I have been thinking about this and can't figure it out. If you have a car that is supercharged the pressure in the motor is higher than the pressure outside. The MAP sensor will show 100KPA at atmospheric pressure which is what the pressure is under WOT in an N/A motor. Now lets say that you introduce 10 pounds of boot pressure. Now the pressure is higher than atmospheric. How does the MAP sensor measure this? Is that what a 2 bar map is for? I’m trying to get an idea how this works with the VE tables only accepting values as 100 max. I’m assuming that with a 2 bar map all the values are cut in half. In other words, where in your N/A VE table if you had a value of 90, with a 2 bar map this would be 45. Is my assumption correct? If so how do the timing tables work and all the other tables that use MAP voltage for calculations? I have a few years experience with the $6E code and $8D code but all N/A applications.

Thanks,
Jason

 

Yup - that is what a 2-Bar MAP is for. But, you can't just plug a 2-Bar into the 730 and go. There is A LOT of code behind the scenes that depends on MAP. You would need to go through all the tables and all the MicroCode to search for these dependencies. The best thing is to just switch to the 749 ($58). It was built around a 2-bar for the Syclone and Typhoon.

Tim

 

What about the LT1 ECM's? Say I had a 92 Corvette that uses Speed Density? I know there are people that have tuned these using 42 pound injectors and no FMU. I'm just surious as to how they do it.

Jason

 

They are doing it based on RPM. Basically, they force Power Enrichment quicker (lower TPS Values) and richen the beast up using a Power Enrichment table (AFR additions and subtractions based on RPM). Definitely not the way you WANT to do it - but, it does seem to work somewhat ok for those cars that aren't pushing too much power.

Tim

 

I understand what you are saying. There is a guy that used to be on the Corvette Forum that had a 93 blown Vette with a 355. He had almost 600 HP to the wheels and over 600 ftlbs of torque. He did all hiw own tuning. His name is Shalin. Do you know of him?

Jason

 

Absolutely. He knows how to work it.

Tim