368 WHP, My car sucks!

[Stewart, Joe (COX-Atlanta)]

>Earler this week I was trying to tune my turbo classic
>with an of the shelf F-Max kit and S-3 cams and am
>perhaps learning more stuff about turbo cars.

Define tooning. :) Playing with a custom JWT ECU, or what? (Do you have
full fuel and timing control, or are you doing something like playing
with fuel pressure.)

Your HP and torque numbers look pretty normal. Usually if there is a
large tuning problem the numbers will be out of whack with each other.
That's what I usually see.

Have you layed your dyno graph over a 400HP one to see where you are
missing power? Is it up top? Does your HP and torque peak sooner, later?

>that if you want big power, I guess you need that 3"
>downpipe and a worked over turbine housing.

I think this is the part where I bring up the black box tuned DSM's with
2.5" downpipes and the 7cm (.48 AR) housings, right? Stick a gauge in
there and measure backpressure, I can't believe I am the one telling you
this, Mike! Don't throw parts at the car without knowing what the
problem really is.

That being said, I am 100% convinced that the key to turbo power is in a
free flowing exhaust side. Otherwise you get nothing but a really big
EGR valve. In my experience picking an exhaust wheel with enough flow is
more critical than picking a compressor wheel.

What sort of gas were you using? Pump? Race gas? What kind?

As far as porting goes, someone once told me: "Port until you go through
the housing, then weld it, and don't go that far again." This is pretty
much what I do (within reason) and it works really well. That is of
course an over simplification, but for the hot sides of turbos I have
found it to be mostly true.

Pics of my portwork:

http://nx2k.dynip.com/thumbs/assembling%20the%20gsx%20day%205%20web/page
s/assembling%20the%20gsx%20day%205%20011.htm

-Jay