T04Z Exhaust Housing

[czy18e]

Hello,

I have been running a t04z with a .70 exhaust housing on my rb 25 at 22.5psi (140mph) for a while and have been thinking about upgrading to a bigger turbo to try push for 145 mph (parachute territory) but I am hesitant to run much more boost. Maybe 25psi tops.

So was wondering weather going to a 1.00 exhaust housing would net me enough top end at 25 psi to not warrant the cost of a bigger turbo?

Does a bigger housing allow more power at the same boost?

Lag doesn't bother me as this is a drag car.

Any ideas or feedback is welcome.

Edited September 24, 2014 by czy18e

[GTSBoy]

Yes, a bigger housing does mean more power at the same boost. The bigger housing reduces hot side pressure, which improves flow through the engine. Same boost on the cold side + less pressure on the lower side = more power.

Of course it might not work out right - the turbine might not be as happy to drive the compressor in the bigger housing, and the compressor may or may not be able to give you more than you're getting now, even if driven harder. But barring those possibilities, your idea is valid.

[czy18e]

Thanks mate good info there.

Has anyone changed their exhaust housing before that can post results?

Doesn't have to be t04z, just interested.

I have a mate with a 2.7l 4cyl that runs a 1.15 instead of his original .84 so he could run more boost but rb info is better.

[wolverine]

I thought I posted earlier but it must have gone into the ether.

Why don't you screw boost into it until it stops making power and see where that gets you?

[czy18e]

The motor is 8 years old and very tired so as I said I'm not too keen on pushing much more boost.

I will go up to 25psi if I have to but looking for other ways to make easy power.

[wolverine]

I am intrigued what you think will happen to your engine with more boost?

Once the turbo stops making easy power relative to the boost increases then I would consider changing something.

[czy18e]

Just a wuss I spose.

And waiting on a morristech igniter to try and get to 25 psi.

The difference between 21psi and 22.5 psi was 2mph does this seem high, low or indifferent.

Just thinking 1.00 hsg and 25psi might net a decent gain?

[wolverine]

In cylinder pressures are well over 1000psi.

I would maximise the current setup before reaching in my pocket for more hardware. An hour on the dyno should give you the information you need to proceed the best way.