I have the Greddy MAP sensor and harness, and I am trying to retard timing using a pressure vs RPM map. This is ideal.

But I dont know how to convert the Greddy voltage into PSI...or something that I can understand? If ya ask me...its kinda messed up that Greddy doesnt include a PSI auto coversion to voltage. bastards! I have mmHG, BAR, but no PSI.....ahhhh! Someone please help me.

ETX...I think you might know the answer to this, becuase I think you are the only other person using the MAP sensor.

 

It's about .1vdc per psia. With the motor off (no vac) it will read about 1.49 - 1.5vdc depending on your elevation. So 5.5 psi = .55v + 1.5 = 2.5vdc at 5.5 psi.

 

you lost me on the translation...one more time?

What is the voltage equivalent for

1psi
2psi
3psi
4psi
5psi
6psi
7psi
8psi
9psi
10psi

 

1psi = 1.6 vdc
2psi = 1.7 vdc
3psi = 1.8 vdc
4psi = 1.9 vdc
5psi = 2.0 vdc
6psi = 2.1 vdc
7psi = 2.2 vdc
8psi = 2.3 vdc
9psi = 2.4 vdc
10psi = 2.5 vdc

It's easy, see!

 

sweet...I still dont understand the math...but I will trust you.

 

i think you don't get the math because etx's example is incorrect. the correct answer for 5.5psi is 2.05v...

m

 

SkiDazzle...since you have dazzled me with your math skills, can you take a crack at the voltage convesion table? Lets see what cha got smarty!

1psi
2psi
3psi
4psi
5psi
6psi
7psi
8psi
9psi
10psi

 

its like calling up a train station to see if Train A leaves the terminal at 9:30 @ 65 mph and train B leaves in the opposite direction at 10:40 @ 90mph at what time will the distance between them be 400 miles.


you can do math right?
1.5v + (boost) x 0.1v = your answer (v)

eg
1.5v + (5.5) x0.1v = 2.05 v

 

ok...much cleaner now. Cheston...I knew the thread title "voltage conversion" would attract your attention.

 

Does this look correct? I used Excel just to make sure.

psi greddy voltage
1 1.6
2 1.7
3 1.8
4 1.9
5 2
6 2.1
7 2.2
8 2.3
9 2.4
10 2.5

 

Isn't this the same as etx posted ?

 

yeah...i think they were teasing him becuase he rounded...and was off by 5/100 of a Volt.

 

ha!!

he was off by 45/100 of a volt... geez... did anyone even attempt a GED?

 

In case anyone is trying to figure out what was wrong. The table seems correct, it's just the example which states at 5.5psi it's 2.5vdc where it should read at 5.5psi it is 2.05vdc.

 

I have 6 years of college, and a bar tending school diploma to prove it (and a scuba certificate).

-D

 

ROFL Yes, I am college edumacateded..and I have a Rescue Diver Cert and a CPR cert.


Well, something is definately wrong here...becuae I entered the values, and I was boosting 7psi, and only got 4degrees of retard. Ididnt bother adusting for RPM...just plugged in a 1/1 ration of retard to boost accross the static RPM range...so at 7psi, I should be 7degress retard. The only thing that is retarded properly is my brain!

What the heck did I do wrong?

 

Actually I was being sarcastic. 6 years of college and NO degree.

GQ:
Rescue diver? You need to get Master and then go for Dive Master (I'm assuming PADI). Then NSS-CDS and get in the caves!

-D

 

Actually, I can go straight to Dive Master if I want. Master SCUBA dinver cert is not needed. I used to do about 10 dives a month...been too busy the past 5 months modding my car to do any diving.


Back to the topic at hand.....can someone help me with my Voltage? Still not working correctly.

 

I'm not a mechanic, but I did stay at a Holiday Inn Express last night. GQ, increase the decimals on Excel you you'll be golden.

 

wOooo... harsh.