4x4 or lower PSI and 5.5GPM

I have recently started a pressure washing company and am buying my first set up. Initially I will be focusing on residential houses and surface work in addition to small commercial buildings and restaurant patios. I am trying to decide between the local shops recommendations of a Honda belt driven 4x4 with a viper motor ($1,500) or looking for a 5.5 GPM. From what I have seen it looks like you can get more GPM for the same price if you are willing to sacrifice PSI. My question is should I put priority on PSI or GPM. I would greatly appreciate any input on the pros and cons of these choices.

Id say the 5.5 over the 4. I changed my 4x4 pump to 5.5 and most here say that lands me around 2500 psi. I have not checked with a gauge. Its night and day better to me for everything I wash. There are 5.5 @ 2500 machines out there for about the same as the 4x4 machines

I’m running a 4gpm belt drive at 3500 psi on a gxhonda 390 @11,12hp. I’m replacing the 4gpm pump to a 5.5 over the weekend, I’ll do a pressure test off of a 100’ 3/8 hose. I’ll let you know the psi. They said I should be around 2800 psi. That will be plenty. I have another machine running a 5.5 off of an 18 hp @ 3500 psi. It was to much to hold all day ,so I turned it down to around 2900 psi. Night and day between a 4gpm and a 5.5 gpm. Go gpm all the way man,way faster rinsing time. But I wash trucks. So if your doing houses you will be safe because you don’t want pressure anyways to do soft wash, but flat work with a Surface cleaner you might want more that 2500,2800 psi. Ask the flat work guru’s on here…

I made the switch. First thing I did was a drive way only. Mine. I couldn’t tell enough difference. I was pretty ticked after all the bs with different couplings for the new pump. It wasnt just a pull and switch change. When I did my first whole house plus concrete is when the difference was noticeable. I’d say it cut 30 minutes off a 2.5 hr job.

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Thank you for the input! That is exactly what I was looking for.


If you couldn’t tell the difference it’s because you didn’t change your tips to the correct ones. If you still had tips for 4gpm, you were bypassing the extra 1.5gpm instead of putting it on the concrete. The difference is night and day, close to Twice cleaning speed.
Buying/upgrading equipment is one thing, setting it up and using it properly is another.

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Good advice

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Tips were changed. The job just wasn’t big enough to really evaluate and notice the added GPM.