14mm ve pump

Case pressure rises with rpm, the pumps die with rpm. Coincidence?

Vane pump to blame?
 
I think the only coincidence is that the guys that tend to drain the rotor are also the guys that tend to run super high case pressure. No fuel kills a ve not too much.

Sent from my DROIDX using Tapatalk
 
Quite serious, case pressure is partly to blame but not too much pressure too little. With pressures of 90-150 at idle/ free rev and pressure dipping as low as 60 psi at wot with 6x18's its a safe bet to think that that drop in pressure is killing 14mm heads.
 
chevota84 said:
I think the only coincidence is that the guys that tend to drain the rotor are also the guys that tend to run super high case pressure. No fuel kills a ve not too much.

Sent from my DROIDX using Tapatalk
Click to expand...

How would case pressure be high when the rotor is drained?
 
ahale2772 said:
How would case pressure be high when the rotor is drained?
Click to expand...

It wouldn't that was my point. Shifty's post led me to believe that he thought high case pressures were killing pumps.

Sent from my DROIDX using Tapatalk
 
Oh gotcha, the big idea would be to isolate case pressure, and feed the plunger direct, KTA is working on that, yet to see results
 
So if one were to eliminate the vane pump and be able to run a constant 60psi through the pump from an enlarged inlet ( maybe not through the factory location either) and have to try and squeeze all the fuel through the limited orifice which feeds the vane pump we would be better off?
 
shiftycapone said:
So if one were to eliminate the vane pump and be able to run a constant 60psi through the pump from an enlarged inlet ( maybe not through the factory location either) and have to try and squeeze all the fuel through the limited orifice which feeds the vane pump we would be better off?
Click to expand...

Im sure it would run fine...but I would be curious on the impact of the cc output.

These pumps will work/live with injectors smaller then your typical 6x16/18 hole size...Ive got about 3500 miles on mine with a set currently. Hell ive even ran my pump with a set of stock injectors in the old engine for a few tanks of fuel, I just took it alittle easier then I normally do. Just remember hole size is not all that controls overall injector flow.
 
Last edited:
The problem is you need higher case pressure to force fuel into the plunger via the stock sized rotor inlet. The rotor inlet is smaller than that on a P-pump AND the p-pump allows a longer plunger refill as there are 6 vs 1 on the VE.

I aim to change some of this. :evil:
 
shiftycapone said:
So if one were to eliminate the vane pump and be able to run a constant 60psi through the pump from an enlarged inlet ( maybe not through the factory location either) and have to try and squeeze all the fuel through the limited orifice which feeds the vane pump we would be better off?
Click to expand...

If you deleted your vane pump you wouldn't have variable timing anymore. The steady increase in flow the vane pump provides with RPM, matched with the specific-sized orifice in the return banjo bolt, allow a known amount of pressure build up inside the case. This pressure is what moves the timing piston inside the pump, allowing the timing advancement with RPMs.

If you get rid of this function, you've basically got a crappy P-pump on your hands.
 
One about a boost referenced pressure regulator to move the case pressure up slowly for timing advance?

Sent from my DROIDX using Tapatalk
 
I chose not to go 14mm, as my 12mm flows enough for me. :st:

But I have been following the VE scene for a long time.
Based off of the info I've seen over the last several years:
People that run the 14mm at a high rate of tune (fuel screw waaayy in) run bigger injectors (6x.016s and 6x.018s) to allow as much fuel flow to keep the pump cool. Some have run it at less than crazy levels with smaller injectors, but if I were going to do that I'd stick with the 12mm. Usually a very high flow lift pump is used with a boost referenced bypass regulator. The reason for this is not just for the crazy flow. Setting the fuel pressure low (around 10psi) keeps the timing piston from advancing the timing down low. When your running at full tilt the extra pressure (in the neighborhood of 60psi) acts as a bandaid for the dropping case pressure caused by the big injectors and pump settings. Some of this goes out the window for those running Scheid built pumps, as they lock the timing advance to 0*. I don't know why they do this, because the timing advance is one of the advantages to the VE; unless it is to keep the timing from retarding when the case pressure drops. Only problem is you have to set it so high to begin with.

As far as fuel only horsepower numbers and injector hole size, KTA said he ran several different injectors and 6x.016s seemed to make the most power with a single turbo setup and 6x.018s for a twinned setup. Anything bigger and his power decreased. We've all see what happens when a crap ton of:nos: is thrown in the mix.
 
I dunno, my truck builds up to 50psi (boost) really quick, and stays there throughout the RPM range. You could potentially tune your setup for a specific acceleration style, but it wouldn't really work for all of them. Especially cruising, when you're using the advance to increase efficiency. It would just sit on full-retard all the time, basically killing your MPG and power.
 
Last edited:
Tacoclaw said:
If you deleted your vane pump you wouldn't have variable timing anymore. The steady increase in flow the vane pump provides with RPM, matched with the specific-sized orifice in the return banjo bolt, allow a known amount of pressure build up inside the case. This pressure is what moves the timing piston inside the pump, allowing the timing advancement with RPMs.

If you get rid of this function, you've basically got a crappy P-pump on your hands.
Click to expand...
Exactly. I was hoping someone would point this out. So unless these two adavnatges/disadvantages are addressed I dont think we will have the best of both worlds. The things that make the ve great are also its weakness. Said by someone smarter than I.
rednsilver90 said:
I chose not to go 14mm, as my 12mm flows enough for me. :st:

But I have been following the VE scene for a long time.
Based off of the info I've seen over the last several years:
People that run the 14mm at a high rate of tune (fuel screw waaayy in) run bigger injectors (6x.016s and 6x.018s) to allow as much fuel flow to keep the pump cool. Some have run it at less than crazy levels with smaller injectors, but if I were going to do that I'd stick with the 12mm. Usually a very high flow lift pump is used with a boost referenced bypass regulator. The reason for this is not just for the crazy flow. Setting the fuel pressure low (around 10psi) keeps the timing piston from advancing the timing down low. When your running at full tilt the extra pressure (in the neighborhood of 60psi) acts as a bandaid for the dropping case pressure caused by the big injectors and pump settings. Some of this goes out the window for those running Scheid built pumps, as they lock the timing advance to 0*. I don't know why they do this, because the timing advance is one of the advantages to the VE; unless it is to keep the timing from retarding when the case pressure drops. Only problem is you have to set it so high to begin with.

As far as fuel only horsepower numbers and injector hole size, KTA said he ran several different injectors and 6x.016s seemed to make the most power with a single turbo setup and 6x.018s for a twinned setup. Anything bigger and his power decreased. We've all see what happens when a crap ton of:nos: is thrown in the mix.
Click to expand...

At that point a p-pump would seem more viable to me at that point, since variable timing is what makes these pumps so easy to drive.
 
shiftycapone said:
Exactly. I was hoping someone would point this out. So unless these two adavnatges/disadvantages are addressed I dont think we will have the best of both worlds. The things that make the ve great are also its weakness. Said by someone smarter than I.
Click to expand...



KTA on 1stgen said:
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. 8)
Click to expand...

If you look over on 1stgen, this has been addressed, Shifty.
 
I dunno, my truck builds up to 50psi (boost) really quick, and stays there throughout the RPM range. You could potentially tune your setup for a specific acceleration style, but it wouldn't really work for all of them. Especially cruising, when you're using the advance to increase efficiency. It would just sit on full-retard all the time, basically killing your MPG and power.
Click to expand...
Maybe use oil pressure to reference the fp regulator.

Sent from my DROIDX using Tapatalk
 
Tacoclaw said:
If you look over on 1stgen, this has been addressed, Shifty.
Click to expand...

I am over there a fair amount, never saw that post. Lots of info to fish through on that site, and the search results take a long time see all the posts quickly. Specific though!
 
You must log in or register to reply here.
Back
Top