My new puller motor build

[seeker1056]

didnt gain anything - what?

you dynoed before and after?

In my case I get 25+ psi boost before I get any drive pressure - i would say that is a serious indication of "good change" from larger vlaves and a port job compared to having more drive pressure than boost all the way through the range

[KTA]

I would say you have some bad gauges, or at least one gummed up from soot. I have fooled with well over 100 diffrent twin setups on all kinds of diffrent motors and never have I seen more than a 5psi positive differential between boost and drive pressures. The energy to drive the compressor wheel comes from the exhaust and you have some serious black magic going on if you can get enough energy from 0psi of exhaust to make 25psi of boost.

[seeker1056]

I"ll check that - cuz it is a brand new liquid filled guage

[seeker1056]

checked the guages, had a small leak and ratios changed

But no matter how i cut it, there is 8-10 pd boost to drive pressure ratio till I hit about 45 psi boost then drive pressure is more by about 10 psi and doesnt change much from there to 50-55 psi boost

[dpuckett]

This may be a dumb question- what is "valve shroud?"

[seeker1056]

where either the head and/or the cylinder wall is covering/blocking part of the opening valve thereby reducing valve flow or forcing flow to change direction, not always in a good way

[KTA]

8-10psi differential sounds reasonable especially using mechanical gauges. I find the exhaust pulse makes them read a bit lower average than what an electronic damped sensor reads like on a data logger.

[mprmn08]

didnt gain anything - what?

you dynoed before and after?

we didnt dyno we flow tested them. and like i said that was with only blendig the pockets, not a full port job.

[seeker1056]

I am now officially now a cable fuel shutoff baby, after changin out my third electric solenoid plunger.

Not doin it again - what a pain chasin all those little rubber bits in the delivery valves