Exhaust Types - Better or Worse?

[ProjectRSR]

Hi Everyone,

Since purchasing the R33, I've always wondered about this...

I've got an exhaust which splits into 2 x 2" pipes (could be 2.5, i dunno) from the cat back which then both lead into a single muffler.

As much as I'd like to keep my exhaust, I'm wondering if a single 3-3.5" will achieve more power?

Any thoughts??

[BiZzReVhEad]

I think in theory a straight throu system is much better for back pressure etc.

I would say it would achieve more power yes

[ProjectRSR]

OK... that was the answer I was expecting... I would've preferred if I could keep the same exhaust simply because I can put the money elsewhere...

Do you think that it could be a bottleneck? My Mods are:

- Full Exhaust (3" Dump with hi flo cat & the twin pipe cat back)

- POD

- Hiflow turb running approx 10PSI

My Next step was going to be a cooler, but considering this exhaust thing, i may need to go the cat back first????

[predator]

I would have thought it would have been done for a reason.. and obviously a split pipe would involve more labour than one straight pipe.. so why not stick to it? 2x 2.5" = 5" total flow??

somebody may be able to enlighten us...

[32vspecII]

thats pretty much it . the total area is greater than the single pipe as you have seen . there may be a small loss due to the turbulence where the pipe splits but it would be marginal .The stock xr6t has a twin pipe catback section and owners have found no advantage replacing it with a single system .

[4door_Sleeper]

I would have thought it would have been done for a reason.. and obviously a split pipe would involve more labour than one straight pipe.. so why not stick to it? 2x 2.5" = 5" total flow??

somebody may be able to enlighten us...

not quite

remember your year 9 maths - area of a circle is pi times the radius squared.

so a 3 inch pipe has an area of approx 28.25 inches

a pipe of 5 inches has an area of 78.5

and 2 x 2.5 inch pipes have an area of 39.35 which is about the same as a single 3.5 inch system.

My guess is that the 2 pipes will give similar flow to one larger pipe but will be easyer to fit and have fewer clearance issues.

I think in theory a straight throu system is much better for back pressure etc.

I would say it would achieve more power yes

You dont want ANY back pressure in an exhaust system - this is an old wives tale.

The ideal system would exit via a huge just pipe behind the turbo. In a normally asperated system there are a few complications to do with harmonics. In this case you require some exhaust length to establish the correct harmonic and this is often mistaken for back pressure which is a non desired by-product.

[CerealKiller]

mate I had a thread about your exhaust type a while back. Just wondering if you know if it's a custom job or does it have a brand name? Also is it noisy?

[ProjectRSR]

The muffler has fujitsubo on it... and its rather quiet. It doesn't have a raspy/barky noise... more a muffled tone if you get what i mean. I'm unsure as to whether its custom or not, when i originally purchased the car, the exhaust hung quite low. I had it moved closer to the undercarriage, so perhaps since it doesn't quite fit or hang correctly somewhere it may be off the shelf (however that's a wild, uneducated guess).

reading the above posts, perhaps this exhaust maybe worth keeping??

[CerealKiller]

oooh Fujitsubo eh?

sounds like you have this one http://www.fujitsubo.co.jp/mc-prod/psrs-v....hp3?id=00000081 (Legalis 4)

[ProjectRSR]

Mine is a little different. None of the products on that page are similar. I'll go take a photo...