Adjusting down boost pressure?

[scotty]

Hey,

I'm hitting fuel cut @ around 0.8 bar. I'm going to buy 550's, walbro 255 and lexus AFM, but not right this moment, so I'm wondering if it's possible to adjust down the boost in a simple way? I've got no boost controller etc.

 

[Poodles]

Honestly, not really. Though you seem to be a little low on the boost levels for fuel cut so look for boost leaks to rule it out as the cause.

 

[stolensupra]

If you're using a stock CT-26 the wastegate spring is set at a certain pressure and wont go any lower. Your only options would be to try to find an actuator from an automatic (assuming yours is manual) and I believe they only hit like 6.5 lbs of boost as opposed to around 8. I'm not sure if the springs are replaceable or not. Any lengthening of the rod would cause an exhaust leak inside the hot end of the turbo. Good Luck Buddy!

 

[Poodles]

If you're using a stock CT-26 the wastegate spring is set at a certain pressure and wont go any lower. Your only options would be to try to find an actuator from an automatic (assuming yours is manual) and I believe they only hit like 6.5 lbs of boost as opposed to around 8. I'm not sure if the springs are replaceable or not. Any lengthening of the rod would cause an exhaust leak inside the hot end of the turbo. Good Luck Buddy!

Same actuator in both and nope you can't replace the spring in the factory actuator.

 

[hvyman]

If at stock boost levels you have something else causing fuel cut.

 

[Nick M]

The automatic does not develop as much boost because an automatic has less load. Unlike what you read sometimes about the dyno and the auto making less. The fluid coupling is the cause of the slip and lower load, and less boost.

 

[scotty]

Started another thread and asked if anything was wrong as I'm hitting fuel cut @ 0,8 bar, got replies saying it was just stock fuel cut level. Now I'm having replies here of it being boost leak insted of fuel cut. What is the stock fuel cut level then? I've got doubts that I have a boost leak..

 

[mk3sons]

Started another thread and asked if anything was wrong as I'm hitting fuel cut @ 0,8 bar, got replies saying it was just stock fuel cut level. Now I'm having replies here of it being boost leak insted of fuel cut. What is the stock fuel cut level then? I've got doubts that I have a boost leak..

mine doesn't cut until over 1 bar

 

[Poodles]

You're close to the level for fuel cut, enough so that a small leak would cause it...

 

[Nick M]

I think you are missing some basic information. The TCCS cuts fuel for several reasons. Such as deceleration, engine speed, excess airflow through the air flow meter. The third causes DTC 34, abnormal turbocharger pressure.

That is boost cut as you called it. An intake leak will do the same thing. There is no restriction to air flow, so the amount coming through the meter goes way up. I just went through it with mine. A boost leak causes fuel cut. A big turbo cause fuel cut. A manul controller increasing the flow from a stock CT26 causes it.

 

[stolensupra]

The automatic does not develop as much boost because an automatic has less load. Unlike what you read sometimes about the dyno and the auto making less. The fluid coupling is the cause of the slip and lower load, and less boost.

That makes sense. I shouldn't have assumed that the wg was different because of the difference in boost pressure. However I do know that these guys are right about the fuel cut capability. My mods are entirely basic and I run 12 lbs of boost on and don't believe I've ever hit fuel cut aside from right before my lower intercooler hose blew apart.