Can anyone confirm Tii K&N airfilter myth???

[Guest Anonymous]

I know Gus P. says Tiis must run with the stock aircleaner for max performance. Does anyone Know for sure if this is true.? And if so why as cfm is cfm.....TIA

[Guest Anonymous]

URL: http://www.geocities.com/karlkarlb/BMW.html

The stock canister pulls air from cooler areas than a K&N. There are many who say that the stock canister is the best, not just Gus.

[Guest Anonymous]

The stock tii canister is a hemholtz resonator (sp?).

In brief and hopefully understandable terms, it acts as an air spring that can push more air in at certain rpm points. The tii has a flatter (and better) torque curve because of this.

[Guest Anonymous]

(nt)

[Guest Anonymous]

It's like the other end of the physics that make 2-stroke exhausts nearly the most important performance factor. Fluid dynamics, baybee...

The other way to look at it is -- if they do it to a ricer, then it must be wrong...

Tony

[Guest Anonymous]

(unless its already been done) someone will have to run a tii on a dyno with both setups. Not that I don't agree with you, but I have yet to see actual facts about the "positive flow" housing.

[Guest Anonymous]

(nt)

[Guest Anonymous]

I did it with a G-tech and saw no discernable difference. The testing may have produced a discernable difference if I 1) used the new G-tech that can log acceleration vs rpm (mine is the old style and only outputs times, max accelerations, and hp); and 2) tuned the car for each set up (my car was tuned for the straight K&N).

One big difference was that the stock filter set-up was much quieter.

[Guest Anonymous]

I'm not sure that you could measure the effect on HP even with a chassis dyno, it would be too small of a difference. Also why is the exhaust side of the motor assumed to be cooler than the intake side?

[Guest Anonymous]

The germans spent a lot of time at getting the kooko fish and everything else to work like a swiss clock. There is more to it than just meets the eyes, I would imagine having to do with nozzle design, fluid mechanics, thermodynamics, acustics, etc.

I used to have a K&N single filter, ugly, noisier and didn't add any performance. The box is a lot cooler IMHO

[Guest Anonymous]

Helmholtz resonation will increase the pressure in the plenum at specific rpms.

I don't know anything about the inlets of the tii being in a cooler part of the engine bay. I suspect as do you that it's not cooler. Intake position is probably a fn of the helmholtz intake length.

[Guest Anonymous]

..there's places on it to hook up the rocker cover breather, the fuel tank vapor recovery line and that little vacuum tube under the TB.

The PO had a K&N and all it did was vent(or suck) atmosphere from those lines. A no-no.

When I reinstalled the stock setup, I had to adjust the idle, but that's pretty minor.

Delia Wolfe

'73tii

Inka (aka "Orange Julius")

#2762756

[Guest Anonymous]

URL: http://www.angelfire.com/retro/tii_1974/

their filters flow to much for some applications, the stumble shows really bad at low rpm, when the engine calls for less air. I seen a lots of dyno work , on motorcycles and they just do. Now each vehicle is diferent, I have them on my tii and it feels ok. I need to try some stock ones and see.

[Guest Anonymous]

that it's the length of the actual intake runners, plus the size of the throttle body plus the size/mass/length of the airbox that is what the engine is specifically calibrated for.

I like Bo Black's experimentation which is based on research done in the Roundel back in the 70s. He's taken the airbox and modified the forward runner to input fresh air from the battery box hole in the core support. Talk about cooler air!!

Your thoughts?

Keith

'74tii - Stella

http://www.my2002tii.com

[Guest Anonymous]

It is my understanding that the stock cannister does add more performance. However, to argue that anything other than the stock cannister is inferior, is to argue that everything else on the tii is perfect and you could notice the degredation in performance.

The stock cannister is reportedly better because, as we have questioned in the past, is air pushed or pulled into the motor? If we believe that air can only enter a naturally aspirated motor at atmospheric pressure, BMW 30 years ago tried to alter that, and some say they did with the tii cannister. Some will also claim that the tii's additional hp over a carburated 02 is the cannister.

The theory lays out something like this. Air, at atmospheric pressure enters the cannister. As the cylinders create vacumn, the air tries to fill that vacum by rushing in the open intake valve. As the intake valve closes, the air mass stops rushing, but the pressure waves rush away from the closed intake valve into the cannister. This adds presssure into the cannister to assist air flow into the next cylinder looking for air. Sort of an early man's turbo.

For what is worth....