Does anybody know if the boost numbers seen in the cluster are total engine boost or are they the larger turbo's boost numbers? Where do they tap into for the gauge? Do these turbo's run wastegates? Im tryin to squeeze some more boost outta the turbinators before I use a tuner. Any input is appreciated

Cowboy Steve

 

Those are actual boost numbers in the CAC tubes, and no there is no waste gate, with the VGT turbo a waste gate is not used. Only way to get more boost is to reprogram the PCM or replace the turbos.

 

I guess i didnt know that they were both VGT turbo's. Learn somethin new everyday. Thanks Blackhat!

Cowboy Steve

 

No the first turbo is a small fixed turbo and helps reduce turbo lag off the line, it is sequential with the larger VGT trubo, at low speed the VGT turbo is basically open and does not contribute any boost (this is an oversimplified statement) and as the speed and load increase the VGT vanes change the size and output of the VGT turbo increasing boost. As the engine slows when you lift off the throttle the VGT turbo vanes move effectively changing the size of the VGT turbo and reducing boost pressure. Because there is a VGT turbo in the system, a waste gate is not need to control and overboost situation.

Since a VGT turbo is controlled by the PCM, the only way to increase the boost output is to re-program the PCM. Also more boost is not beneficial unless you can also increase the fuel delivered to each cylinder.

 

Well I already have the fuel situation figured out. I know the "more air needs more fuel" situation but I didnt know what turbo situation i was workin with.

Theoretically I could mod the smaller turbine wheel and maybe housing to produce more air.= at lower boost. All things I will toy with in the near future. I am debating wether or not to go with the SCT or Superchips tuner.....Such a hard life, lol


Cowboy Steve