MAP vs BARO at WOT

[samh_08]

Today I was messing around with the car again and am getting about 93.5kPa average manifold pressure @ WOT. MAP read 97kPa before start up, so Im assuming thats BARO.


Before I start tearing stuff apart looking for a restriction, I'd like to know what others experiences have been. Care to share?

[joecar]

Yes, that's BARO (MAP before starting engine).

It's usual to see about 2 kPa drop depending on vehicle... some vehicles you see less drop.

Post a pic of your intake/MAF plumbing...

What MAF do you have...? It most likely is not the MAF. It most likely is the plumbing and/or air filter.

Remove the air filter (if you dare) and do your measurement again.

Edit: correction.

[samh_08]

2 psi or 2 kPa drop? I will post a pic of my intake later today but its all 4" to a 4" filter with no MAF.

[joecar]

2 kPa

Thanks ( sorry, I was typing ahead of myself )

I always deal with MAP, MAF, IFR in Metric;

( the only objects I use Imperial for are: temperature, speed, torque, oil/ATF/AC pressure... almost everything else is Metric )

[statesman]

I've got a stock LS1 intake with MAF. I'm at sea level, 101kPa baro. At WOT I'm seeing 97kPa @ 5800RPM with IAT @ 26C.

[samh_08]

Im dropping the about the same kPa as a stock intake makes we think its my throttle body/intake opening.

Heres some pics:

[joecar]

What is the diameter of the long pipe...?

Experiment: remove the pipe from the two elbows at the TB (leaving one or two elbows), try this and see what MAP is; the length of the plumbing can influence the drop, either by restriction or by resonance.

[samh_08]

Everything is 4" smooth pipe. Will try removing some parts this aft depending on weather.