Derek M

Do most people here run with double entry decat downpipes as opposed to single pipes?

What is the secondary pipe for?

I have managed to get my hands on a downpipe which is just a single pipe with a plate at the top and I want to know is there going to be much difference between the single and double pipe versions.

Derek

john banks

When you consider how much the wastegate actually opens (very little) I doubt it really matters. Removing the restrictive cat seems to be the most part. FWIW I have a twin dump but just because of what was available locally.

Derek M

Anyone know the price difference between the single and double downpipes?

I paid £50 for the single one is that a good deal?

Derek

nom

There's 3 types, really: single tube with blanking plate (same as standard, but can be without cat such as the HKS one); single tube that is an oval(ish) shape so that the wastegate can dump; and 'twin dump' which is two tubes, one for the normal exhaust gases & one for the turbo.
Points that people agree on - the blocking of the wastegate is restrictive; the cat is restrictive. Better of without either.
The single dump/twin dump is a lot more open to interpretation - as John says, it's what's available! Either is better than the standard...
And, £50 sounds cheap, whatever it is...

BladeRnnr

twin dump is supposed to help with torque better as the dumped air is fed into the system further from the turbo and so doesn't interupt flow where it matters (supposedly)


What ever you do get the new pipe ceramic coated inside and out and have cooler underbonnet temps which helps keep power up.

m.

harvey

iTrader: (48)

Hi Blade Runner. Who do you use for ceramic coating?
I have found from experimentation that the open neck is probably best, certainly ahead of the blanked off top plate but there is little difference with the twin pipe.