Long or short primary pipes? Currently we have long primary pipes and it completely gutless. I'm thinking of shortening them to try to bump up the torque

 

The SpeedSource cars down here have short primary into a borla muffler under the passenger seat area and another one in the stock location.

 

Thank you sir. So I am not crazy.. maybe a little

 

i think with mine i'm gonna go to the dyno with a sawzall, and start long and make it shorter until the engine and i are happy....

how long are yours? tested backpressure?

 

I need to measure, but the header to the rear subframe. Not sure on the backpressure

 

it LOOKS fine... if you put an 02 bung in there, its pretty easy to make a backpressure tester

 

There won't be much backpressure with that system in the picture but it would all depend on the muffler. I use a 6" piece of metal brake line brazed to the exhaust to hook up my magnahelic gauge. The brake line keeps heat from being an issue with the flexible hose to the gauge.

I first did this on an EP car that was running a Spintech muffler and was blowing 93db at the track. With the test port just ahead of the muffler the car pegged the 15"Hg gauge by the time the engine hit 4000 rpm. Not good, the muffler was like a potato. The new exhaust barely registers on the gauge and is, of course, a lot louder. It regularly registers 100-101db.

 

Dynomax Muffler. Should not have much restriction

 

yeah i think that muffler flows like 1100cfm or something....

maybe the primary length is off? i screwed mine up, but i wanted to do a slip fit, so i could just cut it and not have to reweld it back together... but its welded

plan B is to go to either midnight performance, or redzone, cause @midnight the dyno is above ground so you can build the exhaust ON the dyno...

 

I'll be at my friend's shop tomorrow and there happens to be a Speedsource exhaust laying on the floor... just need to find my spy camera...