would that be an over kill for a 3.4 a buddy of mine has a flowmaster catback and said he would sell it to me for 50 bucks he took it off his camaro b4 he sold it

 

Sounds like a killer deal. Yea, overkill would be a good word to use. But hey, it gives you something to grow into.

 

I didn't know Flowmaster made 4" catbacks. Are you sure it isn't a 3"?

If it is truely a 4", it will kill what little performance a 3.4L has. Do you want to spend $50 for more sound and a slower car?

Even 3" is overkill on such a small engine. Stick with 2.5".

 

would i notice the power loss i have a slp CAI on it

 

Mufflex makes a 4" catback with a Flowmaster race series muffler on it. Good for over 1,000HP..... wouldn't do much help or harm to the V6. Let's not get into the "backpressure" arguement.

 

No backpressure arguement here. Didn't even mention the myth.

The problem is that 4" will lose too much velocity on an already torque challenged engine.

 

Sound worse and be slower - yes.

 

Why does the velocity in the intermediate pipe and muffler affect the engine torque? Its the velocity in the primaries that provide for scavenging. Once you get past the collector, high velocity = high pressure loss = high back pressure.

 

Not true. The gasses remain in pulses and as thus the scavenging effect happens all the way down the pipe/s.

Then you also have the fact that he'd probably be going from 2, 2.5" pipes merged into the single 2.5" "collector" of the Y then opening way up to a 4" I. Ya, that turbulence will be great for performance.

The trick is to get the size of pipe with the best velocity and flow for your particular need (engine size, RPM, etc) and 4" on a little 3.4" is way too big.


Don't think it'll cause problems? Try running some overly large pipes on your car then lets talk about it.

 

Some people don't even run "pipes".... just open collectors. I've done it both ways, and measured the HP/torque. No measurable difference.

I agree... a 4" cat back makes no sense for a V6, just for the extra weight it adds. But once you get past the primaries, you're not going to see much of anything as a result of high velocity in the rest of the exhaust, other than increased pressure drop.

 

Your thoughts please Injuneer
420 ci small block
afr 210 comp heads
i guestimate 600 flywheel hp n/a
maybe a lil spray in the future
my question is 3.5" or 4" exhaust?
also if you have any ideas on headers, they have to be square port and fit on a 4th gen.
having trouble finding anything out.

Thanks Mike

 

The difference between open headers and larger than needed pipes is that after it leaves the headers your engine doesn't have to push it anymore. Run that same amount of exhaust through large pipes and your engine is still having to push it, but now you don't have the low pressure from the pulse in front of it to help it along nor the velocity for it to exit quickly. So in essence your engine works harder longer.

Go to the Q&A section on the Magnaflow site and they say the same thing I have. Do a search and you'll find what I've said in many places also. Where did I get my info? From several people that build performance exhausts for a living. I'm not talking about Bubba's Muffler and Lube that specializes in putting glasspacks on trucks either.

Coletrickel, you didn't ask for my input, but I HAVE ran a 4" exhaust on an LS1. Go with the 3.5" Just for the fact that it fits better, especially on a lowered car.

 

Thanks greed

I was thinking of running the 3.5" for pure virtue of clearance of the axle and what not.