Exhaust system for performance

[Newbie GT]

Hi guys would this setup be the best for a tuned get but keeping stock muffs

Xforce dump
3 inch centre high flow cat
3 inch y pipe ?? This is the part I'm confused about as lot of members seem to use stock
Thanks

[Kekotic]

You cannot use the stock y-pipe because the centre pipe and y pipe are one piece. Changing the centre means changing the y pipe too.

[Newbie GT]

You cannot use the stock y-pipe because the centre pipe and y pipe are one piece. Changing the centre means changing the y pipe too.

Thanks Kiern

So would a 3inch system all the way including Y pipe be best for performance ?

[Kekotic]

You cannot use the stock y-pipe because the centre pipe and y pipe are one piece. Changing the centre means changing the y pipe too.

Thanks Kiern

So would a 3inch system all the way including Y pipe be best for performance ?

3" all the way is probably overkill if you are using the stock mufflers. But if you plan to upgrade them in the future you could get 3".

[kiahatsiu]

I would most certainly do 3" to your mufflers. Think of it as future proofing.

[DonGreen]

Regarding stock mufflers, has there never been a replacement twin-outlet muffler made for a 3 inch system?

I would think that would be a preferred option of a lot of STI owners going to a 3" system.

[dr20t]

Twin 3" y pipe is overkill

2.25 or 2.5" y pipes will suffice and are what most systems run

3" will give a heap of drone for not much performance unless you're going for 500kw

[Manaz]

Twin 3" y pipe is overkill

2.25 or 2.5" y pipes will suffice and are what most systems run

3" will give a heap of drone for not much performance unless you're going for 500kw

For an NA engine, I'd say yes (particularly because for a given volume of gas, flow is actually faster through a narrower pipe, and you get better scavenging effects). For a turbo, where the last thing you want is backpressure and scavenging isn't really an issue (valve overlap, required for scavenging, can be your enemy with boost), I'd question this.

3" with appropriate mufflers (may need a centre resonator) shouldn't be too loud.

[dr20t]

Sorry but you're wrong

Twin 3" pipes have a total surface area of 9.42 inches

Single 3" pipe has total surface area of 4.71 inches

Twin 2.5" pipes have total surface area of 7.84 inches

So therefore twin 2.5" pipes have greater cross sectional area than a single 3", by almost double. The limitation will still be at the entrance to the 2.5" y pipe which is 3"

Therefore you are NOT losing flow going from a singe 3" to twin 2.5

As an example, my car made 255kw atw with a 3" to twin 2" y pipes

I'm only now upgrading to twin 2.5" y pipes as I'm chasing alot more power

3" single systems to the rear muffler work on almost all 4 cylinder turbo cars up to 400kw so can't see a single 3" being a restriction

Mick

[Manaz]

Sorry but you're wrong

Twin 3" pipes have a total surface area of 9.42 inches

Single 3" pipe has total surface area of 4.71 inches

Twin 2.5" pipes have total surface area of 7.84 inches

So therefore twin 2.5" pipes have greater cross sectional area than a single 3", by almost double. The limitation will still be at the entrance to the 2.5" y pipe which is 3"

Now that you're clear that you mean 2 x 2.25" or 2 x 2.5" vs single 3", I agree entirely.

[Newbie GT]

So the Y pipe is the best investment am I understanding right ?

Basically 3 inch all the way ?

[Kekotic]

re read the thread...

[Deep Heat]

Sorry but you're wrong

Twin 3" pipes have a total surface area of 9.42 inches

Single 3" pipe has total surface area of 4.71 inches

Twin 2.5" pipes have total surface area of 7.84 inches

Mick

Umm Mick your numbers are wrong, you didn't square the radius.

Twin 3" = 14.14 inches squared

Single 3" = 7.07 inches squared

Twin 2.5" = 9.82 inches squared

[dr20t]

So the Y pipe is the best investment am I understanding right ?

Basically 3 inch all the way ?

R u fkn serious?

No helping some people seriously...

Twinkle I calculated cross sectional area not surface sorry

But you get my point

Mick

[Boostaddict]

Hahahaha

Love this thread.

Newbie ..... No idea.

Mick.... You come out with some awesome shit man!! Love it