8gpm pump for gx630?

I’m not in the market right now to replace my 5.5, but if I was looking to put an 8gpm on my 630, what PSI would I get out of it?

If someone has first hand experience vs a formula I would appreciate it.

A formula is first hand. Laws of math and physics don’t change.

Too many variables to apply a simple formula.

@Anthony28 did it I believe, I can’t remember the psi,ask him @dcbrock ,or it was a gx390. My rememberer is broken

Maybe 3000 psi or so and 7 gallons?

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That is an incorrect statement.

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Mine is a 390

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You are going to push motor to hard you would be better off to sell it and buy a whole unit. Although I dont know why you would want a 8gpm machine anyway

There is no pushing the engine to hard. It will run within it’s specs regardless of what pump is on it.


Really just more efficient surface cleaning. The 5.5 is fine for housewashing.

5.5 is plenty to clean concrete. If you’re washing concrete all the time then yes…8gpm is king. I xjet 3% pre and post treat and almost run behind my WW Eagle Wash. But I don’t do driveways much because I don’t enjoy it as much as house washing. I would think a 8gpm pump would get around 2600psi…ish with a gx630 with 200ft of hose (guesstimate)

If I had to just throw out a number I think you could get. I would say approx 8,575 psi.



Revisiting my thread…

Anyone have a pump brand/model number I could look at for a bit more GPM? Did a house wash today and the breeze wouldn’t let me get the 2nd story peaks very well with the LP shooter tip.

The 630 is only using about 17hp so I have another 3hp or so to play with.