Just a little more . . . . .

How to make it go fast

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Re: Just a little more . . . . .

Postby oldestof11 » Wed May 02, 2018 7:07 pm

We push a lot of fuel into the inlet but there's a bit room for improvement right at the inlet.

It has been a couple years so bear with me.

The inlet is a 3/8" or -6AN fitting size. I think it has enough meat for a -8AN or 1/2". Since it uses a AN adapter, I think it is possible to up the size. This allows more volume to the vane pump. I have a theory we are pushing enough fuel at low RPM's the vane pump is cavitating or even going dry. We noticed by pushing more pressure, the pump and case pressure reacts better. Could it be pushing enough fuel trying to keep up with the H&R that the bottle neck right before it is causing issues?

2nd spot to massage is the passage up to the FSS in the head. I remember enlarging that part to the point there were no ridges for the springs. There was still 3/4 of the pocket left to make sure the springs seated and stayed seated. This also doesn't affect the uses of the FSS plunger or the timing as dictated by the slot of the rotor collar in the head. So now instead of around 25-30mm of passage at, say, 5mm diameter, you have it now at 7mm, or a 40% increase in flow. I remember going 2 steps up on the drill bit selection I had.

Now, if you wanna get ballsy, press the rotor collar out of the head and take that same size through the head to where the collar would be. Time and press the collar back in. Now that 90* turn has less affect on flow being restricted. Yes, it is still a restriction but you made the passages bigger. And the 5-6mm for the collar thickness will have less impact than the additional 4-5mm from the FSS to collar.

One area needing addressed and I haven't quite figured out yet is the return flow. It is not a regulator, it is just fixed orifice. Maybe putting a regulator on it with a 1:1 boost reference would help choke the flow so less is returned during high impact use.

I hope this all makes sense.
93 D250~ Mismatch of cheap parts, trying to look fast going slow
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Re: Just a little more . . . . .

Postby 79Powerwagon » Thu May 03, 2018 10:04 am

With regards to the inlet, i noticed the threaded hole on the bottom of the VE (near lower mounting hole) heads right up into the bottom of the vane pump inlet.

If one could come up with a banjo fitting to clear the lower stud it may be an option for a second feed.

I read somewhere that a guy calculated the vane pump is more than capable of supplying enough fuel, could be an issue with supply to the vane pump?
1979 Dodge Warlock, I/C 12v, 518, TCS89% Converter, 6x13 injectors, HE351cw, Piston lp
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Re: Just a little more . . . . .

Postby BC847 » Mon May 07, 2018 7:18 pm

I'm reading . . . . . up to my ears looking a drain right now . . . . . . :shock:

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