How Restrictive - Open Neck V Twin Dump Downpipe?

[stuarted]

Trying to figure out if it's worth forking out £250 for an open neck down pipe before my next re-map. Want to do everthing possible to extract as much power out of my current set up within reason. Getting mapped for methanol. Would I be better spending the money elsewhere on lightweight pulleys for example?

Am I losing much power with the twin dump downpipe?

Cheers

[Big 'D']

Trying to figure out if it's worth forking out £250 for an open neck down pipe before my next re-map. Want to do everthing possible to extract as much power out of my current set up within reason. Getting mapped for methanol. Would I be better spending the money elsewhere on lightweight pulleys for example?

Am I losing much power with the twin dump downpipe?

Cheers

If you want a good hike in power prior to mapping I can strongly recommend the afterburner manifold and up pipe it saw me an extra 25bhp over the standard manifold and up pipe, I doubt that you will notice any real difference in swapping the down pipe you have for an open necked one if anything the one you have fitted will extract the exhaust gas quicker as the gas flow is not directly mixed with the bypass flow at the wastegate port on the turbo.

Cheers Iain

[stuarted]

If you want a good hike in power prior to mapping I can strongly recommend the afterburner manifold and up pipe it saw me an extra 25bhp over the standard manifold and up pipe, I doubt that you will notice any real difference in swapping the down pipe you have for an open necked one if anything the one you have fitted will extract the exhaust gas quicker as the gas flow is not directly mixed with the bypass flow at the wastegate port on the turbo.

Cheers Iain

Thanks Iain, i've got Lateral Performance GT Spec headers and up pipe on at the moment but note what you say re the downpipe.

Cheers mate

[johnnyr6]

That's the idea behind the twin dump downpipe, it's supposed to speed up gas flow. If it works or not is debatable but all i know is my magnex twin dump gave my car a healthy increase over the oe pipe.

Johnny

[AlanG]

The twin dump downpipe is designed to keep the wastegate gasses separate from the main exhaust gas flow so as not to interrupt the main exhaust gasses as they exit the turbine housing.

It depends on the setup of the car whether there is an advantage to having the wastegate gasses kept separate or not.

[stuarted]

seems i'd be wasting money changing to open neck then?

Think i'll go for the pulleys instead