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Thread: Best Air Filter for a Petrol Smart 450 or Roadster

  1. #1
    Join Date
    Nov 2007
    Location
    BANCHORY
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    2,980

    Best Air Filter for a Petrol Smart 450 or Roadster

    I suppose it may be a bit late since there are not that many 450 Smarts and Roadsters around these days.

    If you want a cheap high capacity good filtration air filter for your petrol 450 or Roadster, then go for the air filter specified for the diesel 450.



    Why you may wonder?

    They sure look alike but are in fact different.

    Height, bore and outer diameter are all same. Part numbers are different.

    Petrol 450 air filter part numbers:
    Smart 000 9997 V 001
    Bosch 1 457 433 739
    Mann C1036/1

    Diesel 450 air filter part numbers:
    Smart 000 4591 V 001
    BOSCH 1 457 433 044
    Mann C1041

    The real difference is in filtration area. The diesel air filter has 12.7% larger filtration area.

    How do I know?

    I just spent the last few hours counting pleats on various makes of Smart 450 paper air filters such as Mann, Smart's own, Bosch and Blue Print. Petrol 450 air filters have 71 pleats. Diesel 450 air filters have 80 pleats. More pleats means larger filtration area.

    Price: The diesel 450 paper air filter is cheap. I only paid 6 today for a Bosch air filter. Bought from the nearest to me garage in Banchory.
    Drives a Smart Cdi - 65 to 85 MPG

  2. #2
    Join Date
    Nov 2013
    Location
    Central Scotland
    Posts
    347
    When I had the 450 and the Roadster, I just picked a medium priced one off Ebay, Maybe not the best of makes, but better than the existing dirty one, Think your advice is far better though.

    As for my latest Smart, which is the 451 Cdi, I have never seen a car with such a difficult air filter to get to, as it is way behind the engine access cover hole, resulting in me not being able to change the air filter since I bought it. This I am not happy about as like to do car maintenance myself.

    is there an easy way to actually replace it, as it looks hellish for access and replacement?

  3. #3
    Join Date
    Mar 2012
    Location
    Burnley
    Posts
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    The 451 CDI is much easier than the petrol and I reckon it is easier than the 450.

    Particulate size is also a consideration on air filters though I doubt that there is any difference in the two Tolsen mentioned.

  4. #4
    Join Date
    Nov 2013
    Location
    Central Scotland
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    Quote Originally Posted by Mjolinor View Post
    The 451 CDI is much easier than the petrol and I reckon it is easier than the 450.
    Any instructions anywhere?

  5. #5
    Join Date
    Mar 2012
    Location
    Burnley
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    Undo the air pipe from the filter.
    Undo the three clips, one either side and one in the middle underneath the pipe (that can be fiddly).
    Lift front of lid and slide the lid off forward. (towards the rear of the car)
    Last edited by Mjolinor; 27-04-2017 at 12:34 PM.

  6. #6
    Join Date
    Nov 2013
    Location
    Central Scotland
    Posts
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    Many thanks, only have to buy an air filter first. Then I will tackle it, with bruised knuckles no doubt

  7. #7
    Join Date
    Nov 2007
    Location
    BANCHORY
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    2,980
    Easy replacing most things on a 450. I replaced two air filters this morning, on my own 450 diesel and on a 450 petrol, both from 2002. Fitted high performance Bosch diesel 450 paper air filters on both of course.

    The petrol 450 had failed MOT on emissions in spite of only having clocked 25,000 miles in 15 years.

    Fast idle test.
    CO 0.54 %, max limit 0.30 %
    HC 240 ppm, max limit 200 ppm
    Lambda 1.048, limits 0.970 to 1.030
    Second fast idle test was similar. It passed natural idle test with CO 0.08 %, max limit 0.50 %

    I removed all six spark plugs. They all looked normal although sooted up on the land at end of threads. All electrodes clean. Lower plugs more sooted up than the upper. I cleaned the plugs using a brass wire brush and swapped upper and lower when refitting.
    Then poured in a bottle of Silver Hook 2.98 engine flush and topped up with oil to near maximum on dip stick.
    Took car for a gentle spin lasting about an hour, then changed oil. Added a bottle of Silver Hook 3.48 petrol fuel treatment to a full tank and took the car for a spirited two hour drive.

    Passed emission test this afternoon:
    Fast idle test.
    CO 0.00 %, max limit 0.30 %
    HC 17 ppm, max limit 200 ppm
    Lambda 1.03, limits 0.970 to 1.030
    Natural idle test.
    CO 0.00 %, max limit 0.50 %
    Drives a Smart Cdi - 65 to 85 MPG

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