CDD DB4 Pump Build
- Thread starter Thewespaul
- Start date
IDIBRONCO
IDIBRONCO
Oh great! As if you need more projects to do.
Really, I understand what you're doing and I think it's great that you want to keep the
parts for our engines rolling.
Interesting thread! And Wes, as usual, I commend you for the experimentation. I do however, have to at least point out that I put a lot of information out that was available before you came on the scene, and I suppose much of this has been lost in antiquity. We regularly manufacture the Omega Moose pump, which is a 130cc pump, and it has a full warranty and many have been sold, and none have come back. We also offered, for a time, the 205cc Super Moose, but due to the custom 10mm plungers, we only sold a couple of them, and I no longer offer them. I have been building a pump for the GM IDI community we call the Omega Moose Plus, which is based on the .033 plunger 6.5 marine head previously mentioned, and those make 180cc. But those are stupid expensive due to the $800 H&R needed, and I do not warranty them, as a seized H&R is a possibility (and did happen for one customer who did not heed my injector warning). All of these experiments result in a pump that does not sell well, and so from a business perspective there is only so much you can do. Increases in plunger diameter and stroke are all easy to do, but increasing the size of the flow passage is pretty much out of reach for most machine shops and becomes a large limiting factor in fuel delivery at higher RPM. What happened to your Cat 3208 pump project? That looked more promising. Keep up the effort!
Interesting Mel, I didn’t see the 130cc omega on your store so I thought that had gone the way of the way of the super moose, how much are the omega moose pumps? An $800 H&R isn’t too bad really, I thought the super was a db4? The db2831-5722 H&R are over two grand now if you can even get one, so building a custom H&R to accommodate 11mm plungers actually looks semi affordable in retrospect. In my experience the discharge passages are not a restriction, but the delivery valve is, which fixing took my 130cc db2 build to a 150cc spec without changing anything else. The feed passages do become a restriction past a certain point which is why the db4 has four fill ports and the db2s have two, a simple fix on a db2. Could you point me to a thread with some of your own experimentation? I love a good db2 thread, thought I had read them all on here but I could be wrong. I know from a business perspective, performance parts are no where near as easy to produce and sell as stock parts that have been proven by their manufacturers, but I haven’t had much issues selling my higher power pumps, I typically sell more of the performance pumps than stock pumps these days and FYI, that db2833-4974 H&R works great on the fords too. The 3208 project’s still on my shelf, I’m waiting to see how someone else’s P-pump conversion works out before I drop any more coin on it.
centennial60
Registered User
Wes, I enjoy hearing about all your findings with these pumps. Most guys aren’t as open as you are and there just isn’t much detailed information out there. Keep up the good work! I may be contacting you sometime in the future to checkout my pump.. I have a hard time believing it’s putting out 130cc as it was advertised.
Thank you for the support, I do my best to make all the info public as I can to hopefully help these IDIs get the aftermarket support they deserve. I think it would also be good to iron out a standard for pump ratings for us pump builders since a pump making say 100cc rating off idle but only 80cc at hp peak is going to drive very different than one that makes 100cc down low, and 95cc up top. I think if all pump builders published that info it would help the consumers pick the pump that suits how they want their engine to perform a lot better.
Macrobb
Full Access Member
I know I'd like to see ratings in CCs at 1400 and 2800RPM - the last being the most critical. And, as far as standards go, stock 7.3 lines(which may be bigger than 6.9 lines, but are easily available), and some sort of standard "off the shelf" injector at a nominal pressure.
Of course, the "best" would be to have a dozen-point fueling curve showing fuel delivery from idle to governed speed on any pump, so you can actually do a good comparison.
Excuse my randomness since testing and cost of the head etc.cost a few grand when a finally product is.done how much would it cost.sorry have not seen the question posted as well as will it be harder to rebuild then your db2 pumps.
Once again excuse my novice questions
Once again excuse my novice questions
Exactly, and that’s a good point on lines and injectors, when I calibrate these pumps I use the factory calibration specs as far as lines, orfice plates and pop pressure. I use a .3mm orfice plate and 1700 psi pressure. I’ve played with different sizes of lines and got no gain in fueling. If you use a .4mm orfice plate (which is used for the db4’s factory calibration for the marine 6.5) you will get a higher flow reading than what you will actually get on the engine running 7.3 injectors. This is why we use the 7.3 spec for calibrating the db4, with the smaller orfice plate and 1700 psi pop pressure. Sure we could use a larger orfice plate and it would show on the stand to make 300+cc but it wouldn’t deliver anywhere near that on the engine, which is what we are trying to replicate as closely as possible.
I don’t know yet, the parts are very hard to come by so it’s more than likely just going to be a made to order setup, but likely 3-4.5k.
Running the db4 with the new advance piston and cam pin in the morning, looking for transfer pressure to be up in the 110-125 psi range, and for more fuel displacement than the 200cc cranking and 130cc main fuel.
IDIBRONCO
IDIBRONCO
Good luck!
First run, 300+ cc at cranking, and 160-170cc main fuel
kla94
Registered User
That's very impressive!
