I’m trying to convert engine load to boost using EvoScan v0.99.

Am I correct in thinking that I can just back out the “loadcalc” from EvoScan v0.99 to determine boost?

I guess I would need to know my atmospheric pressure.

Looking at some weather data, I found that barometric pressure that day was:

Barometric_press = 101.5 kPA



So the calculation for boost would be:

(Loadcalc – Barometric_press) * 0.145037738

So this would be:

(Loadcalc – 101.5) * 0.145037738



Is this correct, or are there other parameters that affect the load and can’t be treated directly as kPa?

 

use 2-byte load to be more accurate. do a search for it.

 

I don't think you can reliably make the conversion from Load to PSI of boost, especially if there's an aftermarket intake involved. As the previous poster said, log 2-byte load if you want to know where the ECU is looking in the timing/fuel maps. If you want to log boost, buy a MAP sensor that you can log via EvoScan, or just buy a JDM MAP sensor from mrfred and replace your stocker with it. It will log up to 33psi for you. No need to do any fancy math to figure out your boost. :-)

 

If I use the JDM map sensor, is there a need to keep the stock MAF sensor?

 

yes

 

Thanks for the 2-byte loadcalc suggestions.

If anyone is interested, here is a completely stock EVO datalog,



17PSI max,

Seem like PSI is close?

 

Its definitely possible to get close, but there will always be an uncertainty of something like +/- 2 psi. Just depends on what's good enough for you.

 

^ That would be about as accurate as most boost gauges.

But doesn't load change with weight?

Someone with the JDM MAP sensor should compare the output to the calculated routine.

 

Actual engine load would change with weight, but not the load% value used by the ECU.

 

its kinda like in humans diet. you can calculate how much calories you intake, and know it takes 3500 calories to gain 1 lb. But it still will be off by 2-3 lbs.

 

So, the stock MAF sensor is mostly calculating the load.

What load is the MAF sensor good up to?

 

I don't think the "MAF" sensor has anything to do with load. It reads air flow and temperature. You might be thinking "MAP" sensor which is completely different. I'm not exactly sure what the stock MAP (MDP technically) measures or even does ...

 

I have read in another post that the U.S. version of the EVO comes with a map sensor that reads only up to 2 psi?

Here it is,

So, the load calculation has to be derived from something other than the map sensor above 2.2psi

 

Correct. Load is not derived from the MAP sensor. Its derived in part from the MAF sensor reading and rpm.

 

Guys - quicky..

What is the 2psi MAP for? Whats it's purpose?