for a good powerful system (302), how much backpressure is needed to obtain ultimate power? whats the ideal system? i have headers to be put in, and two glasspacks, how should i set up my duals to gain some backpressure? a cross pipe connecting the two? any ideas? i want to see how people set up their mav's exhaust, post any pics!
I think the general consensus (not that I followed it) is headers, followed by an X pipe, and then dualled out to mufflers or glasspaks, with flowmaster or magnaflows being the more suggested routes. But, despite this, many of us do headers straight out through muffler/glasspaks. I think the gains are minimal, like 2-5 horsepower. So it is up to you if you want that last bit of power per buck.
well, because today i cut my stock muffler/resonater off, temporarily until i take the rest out to put my new exhaust in. so right now i have the stock ex manifolds and open y pipe; its loud as hell, but a major power loss compared to when i had the muffler/resonater on there causing back pressure. theres just not the same kick when you punch it. whats going on?
Hmmm...I drove mine like that for a few months. It sounded GREAT!!! But I didn't notice any power loss. Watch out for cops until you get it hooked back up right.
the exhaust gases create a pulse or wave(sound wave/pressure wave) that helps to scavenge the exhaust gasses away from the valve.You basically eliminated theat scavenging effect...Thats why it has less power now.
learned something new today. thanks guys. i think i'm going to do a set up like this. headers to straight h pipe to cherry bombs. and then turn downs at the end.. will the H give me enough backpressure
Its more about collector length...desired operating rpm range and your engines ability to breathe (VE) Volumetric efficiency.From your stock manifolds run 2 1/4 to 2 1/2 inch ID pipe...about 14 to 16 inches from the manifolds put your crossover...H or X type....then back to mufflers(low restiction type) and out to the bumper if you can.Try to keep the ID the same from front to back or at least dont go down in diameter after the mufflers.The crossover simply equalizes the pulses from both banks to create a stable pulse wave that wont break up...it does add some torque/hp to the equation but not a huge amount.Good luck!!!Oh!! try to have as few bends as possible in the system (I know its unavoidable) but you get the idea...
What do you guys think about coming off the headers and locating a flowmaster behind the drivers seat and then 12" of pipe . 3" at headers 2 1/2" in and out?
How long are your collectors???Dont step down dia from the pipe to the muffler(you create a restriction this way)Unless your car is jacked up you wont have much ground clearance the way you are describing.How healthy is your engine???
a stock to mild 302 will lose power if you run 2.5 exhast. i cant rember but there was horsepower to pipe size refrence some where. the exhast system is susposed end pulling exhast out. if the exhast pipes are to big the exhast rushes into the big pipes and then stops then the next exhast pulse has to push that last pulse down the pipe. this puting it simple but you should get the idea.
Back to first part about me not feeling any power loss, that was on my stock engine, and I cut the exhaust off just in front of the muffler, so it still had lots of tube length and came and both sides came together to one tube for a while before stopping. I didn't cut it short enough to make it like open headers. Now, when I ran open headers at the track, I lost all kinds of power...
check out this page for some guidelines. Read through the FAQ's. http://www.magnaflow.com/07techtips/faq/question10.asp
So, if I've read this correctly from my headers I should run 2 1/4" in to 2 1/2" out. Collector lenth is aprox. 16-18 inches.The engine is a very mild 302 running around 200 hp. The over all pic would be 3" at the header to 2 1/4" inlet to 2 1/2" outlet. Is this correct? How much distance should there be from header collector to mufflers? I never knew there was so much involved with exhaust and performance, I guess alot of people just put mufflers on the end of pipes and if it quites things down there good.I do understand there is a balance that must occur or you lose performance.With out using a H or X pipe what is the closest configuration for best performance? By the way I did'nt mean to hijack your thread, you and I must have been thinking about the same thing at the same time.Hopefully we both can gain some knowlege about exhaust. Sorry.
dont run 2.5 out of the muffler. as the exhast travels through the pipes it looses heat and contracts. so in theory you want to have the pipes get smaller as you go further back in the system. at the 200 hp level you will probly just as well off with 2" as you would be with 2 1/4".
