St165 Boost cut

[CelicaGT8]

How do you stop the standard st165 gt4 boost cut? My Rona Sedan is hitting it from time to time and its a pain in the ass.

[RunningRich]

Early or late engine? Early had no MAP sensor but late did I think. US did too.

Early uses airflow meter input and (I think) smoke and mirrors to determine boost cut. Ever ask yourself what runs the boost light on the early cars? There is no pressure sensor so I think it is all MAP driven by the ECU.

Been a while so may be wrong.

[sergei]

if it is early ST165 (will have difflock switch), then easiest way to get rid of boost cut is an ST185/1gen SW20 ecu (you will need to rewire plugs).

[matt dunn]

Correct, thet have an AFM sensed cut.

Wew played with one here, and the more modifications they di to the car to improve power, as you improved airflow the lower psi the boost cut would cut in at.

If you put a voltage clamp or similar in the signal to stop the cut,
you also stop it adding more fuel.

[sergei]

Correct, thet have an AFM sensed cut.

Wew played with one here, and the more modifications they di to the car to improve power, as you improved airflow the lower psi the boost cut would cut in at.

If you put a voltage clamp or similar in the signal to stop the cut,
you also stop it adding more fuel.

It got so bad for me that I was getting "boost" cut at ~6psi.

[CelicaGT8]

Its a preface lift engine, so the early st165 engine, not looking for power here, just want a nice dailyish driver.

Not really too keen on changing the computer, not sure if the later 165 engines have a mini map sensor or not....

Anyone no what wire from the air flow sensor effects it? and what to do to it?

[sergei]

Its a preface lift engine, so the early st165 engine, not looking for power here, just want a nice dailyish driver.

Not really too keen on changing the computer, not sure if the later 165 engines have a mini map sensor or not....

Anyone no what wire from the air flow sensor effects it? and what to do to it?

Don't mess with AFM, as it will affect fuelling greatly (can blow up your engine).
If you want a daily driver why mess with it in first place?
Either leave it stock (including exhaust) or put ST185 ECU to accommodate higher flow through AFM.

The ST185 ECU will work with stock injectors, sensors and AFM, the only thing you will need to add is either the MAP sensor or voltage divider to fool MAP sensor input.

[matt dunn]

How do you stop the standard st165 gt4 boost cut?

easiest, cheapest and most relaible way,

fit a more restrictive muffler.

[CelicaGT8]

How do you stop the standard st165 gt4 boost cut? My Rona Sedan is hitting it from time to time and its a pain in the ass.

The engine is now in a st151 Corona, i dont want to mess with it, i just want to avoid hitting the boost cut that it hits for whatever reason now and again.

The exhaust is very restricted, it goes from standard 165 untill the flexi, then goes to standard corona exhaust.

Haha, also, anyone think a standard 2sf fuel pump will do the job