Most Powerful Shop Vac – 7 Ways To Improve

Most Powerful Shop Vac – 7 ways to improve your shop vac are described that will give it turbo charged performance and make it the most powerful wet dry vac in your garage.

Improving the flow rate and even suction performance of your shop vacuum,  will give you not only a powerful shop vac, but also a most powerful wet dry vac. Some of these methods are obvious yet some are rarely considered.

by Titus Nelson, PE

Inventor of the Holey-Moley Digger

Holey-Moley Vacuum Assisted Post Hole Digger
Titus Nelson inventor of the
Holey-Moley Digger and
Mgr of Cat 6 Tools








A number of the items below were implemented and dramatically improved the Ridgid Vac shown below, making it one of the most powerful wet dray vac cleaners available.  And this was done at little expense.  At the bottom of this article we have links to a bonus video that provides good information on how the wrong extension cord with significantly degrade a shop vacuum performance.  Learn how the gage of an extension cord makes a huge impact on performance because of loss of amperage at the shop vacuum.

So let’s get into what you can do to get a powerful shop vac:


This Ridgid Vacuum WD19560 pulls 45 inches of water and has a flow rate of 203 CFM and is the base line vacuum used in our testing.

The 7 items to improve your shop vacuum performance

1 – Upgrade your hose to one with low losses for a most powerful shop vac

Commercial Grade Low Loss Vacuum Hose with smooth borer 2-1/2′ OD, 2″ ID. Direct replacement for standard 2-1/2″ shop vacuum hose.


Flow losses in hoses can be dramatic depending on the bore smoothness and the length of hose.

A rule of thumb on standard vacuum hose – If you double the length of hose, you will double the flow rate losses. We found in testing gravel pickup, that we doubled the gravel pickup in pounds/sec by cutting the length of standard shop vacuum hose in half. 

Therefore if you want to decrease losses, a better hose with smooth bore is the way to go.  We found in our testing that smooth bore vacuum hose increased the flow rate over standard shop vacuum hose by 20%.

When it comes to hoses there are two things you can do:

  1. Keep your hose as short as possible.
  2. Purchase a smooth bore low loss vacuum hose.

Here is a link to our low loss vacuum hose.  It comes in lengths of 4ft, 8ft, and 10ft.  We found that 8ft is a pretty standard length that works well.

2 – Open the air outlet to get a powerful shop vac airflow rate

One of the easiest things you can do with a shop vacuum that has an exhaust vent, is to remove the cover.  The noise will increase, however, the performance increase can be dramatic.  The exhaust port is something to pay attention to especially if you want to put two shop vacuums in series as mentioned below in item 6.

Closed air vent on shop vacuum restricts the airflow performance


Open air vent improve shop vacuum performance


3 – Upgrade your filter

filters-available-for-most-powerful-wet dry-vac-performance
Filter Bucket Accommodates Ridgid and CleanStream filters.


Upgrading to the highest flow rate filter possible can significantly increase flow through a shop vacuum.   If you are not working in a dusty environment, there is no reason to use a HEPA filter when the foam wet/dry filter will work just fine.

We have found CleanStream filters to have excellent all around performance for Ridgid Vacuums. They are slightly larger and have better all around performance.  Get two.  Keep a clean one handy for swapping out. They are washable and can be dried using the warm exhaust port air of your vacuum.   Attach a hose and set it inside the filter while you are using the vacuum.


4 – Keep the filter clean to keep most powerful wet dry vac performance

Dirty filter vs clean filter.  Washable filters allow for cleaning and reusing.  Have a spare.


If you want a powerful shop vac, dirty filters can clog up and reduce the performance, so use clean filters.   We have found that when digging holes in dirt, the filters don’t get as clogged up as much as when picking up fine sawdust.   The dirt is much heavier and settles into the bottom of the drum fairly fast. In general, if your performance drops off, check the filter.  It may just need banging it on the side of the vacuum drum to knock off enough to dramatically improve the performance.


5 – Keep the inlet deflector clean to improve powerful shop vac performance

Dirty shop vacuum inlet deflectors will reduce the vacuum’s performance


The most common place for obstructions to occur in a shop vacuum is at the inlet deflector.  When working with damp dirt, this is the location for buildup and should be checked.  With clay soils, a hard clay buildup will occur and will need to be loosened with a screwdriver.

6 – Use two shop vacuums in series for the most powerful shop vac.


Putting two shop vacuums in series dramatically increases suction performance


A rarely seen method to improve the suction lift of a shop vacuum is to put two vacuums in series.   Take the exhaust from your primary vacuum and put it into the inlet of your secondary vacuum.  This will combine the lift or inches of water by about 80% of the sum of the two.   If you are wanting to lift water out of a hole or out of a basement, this inexpensive method is impressive.  Try to keep the horsepower of the vacuums and the side of the hose about the same.

7 – Use a pre-filter bucket for wet conditions so that you have the most powerful wet dry vac with low losses at the filter.

Adding a cyclonic separator in front of your shop vacuum will make it the most powerful wet dry vac for the size and money.

Cat 6 Tools Cyclonic Vacuum Bucket attached to a Radgid WD19560 Shop Vacuum with Low Loss Hose.


Cat 6 Tools Tangential Inlet Vacuum Filter Bucket with low loss hose attached to a Ridgid WD19560 vacuum


We mention filter buckets as this is our new line of equipment at Cat 6 Tools. We have two types:

One is a Cyclonic Separator 7 Gallon Plastic Bucket.  The deflector inlet and outlet are in opposite directions and bad stuff like clay and water drop out and only a small amount of moisture carries over leaving the shop vacuum extremely clean with very little performance degradation.

Our second is a Tangential Filter Separator 7 Gal Plastic Bucket for wet/dry applications.   This bucket has a very efficient tangential inlet as well as a standard Ridgid Filter holder.   The float assembly automatically shuts off flow when the bucket is full.  You can use a foam filter in the shop vacuum and a foam filter in the filter bucket.  This maximizes airflow rate.

Bonus Video – Don’t Starve Your Vac For Amps!!



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