Silver408z

iTrader: (1)

I just got my engine back, installed and tuned. Overall I am happy with the results but I have a question about the curve went. The power goes up and then stops climbing and then goes straight across. Is this normal?

Engine is a 408 at 10.3 compression, trickflow 225's, harland sharp rockers, cam is 244/248 612/615 on a 112, fast 102 ported by vengence, nw tb, factory 01 z06 maf, dual cone intake, kooks 1 7/8 headers, 3" off road x pipe, B&B prt catback. If more information about parts is needed just ask.

The tuner said there was not a drop in the map sensor which usually indicates a restriction.

Any ideas or thoughts?



http://i910.photobucket.com/albums/a.../Dynograph.jpg

1989GTA

It looks typical for a motor that is running out of air and just flat lining. I have seen that a few times. The question is "why is it running out of air"? I have also seen valve float do something similiar.

Silver408z

iTrader: (1)

I have seen graphs like that also but the vavle float is normally jagged on graphs no smooth. The long block was setup by the machine shop(HKE).

Gary Z

Looks OK to me. Your engine, like all engines, starts “running out of air” beyond the torque peak. Peak torque occurs at peak volumetric efficiency. That power “flatlines” above the torque peak is a good thing. It means that VE is decreasing gradually, not falling off a cliff.