Data from drag strip

[Roger Heflin]

Bruce wrote:
> 
> There are 11 sec GNs using a single 3".
> Just a matter of what you wanna spend,  I think some folks get overly
> carried away.  Muffler type has as much to so with it as anything.
> Bruce
> 
> > Is there an ideal threshold for WOT exhaust backpressure which defines the
> > point at which attempting to reduce EBP further would yield very few gains
> > in a hot street car with a matching cam grind?  Has anyone ever seen a
> > rule of thumb correlation between EBP and lost HP?
> > Walt.
> 

I am running a Borla exhaust, hooker long tube headers (93 Z28 409 LT1).
The borla is a 3" single, and the long tubes are 1.75 each into 3" collectors.

The car has run a best of 12.21 through the full exhaust and a best of 
12.11 through cutouts (dual 3" cutouts).   So my exhaust is not holding
me back terribly much.   

Given the small difference between exahaust and no exhaust, I really cannot
do much better with any exhaust system, since no exhaust only gets about .1.
I was suprised based on what the aftermarket exhaust people say about 
exhaust size.   My car should be running just over 400hp.

				Roger
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