What's the REAL DEAL with the air temp sensor?

[trinitypowder]

My dealer says, "no holes in the air box". My motor guy says "put holes in the box". I put holes in my box last year and my sled never skip, studdered, bogged, or blew up. So, does anybody REALLY know the answer??

 

[badass1000]

what is the difference going to be between in or out of the air box? one or two degrees?
I ran all last year with back of air box cut out and covered with prefilter with no problems on my 08 xp.
Alot of guys I know and I just zip tie the air intake sensor to the throttle bodies on our turbo street bikes. Same thing on all motor and nitrous street bikes. No problems.

 

[trinitypowder]

That's my thinking too! No problems last year whatsoever with my box opened up. I was hoping that somebody could prove to me why you "can't" doo it

 

[trinitypowder]

Where's all the "engineerey" types Chime in boys!

 

[mt.sledder]

I have 2 low boy vents from thunder products in the back of my airbox. They work great. Never have to wipe the snow off my air intake up front. Down 1 jet size and it looks like I can go at least 1 and maybe 2 more. Sled runs like a champ....

 

[triple7]

Cut the holes. The only thing cutting holes in the box could cause is the air temp sensor to read SLIGHTLY warmer air. The only effect that that possibly could cause is the ECM to choose a curve with slightly less advance. Therefore, there is NO danger of a burndown. I would simply continue to enlarge the holes until you can no longer verify a gain or you actually lose something. If you lose something simply tape the hole back slightly smaller and run it. This is how I set my XP up. It runs. But it is JMO!! Happy cutting!!

 

[trinitypowder]

My holes have been there for a year!!! They are 2x3.25 inch monsters covered with pre filter material. I'm just a little more concerned this year doo to the $$$ spent on the 860

 

[triple7]

Leave um then. You're golden. I have been playing with an 860 engine a bit and it is less stick prone than a mod 800 imo. My sled will definatly have one in it for next year. O ya, on the 860 I was playing with it had pods on it and the air temp sensor was zip tied to frame...No issues

 

[mrquick68]

Cut the holes. The only thing cutting holes in the box could cause is the air temp sensor to read SLIGHTLY warmer air. The only effect that that possibly could cause is the ECM to choose a curve with slightly less advance. Therefore, there is NO danger of a burndown. I would simply continue to enlarge the holes until you can no longer verify a gain or you actually lose something. If you lose something simply tape the hole back slightly smaller and run it. This is how I set my XP up. It runs. But it is JMO!! Happy cutting!!

wouldn't the warmer air actual cuase the ECM to choose a MORE advanced timing map to try and make up for the lost power that comes with warm air? I'm just curious...

 

[triple7]

No, after working with the stock XP ecm for a year it has become very apparent that Ski Doo DOES NOT use multiple curves to maintain peak output. Quite the opposite actually. Skidoo uses different sensors (air temp) being one of them to monitor the conditions that the engine is operating in. If any sensors detects anything other than 'perfect' conditions it simply removes timing and/or alters the exhaust valve opening to back total output down. This has been my experience atleast. If anyone else has had a different experience I would like to hear about it.

 

[trinitypowder]

I wonder how much "weight" the Temp sensor has in the "re-tuning" of the timing? I can't imagine it has that much authority in the scheme of things.

 

[triple7]

Well it has more effect than what one would normally think. This is strictly because SkiDoo uses a fairly slim number of sensors to pick from a fairly large group of curves. We were able to cause our mods to lose power from cutting huge holes in the box. Just fyi

 

[trinitypowder]

Here's my testing. With the airbox taped shut, I had to click up to #5 to get 8200RPM. With the tape removed, I went back to #3 to keep 8200RPM. The open airbox seems to work pretty good on my mod. I also switched to the '09 intake screen.

 

[wildcard28]

Hello guys, everyone in this thread seems pretty knowledgeable, I`m not trying to highjack but, is the air sensor on a 98 670 x do about the same as what yu guys are discussing, the reason why i ask is I`ve always wondered if you could remove the stock airbox and install pod filters and the sensor in an aluminum cover plate , about like timbersled does on the Rev chassis when they install the sensor in the aluminum plate that covers the pods of puts the sensor in around the draft of air to the pods? Don`t know if it is done on your guy`s xp chassis but I hope your familiar with what I`m talking about, I`m sure you are. Do you think I should stay with the airbox or can install would this idea work? Thanks I love those XP`s and hope to own one someday.

 

[portgrinder]

I think more what is going on is the effect on the air pressure guage.

Speaking from my Rev knowledge here... not XP. The DPM ties into the airbox on the side panel, thus getting its signal from that box. So if you punch holes in the box that is attached right to the carbs you decrease the signal strength at the DPM sensor.

When we had my 860 on the dyno, with all the airboxes on, big holes made it lose power.