3x3 mod with unifilter air box vents already there?

I just got a 2006 drz400S.  It has stock jetting, but someone has drilled 3 one inch holes in the top of the air box and installed some unifilter air box vents.  I am thinking about doing to 3x3 mod and getting a JD kit, but it seems that with the orignal snorkel and 3 vents, it may have about 6 square inches or so of opening already. 

 

Any advice?  Should a do a smaller square hole and shoot for a total of 9 square inches.

 

I live in CO, bike will probably never be below 4000 feet.

 

Thanks.

9 one inch holes do not flow the same as a single square 9 inch hole.

A one inch hole cover with a mesh ides not flow las well as an uncovered one inch hole.

 

All jetting specs, kits are designed for a single, 3"X3" (9) inch opening. More will not benefit you unless you have major engine mod. Less of an opening will cause you issues. Can you flow bench your airbox and check the flow you have to a regular opened one?

 

If you go larger than 3X3, you will have to experiment on what jets work best. You will not get more power.

9 one inch holes do not flow the same as a single square 9 inch hole.

A one inch hole cover with a mesh ides not flow las well as an uncovered one inch hole.

 

All jetting specs, kits are designed for a single, 3"X3" (9) inch opening. More will not benefit you unless you have major engine mod. Less of an opening will cause you issues. Can you flow bench your airbox and check the flow you have to a regular opened one?

 

>would not know how to do that.  I think I will just go ahead and cut out a bigger hole.

 

 

 

If you go larger than 3X3, you will have to experiment on what jets work best. You will not get more power.

>would not know how to do that.  I think I will just go ahead and cut out a bigger hole.

 

:thumbsup:  That would be the smart way , using known settings keeps jetting advice easier...

 

For stock exhaust with 3x3" mod ...altitude 4000 +

150 main jet

JD red needle ,clip 4

22.5 pilot jet with extended fuel screw

2.75 turns

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