Which BigBoi WASHR Should You Buy? QUAD vs DUO vs TRADIE vs PRO MKII
Alpha Details · Buyer's Guide
Which BigBoi WASHR should you buy?
QUAD vs DUO vs TRADIE vs PRO MKII. Four machines, four jobs — and the number most people shop on is close to the least useful one on the box.
We stock the range, we run them in our own studio in Melbourne, and we wash cars with them every week. This is the guide we wish existed when we were choosing.
The 30-second answer
Complete kit in the box. At 8 kg it is the only unit in the range light enough to genuinely carry. The 4-plunger pump punches well above the price.
Bolt it to the wall and forget it. The trade-off is noise — it is the loudest machine in the range at 87 dB.
The lightest of the three big units at 18 kg, with a commercial triplex pump. Built to be thrown in and out of a vehicle.
Most pressure, most flow, Italian forged-brass triplex pump — and the quietest machine of the four. The PRO MKII kit and the TRADIE kit are both $999. Unless you need to carry it, that decision makes itself.
The full comparison
Every figure below is taken from BigBoi's published product specifications. Where BigBoi's own pages disagree with each other, we have said so rather than quietly picking the flattering number.
| WASHR QUADHome enthusiast | WASHR DUOFixed / commercial | WASHR TRADIEMobile pro | WASHR PRO MKIIHigh-end commercial | |
|---|---|---|---|---|
| Max pressure | 1,500 psi | 1,400 psi | 1,600 psi | 1,850 psi |
| Tuned pressure what you actually get | 1,050 psi | 1,350 psi | 1,300 psi | 1,450 psi |
| Max flow | 8 L/min | 8.5 L/min | 9.2 L/min | 9.5 L/min |
| Tuned flow at the nozzle | 7.45 L/min | 8.2 L/min * | 8.8 L/min | 9.2 L/min |
| Motor | 1,600 W brushed | 1,500 W peak brushless induction | 1,800 W peak brushless induction | 2,000 W peak brushless induction |
| Pump | QUAD 4-plunger | German wobble-plate, brass head | Commercial triplex head | Italian triplex, forged brass |
| Noise | 86 dB † | 87 dB | 84 dB | 80 dB |
| Weight (carton) | 8 kg | 24 kg | 18 kg | 27 kg |
| Max water temp | 60 °C | 60 °C | 60 °C | 60 °C |
| Power | 220–240 V · 50 Hz · 10 A — all four run off a normal household outlet | |||
| Wall mountable | Yes — all four | |||
| Foam cannon included | Yes — FoamR PRO 3-way largemouth cannon, in every box | |||
| Price — unit only | — | $699 | $799 | $899 |
| Price — complete kit | $599 | $899 | $999 | $999 |
Where BigBoi's own numbers disagree with each other
* DUO tuned flow. BigBoi publishes 8.2 L/min on the DUO's own product page and 7.7 L/min in the comparison widget elsewhere on their site. We have quoted the product-page figure. If that gap matters to your decision, check the DUO user manual — that is the number we would trust.
† QUAD noise. The spec table says 86 dB; the body copy on the same page says "running under 80 dB." We have quoted the spec table. Either way, it is a quiet machine for what it is.
And one more. BigBoi's spec sheet prints the PRO MKII's flow as 9.5 L/s. That would be 570 litres a minute — roughly a fire hose. Their own meta description and body copy say 9.5 LPM, which is consistent with the rest of the range. It is a typo, not a spec. We mention it only because if you are comparing machines on paper you will hit it, and it will confuse you.
Why PSI is the wrong number to shop on
Here is the thing that surprises people: BigBoi deliberately tunes every one of these machines down from its peak pressure. The PRO MKII can hit 1,850 psi but arrives set to 1,450. The QUAD can hit 1,500 but arrives at 1,050.
That is not a limitation. That is the entire design philosophy, and it is correct.
A pressure washer cleans by delivering energy to a surface. You can deliver that energy two ways: concentrate a small volume of water very hard, or move a large volume of water at moderate force. On a driveway, the first works fine. On paint, the first is how you drive grit into a clearcoat instead of carrying it off.
What you actually want on a car is volume — enough water, moving fast enough, to lift and float contamination away from the panel and off the car. That is flow, measured in litres per minute. It is why a 9.2 L/min machine at 1,450 psi will out-clean a 7.45 L/min machine at 1,500 psi on a filthy car, despite the near-identical pressure figure.
Flow is also what makes foam. A foam cannon works by drawing solution through a venturi and mixing it with air and water. Starve it of flow and you get thin, watery foam that runs off the panel in twenty seconds. Feed it properly and you get the thick, clinging foam that actually gives your pre-wash chemistry the dwell time it needs to work.
Pressure gets dirt moving. Flow gets it off the car. For detailing, flow wins — and it is the number most brands bury.
What none of these machines will do
No pressure washer removes bonded contamination. Iron fallout, tar, tree sap and industrial fallout are chemically stuck to your paint, and no amount of psi will shift them without also risking the clearcoat. That is a job for chemical decontamination and clay, not water. A pressure washer's job is the safe removal of loose contamination before anything touches the paint — and that is precisely the job all four of these are tuned for.
Pumps: the part that decides how long it lasts
The pump is the most expensive component in a pressure washer and the one that determines its duty cycle — how long it can run, how often, before it complains.
Wobble-plate — WASHR DUO
A swash plate driven by the motor pushes pistons back and forth. Simple, compact, cheap to build and perfectly capable — but it runs the pistons at an angle, so there is more side-loading and more heat. It is a semi-commercial design: excellent for a fixed setup washing cars regularly, less happy running flat out all day. The DUO's brass head is a meaningful upgrade over the plastic heads you will find at this price point elsewhere.
Triplex — WASHR TRADIE and WASHR PRO MKII
Three pistons driven straight off a crankshaft, in line with the direction of travel. Less side-loading, less heat, longer service life and — crucially — serviceable. This is the pump architecture you find in genuine commercial equipment. The PRO MKII's is an Italian-designed forged-brass commercial-duty unit; the TRADIE runs a commercial triplex head in a lighter, more portable body.
QUAD 4-plunger — WASHR QUAD
Four plungers rather than the usual three. More plungers means more overlapping delivery strokes, which means less pulsation — smoother flow through the trigger and, in practice, better foam and a more consistent rinse. It is the reason the QUAD punches above what a $599 machine has any right to.
The noise thing is real, and it runs backwards
- PRO MKII80 dB
- TRADIE84 dB
- QUAD86 dB
- DUO87 dB
Read that again, because it is upside down. The most powerful machine in the range is the quietest. The least powerful of the three big units is the loudest.
Decibels are logarithmic. 87 dB is not "a bit louder" than 80 dB — it is roughly five times the acoustic intensity. That is a brushless induction motor with an in-line triplex pump versus a wobble-plate design, and it is the single most underrated difference between these machines. If your washer lives in a garage attached to a house — or you have neighbours, or you wash at 7am on a Sunday — this is not a footnote.
The two decisions people get wrong
1. TRADIE vs DUO
The TRADIE ($799) has more max pressure and more flow than the DUO ($699). But the DUO has higher tuned pressure — 1,350 psi against 1,300. So which one is "more powerful" depends entirely on which number you look at, and the honest answer is: they are close, and that is not the decision.
The real decision is where the machine lives. The TRADIE is 18 kg with a commercial triplex pump — built to be lifted in and out of a van. The DUO is 24 kg with a wobble-plate pump — built to be bolted to a wall and left there. Buy for the job, not the spec sheet.
2. Buying the unit when you should buy the kit
The PRO MKII is $899 as a bare unit and $999 as a complete kit — hose, professional short trigger gun, quick-release nozzles and fittings. A hundred dollars for everything you need to actually use it.
And note where that lands: the PRO MKII kit is $999. The TRADIE kit is also $999. Same money. If you are not carrying the machine anywhere, the PRO MKII is more pressure, more flow, a better pump and 4 dB quieter — for the identical price.
The WASHR PRO MKII kit at $999
It is the best machine BigBoi makes, it is the quietest thing in the range, and at kit price it costs the same as the TRADIE. The only reason not to buy it is if you need to carry your pressure washer to the car, instead of the car to your pressure washer.
View the PRO MKII kit →What you will want alongside it
A foam cannon that actually foams. Every WASHR ships with a FoamR PRO in the box — but if you are running two chemicals, or want one permanently set up, the FOAMR PRO+ twin-bottle system is the upgrade.
Snow foam worth putting through it. A great machine and a bad pre-wash chemical is a waste of a great machine. See our wash and pre-wash range.
The rest of the BigBoi ecosystem. BLOWR touchless dryers, SUCKR vacuums and D-IONIZR spot-free rinse systems — all designed to work together.
Questions we get asked
Which BigBoi WASHR is best for a home garage?
The WASHR QUAD at $599. It is a complete kit — foam cannon, hose, trigger gun and nozzles included — and at 8 kg it is the only unit in the range light enough to move around easily. Its 4-plunger QUAD pump delivers 1,050 psi tuned pressure and 7.45 L/min tuned flow, which is more than enough for safe, effective car washing. If your washer will live permanently on a wall and you wash frequently, step up to the DUO or the PRO MKII.
Is more PSI better for washing a car?
No. Beyond a point, more pressure increases the risk of driving grit into your clearcoat rather than carrying it away — which is why BigBoi deliberately tunes every WASHR down from its peak pressure. For car detailing, flow rate (litres per minute) matters more than pressure: volume of water is what lifts and floats contamination off the panel, and flow is also what generates thick, clinging foam through a foam cannon. Pressure gets dirt moving; flow gets it off the car.
What is the difference between the WASHR TRADIE and the WASHR DUO?
The TRADIE ($799) has higher max pressure (1,600 psi against 1,400) and higher flow (9.2 L/min against 8.5), and runs a commercial triplex pump head. The DUO ($699) has slightly higher tuned pressure (1,350 psi against 1,300) and runs a German-designed wobble-plate pump with a brass head. In practice they are close on performance, and the real difference is portability: the TRADIE is 18 kg and built for mobile detailers working out of a van; the DUO is 24 kg and built for a fixed, wall-mounted setup.
Is the WASHR PRO MKII worth the extra money over the TRADIE?
As complete kits they cost the same — both are $999. At that price the PRO MKII gives you more pressure (1,450 psi tuned against 1,300), more flow (9.2 L/min tuned against 8.8), an Italian-designed forged-brass commercial triplex pump, and 4 dB less noise at 80 dB. The only reason to choose the TRADIE is portability: it is 18 kg against the PRO MKII's 27 kg.
Why is the WASHR PRO MKII quieter than the cheaper models?
Because of the motor and pump architecture. The PRO MKII runs a 2,000 W brushless induction motor with an in-line triplex pump, which produces less vibration and heat than the wobble-plate design in the DUO. At 80 dB against the DUO's 87 dB, the PRO MKII is running at roughly one-fifth the acoustic intensity — decibels are logarithmic, so that 7 dB gap is far bigger than it sounds. If your pressure washer lives in a garage attached to a house, this matters more than most people expect.
Will a BigBoi WASHR remove tar, iron fallout or tree sap?
No — and neither will any other pressure washer. Those are bonded contaminants, chemically stuck to your paint, and no amount of pressure will remove them without risking the clearcoat. They require chemical decontamination (a dedicated iron remover and tar solvent) followed by clay. A pressure washer's job is the safe removal of loose contamination before anything touches the paint.
Do BigBoi WASHR pressure washers need special power?
No. All four models run on standard Australian domestic power — 220–240 V, 50 Hz, 10 A. You do not need a dedicated circuit or a 15 A outlet.
All specifications above are taken from BigBoi's published product data and were verified on 14 July 2026. Prices are current at time of writing and are in AUD. Where BigBoi's own published figures conflict, we have flagged it rather than guessed — if a specific number is decisive for your purchase, check the relevant user manual, or call us on 0400 976 972 and we will talk it through.