Nate_M

I swapped out my stock LS3 map with an LS9 map so I could read pressure with my Novi 1500. Can I tap one of the three wires coming off of it and feed it into my analog 2 on my Aeroforce Interceptor gauge? Would anybody know the slope and intercept for it?

Thanks for the thoughts!

Quick follow up. I think I found that the linear output for the LS9 MAP sensor is 312 at 5V, so I think the slope would then equate to 62.5. It's published that the intercept is -11.2, so I guess I can start from there and see what happens. My assumption is that at idle, I should see a negative number, implying that is vacuum? Does that check out?

BLOWNBLUEZ06

The linear is 312.5 and offset is -11.25. Any MAP sensor should read 100kPa at sea level and go down with increasing elevation. 100kPa is the breakpoint between vacuum and boost. a 3 bar sensor is 1 bar of vacuum and 2 bar boost. each bar is 14.5psi so if you multiply kPa by .145 and subtract 14.5 psi from the result, you'll be able to convert the kPa to PSI. I'm surprised you're not converting your tune to a 2-bar OS, taking advantage of the increased resolution of the VE table. It's a bit of work but I prefer it. Even though someone changes to a 2-bar OS, it doesn't mean that the MAF can't still remain in play.

romandian

yes, thats a good starting point, probably from the original tune. however i ended up with a bit different values after checking how it is (ls1). like that it underreported by 4-5 kpa with engine off. the original setup underreported by 1-2 kpa. btw, these sensors are not very accurate, +/- 3% is best (out of memory) and gets worse depending on temperature. mine had a huge glitch at 40 kpa i believe.

mn_vette

One other thing to remember is that these sensors are usually ratiometric to the supply. If the 5V supply is only 4.9V, the output voltage will get scaled down the same ratio. The supply voltage and ground voltage at the sensor need to be taken into account.