
A smaller front bar will help create more oversteer. Letting the outside
front tire move up further gives the remaining tires more loading, so the
front tires generate more total force before sliding, increasing the chance
that the rear tires will let go first. This is one of the first things I
did to my neon, back in the days when it seemed I could never get the back
end loose. After about a season of running that way, something started to
change - I'd like to think I started driving better - and I couldn't keep
the rear end behind me, despite lowering the rear pressure to compensate.
When I switched back to the stock bar, the oversteer got much easier to
control - I find that I can still get oversteer when I want it, and just
occasionally, when I try a hard turn or slalom going too fast, it comes
around before I can catch it. Thats basic driver error, I think the car is
set up alright now. I might mention that I have stock (soft) struts. With
firmer struts, a softer front bar might work, but I wouldn't know for sure
without trying it.
> What are disadvantages of having bigger bars?
If you push before changing the front bar, it'll push worse after going
bigger. Bigger bars will make the ride more harsh. Bigger bars may
stress the body mounting brackets beyond the strength of the stock parts
on certain cars.
> I have the Mugen front and rear 26mm bars on my car, opposed to the stock
> 22's.
Ahhh, a non-stock-class setup. You have quite a few variables to play with
once you cross the line with a different rear sway bar - spring rates and
ride height are fair game in SP and above...
> I would think that a bigger bar would make the car more stable, etc.
> Guess not.
Suspension is a synergy of the components - they interact with each other.
Strut damping controls how fast the car rolls on turn-in, while springs and
bars control how far the car will roll. In the simplest terms, stability is
a balance between the suspension not oscillating at all, while being
compliant enough to maintain continuous force against an irregular road.
Be sure you test in competition, or you won't know if your tuning has made
the car prone to snap spins (see the Miata thread where some poor guy
rolled his car while testing his front sway bar change on a mountain road).
On top of all this, tire pressure always plays a major role. Its no wonder
optimal is so hard to find. Make predictable and controllable a priority
for safety's sake. In my experience, the car that doesn't spin and stall
is faster. ;^)
--
Jeffrey D. Blankenship Senior Technical Consultant
jblanken@itds.com ITDS - TRIS
neon enthusiast #478 Champaign, IL, USA
|