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Riffraff Diesel Performance Inc, Engines - Supplies, Equipment & Parts, Eagle Point, OR


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Donaldson Blue® 6637 Filter

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Part Number:

Donaldson Blue® 6637 Intake Filter for Ford 7.3L 94-03

Donaldson Blue® air filters with Ultra-Web® nanofiber technology protect engines by providing better initial and overall efficiency compared to conventional cellulose media. Donaldson invented air filters for heavy-duty diesel engines over 100 years ago and were the first to develop nanofiber air filter media for the diesel engines, with more than 20 years of proven performance. 

  • Longer Engine Life - Donaldson Blue™ air filters provided better engine protection by allowing much less contaminant to pass through than cellulose air filters but still maintaing a higher flow rate
  • Longer Filter Life - Smaller interfiber spaces of Ultra-Web® nanofiber technology hold more submicron contaminant than conventional filters with cellulose media, delivering longer filter life
  • Increased Flow - Utilizing the nanofiber Ultra-Web® media has allowed for a 37% increase in flow over the standard 6637 cellulose filter. It has also been tested to flow over 1300 CFM+.
Media Type
  • Ultra-Web® Nanofiber Technology -- Exclusively in Donaldson Blue air filters
    • Engineered to perform in extreme temperature and humidity conditions, unlike ordinary nanofibers and cellulose which aren't hydrophobic
    • Proven in the real world – used in diesel engines for nearly two decades
    • On-road applications are guaranteed to go twice the distance compared to standard cellulose filters

We suggest buying them in quantities of 2 as your shipping won't increase much and you will save money.

100% Made In The USA


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Product Reviews

Showing reviews 1-10 of 36 | Next

  1. 6637 5 Star Review

    Posted by on Feb 7th 2018

    Replaced my original 6637 with the new Donald blue lowed the egt more flow and better throttle response

  2. Amazing Flow! 5 Star Review

    Posted by on Dec 25th 2017

    Swapped my wix 6637 filter out for Riffraff’s Donaldson blue 6637 and what a difference! 250cc/100% injectors, T4 turbo and I ran 587hp and 1176ft tq. Thank you guys for this awesome well priced filter option.

  3. Makes my truck breathe better no more 5 Star Review

    Posted by on Nov 27th 2017

    I love the product had a K&N. recommend it to all my buddies. nothing like big blue

  4. Perfect 5 Star Review

    Posted by on Nov 1st 2017

    This filter has allowed my truck to breathe so much better than the stock 6637. Since the filter isn’t restrictive any more the engine has better throttle response and it has lowered EGTs Between this filter and the new up pipe gaskets I can honestly say EGTs have dropped 2-300deg and mpg is up to almost 16 from under 13

  5. Quality Counts 5 Star Review

    Posted by on Oct 27th 2017

    I live in a remote town in the North West of Western Australia and my truck spends 70% of its life on unsealed roads. This requires good quality intake filters and Donaldson deliver this.
    I would highly recommend this to any one considering the change.

  6. Fast shipping accurate description 5 Star Review

    Posted by on Oct 24th 2017

    Great product very fast shipping and communicatiin

  7. 6637 Blue Filter 5 Star Review

    Posted by on Oct 23rd 2017

    Put this in place of my factory air box and noticed a little difference mainly in hill pulling power with a trailer. Without a load, not a whole lot of difference which was expected. Fit nicely in factory intake box location. Fast shipping, great company!

  8. 6637 Blue 5 Star Review

    Posted by on Oct 5th 2017

    After reading other reviews i decided to replace my K&N filter with the 6637 Blue setup.

  9. 6637 blue filter 5 Star Review

    Posted by on Oct 4th 2017

    Bought to replace my airaid dry filter on my 02 7.3. The size difference is unbelievable, at least twice as big. Will definitely buy more for my other 7.3s

  10. Blue over White 5 Star Review

    Posted by on Oct 2nd 2017

    I purchased this filter after running the white 6637 for a year. I notice that they turbo is slightly louder in cab and seems to flow/ spool a little better. Worth the price.

    1997 F250, 7.3 turbo diesel

Showing reviews 1-10 of 36 | Next

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