You are absolutely correct on this. That is done with almost every single part you can buy for a car or truck.


I cannot tell him what to purchase either, however, what you said about "back pressure" is incorrect. These engines do not need "back pressure" to run, no gasoline engine really does. What is commonly misconstrued as "back pressure" is actually air density. If you make your exhaust to high flowing, to big of pipe for example, the air will begin to cool before it exits the pipe, making it denser. This means the engine will have to push that denser (heavier) air out of the exhaust pipes, which is bad.

The Magnaflow high-flow converters, for example, are an excellent upgrade from your "standard" converter, and cheaper as well. They do not give you to much "high flow" as long as you have the appropriate pipe for your engine. For our V8s, 5.2L and 5.9L, a 3 to 3.5" single pipe or 2.25 to 2.5" dual pipes is about perfect. Any smaller, you're constricting it, any larger, you're going to have to much.

This, of course, is based on the assumption that you have a mostly stock engine or only bolt on upgrades. If you go all out with a supercharger, stroker kit, or etc. etc., you may need larger pipes, I am not sure.

I mostly agree with this statement. However, one thing you don't get what you pay for: throttle body spacer.

 

That is great information about the air density I am never afraid of learning something new. I completly agree with you about the TB spacer 100 dollar paperweight. I stand corrected

 

Thank you for posting that Jason. I generally quit reading threads after someone says "hey but these motorz need backpressure or your torque will get pwned!"

I'd really like to know who started that rumor...

 

yeah, on my truck i have a single 3" with no cat and a turbo muffler....does great and will spin the tires without powerbraking.....now if he were to go with straight pipes, then yeah leave the stock cat.... but a turbo will outflow a flowmaster, so he should have no prob

 

i also believe that backpressure and density go hand in hand..... afew weeks ago i was playin around and i took the muffler off and took it for a spin......it was a complete dog......loud, but no ***** whatsoever

 

Another thing that people dont quite get about exhaust, is a properly tuned exhaust will actually create a vacuum at the head sucking the exhaust out of your cylinder. This is why if you put 4in pipe on your truck, you will lose hp. Air density plays into this, and also header header design. This explains why Dakotas Ram runs better with a muffler. The muffler increases the velocity of the exhaust gasses by the diameter being smaller inside the muffler, which creates a vacuum.

 

I found this article and I have to say I have been on the wrong band wagon for quite some time. This is good reading for people who beleive what I used to beleive.

http://www.uucmotorwerks.com/html_pr...torquemyth.htm

 

That was a good read. I stand corrected on back pressure.

 

so i have a question. my system is as follows: longtube headers with 2.5 true duals with an h pipe. with no cat, no muffler. is that a decent setup?

 

I want to put true dual pipes but I dont know what to do. I thought about puting short headers, two high flow cats, an x pipe and two glass pipes 2 1/2 pipe. what do you guys think