Ok I am slowly deciding on my exhaust.

 

I am having decats and a double twin tips.

 

The last piece I need to decide on is the centre section.

 

What are the advantages of X or H, resonators or not. I dont want it too noisy, i realise it will be a bit noisier with the de-cats. I currently have a single-exit with cats.

 

I have heard that X pipes are more preferable for performance. Don't know why as I'd have thought this would kill performance as the 2 gasses are fighting against each others flow.

 

Ivan

I've had both and now have X pipes, they sound alot better

I have heard that X pipes are more preferable for performance. Don't know why as I'd have thought this would kill performance as the 2 gasses are fighting against each others flow.

 

Ivan

 

Not at all, they actually work together to help draw the exhaust out more efficiently...

What do the resonators do?

What do the resonators do?

 

make it quieter! but are they advisabe? i.e. do they sap power?

nobody knows if resonators reduce the power?

 

I think it might be too noisy without them, any ideas?

nobody knows if resonators reduce the power?

 

I think it might be too noisy without them, any ideas?

 

yes you will need them with 2 x 3" pipes, i had them and they dont sap power just noise :)

I run straight pipes from the cats with no silencing at all and it's not that loud, the turbos and cats seem to soak up most of the noise! The oem resonator construction only consists of two perforated pipe sections in line with the input/output pipes, it does reduce the low frequency noise a fair bit, can't imagine it'll sap that much power.

nobody knows if resonators reduce the power?

 

I think it might be too noisy without them, any ideas?

 

No they don't sap power, because your exhaust gasses just go stait through as they would a staight piece of pipe. You'll need them for damping down the noise though. I'm looking to fit som sound matting under the carpet because when you on the motorway sitting at 95 ish the resonance does give you headhache after an hour or two.

yes you will need them with 2 x 3" pipes, i had them and they dont sap power just noise :)

 

The decats I am looking at are the 2 3/8" diameter.

 

From another thread you reckon 2.5" is sufficient, 3" is only beneficial for high power applications. How come you mention 3" here? What are the effects of 3" on an engine with stock internals, fuelling and turbos, what is the optimum diameter for this setup?

 

I dont want to go from 2.5" de-cats -> 3" exhaust as this slows gasses down.

The decats I am looking at are the 2 3/8" diameter.

 

From another thread you reckon 2.5" is sufficient, 3" is only beneficial for high power applications. How come you mention 3" here? What are the effects of 3" on an engine with stock internals, fuelling and turbos, what is the optimum diameter for this setup?

 

I dont want to go from 2.5" de-cats -> 3" exhaust as this slows gasses down.

 

If you have a 3" back section then try to match them up, depending on power yes it may actually sap power if you dont have enough gases and yes 3" is only really needed on 700+ bhp applications so 2.5" or around there is more than fine :)

3" single is enough for 900bhp so unless you're aiming for 1800bhp..... ;)

Ok so im happy with 2.5" all the way through. X-Pipe with resonators. Thanks guys :)

 

Am I right in believing the centre section is the same LWB/SWB?

 

I know the tail section is definitely different, and the cats are definitely the same...

 

Am I right in believing the centre section is the same LWB/SWB?

 

 

The SWB centre section is shorter than the LWB version. I've just had to replace mine.

The SWB centre section is shorter than the LWB version. I've just had to replace mine.

 

Could I ask where you got yours from? is it stainless, X, with resonators, and how much you paid? Thanks. :)

 

My current centre section is a 2->1 so I cant keep it.

Just a thought but if you have a single pipe then why do you need a cross piece?

 

When you go from 2 down to 1 pipe then that would do the same thing, i:e balancing the exhaust

Could I ask where you got yours from? is it stainless, X, with resonators, and how much you paid? Thanks. :)

 

My current centre section is a 2->1 so I cant keep it.

 

when i was building my drag car i Alonux was building me a 3" twin system into a 4" single to a 6" backbox :cool:

 

he did say it would be very very loud :dance:

Just a thought but if you have a single pipe then why do you need a cross piece?

 

When you go from 2 down to 1 pipe then that would do the same thing, i:e balancing the exhaust

 

Im changing my exhaust from single to twin!

Im changing my exhaust from single to twin!

 

 

That would be why then :rofl:

Could I ask where you got yours from? is it stainless, X, with resonators, and how much you paid? Thanks. :)

 

My current centre section is a 2->1 so I cant keep it.

 

 

I got mine from Z centre, but it's a H-section and 2.25" stainless pipe with resonators cost about £180 delivered. I got a quote from Exhaust.co.uk first and they wanted £280 for making one, without the balance pipe!!