boost question

[johne30m3]

just wanted to know if theres any way to adjust base boost psi? wastegate rod adjustment? is it possible to overboost with solenoid unpluged? I was also told you can over boost with out setting code 31 .my chip is stock delco aybm 4053.

 

[atc82]

wastegate rod adustment will give no change to base boost. to adjust base boost, you would have to change the wg actuator. the spring in the stocker gives 10 psi base boost. i have seen sites on the internet selling a 15 psi wg actuator for a Mitsu turbo, but i can't remember where. you can overboost without setting code 31 if it is for a short period of time. i *think* you have to overboost for more than a couple of seconds for it to set a code. HTH

 

[Tooky]

Re: boost question

just wanted to know if theres any way to adjust base boost psi? wastegate rod adjustment? is it possible to overboost with solenoid unpluged? I was also told you can over boost with out setting code 31 .my chip is stock delco aybm 4053.

The wastegate rod adjustment will directly effect base boost. If you crank it you will see 15+ PSI in top of higher gears and depending on weather (and how far you've cranked the rod) you can and will get Code 31 check engines at least I did on AYBN 4175.

 

[atc82]

i was under the impression that he meant with the wg soleniod unplugged for the base boost issue.

 

[90syclone]

ECM needs to see "Over 29 psi for more than 2 seconds" to log "Over-Boost" code. Been there seen that!

90SY

 

[InvisiBill]

ECM needs to see "Over 29 psi for more than 2 seconds" to log "Over-Boost" code. Been there seen that!

90SY

Ummmm, the stock 2-bar MAP sensor can only see ~15psi...

 

[atc82]

a stock motor that hits 29 psi will have rods hanging out the block.

 

[smeagol]

ECM needs to see "Over 29 psi for more than 2 seconds" to log "Over-Boost" code. Been there seen that!

90SY

He's right if you are talking ABSOLUTE pressure, but we are talking referenced to atmosphere. Atmosphere = 14.7psi, or as our boost gauge reads, 0psi. 15psi of positive pressure is 29psi in that respect.

If you see 29psi of boost on a stock motor, you'll have a shiny trail behind you, and a newly ventilated oil pan 8)

 

[Syclone#2960]

So what would be the most boost you could or should run at. With the stock chip?
________
FOXYANALL

 

[InvisiBill]

15psi. You can tweak things to get a little more out of it, but if you get over 18 or 19psi, you're getting out of the turbo's efficiency range even. The extra heat and backpressure and stuff cancel out any gains made by the increased boost.

The stock ECM can only see 15psi of boost. 15psi and 25psi look exactly the same to the ECM, so it can't deliver the extra fuel needed to cover the extra boost. Like I said, there's some headroom and you can probably get a little more out of it, but if you want your computer to accurate control things over 15psi, you really should go with a 3-bar setup.

 

[Syclone#2960]

I also have an adjustiable fuel pressure regulator,If I extend the wastegate rod 3 complete turns thst should be 2 psi. Can I just turn up the fuel pressure up to accomidate the higher bosst?
________
SIDE EFFECTS OF AVANDIA