tgleason

Thanks to the advice of Hot Rod Diesel I had a 4&quot; straight exhaust installed on the truck today and what a difference. The sound is awesome and it seems to jump a bit more when accelerating on the highway. Might just be my ears telling me its faster though. Beautiful sound anyway.<br><br>Also got my 2 pod pillar mount with boost and tach from Hot Rod Diesel and they went in in under 2 hours total time.<br>I should also thank all the guys on this site for the great advice that is posted here.<br>Todd<br><br>93' 4x4 Auto

Paws

What is the advantage of 4'' over 3''? besides the 'cool' factor of that 4'' pipe sticking out the back of the truck.

tgleason

Better flow, less restriction. Heath at Hot Rod Diesel told me they have had there best results with 4&quot; exhausts for power and mileage when combined with a high flow air filter which I have also installed. I assume air much like water has different Friction rates for different diameter pipes. As a firefighter I know 4 inch hose has a very low friction loss compared to the smaller 3 inch. Must be similar for exhaust, I think.<br> Plus the four inch does look godd and sound awesome.

haloman

Is the turbodown pipe 4&quot; too??

tgleason

Downpipe is still 3 inches.

Craig93

That is the same set up on mine, 3&quot; downpipe to a 4&quot; straight through to a high horsepower chrome downturned tip....<br><br>The Dyno before and after the pipe install is as follows:<br><br>Stock pipe Max Power 98.2@53 MPH<br> Max Torque 311.8 @ 52 MPH<br><br>4&quot; pipe Max Power 104.0 @51.MPH<br> Max Torque 348.4 @50 MPH <br><br>This was done on a Mustang Dyno fwiw...<br><br>6.4 % Increase in horsepower and 11.8% increase in torque....and the cool factor of course.... <br><br>

tgleason

Was that just a pipe or did you open up the air box as well?

furious70

how much did the system cost?

nascar mark

I have customized some 4&quot; down pipes in the past just like mine. ;D

Craig93

This was with the stock air box and K&amp;N Filter, the system was installed in Calgary by Performance Auto Assist Ltd for $600, this was back in 99....the system was shipped in from an unknown distributor in the good ole US of A.

furious70

anyone in the US put a 4&quot; on lately?