Inside the HPFP

P

philsrb

New member
Joined
Dec 10, 2020
Location
romania
TDI
audi a6 bitdi competition
hello everybody,
after relentlessly searching the depths of the internet for help, i have finally found this thread where lots of you guys seem to know a while lot abkut these pumps.
right now, i have 2 cp4 pumps in my garage, so if needed, i might also post pics of the pumps while solving my problem.
following problem:
it seems my cars current fuel pump cannot keep up with the needed amount after some tuning...
car is a 2017 audi a6 bitdi. the fuel pump from the car is the cp2 r80 variant. i will add the bosch code tomorrow.
i have another almost new cp40hs2/L99/40 lying around here. that is the highest output cp4 i know of.
now, i wanna put that pump into my car. first obvious problem is that it is a left rotating pump whereas my car needs a right rotating pump.
second, i would want to use one of the plunger heads from my old pump since it has the right angle in contrast to the L99 one which goes in a different direction.
how can i achieve this? i will probably start opening up the pumps tomorrow.
i was thinking of taking parts from both pumps to create the pump i need somehow.
but first, i need to figure out if i can use the left pump or not, or how it differs from a right pump so i can start mixing parts until it is what i need it to be
 
R

Rub87

Top Post Dawg
Joined
Dec 10, 2006
Location
Belgium
TDI
Ibiza '99 90HP
What ive done a few times is use the r90 or r93 cam inside audi r70 or r80 pump. It drops right in. If your donor pump has a gear pump to the back just grind away the section that drives it. Logicaly you would think a L cam also would work but I never tried it. If you leave away egr cooler you can normally use the full r90 pump incl gearpump I think from duramax, cant recall. Be careful as some have m16x1.5 (could also be 1.25) threads on the outlets vs m16x1 for the stock. The nissan/cummins pump has for sure m16x1. All us spec pumps usually also have dlc coated plunjers as a bonus
 
2004LB7

2004LB7

Veteran Member
Joined
Jun 2, 2013
Location
California
TDI
2006 Jetta
philsrb said:
hello everybody,
after relentlessly searching the depths of the internet for help, i have finally found this thread where lots of you guys seem to know a while lot abkut these pumps.
right now, i have 2 cp4 pumps in my garage, so if needed, i might also post pics of the pumps while solving my problem.
following problem:
it seems my cars current fuel pump cannot keep up with the needed amount after some tuning...
car is a 2017 audi a6 bitdi. the fuel pump from the car is the cp2 r80 variant. i will add the bosch code tomorrow.
i have another almost new cp40hs2/L99/40 lying around here. that is the highest output cp4 i know of.
now, i wanna put that pump into my car. first obvious problem is that it is a left rotating pump whereas my car needs a right rotating pump.
second, i would want to use one of the plunger heads from my old pump since it has the right angle in contrast to the L99 one which goes in a different direction.
how can i achieve this? i will probably start opening up the pumps tomorrow.
i was thinking of taking parts from both pumps to create the pump i need somehow.
but first, i need to figure out if i can use the left pump or not, or how it differs from a right pump so i can start mixing parts until it is what i need it to be
Click to expand...
Does this CP4 have the gear pump on the back? If so does it have it's own supply/return? If yes then swap the supply and return of the gear pump. The CP4 itself doesn't care what direction it turns. Only the gear pump on the back does. If the gear pump only has internal plumbing then you will have to swap the gear pump for a right turn one
 
P

philsrb

New member
Joined
Dec 10, 2020
Location
romania
TDI
audi a6 bitdi competition
none of the pumps , neither the installed one nor the l99 hsve a gear pump on the back. i will post pictures asap when at the garage. today i will start building the custom pump. also i found differences within the roller unit, seems the newer ones have a mechanism to prevent twisting of it as described earlier
 
2004LB7

2004LB7

Veteran Member
Joined
Jun 2, 2013
Location
California
TDI
2006 Jetta
Well then the only thing to worry about now is the nut that holds the pulley or gear onto the shaft(right hand vs left hand threads). But the CP4 shaft is pinned or keyed so it shouldn't be a problem. I've gone through the CP4 plenty of times and can't see any reason it wouldn't run either direction unless it has the gear pump on the back
 
R

Rub87

Top Post Dawg
Joined
Dec 10, 2006
Location
Belgium
TDI
Ibiza '99 90HP
I am pretty sure that the ‘liners’ have a slight offset to either direction to reduce the side forces on the tappets. Much like you have in any modern engine a crank offset.
 
P

philsrb

New member
Joined
Dec 10, 2020
Location
romania
TDI
audi a6 bitdi competition
Unfortunately i cannot add the pictures i took from phone.
I eill when im back home.
So we movedthe internals of one pistonhead to the old one facing the right way and reinstalled it.
Furthermore, we have moved the nozzle from the L99 metering valve to the old one for the same reason. The whole pump is reassembled now.
i hope this will work
 
R

Rub87

Top Post Dawg
Joined
Dec 10, 2006
Location
Belgium
TDI
Ibiza '99 90HP
I would not mix and match the plunjers in the heads. Keep these as pairs together. The tolerances must be very tight for it to work. So better just put the big stroke cam in the old pump in case the heads are still good.
 
arazvan2002

arazvan2002

Veteran Member
Joined
Sep 28, 2010
Location
Romania
TDI
Audi A4 B6 1.9TDI AVF quattro
It seems someone in Italy found a solution to fix the design of the cp4 pumps. https://www.promot.it/ricambi-iniezione/
The improved pump is affordable, same price or even lower than a refurbished Bosch pump, like 490euros with old pump in exchange.
What do you guys think of their design of shaft and roller? I'm thinking about buying one to change it in the same time with the timing belt of my A4 B8 2.0tdi CAHA which has 0445010507 03L130755 pump.
 
2004LB7

2004LB7

Veteran Member
Joined
Jun 2, 2013
Location
California
TDI
2006 Jetta
warranty is pretty good that's for sure. they should pay me royalties for the carbide roller, see my posts #98 & 113 😁. now they just need to use my idea of pining the piston follower to keep it from twisting in the bore as that is one area of failure that there changes doesn't address. see post #155. infact there cam profile change may increase the chance of that happening. when I was paying around with them I noticed that the flat spot seemed to help realine the roller to the cam. without this the roller can rotate 90° to the cam and destroy it. bit with a warranty like that it's hard to argue
 
You must log in or register to reply here.
Top