I hope this is in the right spot..

i've been tuning my little project for a few months, at the track last night i was datalogging all my runs and noticed that at WOT the MAP was only going to about 92kpa.. Is that usually a good indicator that it's time to go with a larger throttlebody? or is it a by-product of having a large cam?

Thanks

 

A low MAP at WOT can be pointing to a too small TB. Need to check the barometric pressure first. Read your data log MAP value at key-on, engine-off. That is baro. It is then the difference between the WOT MAP & baro that signifies the flow restriction.

Say baro was 95, then having 92 KPa MAP at WOT is OK. However, if baro was 101, then there is a 9 KPa drop across the air induction system. That is nearly 2.9" Hg of drop. Note that this drop includes the the aircleaner and duct work to the TB.

Also check that the TB is truely opening the entire way. Mash the go-depal (engine off) and have someone look into the TB. The butterfly should be fully open. Floor mats have a habit of preventing a fully open TB.

RBob.

 

Sounds good, i'll hook up the laptop tonight and see what it says.


thanks,
Dave