What's the equasion to calculate atm to lbs?
06-21-2000, 03:30 AM
#3
Junior Member
Join Date: Mar 2000
Posts: 633
Likes: 0
Received 0 Likes
on
0 Posts
Help! Need further clarification...
If the vag tool measures 1000mbar at rest, 2000mbar at WOT, then I subtract 1000 from the reading to arrive at 1bar of boost with a chip.
So, does this mean that at rest there is 14.7psi in the system, and when my chip kicks in I have 2x14.7=29.4psi????
Or, is it 0psi at rest and 14.7 at WOT?
-mike<p><a href="http://registry.audiworld.com/audi/registry/details.asp?car=3258"><img SRC="http://pictureposter.audiworld.com/AudiWorldPics/2000/mnpsig2.jpg" BORDER=0></a>
So, does this mean that at rest there is 14.7psi in the system, and when my chip kicks in I have 2x14.7=29.4psi????
Or, is it 0psi at rest and 14.7 at WOT?
-mike<p><a href="http://registry.audiworld.com/audi/registry/details.asp?car=3258"><img SRC="http://pictureposter.audiworld.com/AudiWorldPics/2000/mnpsig2.jpg" BORDER=0></a>
06-21-2000, 03:53 AM
#4
Member
Join Date: Mar 2000
Posts: 4,259
Likes: 0
Received 0 Likes
on
0 Posts
14.7 at rest, and 29.4 at full boost. 1 bar of boost, i.e. 1 bar added to ambient pressure.
This is in front of the throttle, the intake manifold may run well under 1 bar absolute at times.<p>Jim De Arras
<a href="http://www.imola.org">2000 00 Imola/Onyx/Alcantera S4</a>
MTM Stage II (Stage III on order)
MTM Full Suspension
MTM/Pagid Brake pads
UUC Short Shifter (original 20%)
Michelin Pilot Sports.
SmartTire Tire Monitor
<a href="http://www.imola.org">2000 00 Imola/Onyx/Alcantera S4</a>
MTM Stage II (Stage III on order)
MTM Full Suspension
MTM/Pagid Brake pads
UUC Short Shifter (original 20%)
Michelin Pilot Sports.
SmartTire Tire Monitor
06-21-2000, 10:13 AM
#5
Junior Member
Join Date: Mar 2000
Posts: 633
Likes: 0
Received 0 Likes
on
0 Posts
Thanks Jim! ;-)
<p><a href="http://registry.audiworld.com/audi/registry/details.asp?car=3258"><img SRC="http://pictureposter.audiworld.com/AudiWorldPics/2000/mnpsig2.jpg" BORDER=0></a>
06-21-2000, 02:39 PM
#6
New Member
Join Date: Apr 2000
Posts: 35
Likes: 0
Received 0 Likes
on
0 Posts
Re: Help! Need further clarification...
You are confusing ABSOLUTE pressure(PSIA) and GAUGE pressure(PSIG). Let me explain....
0 PSIG is equal to atmospheric pressure. This is variable but as a standard 14.7 psi is used.
0 PSIG = 14.7 PSIA.
Negative pressure(ie-vacuum) in PSIG units are in inches of Mercuruy (Hg), as an example,with "full" vacuum equal to 30 ins of Hg or -14.7 psig
0 PSIA = a hard vacuum---No pressure at all. See how that works!!!! You were absolutely correct in subtracting the "at rest" figure from the WOT figure since your instrument was measuring absolute pressure.
We are all familiar with a "normal" mechanical pressure gauge. A mechanical absolute gauge is built differently in that the element that senses the pressure(Bourdon Tube, Diaphragm, Bellows..) is hermitically sealed, at (1) Standard atmosphere at Standard Temperature (75F), in a temperature compensated envelope to elinimate the affects of expanding gas within the envelope.The thermal compensation insures the instrument's accuracy is maintained as temperature varies from what is called STP conditions (Standard Temperature and Pressure)
A BAROMETER is a an example of an ABS(absolute) pressure gauge.
I hope that helps...
BTW- 1 bar = 14.50377 PSIG
Regards-
LOU
0 PSIG is equal to atmospheric pressure. This is variable but as a standard 14.7 psi is used.
0 PSIG = 14.7 PSIA.
Negative pressure(ie-vacuum) in PSIG units are in inches of Mercuruy (Hg), as an example,with "full" vacuum equal to 30 ins of Hg or -14.7 psig
0 PSIA = a hard vacuum---No pressure at all. See how that works!!!! You were absolutely correct in subtracting the "at rest" figure from the WOT figure since your instrument was measuring absolute pressure.
We are all familiar with a "normal" mechanical pressure gauge. A mechanical absolute gauge is built differently in that the element that senses the pressure(Bourdon Tube, Diaphragm, Bellows..) is hermitically sealed, at (1) Standard atmosphere at Standard Temperature (75F), in a temperature compensated envelope to elinimate the affects of expanding gas within the envelope.The thermal compensation insures the instrument's accuracy is maintained as temperature varies from what is called STP conditions (Standard Temperature and Pressure)
A BAROMETER is a an example of an ABS(absolute) pressure gauge.
I hope that helps...
BTW- 1 bar = 14.50377 PSIG
Regards-
LOU
Thread
Thread Starter
Forum
Replies
Last Post
Jim De Arras
S4 / RS4 (B5 Platform) Discussion
5
08-02-2000 03:50 PM
Jim De Arras
S4 / RS4 (B5 Platform) Discussion
23
07-17-2000 05:15 PM
Jim De Arras
S4 / RS4 (B5 Platform) Discussion
25
07-05-2000 02:12 PM