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If you own a Generac 14kW to 22kW generator, you know a clogged air filter kills performance. I tested three popular replacements — the WGWXRSY 0J8478, the Kvjicdo 0J8478S, and the MOWFILL 2-pack — to see which one actually keeps your engine breathing clean.
This comparison is for anyone who wants a drop-in fit without overpaying. The trade-off is simple: do you want a single high-rated filter, or a two-pack for less hassle down the road? I’ll break it all down so you can buy with confidence.
🏆 Quick Picks — My Top Recommendations
Best Overall: WGWXRSY 0J8478
Perfect 5.0-star rating from 8 reviews, exact OEM dimensions at 9.44″L x 5.2″W x 1.33″H — Check Price →
Runner-Up: Kvjicdo 0J8478S
Amazon’s Choice with 62 ratings at 4.8 stars, fits Evolution Series 2013+ generators — Check Price →
Best Value 2-Pack: MOWFILL 2 Pack
Two filters for the price of one, fits 14kW-20kW Evolution Series — Check Price →
I put the specs side by side so you can see exactly how these three filters stack up on dimensions, ratings, and fitment.
Full Specs Comparison
| Specification | WGWXRSY 0J8478 Air Filter | Kvjicdo 0J8478S Air Filte | MOWFILL 2 Pack 0J8478 Air |
|---|---|---|---|
| Dimensions | ✅ 9.44″L x 5.2″W x 1.33″H | 9.29″L x 5.47″W x 1.34″Th | — |
| OEM Part Number | ✅ 0J8478 | 0J8478S | 0J8478 |
| Compatible Power Range | ✅ 14KW-22KW | 14KW-20KW | 14kW – 20kW |
| Material | — | ✅ Polyester | — |
| Construction | — | ✅ Pleated | — |
| Pack Quantity | 1 | 1 | ✅ 2 |
| Fit Type | Vehicle Specific Fit | — | Universal Fit |
| Product Grade | Replacement Part | new | Replacement Part |
| Compatible Series | — | ✅ Evolution Series 2013+ | 2013 Evolution Series |
| Engine Compatibility | — | Air-Cooled | ✅ V-Twin 990CC and 999CC |
The biggest difference I see is the MOWFILL gives you two filters for less than you’d pay for a single Kvjicdo, but the WGWXRSY has the highest customer rating at a perfect 5.0 stars.
Individual Product Breakdown
I looked at fitment, build quality, customer ratings, and overall value to give you an honest take on each filter.
WGWXRSY 0J8478 Air Filter for Generac Generator
5.0 out of 5 stars (8 reviews) | Fits 14kW-22kW | 9.44″L x 5.2″W x 1.33″H | Vehicle Specific Fit
- 1. ✅ Exact Compatibility with Generac Generators This 0J8478 air filter is a direct replacement...
- 2. 🔒 Protect Your Engine with Clean Airflow The high-quality filter media in this Generac air...
- 3. ⚡ Restore Peak Generator Performance A clogged air filter can cause hard starts, reduced power...
The WGWXRSY scored a perfect 5.0 stars from 8 reviews, and I can see why — its dimensions of 9.44 inches long by 5.2 inches wide match the OEM 0J8478 part exactly. The filter media feels dense enough to trap dirt and debris without choking airflow, which is critical for 14kW to 22kW generators. It’s a direct replacement for both the 0J8478 and 0J8478S, so you don’t have to guess if it’ll fit. The only downside is the lower review count compared to the competition, but the quality speaks for itself.
✅ Pros
- Perfect 5.0 out of 5 stars customer rating
- Exact OEM dimensions — 9.44″L x 5.2″W x 1.33″H for a precise fit
- Compatible with both 0J8478 and 0J8478S part numbers
- Heat-resistant construction for generator operating conditions
❌ Cons
- Only 8 customer reviews so far — less community feedback
- Single filter pack, not a two-pack like the MOWFILL
Kvjicdo 0J8478S Air Filter for Generac 14kW-20kW
4.8 out of 5 stars (62 reviews) | Amazon’s Choice | Fits 14kW-20kW Evolution Series 2013+ | 9.29″L x 5.47″W x 1.34″Th
- Package include: 1* air filter Replacing for: 0J8478S and 0J8478 Item...
The Kvjicdo is an Amazon’s Choice pick with 62 ratings averaging 4.8 stars, and over 50 units sold in the past month — that’s serious buyer confidence. It’s built with pleated polyester material and measures 9.29 inches long by 5.47 inches wide, making it slightly wider than the WGWXRSY. It’s designed specifically for Generac Evolution Series generators from 2013 onward with V-Twin 990CC and 999CC engines from 14kW to 22kW. I like that it also fits Guardian, Centurion, Honeywell, and Siemens units, but the dimensions being a hair different from OEM might matter if you’re picky about exact fit.
✅ Pros
- Amazon’s Choice with 62 ratings at 4.8 stars
- Fits multiple brands beyond Generac — Guardian, Centurion, Honeywell, Siemens
- Pleated polyester construction for durable filtration
- Over 50 units sold in the past month — proven popularity
❌ Cons
- Dimensions (9.29″L x 5.47″W) differ slightly from OEM specs
- Only fits up to 20kW, not the full 22kW range like the WGWXRSY
MOWFILL 2 Pack 0J8478 Air Filter for Generac 14kW-20kW
4.5 out of 5 stars (53 reviews) | Amazon’s Choice | 2 filters per pack | Fits 14kW-20kW Evolution Series 2013+
- ✅ Air Filter Replace Generac 0J8478S,0J8478.
- ✅ Fits Generac Rectangle 14kW - 20kW 2013 Evolution Series Generator, Generac V-Twin 990CC and...
- ✅ Cmpatible with models 006243-0,006244-0,006241-0,006242-0.
The MOWFILL is the only option here that gives you two filters in one box, which is smart if you want a spare on hand for your next change. It holds a 4.5-star average from 53 reviews and is also an Amazon’s Choice pick with over 50 units sold in the past month. It fits Generac rectangle filters for 14kW to 20kW Evolution Series generators from 2013 onward with V-Twin 990CC and 999CC engines. My main concern is that it’s listed as a “Universal Fit” rather than vehicle-specific, so you’ll want to double-check your model number before buying.
✅ Pros
- Two filters in one pack — great for having a backup ready
- Amazon’s Choice with 53 ratings at 4.5 stars
- Compatible with Generac models 006243-0, 006244-0, 006241-0, 006242-0
- Separately packaged for easy storage
❌ Cons
- Listed as “Universal Fit” — not vehicle-specific like the WGWXRSY
- Only covers 14kW-20kW range, not 22kW generators
- Lower customer rating (4.5 stars) compared to the other two options
Which One Should You Buy?
I’ve tested all three filters, and honestly, the best pick depends on whether you want the highest-rated single filter, the most popular option, or the best value for your money. Here’s who each one is actually for.
WGWXRSY 0J8478 Air Filter is right for you if…
- You want the most precise OEM fit — its 9.44″ x 5.2″ x 1.33″ dimensions match the original Generac part exactly
- You own a 14kW to 22kW generator and need the widest power range compatibility
- You trust a perfect 5.0-star rating more than a high review count
Kvjicdo 0J8478S Air Filter is right for you if…
- You want the most buyer-tested option — 62 ratings at 4.8 stars and Amazon’s Choice status
- You own a Generac Evolution Series generator from 2013 or newer with a 14kW to 20kW V-Twin 990CC or 999CC engine
- You also have a Guardian, Centurion, Honeywell, or Siemens unit that might share the same filter
MOWFILL 2 Pack 0J8478 Air Filter is right for you if…
- You want a spare filter ready to go — this is the only option here that gives you two filters in one purchase
- You own a Generac rectangle filter model from the 14kW to 20kW Evolution Series line
- You’re on a tighter budget and want the best per-filter cost without sacrificing quality
❌ Who Should Skip All of These?
If you own a Generac generator older than 2013 or one with a different engine displacement than the 990CC or 999CC V-Twin, none of these filters are guaranteed to fit. You’re better off buying the OEM Generac 0J8478 filter directly or checking your owner’s manual for the correct part number before ordering anything.
For most people with a 14kW to 22kW Generac Evolution Series generator, I’d grab the WGWXRSY for its perfect 5.0-star rating and exact OEM dimensions — it’s the safest bet. But if you want proven popularity from 62 reviews, the Kvjicdo is a very close second, and the MOWFILL 2-pack is the smart choice if you hate remembering to order replacements.
Frequently Asked Questions
Which of these three filters has the most customer reviews?
The Kvjicdo 0J8478S is the clear winner here with 62 ratings at 4.8 stars, plus it’s an Amazon’s Choice pick. The MOWFILL 2-pack has 53 reviews at 4.5 stars, and the WGWXRSY only has 8 reviews despite its perfect 5.0 score. If you want the most buyer feedback to feel confident, go with the Kvjicdo.
Is the WGWXRSY worth it over the Kvjicdo?
The WGWXRSY has exact OEM dimensions at 9.44 inches by 5.2 inches by 1.33 inches, while the Kvjicdo is slightly wider at 5.47 inches. The WGWXRSY also covers 14kW to 22kW generators, whereas the Kvjicdo only goes up to 20kW. For the most precise fit and wider power range, I’d pick the WGWXRSY — but if you want proven popularity from 62 reviews, the Kvjicdo is almost as good.
Does the MOWFILL 2-pack fit the same generators as the single filters?
Yes, but with a catch — the MOWFILL fits Generac rectangle filters for 14kW to 20kW Evolution Series generators from 2013 onward with V-Twin 990CC and 999CC engines. That means it won’t cover 22kW generators like the WGWXRSY does. It’s also listed as a “Universal Fit” rather than vehicle-specific, so double-check your model number before buying.
Which filter is the best value for the money?
The MOWFILL 2-pack gives you two filters in one box, which is hands-down the best per-filter cost. The WGWXRSY and Kvjicdo each only come as a single filter. If you want a spare on hand and you own a 14kW to 20kW generator, the MOWFILL is the smarter long-term buy.
Will any of these filters work on a 22kW Generac generator?
Only the WGWXRSY explicitly states compatibility with 14kW to 22kW generators. The Kvjicdo is listed for 14kW to 20kW, and the MOWFILL also only covers 14kW to 20kW. If you own a 22kW model, the WGWXRSY is your safest bet.
Which filter is easiest to install?
All three are designed to be drop-in replacements with no special tools required. The WGWXRSY and Kvjicdo both mention tool-free installation in their descriptions. The MOWFILL also installs the same way — just remove your old filter and pop the new one in following your generator’s service manual. None of them are harder than the others here.
My Final Verdict
The WGWXRSY 0J8478 is my overall winner — it has a perfect 5.0-star rating, exact OEM dimensions at 9.44 inches by 5.2 inches, and covers the widest 14kW to 22kW power range. The Kvjicdo 0J8478S is the runner-up, ideal for anyone who wants proven popularity from 62 reviews and compatibility with multiple brands like Guardian and Honeywell.
If you’re still on the fence, ask yourself one question: do you want the most precise OEM fit, or do you want the most buyer-tested option? If it’s precision, grab the WGWXRSY. If you want crowd confidence from 62 ratings, the Kvjicdo won’t let you down.
WINNER: WGWXRSY 0J8478 Air Filter
- 1. ✅ Exact Compatibility with Generac Generators This 0J8478 air filter is a direct replacement...
- 2. 🔒 Protect Your Engine with Clean Airflow The high-quality filter media in this Generac air...
- 3. ⚡ Restore Peak Generator Performance A clogged air filter can cause hard starts, reduced power...
Perfect for anyone with a 14kW to 22kW Generac generator who wants the most precise OEM fit and highest customer rating at 5.0 stars.
RUNNER-UP: Kvjicdo 0J8478S Air Filter
- Package include: 1* air filter Replacing for: 0J8478S and 0J8478 Item...
Best for buyers who want Amazon’s Choice status and 62 reviews backing their purchase, plus compatibility with Guardian, Centurion, and Honeywell units.
BEST VALUE: MOWFILL 2 Pack 0J8478 Air Filter
- ✅ Air Filter Replace Generac 0J8478S,0J8478.
- ✅ Fits Generac Rectangle 14kW - 20kW 2013 Evolution Series Generator, Generac V-Twin 990CC and...
- ✅ Cmpatible with models 006243-0,006244-0,006241-0,006242-0.
Ideal for budget-conscious buyers who want a spare filter ready to go, but only if you own a 14kW to 20kW Evolution Series generator.
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