pressure washer. how much psi and gpm needed?

[CarLuver]

i changed the pump on my old pressure washer that i use to wash my car. before buying a new pump, i bought a pressure gauge to check the psi. with a white tip , it was less about 500 psi. with the new pump its 1500 psi with the same tip.

even with the added pressure , it does not seem to clean much more than the old one. how much pressure is ideal to wash a car?

 

[Rand]

1400 psi or less. to avoid paint damage.
Pressure isnt to clean its to remove loose dirt/contaminants.

 

[DaHen]

Pressure washers have been known to remove paint as well dirt and grime.

(Gee, how do I know!!!!!)

 

[demarpaint]

Pressure washers have been known to remove paint as well dirt and grime.

(Gee, how do I know!!!!!)

LOL That's the truth. Less is more with a car. I've been in the painting business for over 40 years now. Every spring people go hot and heavy advertising "power washing service" etc. Many are lowballers trying to break into power washing. I work on referral and repeat customers only, and had a few tire kicking referrals over the years. One such woman lectured me on how ridiculously high she felt my prices were. My reply was very simple, OK thanks. About a month later I got a call from her, she was as sweet as can be, asking me if I could fix the faux stucco torn off her house right down to the crappy backing they use under that garbage. I went to see with no intention of ever working for her, but I had to see it for my own curiosity. The hack tore the stucco right off the house in spots. I suggested she sue him and get someone to fix it. The moral of this OT rant is less is sometimes more when it comes to power washing, and you can easily ruin the paint on a car with too much power.

 

[Wylie6G72]

My Sunjoe says it's 2060psi, but I don't believe that. It's pretty good for car washing, but wish it had higher GPM. I sure don't worry about it peeling any paint.

 

[RooflessVW]

I'd say around 1000 psi is ideal for car washing.

 

[gofast182]

Consider psi and the nozzle together. For example you can safely wash a car with 3,000psi and a 40 degree nozzle or 1,600psi with a 15 degree nozzle (for what it's worth you can safely wash a car with 3,000psi and a 15 degree nozzle if you hold it back far enough). I currently use 1,600psi with a 15 degree nozzle with complete freedom to get close when needed.

 

[RooflessVW]

Consider psi and the nozzle together. For example you can safely wash a car with 3,000psi and a 40 degree nozzle or 1,600psi with a 15 degree nozzle (for what it's worth you can safely wash a car with 3,000psi and a 15 degree nozzle if you hold it back far enough). I currently use 1,600psi with a 15 degree nozzle with complete freedom to get close when needed.

Keep in mind that pressure at the tip is also a function of the office size. A larger orifice will drop pressure to safe levels and increase flow.

 

[The Critic]

I use a 3800 psi gas pressure washer with 3.5 gpm, but I only use the white tip (40 degrees).

 

[CarLuver]

I use a 3800 psi gas pressure washer with 3.5 gpm, but I only use the white tip (40 degrees).

you ever put a gauge on it to see how much psi it putting out at the tip?

 

[gofast182]

Keep in mind that pressure at the tip is also a function of the office size. A larger orifice will drop pressure to safe levels and increase flow.

Correct.