Modded airbox, do I need a programmer?

[Pureadrenaline]

I did a search and found plenty of info on how to make a modded airbox, but nothing telling me if I need a EFI controller.

What I am planning on doing is cutting out the raised portion of the lid like ROCKERDAN did and attach the K&N filter material like apexg88 did.

I am also planning on gutting my stock exhaust for a little more grunt. Does anyone know if I will need a EFI controller if I do what I plan on?

Thanks,
pure

 

[APEX 06]

From what I have seen you DON'T need a EFI controller.

 

[machzrobbie]

You don't "need" one but you will get better performance with a bit of fuel and timng. The A/F will run into the 13's without it and it makes the best power at around 12.5

 

[apexg88]

adjust the CO settings to +10 on each cylinder

 

[apexg88]

Heres a copy and paste from that page so you don't even have to look for it. However the actual page on ulmers site has pics too so you know what wire to put the paper clip or wire ground to.

Stealth MOD Air Box
The Yamaha Genesis 150FI motor is the first fuel injected Yamaha snowmobile. With this technology is very little adjustability for air box modifications, etc. If you experience a hesitation in the low end RPM range with the MOD air box installed these are the steps you will want to take to richen the low speed fuel curve. Always make sure the snowmobile is fully warmed up before adjusting any settings. A cold engine will also result in a hesitation!
This will change your low speed fuel mixture much like the pilot circuit on a carbureted model. It does not effect on high speed fuel mixture. The engine will start and run normally in C0 mode so you can change settings with the engine running or on the trail. To return to the normal gauge functions simply turn the key or kill switch off and the gauge display will return normal functions.
1.
Apex C0 Fuel Adjust: - Install a wire (or paperclip) from ground to the pale green wire in the connector on the left of the delta box. This wire has no mating wire in the male connector and only needs to be grounded to the Delta Box.
2.
Enter Diagnostic mode: - With the key and kill switch off, press and hold both "Select and Reset" buttons then power up the gauge by turning both the key and kill switch on. - Wait 8 seconds and the gauge will go blank except for "DI" in the display. - Press "Select" to toggle between "DI" and "C0", Select "C0". - Press and hold both "Select and Reset" 3 seconds - Gauge will display "C:01", (this is where you select which cylinder you want to adjust) - Press and hold "Select and Reset" 3 seconds and 0 should appear in the odometer section - Press "Select" to increase the number (richer), "Reset" to decrease the number (leaner) - Example: (10 would be richer) (-10 would be leaner) - Press both "Select and reset" to chose C:02 and adjust the same as above (must do this for each cylinder)
You will want to go RICHER (positive numbers). Generally up 10 will be enough to get past any hesitation or stumble you may run into.

 

[aceltx09]

Do you still get the louder engine sound if you go with the ULMER RACING airbox mod? I heard an Apex with the top section cut out like the one described above, Don't like it

 

[MUSKIE]

OK..-Ullmer air Box kit will NOT "bark" at you..The top lid mod. WILL!!..With just the top lid mod. turn your fuel up 7-10 in the controls for each cylinder IF you find first hesatation...That will do the bottom..IF you take the line running to your airbox and add a __ resister it will trick the computor into think it is 10% colder out..That will give you the fuel curve all the way throw ...(go to radio shack)...!!!! Then the air box mod. makes pull all the way ..You will find that this works...Enjoy..I loved my air box TOP lid mod. when i had it..Miss it abit..Loved the BARK..

 

[Pureadrenaline]

Thanks for the info everyone! Should be able to start the cutting next week and will take plenty of pics in case anyone needs them.

pure

 

[tomanytoyz]

What i did to mine was used a DREMEL and removed the front side of the two bumps on the airbox--so its like a scoop--then got a old screwdriver red hot and smoothed the edges--some outerwears on the backside with crazy glue for plastics.medium to low intake bark,and it put my sled in a sweet spot-- no adjustments necessary--the other two bumps i left alone.more airs going in for sure.just some ideas for you.sorry no pictures good luck.

 

[Apex2006]

What i did to mine was used a DREMEL and removed the front side of the two bumps on the airbox--so its like a scoop--then got a old screwdriver red hot and smoothed the edges--some outerwears on the backside with crazy glue for plastics.medium to low intake bark,and it put my sled in a sweet spot-- no adjustments necessary--the other two bumps i left alone.more airs going in for sure.just some ideas for you.sorry no pictures good luck.

Can you snap a pic and post it?

Thanks!