Fun with Powervalves

[Banjo]

Decided to put a powervalve in my alky dominator to lean out the cruise a bit and save some fuel.

I do run a progressive linkage on my carb.

My combo is:
74 Nova 3265lbs
SBC 406, dyno at 750hp.
6000 converter,powerglide
5.11 gears,

Square jetting at 196, it would use around a gallon per pass.

I installed a 3.5 powervalve. I measured the PVRCs at .135, calculated the area, and subtracted that from the area of a 196 jet, added a little fudge factor and came up with a 150 jet. Doing the math, it cuts back about 42% of the jet area.

I made 18 passes last night on 10 gallons. So I using just over a 1/2 gallon per pass. I am pretty surprised it was that much.

When I footbrake, I launch around 3200 rpms. Last week without the powervalve, it was showing in the 4.20-4.3 range. Now its in the 4.7-4.8 range. When I originally saw that test driving, I was thinking I would have to go further.

I do think I am a little small on the front jet because the front 4 cylinders were about 40-50 degrees hotter than the back, so I am going to add some jet to the front. Not sure if the limitation is the powervalve itself and not the PVRC. I do have the 4 window PV, and I plan on measuring the area in the powervalve.

[Banjo]

Also forgot to add, WOT afr going down the track went from 5.4s to 5.6s which indicates to me, I need to add a little more front jet.

[jmarkaudio]

Most likely the combination of the PV and PVCR with the passage restrictions along the way are the culprit. Just add more jet. It is possiblt to tune a methanol carb on the lean side, it may loose a slight amount of power but will gain heat that it should and run more consistent using the least amount of fuel. I ran a methanol Dominator one weekend using 7.5 gallons and running 9 rounds to win the race.

[Banjo]

I measured the powervalve, Opening is .286, and the valve is .186 at is thinnest part. But looking on where it sits naturally, its probable closer to .210. Which is very close to the area of the two PVCR.

I am pretty happy, saving that much fuel and no ill effects thus far.

That will almost cut my fuel cost in half.

[RFSPHPbb]

so you're thinking that the size of the holes in the PV are what control the the amount of fuel flow when the valve is open?

[Banjo]

The windows have plenty of area, but the area where the valve is close depending on the position of the valve.