Headers & exhaust - ZR-1 Net Registry Forums

Paul Workman · 01-31-2014

Performance is quantifiable, sound is more subjective.

Performance wise, Marc suggests the Corsa with headers, sans cats, if allowed. The package delivers performance gains w/o resonance (I'm told), but they do have a "tinny" sound that some like and others do not.

The 3" Magnaflow system gives a nice, deep tone w/o resonance. However, the resonator chokes down the inlet to a single ≈ 3" perforated tube running the length of the resonator. Furthermore, there are several abrupt(!) choke and sudden transition points throughout the Magnaflow system (6 on the right side, 5 on the left) (which I believe any flow dynamics expert will tell us is NOT conducive to performance. FWIW).

The B&B has evolved from a pretty much wide open 3" cat-back with significant drone in the 1900-2200 rpm range, to a more restrictive system and "lesser" drone.

Pete, ever experimenting to get the most hp, is running a modified version of the earlier B&B system with Watson headers, and now using the NPP valves to control in-cabin drone. (The word is he can now carry on a conversation since installing the NPPs. Others too have gone that route and agree). Nobody is going to convince Pete that a Corsa is better for performance.

Experimenting goes on. I'm a Warrior (at least in my mind and I try to be

) which means I'll put up with a little racket if there's hp to be made. I've watched the FBI efforts with great interest, and I believe the gurus have come up with what I consider the best of both worlds - to date at least:

The system that impresses me is the headers (SW or Watson), sans cats, SW type X pipe, no resonator, the Dynamax 17228 muffs with the NPP type gate affixed to one of the two active muffler outlets.** It is a true 3" system from the header collectors to the muffler inlets for least restriction and max performance, and the valve on one of the muffler outlets reduces resonance to a very tolerable level. What's not to like???

I'm not sure what Marc's setup is, but I don't believe it is a Corsa. And, I know he likes quiet for normal driving and has a pair of the Flowmaster dual outlet muffs on the back with 4-bolt flanges on the inlet side so they can be easily removed at the track. A variation of that is to install cut-outs just behind the differential which is perhaps an alternative to the NPP and perhaps just as effective.

Fact is, all of them are a compromise in some respect. Sound, vs. performance, vs. cost... Always room for more experimentation - and new "stuff"!

01-31-2014	#11
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,466	Re: Headers & exhaust Performance is quantifiable, sound is more subjective. Performance wise, Marc suggests the Corsa with headers, sans cats, if allowed. The package delivers performance gains w/o resonance (I'm told), but they do have a "tinny" sound that some like and others do not. The 3" Magnaflow system gives a nice, deep tone w/o resonance. However, the resonator chokes down the inlet to a single ≈ 3" perforated tube running the length of the resonator. Furthermore, there are several abrupt(!) choke and sudden transition points throughout the Magnaflow system (6 on the right side, 5 on the left) (which I believe any flow dynamics expert will tell us is NOT conducive to performance. FWIW). The B&B has evolved from a pretty much wide open 3" cat-back with significant drone in the 1900-2200 rpm range, to a more restrictive system and "lesser" drone. Pete, ever experimenting to get the most hp, is running a modified version of the earlier B&B system with Watson headers, and now using the NPP valves to control in-cabin drone. (The word is he can now carry on a conversation since installing the NPPs. Others too have gone that route and agree). Nobody is going to convince Pete that a Corsa is better for performance. Experimenting goes on. I'm a Warrior (at least in my mind and I try to be) which means I'll put up with a little racket if there's hp to be made. I've watched the FBI efforts with great interest, and I believe the gurus have come up with what I consider the best of both worlds - to date at least: The system that impresses me is the headers (SW or Watson), sans cats, SW type X pipe, no resonator, the Dynamax 17228 muffs with the NPP type gate affixed to one of the two active muffler outlets.** It is a true 3" system from the header collectors to the muffler inlets for least restriction and max performance, and the valve on one of the muffler outlets reduces resonance to a very tolerable level. What's not to like??? I'm not sure what Marc's setup is, but I don't believe it is a Corsa. And, I know he likes quiet for normal driving and has a pair of the Flowmaster dual outlet muffs on the back with 4-bolt flanges on the inlet side so they can be easily removed at the track. A variation of that is to install cut-outs just behind the differential which is perhaps an alternative to the NPP and perhaps just as effective. Fact is, all of them are a compromise in some respect. Sound, vs. performance, vs. cost... Always room for more experimentation - and new "stuff"!