Porting/matching Exhaust Manifolds Gtr

[cefiro]

When I pulled my turbos off I noticed where the exhaust manifold matches up to the head that it doesnt really mat up properly, I have a dremel tool and was thinking about smoothing the area over and opening up the exhaust manifold runners???? the turbos going in are not much bigger than stock, is it worth it of waste of time?????

you can see in the pic the overlapping

Edited June 8, 2009 by cefiro

[doo doo]

When I pulled my turbos off I noticed where the exhaust manifold matches up to the head that it doesnt really mat up properly, I have a dremel tool and was thinking about smoothing the area over and opening up the exhaust manifold runners???? the turbos going in are not much bigger than stock, is it worth it of waste of time?????

you can see in the pic the overlapping

What is worth doing is port matching the turbo to manifold flange, also do the exhaust housing if you're keeping the stockers on (take the exhaust housing off the turbo assembly first of course) You'll see the major mis-match on the gasket marks. Should improve boost response a couple of hundred rpm, Dremel might not be much chop for it though.

[R31Nismoid]

The worst restriction is in the turbine housing - have a look how small it gets.

IMO improving flow to get there isnt going to magically increase getting past the turbine housing restriction and that's where the real drama is

[cefiro]

cheers, I know the housing is very restrictive, the overlap just looks to be a poor design and though opening it up would improve responce and flow if it were matched to the ex port.

[R31Nismoid]

They would indeed improve flow - no arguments there at all.

However improving flow at that point, doesnt solve the problem of the flow at the other point

[Swiper the Fox]

They would indeed improve flow - no arguments there at all.

However improving flow at that point, doesnt solve the problem of the flow at the other point

a chain is only as strong as its weakest link.