Solutions to VE high fuel flow rate problems

[KTA]

Since I saw a discussion on here regarding my dual feed setup I decided it was time to update what I made that I am actually running. Since the timing piston in the VE is driven by case pressure if you have problems with dropping pressure you also are dropping timing and this can be a bigger problem to making power than the lack of fuel. What I have developed is a fitting that isolates the plunger feed from the case fuel. This allows the case pressure to vary exactly with rpms as it is supposed to do to provide the ideal timing curve. Then I cram as much fuel pressure as I can into this fitting to supply the plunger. This solved two problems, but the VE with the 14 cranked still exhibits a rapid decrease in fuel delivery at high rpms. The problem is now the tiny slot that feeds the plunger. It can not be modified or you run into all sorts of issues. I have a possible solution but have not attempted to try it yet. In order to run good pressure(300psi) to use this fitting I am using a gear pump off of a pt fuel system for a 855 cummins. The results are great, but I am still not satisfied. When I get time again I will work on it some more. I won't bother to much until I think I can make 700rwhp on fuel only.

[skilletky]

how much pressure do you think the plunger feed can handle before you start running into problems? do you plan to make more of these fittings and marking them? i am interested in one.

[ahale2772]

KTA,

so the fitting feeds fuel directly into the plunger so that it can stem the loss and try to keep case pressures up?

any ideas on what the Ideal case pressure/rpm/timing curve is? (how much case pressure is too much?)...will it just throw too much timing at the engine and "put out the fire" as they say?

[ahale2772]

second question, that snout on the end of the fitting, is that needed to be that long or did you make it that long just to guide the fuel down? IIRC there needs to be a spot for the oring to seat but i dont remember what was below that.


I made a similar fitting with just a shutoff solinoid, but i doubt it would hold 300psi...i've been using the fitting on my pump to watch case pressure... is that a real indication of case pressure or is it truly "isolated"? , or is it just isolated because it cant flow back?



its cutting those threads that is the real issue...

[dazedandconfused]

So when do you think the old truck is going to break 700rwhp Brian? I hope to see the old yellow truck out breaking records again soon. I'm interested in one of these fittings as well if you make anymore.

[KTA]

I can make more but hadn't anticipated much demand. These CAN NOT be used with a typical electric or mechanical fuel feed system. Unless your pump can safely make in excess of 120psi it is not suffecient to feed the plunger. The snout is long so that it will block off the normal fuel passage from the case to the plunger. That isolates them completly so that pressure changes on the plunger side do not effect pressures in the case.
You are probably fairly accurate on checking pressures the way you have it done. You might get some pulsation from the plunger but other than that it should be fine. With my fitting you would read no case pressure because it is now cut off by the fitting. To me the ideal timing curve would be about 8deg of advance per 1000rpm. I am hoping maybe the plunger could take up to 500psi. I would be worried anything over that might cause the camplate to fail. I am also concearned that it might not even be safe that high as it might start side loading the plunger and cuase it to gall and seize on the opposite side of the fuel feed. This is all experimental and of course play at my own risk.

[bgilbert]

Keep up the good work Brian. How about the no ksb on the Scheid pumps? Is that the ticket to 850+hp? Oh wait that has already been done . Sorry for the hijack .

[dragrdan]

i've been using the fitting on my pump to watch case pressure

And what are you seeing, as far as case pressures go, throughout the rpm range? Are you able to watch the gauge while driving, or only free revving?

so the fitting feeds fuel directly into the plunger so that it can stem the loss and try to keep case pressures up?

The fitting feeds high pressure from a gear driven pump directly into the plunger, and closes off the head and rotor from case pressure. He is using the vane pump to develop case pressure for timing control only.

[Remps]

http://wwwd.graco.com/Distributors/DLibrary.nsf/Files/337597A/$file/337597.pdf So if pump 260112 was used to feed either through the shutoff solenoid or direct feeding the plunger, either way would result in the same fuel flow? Or is there an advantage to direct feeding the plunger besides not affecting timing?

[dragrdan]

if fed through the shutoff, without isolating the case, it would just bleed off pressure through the case pressure regulator, and return and would affect the timing curve also.

[Tacoclaw]

Extremely cool stuff to see, thanks for sharing.

[skilletky]

being the fitting is isolating case pressure from the plunger, will the fuel in the case just return back to the tank? you think maybe a larger return from the ip to the tank will be needed since none of the fuel entering the case will make its way to the plunger and into the engine? you think it would be better to keep fuel pressure going to the plunger constant or have it rise with engine rpm or boost pressure?

[ahale2772]

skilletky, thats a good point....

ive said it before, and im not sure what the quality of these pumps are but OBX makes a rotary pump that makes 200psi... for 250$ its looks to be the same pump that aeromotive makes for 500$ http://www.obxracingsports.com/products.php?pk=1555
...but than again if the vane pump can make 200psi then why bother with the external (besides marginal flow gains)

The snout is long so that it will block off the normal fuel passage from the case to the plunger

ahhhhhh! I see

And what are you seeing, as far as case pressures go

i see about 90psi at idle, normally about 120psi in normal driving and up to 200+ is i rev it out without loading it. If I pour the coals to it and go WOT with a load my pressures dip down to about 120 at the lowest...I do see some fluxuations of the needle but they are not as substantial as my lift pump... but then again the guage i have reading casepressure right now is slowly dieing after a year with no dampening...

here is a video of when I first put the guage on just reving it at idle, the video starts with the pressure at 100psi and they are 50 psi incriments
this is a picture of the guage at idle...

and a video.. the highest pressure it reaches is about 180psi, but thats just me not wanting to rev it any more with no load

[ahale2772]

BTW, KTA, how does that snout on the fitting seat inside the distributor body? I know the oring seats up top but does that snout sit down on something? will some of that pressure bleed off?

[Remps]

X2 on the questions above, and about where would the case pressure regulator bleed off pressure? 250-350 psi?