Ulmer Stealth Airbox Mod for Apex or Attak--need feedback

[jdm]

For those out there lucky enough to have snow for riding and testing, looking for feedback on anyone that has tried Ulmers new stealth airbox mod along with the plugs substitution. Supposedly this mod is good for 5-6 HP gain which should be noticeable. Also interested to know if you had to enrichen the low RPM fuel map . Any info appreciated.

 

[SharkAttak]

i think the mod is good for 2-3 h.p., i have the ram-air and i bumped my low rpm fuel map up to 10 for all the cylinders, it took the stumble out of it

 

[SledFreak]

Where was the stumble, at top end, or on the bottom end.

 

[ROCKERDAN]

Where was the stumble at top end of on the bottom end.

I never detected a stumble myself...but I usually feather into things with the hi engagement of my proline kit...so did the low speed enrichment just a few days ago...added 10..was previously at 0....all 4 cyls.

If i crack it on the stand,it REVS immediately!....Im gonna leave it here for now,hoping it doesnt change my fuel economy...i doubt it should as its strictly like a PILOT jet from an old carbed sled...does similar thing,which is only at bottom end...and we all know when your riding your over 4gs always....

Dan

 

[AIRWOLF]

how do you make the changes ?

 

[SharkAttak]

Where was the stumble at top end of on the bottom end.

alittle on bottom end, barely noticeable

 

[SharkAttak]

how do you make the changes ?

go under ULMER'S website, go to the instruction for the air-box mod

 

[ROCKERDAN]

this is from allens site....when I did mine,i simply pulled OUT the pale green wire(from plugin),and touched it to delta box frame,this was easier then trying to use a paper clip I found to ground out the pale green wire....the pale geen wire is NOT CONNECTED to anything anyway.

Dan


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.
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.

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.

 

[SharkAttak]

it worked took the stumble out of it when you hammer it, when there's snow i'll play around with the #'s maybe i can go alittle lower, i'm sure it doesn't help fuel economy

 

[170plus]

talked to a yamaha dealer mechanic that has adjusted about 25 sleds using the exhaust analyzer today and he said that every sled had diffeerent readings from each other,no 2 fuel injectors flow exactly the same so no two sleds are the same,he also said that its affects it thru the entire rpm range but to what degree he wasnt exactly sure but they have gone over this at the yamaha update seminars and was told that a simple boost of say 5 or 10 to each cylinder "could" make it sound smoother on low end but actually hurt mid and top end performance ,was told that maybe 1 out of 5 sleds actually would gain and the other 4 would stay same or lose,im going to the other end of the county tomorrow and i'll talk to the silver certified yamaha tech up there for a 2nd opinion on this whole deal,let you know tomorrow night what he said

 

[SharkAttak]

talked to a yamaha dealer mechanic that has adjusted about 25 sleds using the exhaust analyzer today and he said that every sled had diffeerent readings from each other,no 2 fuel injectors flow exactly the same so no two sleds are the same,he also said that its affects it thru the entire rpm range but to what degree he wasnt exactly sure but they have gone over this at the yamaha update seminars and was told that a simple boost of say 5 or 10 to each cylinder "could" make it sound smoother on low end but actually hurt mid and top end performance ,was told that maybe 1 out of 5 sleds actually would gain and the other 4 would stay same or lose,im going to the other end of the county tomorrow and i'll talk to the silver certified yamaha tech up there for a 2nd opinion on this whole deal,let you know tomorrow night what he said

thanks good to know, if we get some snow i'm going to play around with it, it's real easy to change on the trail/ice

 

[fourload]

Thanks machzed for the info. Something else for me to play with this winter if we ever get snow. I wonder how lean you can go and if it will help fuel mileage on those 250 trail mile days in Quebec.

 

[ROCKERDAN]

talked to a yamaha dealer mechanic that has adjusted about 25 sleds using the exhaust analyzer today and he said that every sled had diffeerent readings from each other,no 2 fuel injectors flow exactly the same so no two sleds are the same,he also said that its affects it thru the entire rpm range but to what degree he wasnt exactly sure but they have gone over this at the yamaha update seminars and was told that a simple boost of say 5 or 10 to each cylinder "could" make it sound smoother on low end but actually hurt mid and top end performance ,was told that maybe 1 out of 5 sleds actually would gain and the other 4 would stay same or lose,im going to the other end of the county tomorrow and i'll talk to the silver certified yamaha tech up there for a 2nd opinion on this whole deal,let you know tomorrow night what he said

170plus.....keep me posted,and thanks for info....I would love to test this thorougly on the radar gun.....

at least i know mine were set at 0 And can easily switch back at anytime..

dan

 

[PureBlue]

Would this be the same on the phazer. Or is the wiring differant.

 

[snowbeast]

Yup mine were all set at zero too,and now at plus 10 and yes it helped so far,but have not run it on any long runs yet,but my understanding from allen is its like a carbed version of the idle curcuit,it only effects idle and just off idle,alot like your pilot curcuit does,but maybe even simpler than that,maybe just like a pilot jet only,not the needle jet and jet needle,as that controles much more than what allen eluded too,as he got his info from the dyno runs with my fix air lid,plus his homemade air box bottom mod,and they both made comparable hp numbers around 3-5 hp just the air box mods and another 2-3 with spark plugs,so if you add up even on the low side both will net you 5hp min. to possible 8hp,but if you really want stealth hp just take off your heads,send them to fundy performance,for around 2400 bucks he sends back 180+ hp set up that runs on 91 octane fuel,no differance than running a blower that requires at least 91 octane,with out all the heat problems and the extra cash needed,plus the time to install all of it jmo so when i get some extra cash and time,well mine will look stock,but will run much stronger!!