Re: 4 in downpipe
Lot of TurboMustangs gain significant power with 76s by going to larger dp. Go over to TurboMustang.com and do a search. Here's one post I saved and mailed to a buddy with a 76 bowtiev6...
T-76GTS Backpressure test data
« on: June 03, 2006, 10:57:25 PM »
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I've pretty much completed my backpressure testing on the T-76 GTS. Here's what I got:
Recent customer build using a 3.5" downpipe and 377 cid:
10 psi boost - 18 psi backpressure
18 psi boost - 26 psi backpressure
My personal car using a 3" downpipe and 363 cid:
With single 3.5" cat-back and a 3.5" Hooker Aerochamber:
11 psi boost - 35 psi backpressure
21 psi boost - 48 psi backpressure
With no cat-back, 3" downpipe only:
19 psi boost - 34 psi backpressure
The next step is to purchase a Magnaflow 3.5" straight-through muffler to replace the Aerochamber and hopefully keep the backpressure down, but keep it quiet.
The interesting part is that I used the exact same boost controller setting when I removed the exhaust and saw a boost increase from 11 to 19 psi. It seems as though the boost controller and wastegate work more off of backpressure than boost since both had the same ~35 psi backpressure.
