X Force Twin 2.5" Or 3.5"

[Redback]

Hey Guys,

I just picked up an XFORCE exhaust, 4" dump, 4" cat and 3.5" single system.

Is there a difference flow wise compared to the 2.5" twin and has some one actually flow tested them?

Is there an exhaust note difference?

Are there any pros and cons with the two different types?

Sorry about all the questions but I just wanted to pick someones brain on here.

Thanks.

[workxr6]

To be honest, I havent tried either. Mathematically they have almost the same size. Big single would have a deeper tone and perhaps more droney.

I was looking at the twin 2.5" myself so am keen to hear what others have to say.

[Redback]

How do you work it out mathematically? I have been told that exhaust gases flow around the outside of the pipe?

[civillian]

Never heard of exhaust gasses on the outside, perhaps heated clean air but not exhaust.

Mathematically - using Pi.

Area = Pi x r^2

3.5" system:

r = 3.5/2

r^2 = 3.0625

Area = 1 x (Pi x 3.0625) = 9.621127503 square inches

twin 2.5" system:

r = 2.5/2

r^2 = 1.5625

Area = 2 x (Pi x 1.5625) = 9.817477044 square inches

So there is slightly more area available to the twin 2.5" system to flow, but that may be lost in the extra piping, 'Y' pieces etc.

N

[Redback]

Thanks for that, it clears things up.

[jimking19]

I wouldn't brush off the "exhaust gases flowing along the outside of the pipe" thing (by which he means the gases move faster/ or there is a higher mass of air flowing nearer the walls of the pipe rather than the centre). It sounds like it may be true, I'm thinking Bernouli effect or something like that.

I know that more electricity flows on the outside of a thick wire rather than the middle, that's what made me think.

Either way, it would probably take more than to just calculate the area of free space or total circumfrence of pipes for the gasses to flow, because there are other differences like civillian mentioned, extra piping and the fact that the same volume of air needs to go in two directions after each muffler in the 2.5".

Personally I've been told the 3.5" systems flows better and that back to back tests were done that proved it. Needless to say, I haven't seen any proof.

[shaunbags]

one of the fitters at work did some sums for me re the same question and said they were similar but the extra piping would create extra drag therfore more resistance:)

[jaymen]

Hi guys I've been looking at the X-Force Quad exhaust system which has a twin 2.5" system with 3" Dual rear exhaust tips,was thinking about mating it up to an X-Force 3.5" to an 2.5" Twin an 4" cat & a bigbore warehouses 4" Dump pipe, just wondering how this would flow compare to the other exhaust systems mention eg: 3.5" or twin 2.5".

Edited 03/01/10 10:33 AM by jaymen

[buzzdog]

Hi guys I've been looking at the X-Force Quad exhaust system which has a twin 2.5" system with 3" Dual rear exhaust tips,was thinking about mating it up to an X-Force 3.5" to an 2.5" Twin an 4" cat & a bigbore warehouses 4" Dump pipe, just wondering how this would flow compare to the other exhaust systems mention eg: 3.5" or twin 2.5".

Hi Jaymen,

Mate did you end up getting the Quad exhaust installed? If so, do you have any pics? I've considered getting a Quad exhaust for my BA Turbo.

Cheers

Buzz

[jaymen]

Hi Jaymen,

Mate did you end up getting the Quad exhaust installed? If so, do you have any pics? I've considered getting a Quad exhaust for my BA Turbo.

Cheers

Buzz

No not as yet Buzz I'm tosing up between the redback quads now... looks like a better free flowing system compare to the Xforce Quads.