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RV-4 Rinky Dinky air filter design

Sully73

Active Member
It seems odd to cut a piece out of my engine air filter so it fits over the accelerator pump. I am looking for other solutions.

One possibility is to make a spacer that lowers the air box 3/4 inch so it clears the carburetor obstacles.
The questions are:
Is there enough room to do this or is a shorter filter needed?
If a shorter filter used, will it be able to supply enough air to the engine?
According to my calculations the reduction of air filter area goes from 34 sq inches. to 19 sq. inches (41% reduction of air filter area).

Also, the the cowling opening and air box schnozzle is vertically misaligned by 3/4 inch. A modification would be needed to match this.

The other, less elegant, solution is to offset the air filter horizontally to the left it by 1/2 an inch so it clears the obstacles on the carburetor.

Question, does anyone have any advice on either of these solutions?
Thanks in advance
 
Works fine per plans

I built mine per plans, and I'm pretty sure the intent of Van's was to utilize same parts on several models. The gap between the bottom of the FAB and the cowling is minimal but adequate. Its important to set the angle up to make the FAB align with cowling opening to match. The trim out on the reusable KN filter is very simple, and once properly sealed with RTV , it never needs any further attention. I've been cleaning and servicing the same filter for 11 years. I have also seen several others I have inspected that were "non plans" and I didnt see near as good of fit or quality.
 
Some have reported success using a K&N E-3322 filter and a new aluminum top plate. The E-3322 is slightly larger in circumference vs stock and can be made to clear the accel pump without having to make a cutout in the filter. It’s slightly misshapen from oval however (to a slightly triangular shape) potentially requiring a new cover plate to be fabricated.

Search E-3322 here on VAF ....

Peter

It seems odd to cut a piece out of my engine air filter so it fits over the accelerator pump. I am looking for other solutions.

One possibility is to make a spacer that lowers the air box 3/4 inch so it clears the carburetor obstacles.
The questions are:
Is there enough room to do this or is a shorter filter needed?
If a shorter filter used, will it be able to supply enough air to the engine?
According to my calculations the reduction of air filter area goes from 34 sq inches. to 19 sq. inches (41% reduction of air filter area).

Also, the the cowling opening and air box schnozzle is vertically misaligned by 3/4 inch. A modification would be needed to match this.

The other, less elegant, solution is to offset the air filter horizontally to the left it by 1/2 an inch so it clears the obstacles on the carburetor.

Question, does anyone have any advice on either of these solutions?
Thanks in advance
 
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