BoostAllowedFromRPM WSGRPM in BB60 drops off boost?

[Clay]

Ok, now that Ive started looking into this a bit more, I was doing a comparison between my BB60 and a stock 87 TII cal. Now my question is in the line labeled "BoostAllowedFromRPM WSGRPM" in the BB60, the boost drops off from ~20 psi @ 5200 RPMs to 15 PSI @ 6000, which explains why I never seem to hold full boost during a run.

Is there a reason for this? My cal is pretty much a stock BB60, so Im sure if anyone looks at one they will see the same thing.

thanks,
clay

[cordes]

The DC of the injectors gets pretty scary when you really do the math, so Geoff lowers the boost in the upper RPMs to stay in a safer range.

[mock_glh]

Correct me if I'm wrong, but I believe that is done to prevent the duty cycle from maxing out and going lean.

[cordes]

Correct me if I'm wrong, but I believe that is done to prevent the duty cycle from maxing out and going lean.


+1, and I think better stated than what I said.

[Clay]

cool, so if I change to +40s, will this change at all? Im assuming with bigger injectors the boost may be flatter, longer?

[cordes]

cool, so if I change to +40s, will this change at all? Im assuming with bigger injectors the boost may be flatter, longer?

If you look at the yellow and red horizontal lines in chem2 you will get an idea of where the max DC occurs. I think the yellow line is 80% and the red is 100%, but I would have to double check that.

[Clay]

If you look at the yellow and red horizontal lines in chem2 you will get an idea of where the max DC occurs. I think the yellow line is 80% and the red is 100%, but I would have to double check that.

red and yellow lines....... hmmmm which variable has those?

[Clay]

hmmmmmmm the "fuelfullthrottle" variable Im guessing. I can kind of see a red and yellow line, but they sure are faint.

[cordes]

hmmmmmmm the "fuelfullthrottle" variable Im guessing. I can kind of see a red and yellow line, but they sure are faint.

Yes, full, part, and no throttle fueling tables.