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Old 12-21-2009, 03:27 PM
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Jason Jason is offline
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Join Date: Jun 2009
Location: St.Louis, MO
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Default "BIG POWER" pump modification info

After doing lots of research on pump modifications and parts available, I thought I would post up the results of many hours of reading and a few phone calls.

Some VE pump background:

The stock pump on the D24T is actually bigger and has more fuel flow potential than its smaller cousin, the 1.6 TD. Even though the engine is pretty much the same with two more cylinders, for whatever reason VW engineers decided to fit a larger head and rotor for the D24T. Stock in the VW 1.6 pump is 9mm. The D24T is a 10mm head.

Bosch VE pumps are found on many different diesel engines from our VWs to Cummins diesels. There are however two main varieties, the 17mm shaft and 20mm shaft. The 17mm was used for smaller pumps with 9mm and smaller heads, while the 20mm was used for 10mm and larger. While you can swap a larger head onto a 17mm shaft pump, the ideal situation would be to have the 20mm version. Even though most pumps have the 20mm shaft with the larger heads, our pump is the 17mm shaft version. Most likely because our cars are from the early 80s. I think the 10mm head being on the 20mm shaft logic was applied later, as thats how the TDI pumps are.

More fuel=more power!

The 10mm head is only going to flow so much fuel, (supposed to be able to support around 200hp) so stepping up to a 11 or 12mm head opens the door for some real performance. After buying a Cummins 12mm head/rotor assembly, and trying to assemble the pump (which wouldn't go together correctly, I had that "you are a dumbass moment". Unfortunately for us, the Cummins engine has the injection pump driven off the front of the engine. Where is the D24 pump?? On the back of the engine... What does that mean to us? Our pumps are LEFT HAND ROTATION!!! Right hand rotation head/rotor/cam plates wont run our engine. I even called Giles, the renouned hotrod VE pump builder in Canada. I'm still trying to find the part number for the left hand rotation 12mm head/rotor and corresponding cam disk.

Another source is vepump.com. This is a manufacturer of many diesel injection components from individual pump parts, to complete pumps, injectors, etc.. They are in China, and that I'm sure throws up a red flag for many people (as far as quality is concerned). Even so, I have personally talked to a few members through the forum in Europe that are running their head and rotor assemblies along with other misc pump parts and have had great luck. Everone I talked to also commented that the parts looked/felt/fit like OE.


At this point, a lift pump to the injection pump is going to be a good idea. The Cummins engine with 12mm head came with a low pressure lift pump to supply fuel to the injection pump. The stock vein pump will be much closer to its limit supplying a 12mm H&R compaired to the stock 10. A lift pump supplying around 8 to 10 psi will ensure that the pump is never starved for fuel. At 5000rpm and full fuel delivery, the vein pump will be having a hard time sucking enough fuel to keep the pump at full pressure, and performance is likely to suffer. More than 15lbs of pressure has been known to blow the front shaft seal on the pump. A low pressure high volume pump is ideal. A popular choice is a Holley red pump. They come pre set at 7 or 8psi and can handle diesel fuel.
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Back again with a '84 760 GLE D24T/ZF

SOLD but not forgotten! 1984
760 Sedan, built D24Tic/ T-5 swapped

My engine build: http://www.d24t.com/showthread.php?t...t=engine+build
T-5 swap: http://d24t.com/showthread.php?399-W...to-quot-w-pics!