[Fot] Hmod Handling question for your entertainment and my assistance

[Bill Babcock]

I'd try every suspension tuning trick before cutting anything, unless you
really are going to do the cut anyway, then I'd do all the tweaking after
that. Shortening your rear springs would have stiffened them, and that
generally REDUCES understeer. For some reason your car went the other way, so
I'd guess there's something else going on. You are right in thinking
shortening the front springs should increase understeer, but something is
wrong somewhere, so if your determined to lower the ride height, get that done
and start tuning.

The list starts with tire pressure. find a place you can use as a skid pad or
a track with minimal straights (skid pad is better). Run the car around until
tire temps settle and then get a reading. You want center temp the same as
outer or inner (usually inner, though if your camber is really screwed it
could be either). See what that gets you, might be all you need.

Then set your camber. On a skid pad you want even temps across the tire, on a
track you'll probably be happy with inner and center the same, outer a bit
cooler since it gets more cooling in the straights.

Adjust your roll bar--softer reduces understeer.

For sure check your bump steer, sometimes sudden onset understeer is caused by
roll-induced bump steer.


On Apr 13, 2010, at 7:43 AM, <dos_gusanos at msn.com> wrote:

> Gang,  The Renault powered Bunce Buck has developed a small problem in
> otherrwise flawless handling at least at the speeds so far seen in the car.
> At the Coronado race there was a flat out left hand sweeper where I may
have
> been seeing 60 mph.  The car began to push (understeer) beyond my
capability
> to anticipate it.  This caused me to have to left foot brake to reign it in
> and this action did not improve my lap times.
>
>
>
> The Details:  The car is rear engined and I had to shorten the rear springs
to
> bring the positive camber in the rear into line.  The front end is a little
> higher than the rear giving the car an aggressive stance that disguises the
> powerplant.  I want to cut the front springs to lower the front end and put
a
> little more weight up front.
>
> I worry this will make the front end even stiffer bringing on other
problems
> and make the rear end loose at turn in.
>
>
>
> What say you?     I'll probably do it anyway...................Cheers Henry
> Morrison, Albuquerque