Smaller Pull-ups for my Saginaw pump

[Banjer Picker]

Currently running a hydroboost a dual return Saginaw pump from a ‘82 GMC 1-ton diesel. I’m planning to add hydro ram assist soon (4x4x2 box is ported for it).

The pulley I’m running currently is almost 6” in diameter. Wanting to reduce that as much as possible to increase the flow. Anyone know what vehicles would run a smaller diameter V Belt pulley with the same diameter shaft on my current pump?

If not, any thoughts on an efficient way to cross reference smaller V belt pulleys that would fit that pump?

Thank you!

 

[Yeller]

Brandon, look at 80’s 4 cylinder Jeep CJ and YJ. Other option that may be more sure fire answer is call West Texas Off Road in San Angelo, they are pretty good with the “what might fit”.

Are you sure you’ll need a smaller pulley? Running the same set up on my 70 Gladiator and several others without feeling like it needs sped up. You can get a little more flow volume by drilling the orifice pressure relief fitting out to 5/32”, they are usually somewhere close to 3/32” from the factory.

 

[Banjer Picker]

Thanks Steve! I can’t say for sure that I need a smaller pulley but I thought it might be a good preventative measure after reading a bunch of posts on the issues with low volume/poor steering at low speeds that have popped up after folks added hydro assist.

Great to see y’all at OCBR by the way.

 

[Yeller]

Was good to see you too, wish we could have spent some time together.

I usually drill the fitting out during install since most of the fluid is drained anyway and it has to be removed from the pump to drill it out. Don’t get greedy on bigger is better, if you go to large it won’t have any pressure at idle, the pump requires some back pressure to keep the vanes in the pump from fluttering. I usually drill a very safe 5/32’s. At around 7/32’s the flow potential out runs the potential volume of the pump causing issues that will make you crazy.

 

[gnpenning]

Steve gave you some good information that for most should be all you need. Here are a couple things if you want to go a little farther.

Skip to 4 minutes plus. This just shows you about drilling out the orifice

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This one takes you to the dark side with plenty of reading.

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