how restrictive is a std 1.8 gti downpipe?

[paultownsend]

im just trying to weigh up fitting a 4 branch.
iv already got a ported manifold.  but the spacer plate i had quickly made for my taller block does not match, so that needs to be sorted.

so apart from costing alot more, melting everything in my bay, and spending hours fitting it, will a 4 branch really flow more than my ported mani and std dp?

[Diamond Hell]

A GOOD 4-branch should flow better.

Not only that, the lengths of the primaries and secondaries can be used to tune the characteristics of the motor.  Provided you have a basic understanding of what the exhaust gases from the cylinders are doing and what sort of effect you can have on them with a tubular manifold you can acheive a lot.

With an engine that is already set up to breathe harder, you're only going to get more gains from a good 4-branch.

[Reasty]

Ive got a ashley 4 branch on my 16v and the improvement in throttle response was sustantial,and it completely solved the flat spot
that the car used to have,sounds awsome aswell,the one i have is mild steel and was fitted by the boys at the phirm who advised not to go
for a stainless 4branch as they can crack under extreme heat and are not as durable in cars that are very low (mines 80mm) as they donot flex at all,all in all the whole lot including the manifold and fitting was about £450 so its not a cheap job but well worth it,my only advice would be unless your really confident id get it fitted instead of doing it yourself as the manifold studs are prone to snapping off and then that brings a whole new headheache.

[paultownsend]

the head was recently re conditioned,so the studs etc will be fine

@DH  as i have a tall block, i know the 4-2-1 that does fit is the raceland item (below). and theres not else alot out there. tsr do one, but its a 4-1 item and iv heard they dont fit well on the tall blocks.

iv been looking on ebay.de and theres a wider choice. as im looking at mk3 items to suit my block