What are people's thoughts on the best type of airfilter, Foam or Cotton (K&N type)? What are the pros and cons?
i dont run one. and never did on my escorts either never had a problem
Not sure ofthe best but the air intake on a bike engine does as much work as the exhaust as far as shape, size and restrictions. so it does need one
and it will go better with the right one.
Steve.
quote:
Originally posted by auzziejim
i dont run one. and never did on my escorts either never had a problem
K&N's catch 99.99999% of the dust/dirt and restrict airflow by 0.0000000001%.
K&N every time.
Got a pair of foam ITG's on mine. Seem to be ok at the mo 
quote:
Originally posted by auzziejim
i dont run one. and never did on my escorts either never had a problem
There's nothing wrong with my Pipercross foam filter. I just keep it clean and lightly oiled.....
K&N are consistently proven to be more effective and flow better than foam filters.
Having said that, I used ITG's on my race engines and run a Pipercross on my road car.
Max flow of the air filter is likely to be far above the max flow of the total inlet tract so will generally be sufficient with either.
Foam filters do need to be lightly oiled though to catch the finer particles.
I've used K&N's in the past on Mini's and they were great. David Vizard (engine tuning expert) would never recommend running
without a filter because you will quickly lose more power due to wear and tear than you would gain by removing the very minor restriction caused by a
good filter. In fact I think he said that you would damage the engine sufficiently during rolling road tuning without the filter and so would never
actually realise the "improvement" of having no filter.
I'm running twin ITG filter's on my RV8 in my Locost but I can't comment on the performance other than to say that they look quick!!
Something about the red-black combination looks nice. I believe they also perform well but need cleaning more often than K&N's.
Finally, running with a filter (Foam or K&N) will reduce induction noise which might be important for SVA noise testing.
ATB,
Craig.
[Edit: One other thing - Make sure you fit a stub stack ram pipe inside your filter. This is a little mini-bellmouth and can improve BHP by 5-10BHP by
smoothly introducing air into the intake.]
[Edited on 25/2/2007 by craig1410]
I use a K+N cos it's easily available and shouldn't restrict flow much. Also it's a fit and forget part.
Running without a filter seems a waste of time- £20 for a filter which will last for ever versus an engine swap cos the old engine is destroyed due to
grit- surely a no brainer?!? I saw what happened to the oil pump I bought on Ebay after (it appears) someone ran a sand pit through it.... Not pretty-
I'd prefer my carefully installed engine didn't suffer the same fate....
Interestingly, the Graham Bell book on forced induction suggests that all filters are not equal, even when you compare restriction versus power
loss.... I suspect the differences are pretty engine specific though (probably to do with the filter shape / inlet shape / inlet manifold pressure
gradient etc)...
The only good thing about having no filter is that it's not the half-way house of a course mesh filter. They restrict flow (therefore robbing
BHP) whilst only filtering things bigger than a bumble bee!!! Worst of both worlds....