TR4/4A Difference between two Oval Air Filters

[morris ocho]

I'm about to replace my oval air filters.

I see that Moss has these: > AIR FILTER, Aftermarket < (I bought these before and no problems)

But I see these ones that are similar to the Moss but have an added paper tape with small holes,, wouldn't that let in less air?

> Air Filter Oval TR4-TR4A <

Here you can see the filter with the small holes closer: > Air Filter, Oval - Triumph TR4-TR4a 62-67 - British Classic Spare Parts <

Can anybody inform me if the difference is better or not?

 

[JHaydon]

My non-scientific gut feeling is that the perforated outer paper doesn't restrict airflow enough to make a difference on a street car, but I also don't see much point to it -- it might keep a huge bug from getting stuck between the pleats maybe? But it won't improve filtering ability.

K&N published a math formula that was useful for calculating what size filter would give sufficient airflow for given engine size and RPM. Based on that formula I calculated that the single round 3" x 6" OD filter on my 4.5L 6-cylinder was about 3 times the size it needed to be. That's the reason I wouldn't be too concerned about the outer paper on those.

I wonder if that paper is a protective layer that's meant to be removed before use?

 

[mctriumph]

Protects the pleats from accidental damage as they are pretty fragile . Just be happy you dont have
to knit your own. The tr4 a filter had a metal wrap with similar holes.
Mad dog

 

[morris ocho]

I have the same feeling of JHaydon,, I don't think it will improve the air flow and filtering.