MicroSquirt.com read only forum (Jan.15,2018)

Could anyone tell me the approximate map reading at idle should be. i live in the phoenix are, and I was told today that i should have a map reading around 25kpa. I am using msII with 3.0 on a GM 3.1 with 6-8lbs of boost. Also anyone with simular setup that can help with tables.

thanks
Blatzy

Blatzy,

Your MAP reading at idle depends a lot on the tuning and the ignition timing, as well as how good your rings and vales are, your compression, your camshaft timing, and a number of other things.

As a general guideline, around 25 to 35 kPa is normal for a stock engine in good condition.

It is not unusual for people to see values of 50 kPa or more when they first start tuning, and they usually get this down by at least 10 to 15 kPa with tuning.

Lance.

My map reading is currently around 95 at idle,absolutly no vacum leaks and the map sensor calibrated according to tuning recomendations. What would be the cause of this high reading could it still be the iac valve.

Thank You
Blatzy

are you sure it is hooked up to a vacuum source that has vacuum at idle? It is possible that you've picked a ported vacuum source, for example the carby vacuum advance line, that will block vacuum at idle.