Turbo too laggy - GT3076R on 3S-GTE

[TRDcelica90]

using a gt3076r turbo on a 3sgte, with custom manifold and 3" exhaust the whole way. im not sure of the AR for the compressor housing but im assuming its a biggy.. im also usin a FMIC with 2.5" IC piping on a clocked turbo, the turbo is internally gated, but i also have an external wastegate..

the turbo builds boost very slowly up till 3.8ish RPM.. then by about 4.2 will pull hard the whole way to redline with little effort.. im only running 10psi but takes WAY too long for the boost.

Im looking for as much response as possible with this kind of set up..

My thoughts are changing to a small exhaust housing. what is the cost and effort involved with this though?? i dont plan on putting more the 17psi through it for a fair while..

Cheers

[Cuzzo]

So your using an external and internal gate?

[mr1jz]

Post a pic of your setup to give people a better idea of what you are actually running.

[Joshstix]

If you want maximum boost response/area under the curve with the kind of power you can make with a GT3076R at 10PSI I would suggest putting a GT28RS on the thing and run more boost instead.

If you're keen on keeping the GT30 then improving the flow of the setup will improve the boost response so head work and valves etc and well matched cams will help along with good tuning.

[Bananaman]

Or swap rear housing for smaller, assuming its large now?

[Joshstix]

Yep don't worry about the compressor housing size it will have minimal effect on the boost threshold.

[TRDcelica90]

I have NO interest whatsoever to completely change turbos. i know this is too much lag and a smaller exhaust housings can be a lot less laggier.

Here are a few points/questions id like to know.

There is NO vacuum port for the internal gate on the turbo, would this give me slow boost because there is vacuum coming from it?

How can i get another exhaust housing swapped around?

would 2 wastegates be a problem? i have heard externals are better but dont know why..

thanks

[Cuzzo]

Vaccum on the internal gate will be holding it closed. No vaccum will not be holding it closed. You need to remove the internal gate or weld it shut.

[jonathan yee]

i'd say that the internal wastegate actuator isn't connected up and therefore not opening, however unless they've welded the internal gate shut it is possibly still creeping open a little and adding to your lag issues.

best idea would be to get a 0.64 rear housing minus the internal gate, make the sustem a whole lot better/neater

[TRDcelica90]

yeh.. only prob is that the non gated exhaust housing is a different flange (4 bolt) so id have to change my exhaust AGAIN lol.. but probably well worth it, to wipe off some lag and a useless internal gate.

anyone know how much i would be looking at paying for a .63 or .64 housing?

hopefully someone might be willing to trade.

[Cuzzo]

weld the internal gate shut.

[TRDcelica90]

Do you think welding it will make a substantial diff in reducing lag?? because i dont wanna weld it up and then be unable to sell/exchange my exhaust housing if it doesnt help?

thanks for everyones help thus far

[mr1jz]

If the internal gate is not welded and you have no vaccum line hooked up, then this will be causing lag. Weld the gate shut.

[woggin]

you could always wire the gate shut just as a trial and error sorta thing, do this when its cold, if you can reach the internal gate actuator, push on the rod, HARD, it will either open, or stay shut (depending if its a pull or push type setup) find out which it is by pushing/pulling the actuator rod, once you have found wat it is, get a piece of wire and wrap around the joint where it attaches to the lever arm on the wastegate, find a suitable place to wire this to the chassis, exhaust, anywhere, take up all the slack aswell...it needs tension aswell, to make sure it stays shut....make sure you have wired it SHUT and not open,.......next go for a drive, if it builds boost quicker, you know the internal gate is letting you down...

another solution, as its been said, is to just weld the gate shut......wiring it shut shouldnt be used as a permanent solution either!!!

[Cuzzo]

There is quite a bit of pressure trying to force the internal gate open.

Why did you get an external gate if your not sure what they do? Gran turismo style ads 50hp?

Either weld the gate shut or change the rear housing..