formula to covert MAP voltage to boost reading in HP Tuners

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Aug 19, 2005 | 02:57 PM

Blackbird

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From: Bellevue, Wa

formula to covert MAP voltage to boost reading in HP Tuners

I have a GM 2 bar map part # 12569241 that came with my alkycontrol kit.

I would like to monitor it's output in tuners and convert that into a "boost" pid

has anybody done this yet? if so is there a table or formula you could share.

thanks!

Aug 19, 2005 | 03:16 PM

HumpinSS

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From: Waldorf, MD

what is the range

what kpa is 0 volts and what kpa is 5 volts.

Aug 19, 2005 | 03:17 PM

Blackbird

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From: Bellevue, Wa

how would I find that out?

Aug 19, 2005 | 04:19 PM

RedHardSupra

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From: Laurel, MD

it's gotta be in the documentation somewhere. if we have two voltage-pressure tuples, you can make a linear function out of it, assuming it's linear.

Aug 19, 2005 | 04:45 PM

Blackbird

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From: Bellevue, Wa

Found more time to search around and I think I found what I needed.

Any clever ideas on how to verify how accurate this is?

Gonna be pretty tough to watch the guage and the pc at the same time

The chart below describes the pressure-to-voltage relationship of the stock GM Turbo MAP sensor (2 bar):
Manifold Pressure
(relative sea level / absolute) 2 Bar
MAP Output
14.31psi / 29.01psi 4.90V
14.00psi / 28.70psi 4.84V
13.00psi / 27.70psi 4.67V
12.00psi / 26.70psi 4.50V
11.00psi / 25.70psi 4.33V
10.00psi / 24.70psi 4.16V
9.00psi / 23.70psi 3.99V
8.00psi / 22.70psi 3.82V
6.00psi / 20.70psi 3.47V
4.00psi / 18.70psi 3.13V
2.00psi / 16.70psi 2.79V
0.00psi / 14.70psi 2.45V
5.00inHg / 12.24psi 2.03V
10.00inHg / 9.78psi 1.61V
15.00inHg / 7.33psi 1.19V
20.00inHg / 4.87psi 0.77V
25.00inHg / 2.41psi 0.35V
29.10inHg / 0.40psi 0.02V

Aug 19, 2005 | 05:09 PM

Phoenix 5.7

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From: Prairie de Femme, LA

do you have 2 bar support in HP tuners? if not u might want to get the upgrade

Aug 19, 2005 | 05:17 PM

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From: Knoxville, TN

Those numbers worked fine for me. I dont know if you can do a lookup table or calculated stuff in HPt, never tried it in HPt.

I also had to run a restrictor in the line for the map sensor, I had a 1/4" line going to it and it would jump all over the place. You can see it with and w/o the restrictor in these two pics.

It also reads about 1psi higher then the boost gauge in the car using a hand vacuum/pressure pump pressuring both the MAP and the in-car gauge at the same time. I just use the MAP to compare between runs/days/weather/belt slip, not for absolute accuracy. I could fix it reading a little high but I dont know which is off exactly, the boost gauge in the car, the pressure gauge on my mityvac or the MAP sensor output

But using a DMM those voltages do check out right at the MAP.