Pipe Flow

[Xtreme F6]

  ugy said:

  Xtreme F6 said:

if you want to know how to work out what 2.5 inches of pipe flows do this.

1.25 x 1.25 x 3.14 = 4.9 square inches, 1 square inch flows 146 cfm @ 28 inches of water so its 146 x 4.9 = 716 cfm BUT most people quote 20.4 inches when they supply flow figures for carbies or exhaust components so you then need to work that out like this.  20.4 divided by 28 x = square root=.7285713. Then multiply 716 by .7285713 = 521 cfm @ 20.4 inches of water. I hope I did all that right I havent had to work on flow like that for a couple of years, I usually just use a flow bench lol

Thanks for that Simon, so I should be happy with that a lot of hi flow cats dont flow that good.

that inlies the problem, alot of cats dont even out flow the stock exhaust. Hence why a cat change is always the best and cheapest place to look first. The only cars that will gain power from a new exhaust while still using the stock cat is the V8's, why you ask? cos they have 2 of them 2 x 300 cfm @ 20.4 inches is more then the stock exhaust by 40 odd cfm. On the turbos they have one cat that flows 310 cfm with an exhaust that flows 560 cfm (same as the boss) but only 1 cat

ohh and also to answer your question on what a 3 inch pipe flows its

1.5x1.5x3.14=7.065 x 1031 cfm@28 inches 1034 convertered to 20.4 inches is 751 cfm

[jordak]

Simon whilst your passing on some of your wisdom, do centre mufflers tend to vary alot with respect to flow rate or do they all flow pretty well say around the 500 mark?

[Xtreme F6]

  jordak said:

Simon whilst your passing on some of your wisdom, do centre mufflers tend to vary alot with respect to flow rate or do they all flow pretty well say around the 500 mark?

hey mate, I flowed an F6 muffler and complete assembley and a gtp and a xr6t they where all the same.

[jasper361]

  AdamXR6T said:

Could someone tell me how long a piece of string is?

<{POST_SNAPBACK}>

Exactly twice the distance from one end to the middle.

[jordak]

  Xtreme F6 said:

  jordak said:

Simon whilst your passing on some of your wisdom, do centre mufflers tend to vary alot with respect to flow rate or do they all flow pretty well say around the 500 mark?

<{POST_SNAPBACK}>

hey mate, I flowed an F6 muffler and complete assembley and a gtp and a xr6t they where all the same.

<{POST_SNAPBACK}>

So what did they flow @

Cheers

[F6_Tornado]

I’m a hard bugger to get to pay anyone a complement but when it comes to exhausts systems I must do in this case.

Some of you might remember 6 months ago I fitted a Twin Metal Cat Cat system to my old F6 Manual and before and after dynos I picked up some 37rwkws with just the exhaust on the same edit map. 279rwkws >>> 317rwkws

Well I just fitted that same exhaust to my new Stock as a rock F6 auto and it has amazed me once again. I thought the first time it may have been a few fudging numbers etc.

Dyno run Stock STD everything with 300km on the clock pulled 226rwkws.

Swap over the exhaust after adding the second sensor after the cat and it went a staggering 265.6rwkws.

So pretty impressive results and just goes to show how restrictive the actual factory exhaust system is on the Utes.

Having the exhaust flowing nice and free will then allow the tuner to achieve the numbers with ease unlike trying to push Sh!it though the eye of a needle with the factory System.

APC did my system in twin 3.5” stainless with 2 Metal Cat cats up to the rear mufflers then step down to 2.5” from the muffler to second Muffler then onto the tail pipes.

BTW the new F6 has a much bigger Factory Cat on it compared to the Ba F6.

[1axr]

  F6_Tornado said:

I’m a hard bugger to get to pay anyone a complement but when it comes to exhausts systems I must do in this case.

Some of you might remember 6 months ago I fitted a Twin Metal Cat  Cat system to my old F6 Manual and before and after dynos I picked up some 37rwkws with just the exhaust on the same edit map. 279rwkws >>> 317rwkws

Well I just fitted that same exhaust to my new Stock as a rock F6 auto and it has amazed me once again. I thought the first time it may have been a few fudging numbers etc.

Dyno run Stock STD everything with 300km on the clock pulled 226rwkws.

Swap over the exhaust after adding the second sensor after the cat and it went a staggering 265.6rwkws.

So pretty impressive results and just goes to show how restrictive the actual factory exhaust system is on the Utes.

Having the exhaust flowing nice and free will then allow the tuner to achieve the numbers with ease unlike trying to push Sh!it though the eye of a needle with the factory System.

APC did my system in twin 3.5” stainless with 2 Metal Cat cats up to the rear mufflers then step down to 2.5” from the muffler to second Muffler then onto the tail pipes.

BTW the new F6 has a much bigger Factory Cat on it compared to the Ba F6.

<{POST_SNAPBACK}>

well done mate, what does it sound like.

[jordak]

  F6_Tornado said:

I’m a hard bugger to get to pay anyone a complement but when it comes to exhausts systems I must do in this case.

Some of you might remember 6 months ago I fitted a Twin Metal Cat  Cat system to my old F6 Manual and before and after dynos I picked up some 37rwkws with just the exhaust on the same edit map. 279rwkws >>> 317rwkws

Well I just fitted that same exhaust to my new Stock as a rock F6 auto and it has amazed me once again. I thought the first time it may have been a few fudging numbers etc.

Dyno run Stock STD everything with 300km on the clock pulled 226rwkws.

Swap over the exhaust after adding the second sensor after the cat and it went a staggering 265.6rwkws.

So pretty impressive results and just goes to show how restrictive the actual factory exhaust system is on the Utes.

Having the exhaust flowing nice and free will then allow the tuner to achieve the numbers with ease unlike trying to push Sh!it though the eye of a needle with the factory System.

APC did my system in twin 3.5” stainless with 2 Metal Cat cats up to the rear mufflers then step down to 2.5” from the muffler to second Muffler then onto the tail pipes.

BTW the new F6 has a much bigger Factory Cat on it compared to the Ba F6.

<{POST_SNAPBACK}>

Pretty impressive is an understatement

Where abouts in the rev range does the extra 40rwkw show up and are these the same metal cats that Freddy has just organised as a group buy?

[F6_Tornado]

  jordak said:

Pretty impressive is an understatement

Where abouts in the rev range does the extra 40rwkw show up and are these the same metal cats that Freddy has just organised as a group buy?

<{POST_SNAPBACK}>

I dont think so Steve.

I'll take a look at that thread and see if they are the same make.. These are "Metal Cat" Cats and they were not cheap at the time..

[Xtreme F6]

  F6_Tornado said:

  jordak said:

Pretty impressive is an understatement

Where abouts in the rev range does the extra 40rwkw show up and are these the same metal cats that Freddy has just organised as a group buy?

I dont think so Steve.

I'll take a look at that thread and see if they are the same make.. These are "Metal Cat" Cats and they were not cheap at the time..

Greg with no other mods and the 265 odd rwkw's what was the boost and the afr's with the new system?