Jon Clay

It was 37F and my car has never been so fast! I was making about 15 lbs. on my boost gauge and felt every pound of it. This brings me to another problem...I'm only supposed to be getting about 12 and have consistently gotten that until this morning when it would cycle between 12-15 during a good hard acceleration. I think I've always ignored the posts about overboosting because I always wanted more boost so I don't know why this was happening.

This afternoon it was no longer overboosting.

Any ideas are welcomed.

Jon

5000CDQturbo

Re: possibly because the ambient air temp was different AM-PM ?

Jon Clay

It might affect timing however by lowering intake temp so as to deter knocking. Which would make more hp, but not more boost. At least not in my thoughts.

-Jon

5000CDQturbo

Cool air increases the air density but also the amount of oxygen
in the air. More oxygen condensed into a specific quantity of air enriches the mixture of
oxygen and fuel that's required for combustion and ultimately generates more power
with each cycle of ignition.

well something like that . .... I guess in your description you are saying it was cold in the morning and I guess it was warmer in the afternoon .... so it leads me to think it might be more about Ambient air temp than anything else .. regards
Dave

cuatrokoop

So your gauge read 2.0 bar (assuming it was the factory LCD)? That is double the factory boost levels...

audiqv8

That why they have intercooler on turbo engines. Turbo really likes it cold.

Toxcheap

My gauge never went over 1.9 even at 24psi. I don't think they're that accurate, maybe they are when they're new.

shortyq

The stock guage can't read above 2 bar with a 2 bar pressure transducer. The most you should see on a stock PT is 1.95. If you get a 2.5 bar PT you can get the guage to read above 2.0 (btdt). The reason is because the PT reads all boost levels above 1.95 as 1.95 = 4.9v. The 2.5 bar PT shows 2.5bar as 4.9v.

A stock car shouldn't reach 1.95bar boost pressures. If it does, you have a leak in the line to the computer box. A stock car on a really cold day should see 1.4, and will absolutely shut down the fuel pump at 1.5-1.6 depending on whether your PT reads .9 or 1.0 with ignition on (no start).

My own thinking is that if you have more than 1.95bar boost, you aren't "controlling" boost anymore, you are best guessing boost, the "control" ended at 1.95bar.

HTH

Scott Justusson

shortyq

Also, remember that boost on a digital guage is a 3second average trailing boost, otherwise your eyes would go nuts. It's pretty accurate in the "average" sense, it's just an analog guage is instantly accurate.

HTH

SJ

Jon Clay

I never looked at the digital boost readout, just my analog one...it said 15