Jack Stone wrote:
> All,
>
> Is there such a thing as binding in the rear
> suspension of the first gen cars?
>
> Could this be his problem? Could the car be
> bottoming out?
It doesn't bottom out but the Watts linkages bind which has some
adverse affect on the rear suspension alignment under cornering. The
solution to that (in SP/P/Mod) is to replace the Watts linkages with a
Panhard rod setup. This will help eliminate the binding. The other
thing to do in these classes is the replace the lower trailing arm
bushings with polyeurethane and leave the rubber bushings in the upper
trailing arms.
> I run 2#'s less in the rear than the front.
> The actual pressure depends on the tyres run
> and keeping even tread on the ground.
On BFG Comp T/A R1's I ran 34/28. On Hoosier A3S03's I was running
32/26 with about -4 degrees camber. The Street TD's I'm using now
have 30/25 and grip like nobody's business.
> I have both bars 1.125 frt, and .625 rr.
Both? Suspension Techniques or Ground Control? I still have the
factory bar in the rear on my GSL-SE. Is that 5/8" bar adjustable?
Soft or stiffer than the stock bar? Several people have told me that
they used to run without the rear bar on their CSP Rx-7's to combat
the rear suspension binding. It removes a lot of oversteer but not
so much that you can't bring the rear out with judicious application
of the loud pedal.
> Springs play a role as well. If they are
> sagging then they will also make the car
> handle bad.
>
> Another thing is if the shocks are worn
> this also causes problems.
Yes and Yes! I couldn't get softer springs for the rear or I would
have them in right now. MazdaComp said Eibach discontinued the 125#
and 150# rear springs for 81-85 Rx-7s and now only has the 175#
springs. I followed MazdaComp's recommendation of 350# springs in
front on my Ground Control coil-overs. Tokico Illuminas on all four
corners until the 350# springs finally get the better of them. Being
rated for only 200# and using 350# springs can't be too good for them.
MazdaComp suggests Bilstien's after the Illuminas are toast.
> So finding the baseline and correcting from
> there is the most cost effective and productive
> measure. Then with the help of others building
> up the car as you progress.
Absolutely. I did a lot of things at once over the winter in moving
from CS to CSP but _ONLY_ after consulting everyong that cared to
share an opinion on the subject. There are many autocrossers and road
racers on the various Rx-7 mailing lists that have provided invaluable
information. The least of which are Benny Dement, Berny Herrera and
David Lane (who has a lovely turbocharged GSL-SE). I'll be happy to
share any of that information with anyone interested.
--
Tim Schuh - http://www.wankel.net
"If ya ain't hitting cones, ya ain't drivin' fast enough!" - Me
SCCA Texas Region
84 Mazda Rx-7 GSL-SE - #14 C Street Prepared
93 Mazda Rx-7 base - Aftermarket everything
90 Dodge B250 Conversion - #1 Love-nasium and Tow Vehicle
Dallas / Fort Worth Rx-7 list : dfw-rx7@wankel.net
Dallas / Fort Worth Rx-7 webpage: dfwrx7.wankel.net
QwikData Data Acquisition list : qwikdata@wankel.net
QwikData Data Acquisition Docs : http://qwikdata.ugly.net
Texas Region Autocross Video : http://autocross.ugly.net
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