djd2392

So I currently am running a muffler delete on my mustang. Im looking to dropping 2 cats on either side though so there is only one on each pipe. Now can anyone debunk the rumor that this is actually bad for your car since it will be eliminating back pressure? or is it actually not a good thing

Rockwell28

http://www.moddedmustangs.com/forums...-cut-outs.html

#16 is important on this thread http://www.moddedmustangs.com/forums...-cut-outs.html

And i know you didnt say cutouts but you asked about "backpressure" and the str8 through exhaust.

cliffyk

Backpressure Myth I

Backpressure Myth II

GalaxiePete

Those links explain it perfectly. It is the velocity and not the back pressure. If you use anything over 2.5 inch diameter with these engines I am told it is a very noticeable drop in power. That is part of the reason x-pipes work so well also. The pulses are synchronized and help keep velocity up. Long Tube headers also have an impact in particular on low end torque but are great for high RPMs.

rsh0763

This issue has been tossed around since I was child in the 70's and probably even before that. My father explained it to me as I looked at the somewhat smallish pipes on his 4 wheel drive in comparison to the functional "sidepipes" (LOL) on his 69 Corvette. If I was the OP, I would be dropping cats and running mufflers with X or H pipe of near factory size. It has been proven effective for years.

rsh0763

Those links are great descriptions! Now I am going to print them out, in 3 copies. Hand them to my son (who knows everything) and the other two kids on the street who think that the second you put a 3" cat back on your ricer it becomes a race machine.