I logged my first WOT run on my car. Above 4000 RPMs my MAP would go as low as .90. ATM was 1.0. The MAP and ATM should be the same at WOT right?

Does this mean I am pulling vacuum at WOT? The car has a 224/230 cam, Longtubes, Manley Pro Flow valves, etc. But I have the stock air box (The new motor/tranny went way over my 20 year old college budget so I need to catch back up on money ). Does the stock air box account for the restriction that is causing me to pull vacuum? Is .9 pretty low or is that close to normal? I am expecting a pretty good gain with a CAI.

Thanks
Dustin

 

WOT area is usually 95-100 Kilopascals. It also depends on other factors... (such as alititude, etc)

 

I was using freescan. I think the units were in Bar (1Bar = 100 kPa). I will check when I get home. If that is the case, .9 is low right?

Also, at part throttle my BLM should stay around 128 right? That is what it is doing. This is all new to me but I am learning.

The tune you did on my car has been great so far. I haven't got to put it on a dyno to check the WOT a/f ratio, but it runs good. It idles perfect and at part throttle it does great.

Thanks,
Dustin

 

Thanks Dustin.
Yes, the BLMs should be around 128.

 

Any difference between ATM (barometer) and MAP represents pressure loss through the intake track.... dirty filter, restricitve piping, etc. If ATM was 100kPa, I would say 90kPa represents excessive pressure loss. A 10% loss in air pressure represents a 10% loss in the power you can make. I would want to see 95kPa.

For some guidelines on scanner readings, try this.

 

Thanks a ton Injuneer. That is a huge help. The filter is new so thats not the problem. Hopefully when I can afford a CAI I will get the MAP up to 95 kpa. A 5% gain would be pretty nice.

Dustin

 

You could try a quick test to see if it's the air intake tract. Remove the plastic intake and put some pantyhose over the MAF sensor end, and log again. Seriously, it'll filter enough for a quick run and will remove all restrictions in front of the sensor.