Inside the HPFP

[2004LB7]

So, i have an extra HPFP/CP4 with an unknown number of miles on it. i thought with all of the questions and concerns about this pump, i would show you all what makes this thing tick and disassembled it and photographed it.

if any administrators want to integrate or move it into any of the other numerous HPFP threads then feel free.

this is the label on the side of the pump. if anyone knows how to read this and determine what revision this one is or any other information please let us know.

this is the pump.

as a comparison, here is a CP3 next to the CP4. bonus points for anyone who guess what the CP3 is out of

this is what the inside looks like and the fuel flow

and an image borrowed from another thread. this is a nice computer model showing the insides

Fuel pressure regulator valve. this is what meters the amount of fuel that makes it into the plunger. more fuel will increase the pressure, less fuel will lower the pressure. i believe this works the same as the CP3. ie: with pulse width modulation. lower duty cycle will open the valve and increase fuel flow. higher duty cycle will close the valve more and restrict the amount of fuel going to the plunger. item 3 from image above

the FPRV is protected by a fine mesh screen on the input side of the regulator.

this is the spot that the FPRV bolts up to. you can see some fuel supply channels machined into the body. the hole in the top is the supply and the hole in the bottom is the exit to the plunger

plastic cover over the high pressure portion of the pump. this is easily removed with a screwdriver prying up between the discharge and the plastic cover

ta da!

 

[2004LB7]

the spring in here puts a lot of pressure on the head, so careful when removing it

plunger head removed. this is the underside

head taken apart.

the top hides the check valve that allows the fuel to flow into the plunger and not back into the low pressure area. item #14

the low pressure fuel port that supplies fuel to the top side of the of the check valve for going into the plunger

the underside

this is a look into the area where the plunger goes. what you see in there is the roller assembly. item #10

roller assembly. item #10

close up of the roller

inside where the roller assembly sits. you can see one of the the lobes

 

[2004LB7]

shaft bearing housing removed.

looks like a sleeve bearing that gets pressed in

you can clearly see the lobes on the shaft here

shaft removed. at the tapered end there is a pin that holds the sprocket from turning on the shaft. may also help in timing the pump too

close up of one of the lobes. notice the fine scratches. not likely that this is a failed pump but more of an interesting observation.

another sleeve bearing and some fuel channels. the fuel port on the left is the supply coming into the pump. the right one goes up to the plunger and relief valve

the pressure relief valve. this would be item #6

this the relief valve. again item #6

the back side of the pump. the relief valve dumps pressure in to the exit line.

i am by no means an expert but if you have any questions feel free to ask. i will see if i can get the info, take measurements, etc.

i hoped you enjoyed

Thanks Jason

 

[2micron]

Great Pictures!!!

Hello Jason, Awesome pictures and write up!!
Thanks for posting them and showing us the play by play disassembly.
Your pump looks really good. The fine scratches on the cam lobe look very common. The 2009 pump cam lobes seem to have more of a ground finish, the later ones have the "honed" finish on the lobes, like yours shows.
Yours also does not have the grey coating on the cam follower plunger, like the earlier ones.
The aluminum casting also looks like the better Hypereutectic alloy, containing more silicon.
The part numbers show your pump was built 06 Aug, 2010.
One thing for your interest is the Bosch meaning of R35/20.
R is the rotation. R is clockwise, looking at the mounting face. The 35/20 designates the capacity, but no idea of the units.
Your CP3 pump looks like an industrial QSB cummins pump. The larger diameter mounting hub and the 2 ports on the gear pump may be a clue???
If your CP3 indicates L110/70, it will be CCW rotation, looking at the mounting face.
Killer pictures!! I enjoyed them.
Your pump is interesting. Looks to be a perfectly operable pump, with no visible wear or scratches.
Wait until you see the internals of the CP3!!!
All the best,
Andrew

 

[2004LB7]

We have a winner!

2Micron, you are correct on all points. the CP3 is from a cummins, it does say "L110/70" on it. yes, the larger mounting hub is defiantly the best clue. the duramax version is smaller in diameter. an interesting note, the duramax pumps are higher output then the cummins ones. the only significant difference that i could see between the to was the size of the lobes, ie pushes the plungers further up and down.

the one major difference i noticed when comparing the two different pump designs is that the CP3 does not use a roller. the cam lobes push directly on the plunger against a flat surface, much like a lot of valve/cams in the heads of an engine.

i wonder if it would be possible to machine a flat plate that would fit in the place of the roller made out of hardened steel that would just slide on the cam lobes and if it would be any better then the roller. it would eliminate the issue of the rare occurrence of the cam follower plunger rotating/turning sideways.

anyways, thanks for the explanation of the CP4 label.

Jason

 

[85Steve]

Any more info on this Topic? Maybe a way to Retro fit the CP3 at all?

 

[53 willys]

Any more info on this Topic? Maybe a way to Retro fit the CP3 at all?

Read/search some of 2microns old threads.. he was working on it... but I think he may have changed his mind once he came up with his return line filter kit AND his bypass/containment kit...??
As much as I love bosch cp3 pump that won't flake the fuel system when gasoline, water, jet A, jet B, ulsd and even fertilizer are run through it. .and can run as high as 41,000psi without puking its internals out. ..I think a 2micron equipped cp4 is a better option.

 

[Henrick]

What about retrofitting a pump from Euro-spec 1.6 TDI?

I think it should be a bolt-on fit, worst case scenario you'll need to reroute a few pipes and hoses here and there. Should supply enough fuel for a stock TDI IMHO.

 

[2004LB7]

What about retrofitting a pump from Euro-spec 1.6 TDI?

I think it should be a bolt-on fit, worst case scenario you'll need to reroute a few pipes and hoses here and there. Should supply enough fuel for a stock TDI IMHO.

Not familiar with that pump. Please tell. Google searches seams to return issues with the 2.0's hpfp and little for the 1.6.

 

[2004LB7]

Any more info on this Topic? Maybe a way to Retro fit the CP3 at all?

From looking at the size of the two pumps and the space it has to fit in I find it hard to see how the cp3 can fit in the same location. I do remember reading where someone was retrofitting it to run off of the accessory belt. Definitely not an easy solution.

Btw , the taper on the shafts is the same for the two pumps but the cp4 is longer. The belt gear will fit each pump but won't sit in the same spot on the cp3.

 

[Henrick]

Not familiar with that pump. Please tell. Google searches seams to return issues with the 2.0's hpfp and little for the 1.6.

Sorry, I'm not a tech. I gave some info on this subject to Andrew. Give him some time and I think he'll be able to answer your questions profesionally.

Long story short, the 1.6 Euro TDI pump seems to be designed slightly better than what you have there in N.A.

 

[2004LB7]

Long story short, the 1.6 Euro TDI pump seems to be designed slightly better than what you have there in N.A.

true to that. from what i gather it seems most any pump is designed better.

 

[2004LB7]

Up date!!!

i have a CP4.2 pump with zero miles to show you and to compare to the previous CP4.1

here is the CP4.2 it has two pistons and two lobes so for every revolution you get four compression strokes

the label on the side

here you can see several differences between the two pumps. the angle of the pistons, the mounting holes are not threaded and a thrust bushing inside are some that i see

another angle

putting both pumps together at their mounting holes show the angles of the pistons better. it almost looks like the CP4.2 may fit in the same location as a CP4.1 pump. this may be a good upgrade for a higher flowing pump for people wanting to push high HP numbers on their VWs

the pressure regulator has two ports for supplying fuel to each piston vs the one for the CP4.1

this may not be the best image but it shows a screen filter on the line in. i suspect that the other pump has one too but because of the fuel fittings on it being pressed in i was not able to get as good of a look into it as this one

the CP4.1 pump has a cast in place channel for supplying fuel to lubricate the piston follower while this is not the case for the CP4.2

for the CP4.2 it has a machined hole for supplying this lubricating fuel to the follower on the opposite side of the cylinder

the pump shafts are almost identical but you can see here that the CP4.2 has a longer shaft. this may have just been set up to run on another engine like the newer Duramaxs and not for all of them.

 

[2004LB7]

putting them together you can see that the height of the lobes is the same

but for the low point of the lobes the CP4.2 is lower. this creates a longer stroke then the CP4.1. this pump probably has slightly more then double the capacity of the single piston pump. if anyone knows the capacity of the two pumps (hint, hint, 2 micron) they can probably confirm this

here is another view of the lobes on the two pumps

differences in the front face plates. to use the CP4.2 on a VW this part along with the shaft would have to be swapped out from the CP4.1 pump

the roller on the new pump is virtually flawless.

to remove the roller from the follower i pressed it out from the top. the follower is upside down in these photos. the roller slides out from the side. I measured the roller at 0.3935". 10mm is 0.3937 so two 10,000th less then 10mm. I would say this is within the tolerance of my micrometer, so 10mm it is

this is the follower with out the roller. the surface here is polished too

one important point is that only one of the piston heads is a match to the CP4.1's. if the wrong head is put on the CP4.1 then the head will receive the full pressure from the auxiliary supply pump and the regulator will do nothing to control pressure. if the heads are put on the wrong side of the CP4.2 the it will not get any pressure. look at the earlier photos of the two pumps side by side and not the location the blue and black O rings where the heads bolt up. this is where the fuel from the regulator comes from.

the regulators are the same except for the connector. i measured them both at 3.8 ohms

the back side of the regulators showing the numbers, etc. sorry for having it upside down

so there you have it. the differences between the CP4.1 and CP4.2

some day i may get around to showing the inside of a CP3. what do you guys think, yes? no? i have a used Dodge CP3 i could use

2 Micron, if you can kindly decrypt the label on this pump for us that would be appreciated.

let me know if you have any questions

thanks Jason

 

[JFettig]

Awesome thread, does the N290 swap over to the CP4.2? I don't see why we couldn't make an adapter plate and drop the CP4.2 in, not sure how to tie into the rail with both connections.

Could you measure the plunger diameters in each pump?

 

[2004LB7]

sorry, didn't see your post

if you swap out the shaft and front plate the CP4.2 will likely bolt right up without any adapter.

the N290 (regulator) is identical except for the electrical connector so they are interchangeable.

the plungers are also the same. i will measure and let you know as soon as i get the chance

Jason

 

[JFettig]

Thanks Jason,

The orientation of the plungers per the mounting holes are different, so if they really need to be lined up, it would have to be done differently. I also noted that there might not be room for the 2nd plunger in that orientation - it would hit the intake.

I'm starting to think that the increased lift of the CP4.2 would limit RPM

 

[kjclow]

Great pictures. Thanks for sharing

 

[bassman5066]

I'm starting to think that the increased lift of the CP4.2 would limit RPM

Just throwing this out there, but if that's the case, would a CP4.1 can work in the CP4.2?



Sent from my Bosch Motronic ECM via VCDS Version 1.9LVE

 

[JFettig]

That is one of the things I am thinking, otherwise maybe CP4.2 pump(or parts) from a V6 CR TDI

 

[JFettig]

I don't think its gonna fit.

 

[2004LB7]

it may just clear the intake, one would have to try it to see. the plungers are not in the same alignment position as the CP4.1. the CP4.2 is used in the later year Duramax and that engine can easily turn past 4k RPM with tuning so i don't think it is RPM limited

 

[2004LB7]

the CP4.2 would sit approximately here

 

[JFettig]

Its definitely possible, TDC would have to be re-clocked if you want to line up the HPFP pulses with the injector pulses. Still pretty tight.

 

[bassman5066]

Its definitely possible, TDC would have to be re-clocked if you want to line up the HPFP pulses with the injector pulses. Still pretty tight.

If we can make a Cummins 4BT IP fit on a little 1Z or ALH, we should have no problem shoehorning this HPFP into our new cars.

You would definitely wanna line up the pump pulses with the injector pulses. How many degrees apart are the 2 pistons in the CP4.2? It looks like one will be down while the other is up, which could be a good thing since it would maintain rail pressure better than our single piston pumps. From what I understand, its the HPFP that's our limiting factor in power on these CR engines since you can theoretically inject forever with the piezo injectors.

I've seen it mentioned once you try pushing past 250-300 WHP, rail pressure drops to way too low (5000-10000 psi) under heavy load when it should be up around 20k psi. The CP4.2 may be a way to fix that problem.

Sent from my Bosch Motronic ECM via VCDS Version 1.9LVE

 

[2004LB7]

Awesome thread, does the N290 swap over to the CP4.2? I don't see why we couldn't make an adapter plate and drop the CP4.2 in, not sure how to tie into the rail with both connections.

Could you measure the plunger diameters in each pump?

both plungers measure out to 0.2555 in diameter. my micrometer actually says 0.2556 but i dont think its resolution is really that high or accurate.

 

[2004LB7]

Its definitely possible, TDC would have to be re-clocked if you want to line up the HPFP pulses with the injector pulses. Still pretty tight.

timing the pump wouldn't be that hard, the only thing i can see with this is that there will be an extra pump pulse occurring between each of the injector firings.

 

[2004LB7]

polished up the cam and roller on my spare pump. what do you think, hurt, help, indifferent?

before

after

 

[bhutchins]

are the shaft lengths and the front face flange differences the same so a spacer plate could be used?

 

[JFettig]

Brian,

That particular pump might be different than the one you have, we'll have to wait and see. It would be nice if the snout and shaft was even longer, would make for adapting it a lot easier.