2JZ-GTE , standard twins JZS-147, boost cutting???

[wrench]

Hi all, just been tinkering turning the factory twins up on my 2j. Seems up around 12psi or so it feels like it is boost cutting or something? I have introduced a air bleed valve boost tap to the waste gate actuator at turbo no.1. Took it for a run, pulls on 12-14psi at 4000rpm , gets to about 5000rpm and then like cuts out just for a second... like i have lost ignition or something. First time it did it real bad, like 3 times on its way to redline. Stopped, turned up the base pressure a shade on my malpassi ( 1.7:1 ). Next run it only did it once then kept going nicely through to red line with no interuptions. Fuel pressure problem or a factory fuel/boost/ignition cut?
As this is in my drag car it has not cat, just a 3 inch side pipe, fuel cell with external VL turbo fuel pump, 3/8 return line, malpassi fuel regulator ( i tried to use a SARD one but it just floods and won't idle at all, at 8 psi the malpassi works fine ), FMIC. BRAND NEW COILS LOL!
Any ideas?

[YGO 08]

get rid of the factory ecu. i had nothing but trouble with mine and since going after market it goes so much better. best thing i have ever bought and since its a drag car that will be money well spent.

[wrench]

Yes that is the next step. Was going to do Microtech/haltech , single GT35/40 and a tune. Where and which ECU did you buy?
So am i to believe it will just keep chucking shit fits if i try to give it more than standard boost?

[YGO 08]

ive got the wolf v500 but they now have the v550. much better then the old wolfs. really you just need to find a tuner and see what they use/ work with and buy that. you could have the best of the best but its not going to be any good if your tuner cant work the thing. there is guys out there playing with the factory ecu but when i had mine on factory ecu it would go good one minute and crap the next with boost cut etc. as i said buying a aftermarket ecu was the best thing i did and knowing its alot safer tuning it how you want. im making over 500 with a 100% stock 2j with a 35r and surporting mods (fuel,cooler,exhuast etc just boltons)

[wrench]

Did you use the Wolf with the stock twins? Im interested to find out how far people have gone with stock twins.
I was thinking microtech and taking it to blacktrack.

[YGO 08]

nar i went stright to a 35r lol. ive seen a few blokes play with them but i think they link them together instead of having the second one come in later. i put my engine in a non toyota body to start with so needed the room and went single but have since put it all in a mx83 cressida.

[wrench]

Yeah mines in front of a falcon lol.

[VIP-1JZ]

it could be boost cut, what map sensor is on it? 1 bar? you may be getting an incorrect reading off the boost gauge. u will find temperature makes a big difference too. with my cressida, on a hot day it would hit boost cut at 6500rpm... on a cold night it would hit boost cut a couple of times from 4000 onwards. best way around it is a fuel cut defender... or even a cheap jaycar fuel cut defeater... i used the cheap jaycar one and seemed to have no problems since... untill i detonated the motor from hitting the fuel cut and blowing a hole through a valve

[wrench]

It has a brand new genuine Toyota MAP sensor on it. Temperature was about 20-25 degrees at time of test runs. Will the fuel cut defender remove the rev limiter? I'd still like to retain the rev limiter.

[VIP-1JZ]

What size map sensor? 1bar? 2bar? 3bar?

The fuel cut defender fools the computer by sending a false signal from the map sensor... Only stops boos cut... This is all... Lol

[PlacentaJuan]

use a supra ecu its a different tune and will solve this problem