Originally Posted by 65 Imp SS
Here are a couple of articles to check out:
I ended up running an x-pipe with a "warmed" over bbc (pic in avatar) and it is different from the norm dual exhaust but it does not even come close sounding like a v-6...
I recall reading Hand's take on X vs. H pipes, don't remember exactly where I saw it but IIRC he had graphs and such showing et/hp/back pressure or something like that. On his
car the X was better- but you can test different cars and get different results, so IMO there is no clear "winner". In Hand's case, the difference was so
great (over 1.5 tenths IIRC) that it makes me believe there were other problems besides just the difference between an H and an X. Anyway, I use H pipes because of the ease of fabrication.
FWIW I had a set of 3" Flowmaster 40's and like them just fine, tests be damned. They were what I found for a deal, I ran them, the car ran better than expected regardless of being "hampered" by the FM's. One concession I made to comfort over speed was to insulate it; I used recycled floor insulation out of the 'yard. Weighed a little but kept the drone and heat out.
But one thing I can GUARANTEE you- no one
mistook it for a V6 unless they were brain dead!