Topic: Message #1085910

[Nation]

I did not see a bypass valve on there are you running one? When you come off of throttle, the turbo is still spooled, air pressure builds at the throttle plate. But there is fuel being added momentary due to the MAF reading air flow, that is until the injector cut out happens. It causes a momentary rich spike, then the fuel cut happens and the pressure on the throttle plate will actually cause the air to flow back through the turbo, you will see a momentary 0 grams per second MAF reading, it can cause off throttle problems due to lean or rich conditions and can cause it to stall.  A bypass valve will help dampen the affects of this.

The best option is to run the bypass valve from the intake pipe back to the inlet of the turbo. It can help with a quicker spool, and less lag between shifts. Since the air hitting the throttle plate is bypassed back into the turbo inlet allowing it to spool, versus backing up in the throttle and allowing it to spool down. It also will keep the MAF from getting false readings. Much better option then a BOV, since you are effectively venting air that was metered by the MAF to atmosphere, so ECM adds fuel to compensate for air, air go PFFT out of the engine, the fuel is still getting injected.

Just some of the problems that I have run into on my home brew turbo projects. White smoke can either be coolant or fuel. Over fueling can cause white smoke, but normally will be accompanied by a raw fuel smell near the exhaust pipe.

No bypass valve. Thats all very good advice and the motor has actually died on me a few times already haha. wouldnt want it to happen at a traffic light coming up behind someone haha. I will incorporate a RBOV soon. I need to get a job asap haha. I was going to put this evo intercooler I have on the truck and bend up some piping.... My energy is still drained from the motor swap and these transfer cases haha