88da3

new to the FI community but i searched and didn't find the answer i was looking for. here is the setup:

stock b17
greddy td05h 18g turbo
greddy manifold
b&m fpr
hondata
2.25in piping
2.5in exhaust to a magnaflow muffler

in the hondata will datalogging i am registering 30-32in Hg vacuum while idling. it idle's fine at 850rpm just want to know if i should be worried. never saw any car idle at anywhere higher than 25in-Hg. i will hook up a gauge to see if the reading is consistent. any ideas on why my it is so high? n/a the motor idled at around 19.5-21in Hg. any feedback would be helpful.

m R g S r

yeh b17's r crazy, they pull crazy vaccuum

88da3

so is the high vacuum normal for a turbo car?

tannerLSt

it should idle around 19-21

rsintegra

mine is idling at 20, but everybody is different

tgreaves

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 88da3 &raquo;</TD></TR><TR><TD CLASS="quote">so is the high vacuum normal for a turbo car?</TD></TR></TABLE>

It doesnt matter if its boosted or na, vacuum is vacuum.. Now alot of na cars have bigger cams witch pull more vacuum at idle but the addition of a turbo doesnt change the vacuum..

And I assume that you are reading this from a map sensor.. What is your pressure reading at key on engine off?

beepy

You aren't getting a reading from your MAP sensor.

32 inHg = perfect vacuum. Unless you have an engine that came back in time from the 25th century, there is no way that is possible.

More than likely, a reading of 0 volts corresponds to 32 inHg, and you have a short somewhere.

Black R

my boost gauge shows ~18psi at 800rpm idle.

(b18c5/ itr motor that is stock except for toda spec A camshafts and greddy 18g turbo kit + fmic.)

Finland

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beepy &raquo;</TD></TR><TR><TD CLASS="quote">

32 inHg = perfect vacuum.

</TD></TR></TABLE>


He is correct, and perfect vacuum is strictly theoretical and doesn't exist anywhere, not even in space. There's definitely a sensor/signal problem there.

tgreaves

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr. Helsinki &raquo;</TD></TR><TR><TD CLASS="quote">


He is correct, and perfect vacuum is strictly theoretical and doesn't exist anywhere, not even in space. There's definitely a sensor/signal problem there.
</TD></TR></TABLE>

Either that or his engine has done what no scientist has been able to..

88da3

i got a boost/vaccum gauge so i will hook it up this afternoon and see what it reads. thanks for the help so far.

88da3

hooked up my boost gauge this afternoon. i'm pulling 20in Hg. guess i'll be looking for a new MAP sensor. thanks guys.