Write ups and tutorials for maintenance and modifications.
Mon Oct 09, 2006 2:06 am
QIK_GT4 wrote:would that be the same source i would use for my BOV vacume?
can u T it off for both boost gauge and BOV?
Mon Oct 09, 2006 3:51 am
Yes you can T it off for your BOV vacuum.
Gary wrote:For people without an empty port, you can just use a "T" on any vacuum line from the intake manifold.
Not that this is important at all but I recently found that my boost gauge had been T'd into the line going to the I think AC idle up valve. This line had a filter or check valve or something in it which affected vacuum reading and sometimes boost. I changed it to the way described here.
This thing here from
This port here. You can see all the other ports on the manifold in this picture. There is a largish one under the last "hole" on the TVIS.
Thu Oct 26, 2006 6:35 pm
Correct me if I'm wrong but with this setup above, boost would be indicated by an increase in vaccum? If I just wanted it to read boost alone, how would I hook it up...someone told me to 'T' the hose between the wastegate and the intake side of the turbo.
Thu Oct 26, 2006 6:44 pm
gt4tified wrote:Correct me if I'm wrong but with this setup above, boost would be indicated by an increase in vaccum? If I just wanted it to read boost alone, how would I hook it up...someone told me to 'T' the hose between the wastegate and the intake side of the turbo.
It depends on your gauge. Most boost gauges can also read vacuum (which is very infomative).
You can T that hose but it will only read pressure before the IC, not the real reading of air pressure entering the cylinders.
And 99.999999999% of the time, we don't refer to the boost reading from the that location.
Thu Oct 26, 2006 7:32 pm
Gary you're a trip!
Anyway, what u say makes sense. Tell me though, with the boost gauge that reads both vaccum and boost (me gots one of doze) connected the way you described to the vaccum port on the rear of the manifold, under boost would the gauge read an increase or drop in vaccum?
Fri Oct 27, 2006 1:10 am
It'll read "actual pressure".
Note that "actual pressure" can be negative (a.k.a. vacuum) or positive (a.k.a. boost).
When you go from idle and start to open the throttle, the gauge should move from 17-19 in.Hg of vacuum and goes to "0" vacuum (which is "0" boost).
And if you still keep pushing your right foot on the pedal
, the needle will keep going from "0" boost to 1 psi, 2 psi, 3 psi ..... Then when you lift your right foot, the needle will move back to vacuum.
watch this clip:
http://video.google.com/videoplay?docid ... 8322914594
Fri Oct 27, 2006 11:52 am
Yeah my gauge does that but how do I know how much boost I'm making....is it just the max reading on the boost/positive side? I thought it would be a kick in the needle or something...
Fri Oct 27, 2006 12:33 pm
gt4tified wrote:Yeah my gauge does that but how do I know how much boost I'm making....is it just the max reading on the boost/positive side?
Thu Jan 25, 2007 4:03 am
ok my guage reads about 22-23in.hg at idle..... is this ok? or should i get a new vacuum line?
Fri Jan 26, 2007 9:53 pm
Fri Jan 26, 2007 10:29 pm
Thats about what mine reads at. Its usually around 20 or 21 (when the car isn't broke
) so your okay.
Sat Jan 27, 2007 12:28 am
What gauge are you using?
It's a little bit high (vacuum)
But I know people that has the same reading as yours but everything seems OK.
Sat Jan 27, 2007 12:30 am
I'm using an autometer phantom. I thought that was about normal? What would cause it to be that high?
Sat Jan 27, 2007 12:49 am
I wouldn't say that 22-23 is too high. Gauge can be error too.
But normally, high vacuum reading may be caused by advanced timing.
Sat Jan 27, 2007 12:53 am
Thats good to know. You learn something new everyday. Thanks Gary
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