devildog5001

Is it possible to grind off half of the lever (still a boot shape minus the toes) for some power without all of the low end smoke. If a guy took .100" off once of twice would it be worth the effort/risk that you would pass an emissions test? Just 12 more years and in Colorado I'll be eligible for a 'collector's plate and one final emissions test, if the law remains the same. In 12 more years that lever might be worn off!

Bushy

The more you take off the more smoke you'll have...having said that I have (currently) just a bare hint of the 'foot' remaining and I passed our emissions up here...I did have to back the timing right down and pull the FF screw out a couple turns but I passed with no problems...surprised the heck outta me actually...

p-b...

gman07

Here's what mine looks like with the lever 1/2 gone and the FF screw in a couple turns. The starwheel is in the stock position and the smoke screw is out as far as possible.

Alec

I apologize that I have not had time to do any actual testing of this, but, FWIW, looking at how the pump works, the shape of the AFC grind is quite important to its operation. That foot has a curvature that I believe is intended to minimize any effects from the geometry of the lever it is attached too -- that is, in the original design, all of the relationship between boost and fueling is supposed to be defined by the AFC eccentric.

If you change the shape of that foot, I believe it is possible to make it almost stock at no AFC travel (no boost), and much more fuel at full AFC travel. Something more like this:

I also think that you can get maximum fuel a fair bit before the foot is ground off flush, so a "half grind" might really be closer to a "7/8" grind, if that makes sense.

Once again, I apologize that this is all from reading up on the VE and looking at my pump core -- no testing as of yet.

Underpsi

if i knew that the afc lever rode on I might understand but I really have no clue. If what you say is true then we would still be able to pass the etest with the afc grind

Alec

The AFC lever (#3) is the maximum travel stop for what Bosch calls the "Tensioning Lever" (#12).

#12 is what moves the slip collar that covers the spill port that controls how much fuel is pumped per stroke.

bgilbert

Well said Alec. FWIW, I made 337hp with a 1/2 ground afc lever, 35-16, pod's..

Underpsi

thanks for the info, the picture is a little unclear of which way the levers move and that though.

G1625S

yeah, you've gotta live with those diagrams for a little while till they start to sink in

devildog5001

Great details, cool pump diagram too. Thanks for all the info guys.