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3,047 Posts
http://laf.cioe.com/~benbobbo/turbo/dynocharts
The 91 cam one was my car dynoed in July right after I put in the 91 intake
cam. I lost some torque immediately after (stock 98 cam gave me 124 ft-lbs)
but I gained it back several hundred miles later SOTP by the computer
learning the cam.
All turbo hp and All turbo torque are the three exhaust configurations.
DYNORUN.008 is with full exhuast (Stroker's 2.5" downpipe, stock cat, stock
catback). DYNORUN.011 is with the exhaust uncapped in front of the cat, so
just that 2.5" downpipe. pic of it here:
http://laf.cioe.com/~benbobbo/turbo/112500/DSC00019.jpg
DYNORUN.012 is no exhaust, just uncapped at the turbo elbow thing, like
this: http://laf.cioe.com/~benbobbo/turbo/112500/DSC00021.jpg
You notice how the 008 and 011 hp curves die right at 5.5k to 6k RPM, then
just kinda stutter around til redline? We think it was because of this:
http://laf.cioe.com/~benbobbo/turbo/112500/DSC00020.jpg
Mike Jez's wonderful $250 downpipe.
Eric was kind enough to die grind
that restriction away. Didn't get to dyno it after that though. Anyone else
agree?
So that proves how much the stock catback sucks for turbo cars.
Killing
over 30hp and almost 20ft-lbs on my car right now.
And finally here's before and after the turbo (full exhaust on both)
http://laf.cioe.com/~benbobbo/turbo/dynocharts/cam%20turbo%20compare.jpg
Going back to the torque curves, it looks like turbos need SOME backpressure
to keep torque going. Just having the 2.5" downpipe really helped mid range
torque in comparison with no downpipe. I'm sure if the downpipe didn't have
that silly restriction it would have made more torque at the top end over
the no downpipe run.
I also notice I make more torque at the ultra low end of the RPM band with
the full exhaust.
Also the downpipe only seemed to be doing better on power upto 5.5k than no
exhaust. The reason again no exhaust was better at the top end was probably
because of that restriction.
I still like this one the best. It's like two different cars!
http://laf.cioe.com/~benbobbo/turbo/dynocharts/cam%20turbo%20compare.jpg
Comments? Analysis? Questions?
Oh, and here are general pics of the dyno day in Nashville, TN.
http://laf.cioe.com/~benbobbo/turbo/112500
The 91 cam one was my car dynoed in July right after I put in the 91 intake
cam. I lost some torque immediately after (stock 98 cam gave me 124 ft-lbs)
but I gained it back several hundred miles later SOTP by the computer
learning the cam.
All turbo hp and All turbo torque are the three exhaust configurations.
DYNORUN.008 is with full exhuast (Stroker's 2.5" downpipe, stock cat, stock
catback). DYNORUN.011 is with the exhaust uncapped in front of the cat, so
just that 2.5" downpipe. pic of it here:
http://laf.cioe.com/~benbobbo/turbo/112500/DSC00019.jpg
DYNORUN.012 is no exhaust, just uncapped at the turbo elbow thing, like
this: http://laf.cioe.com/~benbobbo/turbo/112500/DSC00021.jpg
You notice how the 008 and 011 hp curves die right at 5.5k to 6k RPM, then
just kinda stutter around til redline? We think it was because of this:
http://laf.cioe.com/~benbobbo/turbo/112500/DSC00020.jpg
Mike Jez's wonderful $250 downpipe.

that restriction away. Didn't get to dyno it after that though. Anyone else
agree?
So that proves how much the stock catback sucks for turbo cars.

over 30hp and almost 20ft-lbs on my car right now.
And finally here's before and after the turbo (full exhaust on both)
http://laf.cioe.com/~benbobbo/turbo/dynocharts/cam%20turbo%20compare.jpg

Going back to the torque curves, it looks like turbos need SOME backpressure
to keep torque going. Just having the 2.5" downpipe really helped mid range
torque in comparison with no downpipe. I'm sure if the downpipe didn't have
that silly restriction it would have made more torque at the top end over
the no downpipe run.
I also notice I make more torque at the ultra low end of the RPM band with
the full exhaust.
Also the downpipe only seemed to be doing better on power upto 5.5k than no
exhaust. The reason again no exhaust was better at the top end was probably
because of that restriction.
I still like this one the best. It's like two different cars!
http://laf.cioe.com/~benbobbo/turbo/dynocharts/cam%20turbo%20compare.jpg
Comments? Analysis? Questions?
Oh, and here are general pics of the dyno day in Nashville, TN.
http://laf.cioe.com/~benbobbo/turbo/112500