Hey guys, since the afc can display intake manifold pressure, could someone just use that display as a boost gauge? When i was driving home last night I was comparing my Greddy boost gauge to the afc intake pressure display and they both moved pretty much the same. I think the afc only goes up to like 1 bar or so though, I'm not sure

 

Yea, you can, there is a converstion chart on here somone where..i'll try and find it.

 

this is interesting,

sorry to wake an old thread, but did you ever found out if this was true?

 

WOW i thought this was common knowledge.

Yes you can use the afc for this purpose but your limited by the factory MAP sensorto about 11psi. however the AFC can be setup to read a full 2 BAR!!!

pretty cool IMO i was using this as my boost gauge until I blew my motor now I need to do something else cuz I opted for hondata and am going to sell my AFC.

ANYONE WANT IT?

ohh BTW it displays pressure in BAR form only.


[Modified by T-sohctec, 6:00 AM 2/19/2003]

 

whats thew conversion for bar to psi??

 

85-91 9.25 psi

92+ 10.65 psi

You try for 11 psi on stock MAP regularly, something goes pop.

 

one thing i noticed about this is that the greddy boost guage and the afc show slightly different readings, kinda like the afc indicated rpm and the tachometer. Now, I have only noticed this difference when the car is in vacuum, not boost, mainly because if I'm ever in boost I'm staring at the boost guage, not the afc. With that said, which of the two is probably more accurate?

 

1 bar ~ 14.5 psi

 

Its very easy to convert.
Also, the afc reads in kg/cm2 and not bar. Its very close however.
Just take the reading on the afc, and divide it by .070307

for example: .45 on the afc would be 6.4psi
or: .45 / .070307 = 6.4

This is all from the top of my head, but i'm pretty sure its correct info.

 

Some gauges are very accurate... but the AFC reads the same input your ECU monitors. You probably want to keep track of both. It would be pretty easy to diagnose when you eventually pop a MAP sensor.

 

I have been using my vafc as my boost gauge for a while, set on analog readout. It seems like most mechanical gauges read about 1-2psi higher than the vafc.

 

Uh, what's your max AFC reading?

 

It tops out at .64, which equates to roughly 9psi.

However, the voltage reading from the map at this pressure level is 4.5x (if i remember correctly is the maximum it will put out). I seem to remember having readings of .7x at this same voltage level in the past, so it kind of bothers me. I know others on here have reported the same levels.

I have a ton of map sensors laying around, and they all top on at .64 now, so i take it with a grain of salt. As long as it remains consistant. I think its more of an issue with the way the vafc is calibrated to read the voltage vs pressure.

 

My afc maxes out at .73~.74, never higher, I guess thats the limit of my MAP sensor???

 

I use this link yo convert my max manifold pressure after I record a dry run w/ my AFC...

http://www.worldwidemetric.com/metcal.htm

For example...last night a did a dry run and top out w/ a .55 manifold pressure...thats roughly 7.8psi....

 

I said about, and yeah I know what happens after 11psi on a MAP.

Trust me it wasn't a pop, it was more of a BOOM!! clank clank clank

I must say though you are on point with your info.

 

So I can't boost over 9.25 psi on my 91 teg??? Unless I get a GM Map??

 

[Modified by J. Davis, 9:33 PM 2/19/2003]