Extractors and cats... *UPDATE Pg 6 Dyno Results

[mikey-]

Was thinking of trying to adjust it on the rubbers.

Thanks, I'll go do it now

I've just taken a photo of how high it in, but camera is being a POS and wont connect to the computer.

I recon I got it 5mm higher... The cat piece is now sitting at the top of both the extractors flange and catback flange. It aint going no where higher haha.

 

[helmotbros]

Exactly, how long IS a piece of string. When talking the 2 1/2" and 3" on the same car, IE fit a 2 1/2", then take it off and fit the 3", it will be deeper and louder. I don't know the exact dB difference, but a definite noticeable increase in noise. Not illegally loud if you use the muffler/hotdog combo on the front. I can still do a pretty good deal on the 3" stainless combo as well. Obviously, it won't be as cheap as other stainless polished systems, and that is the key word, it won't be as "cheap".

Okay so lets come at it from a different angle, if i was to go 2.5" and put a cam, heads and blower on, would i lose ridiculous amounts of power? Im not gonna be chasing numbers on a dyno, im not really into that, but if im gonna be putting time and money into my car i want the best i can get... for the cheapest lol.

I think atm im leaning towards a 3" catback and then going extractors and cats before i do any engine work or forced induction. But im happy to have my mind changed.

Sorry for stealing your thread a bit mikey.

 

[mikey-]

Sorry for stealing your thread a bit mikey.

Go nuts...

When I spoke with WA Performance regarding exhaust size, I was given the impression that twin 2.5" will not restrict power on a reasonably sized cammed street car.

If you wanted to go for a very large cam (fly cut pistons) with high comp ported heads, twin 2.5" will be OK, but a small gain might be noticed with twin 3".

For a blown application, twin 2.5" will also be fine, but a twin 3" will give slightly more power.

Twin 2.5" is 10 sqaure ".

Twin 3" is about 14 square "

Single 3.5" is about 10 square ".

Single 4.25" is about 14 square ".

Gives you a rough idea of the volumetic area between twin and single pipes.

 

[Not_An_Abba_Fan]

Let's look at from a different angle again.

How much "power" do you want to make? A twin 2 1/2" straight through system will flow around 450hp. On a dyno, you will achieve a higher reading with a bigger system, but it doesn't necessarily make the car go faster. On the other hand, with forced induction, generally, the bigger the exhaust the better. But....if all you want to do is have it running at WOT all the the time then 3" is definitely the way to go. If on the other hand, you want a car with good road manners that has the punch when you want it, then I would stay 2 1/2". Keeping in mind that a 3" will be a shitload louder on a supercharged car than a 2 1/2". A bigger difference in note than on an NA car. Also, something else to keep in mind, stainless is louder than mild steel as well.

 

[helmotbros]

Thanks for the info guys, i think that makes my decision a little bit easier. Ive been wrestling with it for the past couple of weeks.

As i said before im waiting on the sale of my old ute but as soon as that goes through ill hit you (NAAF) up for a quote and we will go from there.

Cheers

 

[mikey-]

What does everyone prefer? Personally I prefer the poilished tips with the black muffler, I think the silver stood out abit much.

 

[helmotbros]

I would agree with you, nice work

 

[Yergin]

How did you do such a clean job??, did you tape it off? and was the paint in an aerosol can?

Looks good with the black.

 

[Grumpyoldb]

Yea the black looks better.

 

[mikey-]

Yeah, I just taped the edges I wanted to look clean the the blue masking tape that is in one of the photo's, I just covered the rest of the muffler and tips with some old newspaper.

I used 3M high temp matt black paint, in a can yes.