Manifold Air Pressure – expected values

[Paul(notts)]

Manifold Air Pressure – expected values

Started looking at the readings off Megajolt toady and got a little confused by the MAP values.

Could some one explain what I should expect to see and how it will change when the engine is revved but car is stationary.

Hope to do some runs out in the car next weekend and start to develop a map – But first have to get my head round the MAP readings

Paul

3.5 Rover V8 - getting 34KPa at idle

[brentp]

Hi Paul,

That's a fairly typical value at idle.

The MAP readings is in absolute pressure, measured in Kilopascals (KPa). The lower the number, the higher the vacuum. Approximately 100 KPa is atmospheric pressure- you'll see a value close to this when the engine is not running, or when the throttle is WOT.

Hope this helps!

[Paul(notts)]

Thanks for the reply..

Just like to say how impresesed I am with the difference megajolt has made to the car, compareed with the 20 year old dizzy and coil I had.

Next task is to do lots of data log runs and develop a map for my engine.

3.5 Rover V8 with hurricane cam shaft , Road lifters and webber 500 carb. car weighs 750KG
0-60 run yesterday was 4.9 secs and recon with a better map could get this down to 4.5 secs.

Paul