K&N air cleaner vs original oil bath?

[jac04]

Another option for mounting an aftermarket filter. I used an AEM Dryflow:

[kevkon]

The issue isn't really between the stock oil bath filter and and an aftermarket dry filter, it's actually the air duct. That alters the velocity of the airflow into the carb.

[jac04]

^^ Are you trying to say that the air duct is more of a restriction than the oil bath air cleaner?

[kevkon]

I don't think it's an issue of it being restrictive. The oil bath air cleaner is probably more than adequate from a cfm perspective for the normally aspirated 2 1/4 l motor. So is the duct. However, there are other considerations beyond air volume. Velocity, pressure, and turbulence are important factors to consider. In short, there are aerodynamic factors involved in the delivery of air through that duct which are related to the operation of the engine.

[gudjeon]

I agree ^^^^^. I converted a '57 from the 2 litre to the 2.25 and I used the original ser1 oil bath cleaner. It has a smaller diameter hose and a sharp right turn right out of the canister. I can get this to pull on the highway at 60mph and it can keep on going (no O/D). This set up does not seem to hold it back.

[JimCT]

restrictions

each 90 degree elbow is about the equivalent of 6' of hose, the the corrugated hose does not help either, the inner wall should me smooth.

[KingSlug]

I find the K&N work really well for the paved road. If I am in dusty conditions offroad I run an oiled UNI foam filter over the K&N (http://www.unifilter.com/online%20ca...universal.html bottom of the page). I keep it in a bag pre-oiled and ready to go.

I am thinking about getting another foam filter to use dry over the K&N.

Jared

[jac04]

each 90 degree elbow is about the equivalent of 6' of hose, the the corrugated hose does not help either, the inner wall should me smooth.

At least the factory hose is helically corrugated, which is better than a standard corrugated pipe. The factory 90 degree elbow is the real killer because it is such a tight radius. That's why I used a long radius elbow to connect to the filter in my set-up.

[gudjeon]

If the 6' hose equivalency thing is true, no one told my rover about it. I had to make a system to cope with the reduced clearance of the 2.25 in a ser1. I thought I would have to refine it, but it works well so I am leaving it alone. 24mpg (imp) at 60 mph on the highway. Can't be too bad.

[kevkon]

I doubt the hose is the reason, rather it's the custom plenum you added. Plenums can be extremely effective at making for better airflow due to the reduction of turbulance and pulses that occur in the breathing cycle. As I said, it's not just about cfm ( volume). There are more factors at work and an improvement in any single one can yield better performance at certain rpms at the expense of others. That's why cylinder had porting is so involved. If it were a matter of just smoothing things out and making them bigger almost anyone could do it. It's a science of flowing the heads and determining what works with specific components and at various engine speeds. Same is true for the lowly Series air cleaner.

[TedW]

I'm going to use JB Weld between the metal ring and the carb throat.

That's exactly what I did three years ago, and everything is holding up perfectly.

Just be sure to use the nastiest solvents you have to clean the mating surfaces. If everything is kleen the JBWeld will do the trick.

[Apis Mellifera]

Certainly you're running an overdrive also for that kind of top end speed?

Jeff

Yes, a Fairey.

Here's the K&N fitted.


David Vizard did flow comparisons of various filtering systems and found that a K&N out flowed a standard paper element filter and this was after the K&N was removed from a vehicle that had completed the Baja 1000. I'd say a properly oiled K&N provides sufficient filter in most applications, but if you routinely drive through clouds of fine silt, the oil bath is probably better. Of course, if you're driving on a silty dirt road, the ability to do 75mph is probably not important.

[gudjeon]

Errrm, thanks kevkon. That what I was going for when I designed it.

Ever wonder why a K&N breathe so well, hold them up to the light.

[kevkon]

Ever wonder why a K&N breathe so well, hold them up to the light.

Well, they do keep stones and small mammals out.