13mm pump questions.

RonA

RonA

Active member
Joined
Feb 26, 2008
Messages
11,076
I'm searching for more fuel and have noticed that pump output claims don't seem to match collected data or logic. When talking about 12mm pump output a high end number seems to be between 550 and 625cc depending on who is making the claim. I see claims for 13mm pumps that range from 750cc to 1100cc. The paperwork from mine says 550 to 750cc depending on plate position with the stock 180/215 cam. 13mm plungers in any given pump will produce 17% more fuel than 12mm. So if 575cc is the max for a 12mm pump, then a 13 will make 672cc. When I switched from a 12mm to a 13mm pump my hp went from 711 to around 840(an 18% increase). By changing turbos and tweaking it went up to around 870(an increase of 22% over the 12mm numbers). I would assume the faster injection rate would be partly responsible for the difference. If I back calculate from 13mm claims, 750cc would be 641cc with 12mm plungers, 900cc would be 769, and 1100cc would be 940cc. If someone said they had a 1000cc 13mm pump no one here would bat an eye. If someone said they had an 850cc 12mm pump they'd get the usual CompD rail ride. The math says 17%, the dyno #'s seem to support the math. I know of a 12mm pump that has done over 1k on fuel, and i know of 1 13mm pump that has done a bit more. What pump shop knows the secret, and who's ass do i need to kiss to get one built?
 
Last edited:
It seems alot go with a CDS but I'd go look at Scheid and Northeast.
 
CDS usually installs their HFDV's(slight hp gain, 3X the smoke) I figure those are probably good for another 50-60cc of fuel making the output of my pump with 024's closer to 675 or so. I don't know what test nozzle they use. I will send both pumps in when i have a new one built and specify that i would like another 100cc of fuel over this 13mm pump in it's current configuration. New pump will need to be tested with the same 024 dv's. That's the only way i can be sure of what I'm getting.
 
On a 12mm P7100 @ 21mm rack I've seen an 80cc gain with a competition style delivery valve over an "024". Are the delivery valves you are running now 7mm or 8mm diameter?
 
Mine is a scheid pump and flows between 450-950 by the card that came with it. Some depends on the speed of the pump stand that is being used as to the differences in the flow numbers.
 
Obviously must be some variables in pump building. As iirc Big Bad Dodge, runs a 13mm pump, and I would hazard a guess that it makes a little more then 1000hp...
 
My buddy has a brand new top of the line Northeast 13mm ag pump and I have a Schied 13mm SS ag pump and its amazing the the differences in the outside of the pumps.......
 
Well the delivery valve holders on the Northeast pump take the normal splined socket to remove and my schied pump is hex for a regular socket, then the northeast pump is rounded on the bottom, and my schied pump is completely flat. Then where the throttle linkage goes on to the notheast pump it has a stop for WOT but not on the throttle down side, my schied pump has both. Where you adjust how "choppy" you want the ag governor to make the motor run is different, just crazy.
 
blos101 said:
Well the delivery valve holders on the Northeast pump take the normal splined socket to remove and my schied pump is hex for a regular socket, then the northeast pump is rounded on the bottom, and my schied pump is completely flat. Then where the throttle linkage goes on to the notheast pump it has a stop for WOT but not on the throttle down side, my schied pump has both. Where you adjust how "choppy" you want the ag governor to make the motor run is different, just crazy.
Click to expand...

Sounds like you have a Denso pump.
 
blos101 said:
Ok now I'm feeling dumb, enlighten me.
Click to expand...

Denso pumps have different dv holders then the bosch pumps and they have an external idle stop screw. They are good pumps don't get me wrong just not as good as bosch.
 
01PPUMP said:
Denso pumps have different dv holders then the bosch pumps and they have an external idle stop screw. They are good pumps don't get me wrong just not as good as bosch.
Click to expand...

Ok I got ya. Didn't know scheid would use them instead of bosch? I did google it and found out about them.
 
Thanks for all the info. I'll do a bit more checking around and figure out if i want another from CDS or try someone else.
 
You must log in or register to reply here.
Back
Top