K&N vs. Unipods

[pjv]

David - (awesome write up btw). I have a related question. My 89 fj12 (just purchased) has K&N's, (and a horrible loud pipe). The first thing i did to the bike was have the carbs cleaned/balanced and they needed re jetting. This cost lots of cash, but it runs great. My issue is now that there are four individual K&N filters in place, that barely fit inside the frame and can actually be wiggled off quite easily.
I want to replace them with the uni pod dual (two per bike) filters http://www.rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod&cat=39
Primarily because i think they'll just fit better.
Do you think this will effect the mixture? I would assume the air flow through the two types would be very similar?
I'm trying to avoid a trip to the shop to have them tweaked, this is not something i'm comfortable with messing with myself right now.
Regards,
Pat.

[andyb]

Fun way to consider this, is that the volume of air never changes in the chamber.  The density does.  If that doesn't give you an immediate headache...

[Pat Conlon]

Pat,  I moved your question out of the Files section. My answer is, no you don't need to change anything.
If your bike was re-jetted for the K&N individual filters, you can install the Unipods with no worries.
Be sure to use foam filter oil with your new Unipods. K&N filter oil is designed for paper filters, and is too light bodied for foam.

Cheers!

[fj11.5]

having used both types k&n and now uni pods, I noticed no difference in performance, but uni,s fit so much better, look better , and don't fall off in use,

[pjv]

You guys are awesome, thank you so much.

Pat C - sorry for the misplacement, Ill get the hang of this. Thanks for the info, i'll go for the uni's.

Andyb - Boyles Law I presume?

Cheers lads, beers on me.

Pat.

[andyb]

A motor of a given size always flows the same volume of air per cycle.  Air will compress and expand to fill whatever displacement.  It can dramatically change density.

I agree with the filters too.  Ran K&N's vs UNI's back to back at the dragstrip, zero measureable difference.  And the UNI's don't fall off, and actually fit properly.  The K&N's will fit slightly better if you crush the outside pair a little and use wider hoseclamps, but are a hassle at the best of times.

[carey]

Whenever I install Uni or K&N pods, I wipe the exterior carb throats and inside the filter mouth with a paer towel soaked in carb cleaner to remove any oil.  They don't slip off .

[andyb]

Whenever I install Uni or K&N pods, I wipe the exterior carb throats and inside the filter mouth with a paer towel soaked in carb cleaner to remove any oil.  They don't slip off .

The problem with the K&N filters sold as fitting FJ's is that they do not fit, and hit the framerails really hard.  The outside pair needs to be flipped upside down and slightly to an angle, and they will slip off more frequently than most.  The final answer was safety wiring them, and then throwing them out for a set of UNI's.  I tried pretty much everything on the workbench to try and get them to stay mounted, including hairspray on the carb mouth.

A little wipe with a rag isn't gonna manage it, doubly so if they're older filters, as their rubber gets harder over the years and won't stretch to fit properly, compounding the problem.