For my camaro my exhaust s gonna be set up like this headman shorty headers and y-pipe to a stock cat and then to a dynomax 3 1/2 inch race muffler with 2 1/2 reducers on each side? This will go to the end of the passenger side door.

 

no


nick


Why stock cat??

 

I need somethin to quite it down. and i need some back pressure this muffler is straight through.

 

He said...back..pressure....

 

and

 

I run 1 3/4 slp dual cat headers with dual exhaust, no cats, no mufflers, I would not worry about backpressure.

nick

 

why is it that so meany people think having some back pressure is good?

 

ditch the cat for good it wont be too loud - the stock cat sucks and is old you dont need backpressure and you dont need a cat

 

if i run without the cat i will need to fatten up my carb and maybe even get a bigger carb

 

I have a dynomax super turbo muffler thrown on the end of my y-pipe with no cat. It's really loud. But it sounds good. I had a pipe running so that the exhaust exited behind the passenger side door and it got really really quite. Even quiter than my regular cat-back was. But I really like the sound of just the muffler with no pipe, so thats how i left it, even though it gets annoying at times. And as far as my carb, I haven't had any problems with my stock Q-jet.

 

I know it's a different animal but when I went from aftermarket slip on mufflers to straght drag pipes on my bike I lost some power in the low end.
biker

 

That is not from a lack of back pressure. It is probably because you lost some scavenging. What size pipes are you running now? Backpressure always causes a loss of power, but there are other things that play into the scenario. The reason backpressure causes you to loose power is because the more backpressure you have the more energy it takes for the piston to move the air out of the way. This results in a loss of power clear across your rpm range. This is not to say that you want the biggest pipes possible, but just that it needs to be matched to your system.

Ben

 

I'm running 1 3/4" drags
everyone tells me (in the bike world) that it is always better to have some sort of back pressure.
biker

 

on the other end of the specttrum... look at NHRA cars. im sure if you bent up those headers to give it backpressure its not going to make the car faster...

 

and-what-is-there-cfm-my-only-guess-is-a-hell-of-a-lot-more-than-myne-this-is-a-street-car-not-a-race-car

 

I run hedman longtubes, 2.5 true duals, to 2 2 chamber flowmasters on the street. F*ck backpressure. Dont put the cat in the new exhaust....one day you will be driving down the road and your old *** catalytic convert will stop up and guess what...your stuck....

how much hp are you making with that 357??? dont you think a 600cfm carb is a tad small? Im running a 670 cfm holley SA on my mild 350 with no problems.

 

I've-tried-different-combos-on-desktop-dyno-and-it-only-showed-a-17-hp-increase-if-i-went-to-a-750.-17hp-aint-worth-the-gas-to-me.
o-ya-i-should-be-pushin-around-350-at-the-flywheel-even-though-i-still-havent-been-able-to-find-the-flow-numbers-of-the-stock-461-double-hump-head.-anyone-got-em??