Air filter box restrictor plates.

[trunt]

Are they really needed? is anyone running without them?

Its just that I dont have any, Mine are wide open. Looking at some photo's I found on ebays across the world it seems that mostly the holes were just cut with the restriction, was there ever seperate plates?

s-l1600 (3).jpg

Terry

[sujitroy]

ISTR they are required for better running. i have the plates in my box.

[sujitroy]

sorry. I looked the photo. u don't need them. my box has an oval hole and needs the plates

[flying farmer]

I used to have an early airbox without the plates, but restrictors had been bolted in place in the pattern of the later ones with the restrictor.

I would suspect this was an interim factory measure as I can't imagine a previous owner would have bothered

Neil

[dasadrew]

My Mark 2 has both the shaped holes and the restrictor plates which exactly overlap. I use them as I believe it spreads the load and avoids the "tin" airbox cut-outs from bending.

Drew

[trunt]

sorry. I looked the photo. u don't need them. my box has an oval hole and needs the plates

That’s not my box Sujit, it’s a pic I found online, mine do not have them. I guess I should fabricate some.

terry

[maverick]

I removed mine for improved air flow made very little difference,I was told by very experienced classic car racer/tuner that the flaps were there to reduce induction noise
Mark

[flying farmer]

I believe the main reason for the plates is that at the airflow around the tight bend into the carbs tens to be biased towards the outside of the bend as air is actually quite heavy and doesn't like turning the corner.
The turbulence created by the restrictor helps the air turn the corner and evens up the airflow across the width of the carb venturi which creates a more even mixture distribution.

I would think this was leading to some cylinders running too rich or too lean compared to the others, but I suspect at normal light throttle running there would be very little difference

Neil

[trunt]

That makes more sense Neil, it looks like the shape is pretty simple so I’ll use the pictures I have to make a couple up, doesn’t look too difficult.

Terry