2jz-gte Turbo/Manifold Porting Ideas?

[Z2TT]

Hi Guys,

I want to get the most out of the Stock Sequential system on my 2jz-gte before I put it into my car.
Few people have done such mods on 1jz-gte by porting out the Manifold to turbine housing flange a little bit and resulted in better response and also ported out the wastegates a bit to avoid overboosting.

Has anybody experimented with any mods to the factory system on the 2jz-gte e.g porting any of the pipes out with good gains?

Thanks.

[slipway]

Wastegate porting sounds good as I've often read they overboost with an exhaust on.

[Daddio]

Wastegate is certainly a limiting factor in controlling boost, its pretty tiny, but there isnt an awful lot of room to enlarge it (maybe 1-2mm at best) before the risk of cracking at the seat becomes an issue.
Matching the exhaust mani and head ports to the gasket is neat and pretty easy with a die grinder (dont expect a whole lot of gains)
Biggest down side are the ceramic turbines which tend to shatter at above 18psi (some can run a bit more, some cant, it seems to be just luck!) however if you are not going to hi flowed steel wheeled ones (eg Munro) theres not much you can do with them.
With a decent exhaust, response on sequentials is nothing short of awesome (15psi at 1800rpm!) and porting the flange is likely to create spiking issues rather than improve response very much (I cant say if this is true in TTc mode, but logic says it should help in TTc mode)
If you run a big dump without cat, and a decent exhaust, you will almost certainly need a restrictor in the exhaust to prevent spikes...even with an enlarged wastegate (3mm oversize) on my hiflows, spikes to 22psi+ on a set point of 19 have proved virtually impossible to eliminate (running GReddy EBC, 3.5" dump into 4" Apexi exhaust. no restirctor)

[Z2TT]

Yeah I'm not to keen on running restricters since the whole point of the exhaust upgrade is to remove restrictions. I had zero spiking issues with my 1jz-gte with a Ball and Spring boost controller, would rush upto 18 PSI and not go any higher.

Ok So from what I get it there is not much gains to be had from porting, one last thing i was after is a Aftermarket Dump pipes and this seems to be hard to make for the 2jz-gte..... is there anything available to buy?

The only one I ever knew of was called "Tune Agent"..... does somebody in Japan make something Similar?

[Supra967]

1JZ has two waste gates? 2JZ has one gate for both turbos, hence the spike issues. The exhaust valve is in the dump pipe(s) so it's hard to replace without some trickery. I've got a 3in front, 3.5in rear pipe, factory first cat in place, no boost cut/over boost.

Should be some good gains on the intake side. Bare minimum make sure your couplers haven't collapsed, clean any gunk out.