tephra

iTrader: (6)

Hey Guys,

Does anyone have an accurate formula for EvoScan?

Currently I have "0.175934*x - 14.5"

Any other GM 3bars confirm?

Cheers
D.

tephra

iTrader: (6)

no replies

I have a closer number 0.17573 - I think its correct, from the manual:

240kPa is 3.884volts

THUS:
(3.884/5)*255 = 198.084
198.084 * 0.17573 = 34.80930132psi

In Google:
240 kilopascals in psi = 34.8090571psi.

This also works for my zero-psi reading ie:

evoscan logs 82 as engine off pressure
82 * 0.17573 = 14.40986psi
Which is about correct for my altitude (300ft above sea level)

tephra

iTrader: (6)

hrmm so the only thing that is bugging me is that my bone stock IX seems to be getting good boost:

http://img527.imageshack.us/img527/1...3barmaplu9.png

as opposed to my old car:
http://img299.imageshack.us/my.php?image=dynoxd0.png

tephra

iTrader: (6)

bit better graph for #1


So yes it does drop from 19psi to 15/16psi, but i don't see the regular "taper" just a drop at about 4500rpm.

any ideas? obviously I will tune this out, but the main aim is to ensure my GM 3bar map is accurate.

JohnBradley

iTrader: (30)

I have the voltage listing for the JDM MAP and a GM 3 bar somewhere but I will have to look for them. Sorry I didnt see this earlier and I cant believe no one else jumped in...geesh guys. I will send it to as soon as I find it Dave.

To be clear you are just looking for the pressure to voltage conversion or the scaling for the ECU MAP check?

JohnBradley

iTrader: (30)

Here is the quick teaser:

http://hhscott.com/93tmv/3-bar_map.htm

I will see if I cant find all my hard copy paper research tonight. I have it all written out when I was trying to figure out stock ECU speed density with a different MAP sensor, but I am not sure where I put it after I abandoned that project.

tephra

iTrader: (6)

Thanks John,

Yah basically, I have the gm3port spec.pdf that is floating around, unforunatley below 70kpa and above 240kpa the relationship between volts and pressure changes.

But that's ok because I don't plan on doing anything on the above two conditions.

I am pretty sure I have the "conversion" (volts to pressure) formula correct now, but wanted to bounce it off other ppl

Cheers
D.

JohnBradley

iTrader: (30)

Now that I thoroughly reread the post and looked at the pix, I would set the correction value to what it should be assuming perfect sea level. I would then adjust the stationary pressure value to compensate for any altitude. I apologise for being a little obtuse earlier.

JohnBradley

iTrader: (30)

https://www.evolutionm.net/forums/sh...0&postcount=31

http://hhscott.com/93tmv/3-bar_map.htm

tephra

iTrader: (6)

Not at all

yes, I feel I need to drive down to the sea just to see what the @SL raw value is heheh