Boost Question

[Shawn89255]

Where is the boost measured for the computer to read? I know the wastegate controls the boost and in my situation, the Unichip Boost solenoid controls it as well. What sensor does the computer read from for boost?

 

[lp216]

The computer dont have any MAP sensor, he only read throught the MAF

 

[Shawn89255]

Okay...So heres is my problem. I have the Unichip with its factory maps, and i just replaced the boost solenoid. The car runs fine on stock boost, and holds at 9psi. When I use the high boost setting, it hits around 16psi and then fuel cut. My mods are listed in the beginning of the thread. I also replaced the wastegate actuator and i know it works properly because it run steady at 9psi. What can be the problem? It could be possible that I just need a new tune, but I dont know. Any input would be nice.

 

[lp216]

Look like the boost solenoid of the unichip complety stop the vaccum to the wastegate. So it's like if you are running with no vaccum line to the WGA. If you are by-passing the solenoid, you are running how much psi? 9 seams to be pretty high, but as long it's steady it's not that bad.

 

[sean22306]

its forged so 9psi isn't that bad. i take it youre still on stock injectors? I think thats the problem. They don't like 16psi. I used to occasionly around 4500-5000 rpm at 14-16psi. Now with the 440's no cutting, i can run high boost all day.

 

[Shawn89255]

Yea, Its steady at 9psi on regular boost. I figured it is that because of the open exhaust, head work, intake manifold, & fmic.

Im pretty sure the boost solenoid is working correctly...but I dont really know how to check it. Any ideas?

 

[Shawn89255]

I dont have the 440's installed yet...So your saying i just need a new tune? which is what i thought...Just need to go dyno tune it.

 

[Outlawstar98]

so when boosting on high, your car cuts the fuel? then its the injectors, causer are you sure its cutting the fuel? or is it the injectors arnt pushing enough out!

 

[Shawn89255]

Good point...How can i check this?

 

[Outlawstar98]

upgrade to 440's and see if it works then ? haha

 

[Shawn89255]

haha...Nice...Im going to get it tuned soon anyway. Costs about $560 though...at the most. As low as $370

 

[Outlawstar98]

U still have stock turbo? right?

 

[Shawn89255]

Yea...Stock Turbo

 

[Outlawstar98]

Yeah, at 14ish PSI u need 440's I know that much. So upgrade and find out!

 

[Shawn89255]

Yay.....I was gonna do it anyway...Just not right now

 

[speedy gonzales]

The boost controler that came with the unichip is program for a MSP with 6 psi ,when the BC is ON you suppose to have 13 psi in mid-range and 10 psi at redline so if you have 9 psi stock it's normal you hit 16 psi.The Unichip push back the fuel cut but it's still there,solve the boost problem before or go see a unichip tuner to tune the boost controler and your MAP with 440cc .

 

[Shawn89255]

Sounds fair... I just don't know how to fix the problem without getting it tuned.

 

[speedy gonzales]

You can't so dont use the BC to up the boost, try the spring on the wastegate actuator for +2 or 3 psi .When I have the unichip I finished to buy a turbosmart E-boost 2 to have full control of my boost.

 

[NJ MSP]

I had the same problem man once i got the 440's in, the car ran smooth again.