i seem to get differing numbers..... when i see ten on the boost gauge it doesn't necessarily translate to 10 by the pfc when i do the conversion. 1 bar = 14.7 psi right. which is more reliable??? trying to dial in the profec b and don't know which to go by the boost gauge(autometer-mechanical) or the pfc. thanks is advance. kevin

 

Do a search, there are many topics on this. I don't know if it's completely understood yet, but some believe the PFC has an internal conversion error. Most people seem to read 2 psi higher on the PFC than they do on their boost gauges. Oh and BTW the PFC reads in kgf/cm^2 not Bar, 1 kgf/cm^2 = 14.22 PSI.

 

actually the opposite....

boost gauge(s) will show 1-2psi more then PowerFC....I see 1 psi difference and many as much as 2 psi.

 

well the point of read is also different. the gauge is read at a bend in the manifold where the pfc takes its reading from the plenum (a larger area). i think that is the difference in the reading. . . maybe im wrong. somebody should read their boost straight from the map sensor line. that would more than likely determine whether or not im wrong. id do it but my FD has been parked for about 7 months now. haha. gimme a month and ill do it.

paul

 

I have my mechanical boost spliced into the hose with the car's boost sensor and I get the boost difference as well, I also have a blitz Dual turbo timer, (it has boost measurement in it as well) and it reads different also...
I think I am going to get a digital boost gauge, do away with the mechanical.

 

still confused. which reading is more accurate. the pfc or the gauge. did a search nothing definitive. thanks.

 

Well, your mecanical gauge is reading what the real manifold pressure is in the manifold.

Which one is more important just depends on what you need the numbers for. It wouldnt really matter if it said 20psi as long as all your parameters are safe like a/f and egt's. Its really just a number to associate pressure with. As long as it remains constant the number itself is meaningless. It could just be little dashes on the gauge and it would serve the purpose.

STEPHEN

 

This has been discussed many times before, the PFC is wrong! Reads lower and lower as pressure goes up.

ALSO: one ATM = 14.7psi
one BAR = 14.5psi
one Kg/CCM^ =14.2 psi.

Please get your boost readings correct.

 

Ditto here.

 

When you had the stock ECU you used your boost gauge to tell whether or not you had a healthy boost pattern, 10 - 8 - 10. You trusted this as a fairly accurate measure of your manifold pressure, i.e. the pressure being produced by your turbos. Now, if all you do is swap out the ECU (assuming it handles the turbo control system identically), why would you doubt what your boost gauge is telling you?

It sucks that they're not the same, and it's valid to wonder why, but I'm with Chuck that it's a conversion error, with some differences thrown in there because of altitude as well.

-Scott