Air cleaner mod

[BlackDog]

I was replying to a post in the classifieds but thought better to post it here as a 'tech tip'

I'd like to be running the taller K&N filter ( can't remember the # ) that fits the stock housing

I did some work on various thickness of the K&N Filter that will fit the "factory" air filter housing; the first I have listed below (1.5in depth) is equivalent to the standard setup. The others are available from a UK Tiger parts specialist who is a recognized agent. Clearly, clearance issues will be a consideration depending on what carb/inlet manifold you are running.

Fron K&N technical desk, I also got the CFM flow ratings and have listed these also, as it will be a consideration for some of the "big carb" brigade

E-2859: approx. (1.5in), 381CFM @ 1.5” of water

E-3710: approx. (2.0in), 508CFM @ 1.5” of water

E-3717: approx. (2.5in), 638CFM @ 1.5” of water

E-3720: approx. (2.75in),699CFM @ 1.5” of water

E-3723: approx. (3in), 763CFM @ 1.5” of water

I recently ordered a new custom built Quick Fuel carb and the fellow asked me about my air filter size. He told me that the stock filter setup just wouldn't flow enough for my particular engine so I set about trying to remedy that.

I ordered an E-3710 and was surprised that it isn't actually the same diameter as the stock one... It's curious that K&N list all 5 with the same dimensions ( except height ). I'd say the E-3710 is at least 5/8" smaller in circumference... doesn't sound like much but if you fit it nicely on one end, the other has at least 1/4" gap all around the curve ...

I don't have room to just throw in the new element as I only have 3/8" clearance ( RPM 'Air Gap' manifold, no carb spacer) to the underside of the hood ( bonnet) but by virtue of using the dual fuel bowl 'Holley style' carb there is room to lower the bottom plate of the air cleaner. It would be easiest to just cut the riser off the bottom plate but with the value of original parts, that wasn't an option !!
I made a new bottom plate that was dead flat off of the flange without too much difficulty and managed to get it fit between the fuel bowl level adjusters...

The GOOD news is I now have a 2" high element and the top of the air cleaner assembly sits just a tic over 1/8" above where it used to be !!

I believe that the CFM gains are at LEAST what was quoted above... if you measure the actual filter part height... on the stock filter, there is about 15/16" of element showing and on the 2" unit there is about 1 7/16" which is a full 50% increase in area !!

Jim
B382000446

[gtsmrt]

Thanks for the reply Jim. At one stage I was going to purchase that same element and going by K&N's specs they were supposed to be identical other than height(as you stated). It's a shame that no one makes a drop base oval air filter assembly, but I think I know why they haven't.

Regards, Robin.

[Tomaselli]

I ordered an E-3710 and was surprised that it isn't actually the same diameter as the stock one...

Send it back Jim, coincidentally I'm trying the same size at present and it's a perfect fit in the factory air filter surround. I also have the E-3717 which I have been trying out and that also is great fit. I know that K&N are a UK company, maybe they have a different manufacturing process/method in the USA which is leading to a quality issue - any other owners having probs

[gtsmrt]

I thought they were all manufactured in the same place? Obviously something went wrong, but it shouldn't matter even if they are manufactured in a number of different sites as they should be exactly the same.

[BlackDog]

I ordered an E-3710 and was surprised that it isn't actually the same diameter as the stock one...

Send it back Jim, coincidentally I'm trying the same size at present and it's a perfect fit in the factory air filter surround.

Thanks for that info, Tony... I will have another one brought in to see if there's a difference. I was just comparing my old 1 1/2" to the 2" and curiously, they both have the same # ... A135A8 cast into the rubber part!
I had already started thinking of alternatives... what I've done in the past on oddball setups is buy a bigger diameter filter and saw through it, cut it to the right length and silicone it back together... unfortunately, the 13.5" diameter is the largest 2" height element that K&N makes ! I suppose if I can't get the proper one, I could cut it and silicone in a small spacer to make up the difference and position it at the back where it wouldn't hardly show...
Such is the way with modifying Tigers... nothing is ever straight forward... although if it was easy, it wouldn't be as much fun now would it??

Jim
B382000446