Issues With Stalling, And Hesitation

[rj180sx]

So first off I want to say hello again, as I am new to this forum. I own a 1992 Skyline GT-R, which I bought without any modifications to the engine. This car is also my first twin turbo car ever owned.

Here are the issues I'm having, basically one day I got bored and wanted more power. I cut the boost restrictor out and the car went from 0.7 bar to 1.0 bar, which is fine, but some days when its cold out the car would boost up to 1.1 bar consistenly and it was stable for the most part, of course the was the boost leveling in higher RPM, which is also okay. I figured the wastegate springs got a bit weak over the years as the cause of the slight "boost spike".

I decided to buy an electronic boost controller (Greddy Profec) to have a more consistent boost level and regulate the leveling. I used the factory lines for my boost source to the plenum and ran new lines to the wastegates. I blocked off the lines not used as well. The EBC works great and performs as it should.

I have my low boost set at 0.7 bar and high boost at 1.0 bar. I ran into my first problem with the high boost setting, no matter what i do, the car hesistates/sputters between 5000-5400 RPM and 6000-6300 RPM, only at high boost.

I just finished the turbo upgrade yesterday, I went with some HKS GT-SS and Tomei Dumps/Outlets. While I was pulling the front/down pipe off, I saw that some previous owner stacked about 8 gaskets between one turbo dump/outlet and the front pipe. When I was putting it back together I decided to just use one gasket on each outlet.

Of course I had a nasty exhaust leak, but now thats where my second problem showed up. When I'm driving, the car runs fine but when I roll/ coast up to a stop and disengage the clutch, the cars RPMs drop past the idle to about 300 RPM to near stall. I fugured maybe its just due to that nasty exhaust leak, so I just parked it.

Today I bought a new front pipe and fitted it to the car, well the problem is still there, so I need help on these issues, and yes the boost problem is still there, basically at 1.0 bar and above, and now the boost controller is useless right now, because the wastegates are set to 1.15 bar. If someone has info on how to go about adjusting the wastegates (since its twin turbo) that be awesome.

Any good help would greatly be appreciated.

[KiwiRS4T]

If you upgraded the turbos to make more power then you will need to retune the engine which will only be possible if you have an upgraded ecu (with Nistune chip, PFC, Link, etc).

[Badgaz]

before you give yourself an expensive headache consider wether any of the modifications it has has been tuned for...if not....you're making a good grenade.