3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

boost guage reading vs. PFC datalogit

Thread Tools
 
Search this Thread
 
Old 10-21-03, 09:50 PM
  #1  
Senior Member

Thread Starter
 
silver93's Avatar
 
Join Date: Mar 2001
Location: winston-salem, nc
Posts: 712
Likes: 0
Received 0 Likes on 0 Posts
boost guage reading vs. PFC datalogit

my boost guage reads 13psi at max, but the datalogit gives me .75 - .76 which is about 10.8 or so -

what gives with the difference?
Old 10-21-03, 11:06 PM
  #2  
Yes it is for sale.

 
FormerPorscheGuy's Avatar
 
Join Date: Aug 2002
Location: The Houston Club's Resident Lush.
Posts: 1,905
Likes: 0
Received 1 Like on 1 Post
The PFC boost reading is known to be off. Go with what your boost guage is telling you.
Old 10-21-03, 11:11 PM
  #3  
The Power of 1.3

 
911GT2's Avatar
 
Join Date: Aug 2001
Location: Shrewsbury, Massachusetts
Posts: 2,837
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by FormerPorscheGuy
The PFC boost reading is known to be off. Go with what your boost guage is telling you.
Old 10-22-03, 12:09 AM
  #4  
-

iTrader: (3)
 
rockshox's Avatar
 
Join Date: Nov 2002
Location: SF Bay Area
Posts: 624
Likes: 0
Received 0 Likes on 0 Posts
the stock map sensor isnt very accurate and is known for being 1-2psi off.
Old 10-22-03, 03:01 AM
  #5  
Lives on the Forum

 
rynberg's Avatar
 
Join Date: Dec 2001
Location: San Lorenzo, California
Posts: 14,716
Likes: 0
Received 8 Likes on 8 Posts
Originally posted by rockshox
the stock map sensor isnt very accurate and is known for being 1-2psi off.
I have never heard anyone on this forum say that the stock map sensor is that inaccurate. Please list your sources of info for that.

On the other hand, it IS well known and documented that the PFC commander displays lower boost than what the car is actually running (and what the PFC is actually seeing). If you run a ghost trace, you will see that even though the PFC may display 0.75, it is reading from the next highest load cell. It's an error in the PFC commander display, not an error with the PFC or the map sensor reading.
Old 10-22-03, 05:59 AM
  #6  
Senior Member

Thread Starter
 
silver93's Avatar
 
Join Date: Mar 2001
Location: winston-salem, nc
Posts: 712
Likes: 0
Received 0 Likes on 0 Posts
ok, sounds good - thanks!
Old 10-22-03, 06:10 AM
  #7  
-

iTrader: (3)
 
rockshox's Avatar
 
Join Date: Nov 2002
Location: SF Bay Area
Posts: 624
Likes: 0
Received 0 Likes on 0 Posts
oh really, i had always thought the difference between the pfc reading and a real boost gauge was due to sensor inaccuracies. thanks for setting me straight.
Old 11-02-03, 08:59 AM
  #8  
mb7
Full Member

 
mb7's Avatar
 
Join Date: Aug 2001
Location: Greenwood, SC
Posts: 89
Likes: 0
Received 0 Likes on 0 Posts
When I turn my ignition on, but do not crank the car the PFC reads -40. I thought there was a problem with my MAP sensor so I replaced it with the GM 3bar. It still reads off, Today I'm going to check the grounding around the PFC and see if that might help, I really would like for the PFC to show accurate information.
Old 11-02-03, 09:38 AM
  #9  
Ozone Depleter

 
teamstealth's Avatar
 
Join Date: Jul 2002
Location: StL
Posts: 1,610
Likes: 0
Received 0 Likes on 0 Posts
its reading absolute pressure (or pressure relative to sea level...cant remember which) when there is a negative number. Theres also a way to change it so it reads zero. Search for it in the PFC forum
Old 11-02-03, 10:16 AM
  #10  
Full Member

 
odditysmurf's Avatar
 
Join Date: Oct 2003
Location: Washington State
Posts: 141
Likes: 0
Received 0 Likes on 0 Posts
I would say the guage is more accurate its using actual vac pressure for its reading. less computer calculations involved
Old 11-02-03, 10:22 AM
  #11  
ttb
No Cup Holder Racing

 
ttb's Avatar
 
Join Date: Apr 2002
Location: Bay Area
Posts: 1,446
Likes: 0
Received 0 Likes on 0 Posts
yea, i've been meaning to ask since the reading on the commander is off how does that affect the performance. if the PFC is thinking it's seeing 10psi but in reality in'ts 12psi i would imagine that's big trouble, but i guess it's an error with the commander and not the actual PFC unit. good to know.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cristoDathird
Introduce yourself
28
05-30-19 08:47 PM
turbojeff
Group Buy & Product Dev. FD RX-7
243
11-03-18 10:57 AM
sen2two
AEM EMS
9
10-23-15 07:51 PM
ricardo.benin
Power FC Forum
1
08-24-15 04:16 PM



Quick Reply: boost guage reading vs. PFC datalogit



All times are GMT -5. The time now is 02:45 PM.