my new muffler

[4571N4]

like i said in my other post. i said ill get my muffler (just the muffler) fitted in a few days and today i did. i have mixed feelings bout it tho. im happy it replaced my old, stock, rusting muffler. but now im afraid its going to defect my car. it has a 2.5" inlets and a 4" tip. its very loud, even louder than the rexy's, imo. the bad thing is that my car has lost alot of power. dont know exactly how much but i can tell the difference from b4 and now. here is a few pics i took. they not clear cos i just took them, and its dark atm

[arden]

yeh 2.5" is hella loud.

[4571N4]

u reckon defect?

[arden]

well i had a 2.5 system with extractors and it was heaps loud
i had to put 2 resonators to tone it down and to me it was still loudish.
but ive never been defected.
guess it depends where u live.

[mazdamanik]

ur power loss may come back once the computer learns the new mod, mine did the same after bout a week of driving it was back to normal

[4571N4]

Originally Posted by mazdamanik

ur power loss may come back once the computer learns the new mod, mine did the same after bout a week of driving it was back to normal

so u r saying my car would be back to normal without me doing anything except drive it?

[arden]

i bet uve lost power down low revs right mate??

[4571N4]

basically anything below 3500rpm. and take off is ****

[arden]

i hate to say it but u'll never get that low end power back.
even if u reset ecu or wait a bit longer.
ur mufflers too big.
stock piping is close to 2", and ur new muff is 2.5"

[skippy]

Did you replace piping or just the actual muffler,

[AstinaBoiV6]

the stock pipe is 2" in the BA but ive been told that its a dual layer so theres another pipe inside.. the exhaust place guys said that its actually flowing through about 1 3/4" of pipe stock and recomended i dont go past a 2 1/4 " catback as i will lose power.. as soon as i put the cannon on with its 2.5" in and 4" out i cold feel the backpressure wasnt there and it was slower off the line. even with a 2 1/4'' u still lose a lil power depending on how much power your engine puts out initially. they actually said straight 2" throughout is better.

[skippy]

yeah 2" is what I was recommended then I got told BA has a stock 2" so I wasn't going back but now hmmm a new light there, twin pipes hey how very odd,

[4571N4]

Originally Posted by arden

i hate to say it but u'll never get that low end power back.
even if u reset ecu or wait a bit longer.
ur mufflers too big.
stock piping is close to 2", and ur new muff is 2.5"

wen i asked ozmazdaclub what is the muffler inlet size, some replied it as being 2 1/4

Originally Posted by skippy

Did you replace piping or just the actual muffler,

what do u mean? my old muffler was chopped of just behind the muffler and a approx 15cm connected was welded

[arden]

Originally Posted by 4571N4

wen i asked ozmazdaclub what is the muffler inlet size, some replied it as being 2 1/4

hmm i think they meant 2 1/4 is what u should be looking at getting

[ezin]

The computer wont learn crap, if there is a change it does it dam quick, basically when u remove some back pressure it slows the air thats going into the engine at low speeds but gets better air flow high in the rpm. Our cars have air flow meter which work instantly, so it puts the right amount of fuel in for the air coming in, since there is less air there will be less fuel thus equaling less power. this will never improve. Ur car should go quicker when u rev it out to the limiter, since the engine will be at 5000rpm when u change to 2nd, so in reality u have to drive like a madman (with a loud car now) to get any good power out of it. Plus day to day driving will be no where near as good. As they say u dont get somthing for nothing.

People say it improves but in reality u just get used to the lower power. The dyno never lies, it clearly shows the peaks in the graph dramatically change going a lot further up the rev range, some sp20 graphs show power at 2000rpm drops by 50% with an exhaust on so not only is it loud it will have no power while driving it soflty.

[Laser the Amazer]

Originally Posted by arden

yeh 2.5" is hella loud.

I had 2.75" on the Lynx and was basically as quiet as stock.

depends what muffler's are used

if its really loud I reckon you'll be sick of the noise in a week or so

Rob

[AstinaBoiV6]

haha u should just get a silencer put in for $40 coz the droning noise sux after a while.. see how u go..

[Ian]

omg cannon!

[AstinaBoiV6]

omg turbo!

[Ripper323]

Oh, a starry blue one, aren't they purdy?
Any way, I've just taken a cat back system off my car and returned to the standard one and I noticed a performance increase down low, but it seems a bit asthmatic at the top of the rev range. I had a 2 1/4", and even that was too big. Ideal would be 2" mandrel bent, with a straight through 2" muffler on it, properly designed extractors and high flow cat.
In a small NA engine, you are after exhaust gas speed, not volume.