New cam-24V with mecanical fuel pump lobe
#1
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New cam-24V with mecanical fuel pump lobe
Anyone put a new cam from Piers with a mehcanical pump lobe in a 24V and using the mehcanical lift pump from a 12V. If so how did you control pressure or did you have to.
#4
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CTD89-99 is correct, the cam we grind has a pump lobe, but it is not like the lobe on other cams. We redesigned the lobe to give a much more even pressure. This gives a max value of 30 PSI VS the 50-60 PSI the other cams run in pressure when using a 12 V mechanical pump. The pressure is very even and has less and milder pulsations than other systems.
We have the complete system: the pump, the cam and the fuel line kit that works as a tuned set up.
Don~
We have the complete system: the pump, the cam and the fuel line kit that works as a tuned set up.
Don~
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This is for a 24 V with the VP-44. 30 PSI is perfect for performance. We have another system as well, but the pressure is typically only 22 PSI at WOT and around 6 at idle. Most guys opt for the 30 PSI system. The only difference is the supply pump we supply.
The 30 PSI system is the best route, IMO. Back when the 12 V mechanical pump started being installed in the 24 V with the VP-44 pumps, people were seeing around 55 PSI on average. Even at idle it could be as high as 50. That was years ago and no reports of failures were reported from this pressure. Remember the internal feed/suction vane pump inside the VP44 is raising the pressure over this value to the plungers. Anything you can do to increase pressure to vane pump is a good thing. To a point of course.
Back when things were getting going hard we tested, on the dyno, many pressures that made the best HP for the 24 VP44 engines. 22 PSI and up was the best, with no more or less power made at 50 up to 72 PSI. At 72 and up we lost a few. Probably from cavitational losses.
Don~
The 30 PSI system is the best route, IMO. Back when the 12 V mechanical pump started being installed in the 24 V with the VP-44 pumps, people were seeing around 55 PSI on average. Even at idle it could be as high as 50. That was years ago and no reports of failures were reported from this pressure. Remember the internal feed/suction vane pump inside the VP44 is raising the pressure over this value to the plungers. Anything you can do to increase pressure to vane pump is a good thing. To a point of course.
Back when things were getting going hard we tested, on the dyno, many pressures that made the best HP for the 24 VP44 engines. 22 PSI and up was the best, with no more or less power made at 50 up to 72 PSI. At 72 and up we lost a few. Probably from cavitational losses.
Don~
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#8
I just want to get this striaght, I have never heard of this on a vp44 24v truck. Is this another lift pump replacement? Do you keep the lift pump with this mod? Do you get hard starts with that high of a pressure? Were does the pump mount (never seen a 12v)? Any pics? Is the rest of the cam stock or are there improvments there as well? Is it a mod that has to be done in conjuction with other mods like sticks, turbo ect ect? Sorry for all the qestions
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I don't know for sure, but you shouldn't have hard starts with a mechanical lift pump...it takes a couple cam rotations to build pressure! Once the engine fires, then it starts building constant pressure.
Chris
Chris
#11
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I think Don has 3 stages of cam profiles Helix 1 through 3. There is a plate behind the stock lift pump that will have to be removed that is where the new mech. pump mounts.
#12
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Originally Posted by ratsun
shawn085
This set up is if you are doing a P-pump conversion and scrapping the VP
This set up is if you are doing a P-pump conversion and scrapping the VP
OOPPPS my bad.
I thought you were running them for a pump conversion.
When I had my pusher pump with the stock LP I seen 23psi but no noticeable gains or losses. Perhaps the hard starting issues were with VPs that were on their way out already?
#13
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Originally Posted by shawn085
I just want to get this striaght, I have never heard of this on a vp44 24v truck. Is this another lift pump replacement? Do you keep the lift pump with this mod? Do you get hard starts with that high of a pressure? Were does the pump mount (never seen a 12v)? Any pics? Is the rest of the cam stock or are there improvments there as well? Is it a mod that has to be done in conjuction with other mods like sticks, turbo ect ect? Sorry for all the qestions
It delivers plenty of fuel and this keeps a steady supply of fuel moving through the VP44 to keep everything lubricated and cool.
Even though the 24 Valve engine in the Dodge is equiped with an electric pump Cummins left a fuel pump boss cast and machined in the side of the block casting for their other customers that wanted to use a mechanical pump. This cast boss is covered over with a cover plate and two bolts. You simply remove the cover plate and replace it with a pump. Of course you need a camshaft that is equiped with a lobe on the shaft to drive the pump. The stock 24 V cam does not have one.
Once replaced, you have a bullet proof fuel delivery system that will outlast the truck and engine in nearly all cases. You retain the stock filter canister and no special type of filters are needed or will need to be tracked down. Any Cummins or Dodge parts house will the filters.
No hard starts, EVER! With the pump lobe we have ground on the cam, we have a lower pressure and much less pulsations than anyone. Smooth and consistant.
I believe the entire kit with the pump, cam, pump install kit, and complete fuel lines from the VP44 back to the fuel line under the cab is around a grand. I dont want to post specific prices.
With electrics in the 500 dollar range and up and needing special filters, it seems cost effective to get a better camshaft and a mechanical pump that simply wont fail instead.
Don~