Lotus Elan

air filters..

PostPost by: rocket » Mon Mar 30, 2009 9:47 pm

I am considering changeing my standard filter set up for a cone filter in a similar position to the current air filter,just behind front grill.Would this affect my carb set up requireing a retune? I see Cliveyboy offers a kit anyone use it?


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PostPost by: bcmc33 » Mon Mar 30, 2009 10:20 pm

I am looking for the same sort of filter to fit before the car goes to the rolling road in a couple of weeks.

The K&N RF-1023 or 1035 seems to be what Clive shows on his website. Clive does say that his filter is oversize for the Twink - so maybe a smaller filter would suit.

I plan to make a bracket to hold the filter in the nose.

If anyone has any better information or ideas - please tell.
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PostPost by: rgh0 » Tue Mar 31, 2009 7:10 am

My experience with the Elan on a rolling road dyno was that running an open pipe with no filter and running the standard filter made no diffreence in power output or carb tuning requirements. SO I dont beleive changing to another filter provide it is not more restrictive than the standard filter would require any jetting changes.

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PostPost by: jimj » Tue Mar 31, 2009 9:23 am

In the late 60s the great Jim Jackson wondered why the standard air filter in the Elan nose didn`t face forward so the ram effect would pressurise, like a supercharger, the incoming air. A couple of years later forward facing airboxes appeared on F1 and soon spread tp other formulae. In `74, I think, he had another idea so this time wrote to Colin Chapman. Instead of having the wide "sportscar" noses on F1 cars trying to encourage air over instead of under the cars, he suggested that the air be allowed to flow under but angled tubes through the bodywork and at the rear would rely on the venturi effect of the air passing over to suck air from under the car, creating a lower pressure area, later to be known as downforce.
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PostPost by: prezoom » Tue Mar 31, 2009 5:33 pm

When I first got my S2, it was equipped with two K&N's Always a believer in cool air to the engine, I purchased the back plate and fiber glass cover for the carbs. I constructed a mount for the filter similar to Clives and machined an adapter between the hose and the filter.

In my race car, 1200cc engine, spec'd to a standard intake manifold with a 40DCNF carb, fitted with two 26mm venturi's, I experimented with ducting air directly from the headlight to completely sealed air cleaner on top of the carb versus an open topped carb. At Willow Springs Raceway the difference between between the rammed air and no rammed air was 600rpm at the end of the front straight. So I added another 4" hose from the other headlight to the air filter. More's better, right? Actually didn't make any difference in performance, but it makes me feel better.

DSC00451v1.JPG and
Hey, green car, green filter.
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PostPost by: terryp » Tue Mar 31, 2009 6:38 pm

I purchased a kit from Clive together with the T piece for the oil breather. The car runs a lot better and is more free revving. You do get an extra bit of intake roar at 5000rpm which sounds great! Clive's kit is beautifully made.
see elan-f15/cliveyboy-breather-and-filter-conversion-t17520.html

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PostPost by: peterako » Tue Mar 31, 2009 7:02 pm

Hi Terry,

How are you?

Clive does not just make good, useful, kit. He's a very nice gent too!

Your 'secret' link on your sig does not seem to work anymore :(

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PostPost by: terryp » Tue Mar 31, 2009 7:19 pm

How are you? Are you coming to France this year?
Fixed the signature! I think it has something to do with all this upgrading, but we do all get to have a little avatar thing

Back to the post I forgot to say the ducting Clive supplies is really good as well

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PostPost by: TimButDim » Fri Apr 03, 2009 12:49 pm

I'm after the standard filter element for a 1971 +2 130S with Dellorto carbs. What size does it take?

For some reason the previous owner didn't seem to think he needed one...
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PostPost by: Jason1 » Fri Apr 03, 2009 1:10 pm

I bought a FRAM Part No CA614PL it is a tight fit, a bit too deep for the filter housing.
But the housing is new so maybe the housing is a bit small?
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