Exhaust Options: Is It Better To Keep This Big One Or Go Back To Standard?

[Houdini]

Found out it's just the rear part so I'm opting for exchange with the standard twin as I agree that one big pipe looks silly on these cars. I can then save up a bit and get a proper exhaust fitted all the way through. The Xforce looks pretty cool.

[zei20l]

mine mine mine mine mine mine mine !!!!!!!!!!!!!!

ill swap ya plus some cash

[Houdini]

mine mine mine mine mine mine mine !!!!!!!!!!!!!!

ill swap ya plus some cash

Bummer, sorry, wish I had got this earlier, I told the dealer he could just keep it . Sorry Mate.

[zei20l]

omg what??? *slaps you*

go back and get it!!!!

if it was a sydney dealer id probably buy it. no biggie mate!

[Houdini]

Slight change of plan....it's an apexi apparently:

And it really looks halfway there for me so I might keep it and change the tips to some nice looking twins pipes (or 4 pipes )

Edited April 24, 2009 by Houdini

[zei20l]

eww it looks ugly, nah man seriously take my stock one and ill be doing you a favour

[iamhe77]

eww it looks ugly, nah man seriously take my stock one and ill be doing you a favour

Actually, you may well be.

I don't believe that the Apexi exhausts cleared JASMA requirements as they were too loud.

Could be a problem if you were pulled over and issued an EPA notice (or even through the mail)... or do they only to that in Vic?

[Houdini]

The exhaust is coming off! I've never really liked the big canon style so I'm getting a nice twin pipe custom setup fitted on friday. The apexi N1 is a nice unit but too loud and too loud looking!

I'll probably put it up for sale here on the forums (know someone who'll call dibs ).

[Houdini]

Funny thing is (well not so funny): the car has a big 4-5 inch rear tip and 3 inch piping but only to the quite small cat in the middle.In front of that to the first cat is only 2.5 inch piping. I'm going to run new 2.5 inch to a new twin rear muffler until I can afford a nice legalis or something.

[kidafa]

No whats the point going back to 2.5" you clown!

Just cut the old muffler off that you dont like the look of a weld up something more your style. then get the dump and front pipe piece down the track and youll have a 3inch system from your mate back!

[Bis-e Bee]

+1 on 3 inch all the way through

Rather silly to go back to a 2.5 inch system through out.

[RBPOWA-(TJ)]

you checked the x-force range for twin tips ?

[zei20l]

dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs

if you dont PM me first ill track you down and ill....... i really have no idea what ill do. but it wont be nice!

[Bis-e Bee]

I'll probably put it up for sale here on the forums (know someone who'll call dibs ).

dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs dibs

if you dont PM me first ill track you down and ill....... i really have no idea what ill do. but it wont be nice!

You must be psychic Houdini!! But yeah your right, Iain is extremely desperate for some more go fast bits.

Good note of advice, don't let him near your car if he has a tool in his hand..... (ahem... I know what you'll say, he ALWAYS has his tool in his hand!)

[zei20l]

hey i only have THAT tool in my hand if there are women around..... generally is scares them off and leads to the police being called lol

[iamhe77]

No whats the point going back to 2.5" you clown!

Just cut the old muffler off that you dont like the look of a weld up something more your style. then get the dump and front pipe piece down the track and youll have a 3inch system from your mate back!

Agreed.

DO NOT GO BACK TO 2.5"!!!!!!!!!

Get as much flow from your exhaust as possible.

[Houdini]

Agreed.

DO NOT GO BACK TO 2.5"!!!!!!!!!

Get as much flow from your exhaust as possible.

Agreed, my bad not being clearer in the post: the system is 2.5 from the turbo to the mid (only cat conv) and then bigger to the rear muffler. The guys at powatone said your basically onyl as good as your smallest but so it was pointless doing a bigger pipe to the new rear muffler as the front 2.5 was restricting it. The new rear muffler has 2.5 in and twin 2.5 out.To get a 3+ inch was going to be more expensive (heaps) and take ages to get in whereas the unit they had was in stock and cheap. I'm taking the advice of the experts here in them saying that I'm not getting any reduced flow doing it this way but saving some $'s until I get my whole mandrel bent 3.5 inch system.

Am I wrong?

[iamhe77]

No, no. I understood your post. What I don't understand is why they would make you pay for a 2.5" rear pipe & muffler to be installed when it would have cost you about the same (maybe less) to have a larger front pipe installed, therefore increasing flow.

The aftermarket exhausts for the VQ25DD (N/A) are 2.5", so I am confused as to why they recommended a 2.5" (even for now) on a turbo that pushes ~0.8bar

I am aware that I am not an expert (far from it), but if you have a large rear pipe and a smaller front pipe and one of them needs to be replaced, logic dictates (at least to me) that it is the smaller one that gets ripped off, not the larger one... particularly if the purchase/installation price is similar...

Please correct me if I am wrong... or have mis-interpreted your post.

Oh, and I agree with what they say about putting a 3" cat-back system on the 2-2.5" stock front pipe. It does nothing but add a little bit of noise

Edited May 29, 2009 by iamhe77

[zei20l]

catback systems do more than add noise, there are massive restrictions in stock mufflers.

and a dump/front pipe wont make THAT much of a difference IMO. to get air away from the turbo faster you need velocity. exiting gas into a larger area slows the gas down, if its smaller it will move faster. that said, yes the stock dump is TOO small, but comparing 2.5" to 3" will probably not make all that much difference. if you have seen some well made dump/front pipes, off the back of the turbo is a 2.5" pipe, before it moves into a 3". there is a reason for that.......

[iamhe77]

catback systems do more than add noise, there are massive restrictions in stock mufflers.

and a dump/front pipe wont make THAT much of a difference IMO. to get air away from the turbo faster you need velocity. exiting gas into a larger area slows the gas down, if its smaller it will move faster. that said, yes the stock dump is TOO small, but comparing 2.5" to 3" will probably not make all that much difference. if you have seen some well made dump/front pipes, off the back of the turbo is a 2.5" pipe, before it moves into a 3". there is a reason for that.......

Actually a front pipe makes a fair difference. Mine and my mates cars being the example - normal exhaust allows turbo to boost to 0.8bar on an RS/RX.

My car with highflow turbo and stock dump, stock front pipe & stock exhaust - Max boost = 0.8bar

My mates car has the stock dump & front pipe with the Fujitsubo Legalis exhaust - Max boost = 0.8bar

My car with stock dump, 80mm Kakimoto front pipe & Fujitsubo Legalis exhaust - Max boost = 1bar

I understand your theory which is needed for N/A cars as they require the back pressure produced by the smaller diameter pipe to work effectively. But not so much for turbo charged cars as the velocity is produced by the exhaust wheel of the turbo, so eliminating as much resistance on the escaping exhaust gases, which in turn reduces resistance in the exhaust wheel, which allows the turbo to spool faster more easily is paramount, both for power and for turbo longevity... thus the difference in power my car producted when the larger diameter pipe was fitted.