Under Tank Air Filters
 

Having read and re-read posts in the past on this subject, decided today was the day to run back to back tests with and without filter to see if there was any difference.
First run gave 121 rwhp and 73 ft/lbs of torque. Removing the filter gave an increase of 5 hp at 4000 rpm, 10 hp at 6000 rpm, 20 hp at 7500 rpm and 8 hp at 8500 rpm. Max power now 130 rwhp, max torque 80 ft/lbs. Unfortunately my Power Commander has snuffed it :(:( so I can't change the fuelling, but it is running weak in the mid range so there may be another 5hp hiding there, and rich at the top end so am looking for another coulpe of horses on top. Anyone want a slightly used Ramair filter:D:D:D

Wot bike, Wot under tank filters, JHP ones?

I think from past posts, its a 996SPS:)

Yes its a 99 996 SPS, standard except for corrected valve timing. Filter was a ramair foam type, which fitted over both bellmouths and took up about half the airbox volume. Think other types of over bellmouth filters are the same. Shazaam did some posts some time back about these types of filters, which is what set me thinking.

[Edited on 14-1-2005 by ducv2]

Have you tried Pipercross OEM-style replacement filters? These are the different-density foam style filters but fit in the airtubes.

Pipercross part number MPX-038 and about £18 a pair from http://www.Demon-Tweeks.co.uk/

Should give increased flow rates through better foam design, but keep the large volume of clean air available in the airbox.

Would be interesting how these rate against under-tank filters.

This is the first under tank system filter I fitted.

After having a minor problem with the first filter I fitted these filters which were a direct replacement from JHP, also. Very satisfied with them now.

I've got the Pipercross replacements fitted in place of the undertank filter that was in there when I bought the bike. There's a noticeable improvement.

Pipercross quote only a 1BHP drop in power when compared to no filters.

I'm running the Pipercross filters too, but just wanted to be objective and get it measured on the same bike/dyno to give a decent comparison.

An interesting thread this, has anyone done dyno tests with standard cleaners then JHP under tank items to see what the increase might be or even dynoed a bike with under tank filters as well as a set of Termi`s in place!