Mazda Rotary Club

General => General Technical => Topic started by: SteveM on October 19, 2003, 07:12:27 PM

Title: Boost Pressure Units
Post by: SteveM on October 19, 2003, 07:12:27 PM
Hi,

I\'ve got Apexi ECU and FC Commander and I want to use the Commander as a double check on the boost pressure against my existing boost guage.

The thing is the units for the boost guage are \'PSI\' which is fine but the unitsd for the FC Commander are \'mmHg\'.

Does anybody know what \'mmHg\' are and what the conversion rate is to PSI.

Any help appreciated

Steve :confused:
Title: Boost Pressure Units
Post by: bnaellis on October 19, 2003, 07:26:53 PM
The power fc is not in mmhg or altelast should be. It should read in bar as in 0.7 bar I believe it only uses mmhg when measuring vaccum at idle or basically off boost.

rgds
Title: Boost Pressure Units
Post by: 20B_boy on October 19, 2003, 07:27:20 PM
Millimeters of Mercury.

1 psi = 51.71493mmHg

1 bar = 750.0617mmHg

1 bar = 14.50377 psi

This is handy:

Converter (http://www.3rotorfd.com/main.htm)
Title: Boost Pressure Units
Post by: 20B_boy on October 19, 2003, 07:34:45 PM
QuoteOriginally posted by BNA_ELLIS
The power fc is not in mmhg or altelast should be. It should read in bar as in 0.7 bar I believe it only uses mmhg when measuring vaccum at idle or basically off boost.

rgds
Power FC reads boost in kg/cm2; 1bar = 1.019716kg/cm2...
Title: Boost Pressure Units
Post by: SteveM on October 19, 2003, 07:37:54 PM
Thanks all.

I\'m pretty sure its reading mmHg, never seen anything else, but saying that the peak hold has never been over +0.91
Which would make me believe its Bar. It definetly shows the units as mmHg.

Try to keep my eyes on the road at full boost :D

May have to try it on a wide empty road one of these nights.

Steve
Title: Boost Pressure Units
Post by: iaint on October 20, 2003, 09:38:08 AM
QuoteOriginally posted by SteveM

Try to keep my eyes on the road at full boost :D

May have to try it on a wide empty road one of these nights.

Steve


Passengers are very useful for this :)
Title: Boost Pressure Units
Post by: boltoa on October 20, 2003, 10:50:29 AM
A lot of boost gauges read vacuum in mmHg and positive pressure in psi or bar or kg/cm^2. So you look at it on idle and it\'ll be mmHg, but probably flip over to bar when you\'re boosting. Problem is keeping an eye on it when you\'ve got you\'re foot down :).

Andrew
Title: Boost Pressure Units
Post by: 20B_boy on October 20, 2003, 10:54:52 AM
As does the Power FC; mmhg in vacuum, kg/cm2 in boost.
Title: Boost Pressure Units
Post by: SteveM on October 20, 2003, 03:59:31 PM
Roger, Roger

Checked it out.

mmHG off boost and Kg/cm2 on boost.

And oh yes passengers are useful after all ;)

Steve