Lotus Elan and Lotus Elan Plus 2 Forums

Just found this article which makes interesting reading as I have been cosidering changing to a K&N air filter? Perhaps I should stick with my paper one and change it on a regular basis..

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

Carl

I used K&N filters on 7's for a long time and always felt whet the tests proved, a brand new filter flowed more but became clogged and restrictive much quicker, that said I could not put a paper filter on the outside of the bonnet exposed to rain.

When I did a motorcycle engine conversion of a 7 I tucked away the biggest metal canister paper element filter I could find (it was off a light truck) Under the nose cone in the same way that a stock Elan has its filter.

I am convinced that after maybe a few hours of running it flows better and protects the engine better than an oiled cotton filter and will continue to do so for many thousands of mile until very very dirty by which time most owners will have replaced it,.

I know the fuel consumption of my road vehice a turbo diesel Under all driving conditions with a clinical exception, I know exactly when the paper filter needs changing and never do it before although i may inppect it and brush it off every few years, I get 8 years and 100000 miles between filter changes with no loss of economy.

K&N's look and sound good though!

K&N's look and sound good though!

I think the best sound comes from running without air filters like some track cars ... but I would not do it on a road car

Food for thought...................................

Good to see some basic science applied to the topic about which there are many myths

Many years ago i ran a series of dyno tests on a 150+ horsepower road going 1600cc twin cam

test 1 - stand inlet air filter and air box to establish base line
test 2 - remove air filter and housing just trunking and air box - no change in HP curve
test 3 - remove air box and trunking - a small (1 to 3 hp) increase across the top end of the power curve but no difference in the up to 5000 rpm range you normally use on the road

My Conclusion
The standard air filter arrangement is not a limit in a developed road engine. The airbox creates a slight restriction in a developed engine at the top end of the power curve. This is due to the rear carb throat being starved a little due to the air box taper. people make wider air box covers due to this.

For a road engine I would stick with the standard air box and filter

cheers
Rohan

So 50 years ago a bunch of backstreet boys created something with components robbed from standard road cars that still cannot be beaten, that pretty much sums up all of the Elan design.

Doesnt stop companies from using false science to sell nothing but blind hope and/or snake o?l all these years later.

Doesnt stop companies from using false science to sell nothing but blind hope and/or snake o?l all these years later.

Companies have to make a living ...