Im currently running in a street class and am fighting a battle of spoolup. Im usually hitting full boost at 4k rpm. Im trying to stay in 2nd gear. When coming out of corners i have no power under 4k rpm, because of this im only able to get 3rd in IMS class. Call me crazy but ive been experimenting by using a ebay 60-1 with a .68 exhaust side, been using this setup for 2 years. Also using straight meth injection to keep things cool also. Using an hks cast log mani all undivided. I know going divided would help things but what are you t2 guys using to get power on the bottom end.

 

I have never tried to autocross a TII with a bigger turbo so I don't know exactly what to tell you to do mechanically with the car. Have you tried left foot braking? Maybe feathering the throttle mid to exit of the corner could keep the turbo spooling slightly for a better corner exit.
You could also brake sooner and get the car positioned better and then get on the throttle sooner. I know it is probably hard to be smooth with light switch power but do everything you can to look ahead and be smooth with your inputs.

 

While a less than elegant solution (and possibly banned by whatever regulations you're running under) the single turbo skyline guys tend to use NOS only in the lower rev range to help the turbo spool, controlled solely by the ECU.

 

Get a smaller hotside turbo.

 

You could find the HKS to4E 57 trim that matches your hks manifold. I believe it has a .69 A/R hot side. I had one and it was good at auto-x. It is not going to make much power (250 ish). I might have the manifold some where.

You could also switch to a taller rear end, if you haven't already, I believe you can find 4.30 and 4.88.

Just ideas...

 

+1 on taller diff, 4.3 from an infini. Where do you get a 4.8 from?
What size exhaust? Bigger downpipe?

 

BNR Stage 4 S5 based stock hybrid with "P" trim exhaust wheel, 60-1 compressor. 60mm external wastegate and heavily ported manifold/turbine housing to stop boost creep.

90mm downpipe/midpipe to RB REV TII rear section on exhaust side and 3" to 6" velocity stack on intake with 10" truck filter on intake side.

Not as snappy on the low end as my sequential FD turbos but full boost is before 3,500rpm, 380rwhp @14psi. Couple psi @2,000rpm, ~7.5psi @2,500rpm, 10psi @ 3,000rpm.

Some Miata courses with tons sweeping turns/transitions I had my best time shifting into 3rd so I didn't have to be so careful with the throttle trying not to spin tires in 2nd. But I am just on 275/255 NT01 not wide Hoosiers or anything. I have to short shift out of 1st a couple feet off the start line.

I think you would do well to use a knock off FD divided T3 manifold and a "P" trim exhaust wheel 60-1 T4 turbo in a bored out 1.00 AR T3 exhaust housing. The small T3 runner volume helps spool and won't kill the top end flow so much as going to a restrictive small AR housing.

Go big on the exhaust and intake. On RB 3" exhaust my turbo wouldn't get full boost till 3,800rpm. Data logs showed the velocity stack/filter added ~1psi of boost @2,000rpm and carried the increased spool through the powerband. The only downside is you have to port the manifold to get the wastegate to flow to avoid boost creep.

 

if you have a stand alone , you may want to tune for more low end torque more advanced timing in the lower RPMS. a smaller intercooler is supposed to help with spool to isn't it?

 

get a smaller turbo that fits the application

 

Get a smaller hotside turbo.
get a smaller turbo that fits the application

Most people don't put something smaller than a 60-1 .68AR exhaust on a rotary- Would make make more sense to keep the a stock hybrid turbo.

I have been hearing of the ebay knock off turbos being laggier than legitimate turbos of the same trims/ARs- probably from poor housing to wheel tolerances and chunky compressor wheel and housing castings.

Fairly aggressive timing and AFRs in the low boost areas coupled with low timing split can liven the response up a bit, but it isn't going to be magic torque like when you get the turbo boosting earlier.