Neice Anne

Hey guys, I was wonderin if anyone knows where a straight pipe (as opposed to a muffler) fits in performance-wise? I really like the sound/noise level of no muffler, but I'm putting a full exhaust system on my car next weekend (y-pipe, no cat, b pipe, and straight pipe replacement) and if a good muffler is gonna help performance more than a straight pipe, I'll get a Greddy or somethin. However, if a straight pipe is the best performance wise, I'd much rather keep it that way! So if anyone could help me out on this issue I'd greatly appreciate it!

DA-MAX

iTrader: (10)

I think you might lose a little low end...if you have no cat and no muffler you are loosing some backpressure along with some "off the line" torque...no my vote goes for a muffler! and having no cat has proven to have negative effects on the VG Max(not sure on the VE, but probably the same)..."Maximum5spd" lost .3+ seconds off his 0-60 after removing his cat, so you might wanna think about that too!

Neice Anne

Okay, won't remove the Cat then (I'd feel kinda guilty about destroying the enviroment anyway) but do you think the lack of a muffler would either a. Lose a lot of low end power or b. add enough mid/high power to make up for the loss? I'd rather not buy an expensive muffler if the performance difference will be rather unnoticeable.. wtf happened to our sigs btw?

DA-MAX

iTrader: (10)

I doubt the gain in mid range will be noticable enough to make any serious difference! from a 1/4th mile race perspective, it will probably just "equate" itself....your starts will suck but it will be made up in the midrange, but by then the race is over...so in a sense no real gains in power! but why not try it...custom Y, hi-flow cat and straight pipe(no muffler), but if you're looking for cheap mufflers there are plenty avaible for around $60-70!

Neice Anne

Heh, you're a one man question-answering machine.. lol. So a hi-flow cat will add hp, but no cat will hurt it... okay... will check out hi-flow cats sometime.. but first I wanna get my car lookin perty (bodykit, paint job.. both kinda expensive

mykizism

its not that a high flow cat ADDS hp its frees up Hp, the old one(stock cat has poor flow inside) as opposed to the more better flowing of a high flow cat, they are both the same thing but the high flow cat has better transition inside the cat, that doesnt mix the flow.. plus the high flow cat is A LOT lighter than the stock cat

also its not surprising that adding a cat will actually give you more low end power.. because if you gut the cat, you will suffer from flow stagnation which inturn will hurt low end power.. because you need flow to be smooth.

"quoted from Sports compact car"
"An old hot rodders tall tale: engines need some backpressure to work properly and make torque. That is not true. what engines need is low back pressure, but high exhaust stream velocity. A fast- moving but free-flowing gas column in the exhaust helps creat a rarefaction or a negative pressure wave behind the exhaust valve as it opens."

so you want to go with a larger diameter but NOT too big, because you dont want to lose smooth , fast moving gas. if its too big then your exhaust gas's wont move very fast. so you gotta find a good size , for our engines 2.5 inch is a decent size.

as of now i have 2.25 inch but when i have time im gonna get rid of it and weld my self a new 2.5 inch cat back.

mykizism

i beg to differ about the gains will equate, because your starts will NOT be that slow, depending on how tuned your engine is.. i have 2.25 inch cat back and the starts are not that noticably slower. as for mid range my system so far is good and high end is good as well, but like i said im swapping out my 2.25 system for a 2.5 system for better mid and high, because i need to go faster haha

and about mufflers, they are not for performance... they are only there to quiet the exhaust note. Yes there are muffers made for peformance, but thats only comparing them to stock mufflers or other restrictive muffler. They are considered "performance", because they are more free flowing and quite the exhaust note a good deal.

the more expensive mufflers are designed to have the best flow, nice quite deep sound, and, looks like stainless steal and all that good stuff.

94Max

ditto, ditto, ditto to what mykizism says....

Find that SportsCompactCar magazine article and read it. (November issue, I think).

The VELOCITY of the moving gas is what's important. Hi-flow devices usually increase the VELOCITY of the gas, but not all necessarily do. Ditto what he says about gutting a cat, or even going with NO cat or going with too large a diameter of pipe.

Neice Anne

Okay, so what do you think about straight pipes (that is.. no muffler) is it different only in that it's louder than most mufflers.. err actually all mufflers, or is it better? It seems to me if I have a big pipe as my straight pipe my flow would be further increased over having a muffler... is this true? Cuz I'm replacing my straight pipe this weekend (bad weld job on my current one..) what size pipe do you think I should use?

SuDZ

I seen some on Ebay before. Try searching there.

SuDZ