Custom exhaust built up on Borla muffler

[RotoFlexible]

I purchased an "SS" muffler but my engine builder rejected it out of hand after putting it on his flow bench. About the same time, I located a Borla 2" muffler and tip at an excellent price from an online retailer that was reducing inventory. I bought a length of 2" straight pipe and a couple of J-bends, all stainless, from Classic Tubing in New York, and turned it over to my master welder to fabricate and hook up to my Dave Bean header. This is the result.

Unless you can do the welding yourself, I doubt this is cost-effective (compared to an off-the-shelf big bore exhaust), but I like the result. The sound is pretty mellow at part throttle (though still a little louder than stock), but it really snarls under acceleration. (The upgraded engine has something to do with that, of course.) The tubing is all 16ga and the welding is superb, so I expect this will last forever unless it's damaged.

[Greg Foster]

Nice job! Did you install the big bore headers? What diam. header pipes and outlet? Was there any interference with the frame?
Greg

[RotoFlexible]

Greg,

This Dave Bean header is not the Tony Thompson big bore header that requires frame surgery, but it's bigger bore than the stock item. The data I have is: 1.38" primaries into 1.5" secondaries (very long at 25") into a 2" outlet to the intermediate pipe. It fit pretty easily after I removed the engine mount - couldn't thread it through otherwise, and getting the engine mount back in was a bear.

We didn't dyno it against the real big bore header, but Bill did try it with shorter secondaries - as I recall they lost some top end but filled in a lean spot around 2800 RPM. In the end we went with the long secondaries.