Where are the restrictions on our stock exhaust?

[1998Venom]

I've searched past threads, and haven't found one that answers this question completely - where are the restrictions on our stock exhaust? Headers, H-Pipe, Cat-back?

As a segway from this question, what kind of gains did you experience by replacing each component? This is what I've found in past threads:

Originally posted by 98cobrancali
i had off road h with 2 chamber flows welded in and put down 275rwhp and 272rwtq, and switched to a magnapack catback and put down 288 rwhp and 287rwtq, given it was different days, but both days were in 90+ degree heat, nothing else on car changed, i wouldnt call that little, having all your piping the same size helps out quite a bit

Originally posted by myblk32v
The stock mufflers are actually quite restrictive. I felt a good gain when going to my Magnaflows. And teh stock H on 96-98s only has 4 cats. But yes it will sound pretty good and will free up some HP. I gained around 25hp and 22rwtq when adding my Catback and X pipe.

Thanks.

 

[Tabres]

The stock H actually has 6 cats. There are two each in the larger shields and one each in the smaller shields. I can't give you numbers, but my SOTP meter says there was more power uncorked after I put on my o/r X than just the catback.

 

[rtusnake]

i have read the h pipe and catback are pretty restrictive on a N/A car and when you add a poweradder the headers become pretty restrictive

 

[cobra4v]

Tabres is correct. You would get the best bang for the buck by installing an off road h or x pipe. You would feel the difference just by doing that mod.

 

[98cobrancali]

the whole system is restrictive, starting with the exhaust manifolds, the 96-98 cars have the worst flowing, the h pipe 6 cats is pretty restrictive, and the mufflers dont help either, when i dynoed 275/272, which was quite a while ago, i had a 2 1/2 inch off road h and 2 chamber flows welded into the stock catback, my 288/287 was with said h pipe and a whole 2 1/2 inch maganpack catback, the biggest gain you are going to see though is to replace the h pipe with either a high flow cat or off road pipe, since the typing of the above statement from me i have added jba style short tube headers and have yet to dyno the car with the few other things i have done, but i am shooting for 300 rwhp untuned, a nice free flowing exhaust will help out nicely, of course i got to smog my car next month so back on the stock h goes, i will probably end up selling the off road h cause i want to get a magnaflow catted x pipe

 

[Doug]

Originally posted by 98cobrancali
the whole system is restrictive, starting with the exhaust manifolds

 

[1998Venom]

Thanks so far for your feedback.

MM&FF just did a complete Bassani swap on a '03 GT (headers, catted X-pipe, cat-back) and gained 17 HP and 17 lbs/tq. I'm shocked at these numbers - I figured 25 or so for both. Should I expect similar results on my Cobra?

Thanks again.

 

[98cobrancali]

yes, you can expect more if you go with an off road pipe, headers and catback

 

[1998Venom]

How similar is the Mach 1 to our SN95 Cobras?

5.0 Mustang & Super Fords dynoed a complete Bassani system (headers, catted X-pipe and cat-back) on a Mach 1 and netted 24 HP and lbs/tq. Is this more like the results that I can expect?

Thanks again.