anyone using 2bar or 3bar map sensor
Thread Starter
Instructor
Joined: Jun 2003
Posts: 100
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From: broken arrow ok
anyone using 2bar or 3bar map sensor
Anybody here using a 2bar or 3bar map sensor and custom chip with their supercharger or turbocharger. I was wanting more ability to tune the car with the supercharger instead of just the fmu.
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Re: anyone using 2bar or 3bar map sensor (new'92)
I am going to do the best I can at explaining this, but I can't verify it works or give all the specifics. Here goes. If you use your 7727 ecm, and your memcal but use a $58 mask in place of your DA2, then repin for the $58 because some of the inputs and outputs are in different address locations, you now have the ability to look at and use "boosted" map readings. The $58 is from a Syclone/Typhoon and is capable of controlling the boosted application ie...timing and fuel. I am using the 7749 sy/ty ecm because I want to use peak and hold injectors. The third gen diy forum is about the best place to look for this kind of info. Good luck.
Advanced
Joined: Sep 2000
Posts: 51
Likes: 0
From: Pembroke Pines, FL, USA
Re: anyone using 2bar or 3bar map sensor (AKS Racing)
I'm running a GN 2 bar....custom chip on a factory computer..93 speed density. P1SC....no fmu.....42lb injectors.
[Modified by Metlegleo, 10:32 PM 4/28/2004]
[Modified by Metlegleo, 10:32 PM 4/28/2004]
Melting Slicks
Joined: Sep 2000
Posts: 3,150
Likes: 1
From: Carlsbad, CA CA
Re: anyone using 2bar or 3bar map sensor (Metlegleo)
I'm running a GN 2 bar....custom chip on a factory computer..93 speed density. P1SC....no fmu.....42lb injectors.
[Modified by Metlegleo, 10:32 PM 4/28/2004]
[Modified by Metlegleo, 10:32 PM 4/28/2004]
Advanced
Joined: Feb 2004
Posts: 64
Likes: 0
From: Gushikawa Japan
Re: anyone using 2bar or 3bar map sensor (zelement)
To try to put it simply: The ECU does not see boost, it sees voltage (or signal) from the MAP sensor. 0-5 volts. With the stock 1 bar sensor, 0.8 volts might be idle vacuum and 4.5 volts might be WOT. You can install a 2 or 3 bar sensor but the return signal will be less. with the 2 bar sensor wot might only be 2.5 volts, etc. The ECU will interpret this as half throttle. You can run any sensor you want as long as it's a 5 volt sensor. However, you will have to reprogram the entire MAP range. Best left to the pros.
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Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
Re: anyone using 2bar or 3bar map sensor (JordonMusser)
can this be acomplished with the 94up LT1's? I would like to run a 2 bar Map if it would help with tuning and keeping everything in perspective for the ECM..I am a little nervous about the ecm running blind under boost, and then there is the issue with maxxing out the MAF, you start dropping off sensors left and right like this and I would think that there could be consistency issues as well as making dialing theboost up or down much tuffer to tune for.
Jordon,
I follow all your posts on the various boards, and was wondering about the Pro-M maf, how is this working for you? I am considering going this route as well. I am determined to utilize the stock ECM for engine management and using the larger motron High Z injectors to get around the fueling issue as i have read they are working if ya get the constants set right. i know it is going to require some finesse with tuning, but i just would like to have as many of the sensors active and working to help nail fueling and spark. please elaborate if ya have some time or even maybe post a thread detailing your accomplishments with the various sensor upgrades, it would certainly help build a platform to work from for us not as talented as you in tuning and aftermarket equipment upgrading. thanks iun advance1
Chris
Jordon,
I follow all your posts on the various boards, and was wondering about the Pro-M maf, how is this working for you? I am considering going this route as well. I am determined to utilize the stock ECM for engine management and using the larger motron High Z injectors to get around the fueling issue as i have read they are working if ya get the constants set right. i know it is going to require some finesse with tuning, but i just would like to have as many of the sensors active and working to help nail fueling and spark. please elaborate if ya have some time or even maybe post a thread detailing your accomplishments with the various sensor upgrades, it would certainly help build a platform to work from for us not as talented as you in tuning and aftermarket equipment upgrading. thanks iun advance1
Chris
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: anyone using 2bar or 3bar map sensor (lcvette)
It would be real tough on a 94/95 PCM not because you can't remap the VE and spark curves for use with the 2 bar map. But because the PCM uses the MAP to get its BARO reference everytime you start the engine initially. The ECMs way back a few years ago had a separate Baro sensor to get its barometric reference. But since then the engineers figured out that the MAP can also double up as a baro sensor before the engine starts. So the re-engineered the PCM strategy to do this.
So this means that if you change the present 1 bar sensor to a 2 bar sensor to the PCM, it will go nuts because at zero vacuum the voltage would be about 2.4v versus 4.9 or 5 of a stock sensor. Plus with using a 2 bar sensor your resolution is cut in half.
So this means that if you change the present 1 bar sensor to a 2 bar sensor to the PCM, it will go nuts because at zero vacuum the voltage would be about 2.4v versus 4.9 or 5 of a stock sensor. Plus with using a 2 bar sensor your resolution is cut in half.
Drifting
Joined: Aug 2002
Posts: 1,475
Likes: 0
From: Speedo Indiana
Re: anyone using 2bar or 3bar map sensor (tjwong)
Maybe I'm way off base here... but could you simply use a boost referenced fmu to take care of your fuel, and then use a vacuum referenced boost control MSD to handle the spark duties. The only part you would be missing is the A/F and V/E.. which I'm guessing could be partly solved by playing with your starting fuel pressures....not a perfect system... but it might get you close....no?
Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
Re: anyone using 2bar or 3bar map sensor (TONYDEE64)
TJ,
Thanks for the info. how difficult is it to get the 94/95 PCM dialed on for boosted applications? and how well do cars run under normal conditions? i would assume for day to day driving as long as the fuel injectors are set correctly in the constants table, that driving around under vacuum would be like stock. it would just be the boost side that required alot of tuning and time. am i wrong in assuming this? also, what options are there besides going with an aftermarket management system? and/or how would somehting a litle less expensive, like say a Gen6 setup work for mycause? any help is greatly appreciated!
Chris
Thanks for the info. how difficult is it to get the 94/95 PCM dialed on for boosted applications? and how well do cars run under normal conditions? i would assume for day to day driving as long as the fuel injectors are set correctly in the constants table, that driving around under vacuum would be like stock. it would just be the boost side that required alot of tuning and time. am i wrong in assuming this? also, what options are there besides going with an aftermarket management system? and/or how would somehting a litle less expensive, like say a Gen6 setup work for mycause? any help is greatly appreciated!
Chris
