"tell me more..." Part 2
By Jim Alderson.
...I used Eibach springs over Konis for the front
suspension and the old front springs over Konis for the rear suspension.
(If I remember correctly, Kim John Crumb, PCA's 928 Tech expert
recommended this...he may have an even better solution now.) I have a
DEVEK front sway bar and have disconnected the rear sway bar. Red
recommended that with higher horse power 928s using a big front sway bar
(such as the Devek), no rear sway should be needed on the track.
[Additionally, for the best autocross and track lap times, he recommended
that the rear axle should be pinned...but you lose the benefit of the
Weissach axle which allows you to be a less precise driver without getting
in trouble.
With a pinned axle, one
must always use power during turns. Pinning involves drilling two holes
and inserting a bolt into the axle on each side of the car. (I have not
tried this but mention the idea as food for thought.)
The first step to increasing the output of my (219 HP
stock) CIS engine was to improve it's 'breathing.' I could have gone
through the expensive process of installing bigger valves and bench
flowing the existing heads. Or do what Red suggested...put 944 heads on my
928 block.
(Porsche had already gone
through the trouble of trying to squeeze all the HP it could out of the
944 engine's four cylinders).
The 944 heads fit right on! The only custom work
required is to fabricate two metal plates to act as plugs for one coolant
hose port on each head. Even the original 928 bridge for the coolant
between the two heads bolts right on. Red found two used 944 heads for me,
had a complete valve job and guides done on both and installed
stiffer-than-stock valve springs. He cautioned me that I needed to
carefully follow the latest Porsche Repair Manual instructions on
tightening the heads and to use YAMABOND (Yamaha motorcycle) gasket cement
and an OEM gasket.
In 1988/9, there was a very limited selection of after
market cams for the 928. Red suggested Dial-in-Cams and Dial-in-Cam
sprockets. I ordered same from California and installed the 944 heads on
my engine along with headers.
I also had to change out 2
sprockets because we upgraded to the newer cam belt pattern.
I was still using the original (small U.S.) plenum and
intake runners, but the new heads had larger intake ports than the early
4.5 heads. I had Al Collins of Autothority, Fairfax, Virginia grind out
the original runners to fit the larger ports.
This is not an optimal solution. The Euro S runners or
the even larger runners now on the market are the better solution. I
upgraded to the Euro S plenum & runners and the Euro S distributor
when I moved to England in 1989...Later I also wrapped the headers to keep
exhaust gas temperatures up & improve the exhaust flow.
If I were buying cams for
two valve heads today I'd probably buy DEVEK's
...they are ground from new cam billets which were obtained from
Porsche's original supplier.
One of the most important things I did early on was to
install a six-point harness. It makes the driver a part of the machine so
you can concentrate on driving without being distracted by trying to hold
on to your machine. I had a custom harness fabricated which attaches to
two 'eye' bolts welded to the floor by the tool panel in the rear of the
car (there is an easier solution available now--a bracket which bolts to
the shock tower). One of the nicest things I've done of late is to install
a 930 steering wheel...It feels great! Alan Johnson Racing sells them for
non-airbag 928s for about $300 U.S. It is an easy upgrade.
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