My take on AXYS down HP/fade

[Brock]

First off, this is my opinion and findings. It's not the law or the exact to what's going on with every sled.
We started doing all this back in February of this year.

The thing is, I have proof of dyno (hundreds)sheets from good one's to one bad one. I also have over a dozen video's of the digital wrench while sled's were on dyno.

My findings are not speculating(chasing my tail with heat shields and cooling), it's all factual data from the dyno to digital wrench.

Since the Polaris Team tips came out about low RPM and probable causes. I believe that 90% of the guys that think they have a problem fall into what Polaris has mentioned in their team tips. Sorry guys, it's the cold hard truth. To prove my point. A guy brought his axys to DTR and said it was under performing and couldn't get it to go. Well, let's just say the dyno showed he made tons of HP and torque, so it was all in his CVT system(clutching).Internet chatter can be evil to some guy's. Off to his dealer to get it clutched after he spent $250.00 for dyno.

As I mentioned in another thread on here, everything on this under performing sled was checked over. We did two full service reports on digital wrench while sled was idling and was sent to Polaris. We did a system check on digital wrench on every component that can/could be checked. I also checked resistances,continuity,voltages all with a Fluke multi-meter to verify digital wrench findings were the same.Everything was within spec and parameters but the TPS and T-Map was a little off. All good components stayed on sled that were within spec and parameters.To back up our findings this was all compared to a good running axys that made great HP and torque.

The only we didn't do was change the wiring harness.

On to the good stuff.

Several trips to dealers and dyno to figure all this out is hard but it is paying off. I won't stop until it's within 1% of all the great sled's dyno'd.

Summary: this has only rev'd 8200 RPM tops ever and the digital wrench history backs this up. I clutched and geared it to 8100 RPM as it fell hard after this.All my field testing proved what I was doing was correct to dyno sheets.

All dyno runs are done in three's and consistant with every sled done at DTR to keep it the same results.
First:engine temp was around 75f and rev'd around 7000RPm to get pipe heat to 900f
second:engine temp was around 120f now and get pipe to 1000f
third:engine temp was over 135f+ and pipe a good 1050f+

put on something new and repeat............

This sled makes HP to 8100 RPM and then falls hard. The other good axys dyno'd make power to 8300 RPM+.

We changed ECU's with a great dyno'd axys and still the same(thanks Heath )

The problem was the bsfa's were to rich(mid 0.65's) from 7200 RPM up. The cfm's were down a little. Afr was ok. We needed to get the bsfa's down and the cfm's(scfm) up.

This sled made around the same HP and torque right up to 7500-7600 RPM as great sled's dyno'd then started falling after this. This is why I'm mentioning the bsfa's and scfm's. This seemed to be hurting this sled up top. From 7600 to 8400 RPM. There are ways to get this down and up.

After tons of dyno runs,we suspected the pipe, pipe sealing and muffler(back pressure). We put another pipe on that fit better and snug around the y-pipe and tried it.This run showed promise as the bsfa's came down(mid 0.55's) and the scfm's came up 7.The stock pipe was not putting heat in the pipe and the is why the bsfa's were in the mid 0.65's and scfm's were down. When in this state the sled would only make power to 8100 RPM and that's it.The bsfa's and scfm's were hurting this sled up top. By changing to a better pipe the bsfa's and scfm's were a lot better just because of this. Putting the pipe on brought the RPM up 150, which now made better HP and torque.Were suspected the pipe and muffler on this one and probably more out there like this particular one.

With the stock pipe on, the pipe would only get to 1050f on third dyno run. By this time the engine temp was to high.Most great HP axys sleds were getting good pipe temp at first and second dyno runs.This is were engine temp was from 90f to 120f and the pipe would reach 1050f. By the third run the engine temp was up 135f +. These were all done the same on all axys sled's so it was consistent and accurate findings.The stock pipe I had on there wouldn't get the pipe heat the great HP axys sled's did. Like I said, it toke the third dyno pull to make good pipe heat and by this time the engine temp was to high and hurt the numbers.

By putting on another pipe that fit better it made better HP/torque, brought the bsfa's down to mid 0.55's and the scfm's up 7. This also was now getting pipe heat to 1050f on the second dyno run now and the engine temp was from 110-130f which is better to have a cold engine and hot pipe. By the way,on DTR dyno the 1050f pipe temp is were these sled's are making great power but also to have a colder engine( around 110-130f).

I'm blaming the pipe,muffler/can TPS,CVT system and Polaris's poor fuel mapping from factory. To back up my findings the pipe was just proven above. The TPS are used in everything Polaris makes from quads to sxs,to sled's for years. The TPS needs to be around 0.705 volts at base, 0.913 at idle,and 4.240-4.330 at WOT. As for the poor Polaris fuel mapping. Changing the fuel and some timing ALONE gets 4-5 HP more and 2lbs of torque. I blame the warranty department for this way to safe fuel mapping. There is a lot left on the table for fuel/timing.

This is were I can see guys getting low RPM/fade in the field,all this combined. The CVT system,ECU fuel mapping,bad pipe/fitting pipe,TPS out of parameters,valves, etc.....etc......
Pulling raw fuel through the pipe makes no HP and would drop PM down in the feild, add a TPS that's richening the fuel and the bad fuel mapping,bad clutching,and this is were you'll see an RPM drop/fade I think. Sometimes the sled is pulling and putting some heat in the pipe, sometimes there's no heat in the pipe to make HP and this drops RPM everytime.

I'm including some pictures and stuff of the findings.

I hope this helps answer some questions as I have more.

 

[Brock]

If the inside of your sled looks like this, your pipe doesn't have a good seal.
This isn't good and will only hurt your power .

I emailed polaris higher up's about this over a month ago and now I see in the Team tips they posted to make sure your pipe is sealed. That's one thing. Bad pipe is another.

I have more ..............

 

[Eagle1]

Wow, great work Brock. Can't imagine time put in on this. Sure to benefit many. And like you said not all sleds may have same problems but give many place to start looking.

In my opinion I'm surprised we don't see more these problems. I mean 160+ hp from 800cc!! Mass production, electrical component variances, weather conditions and like you said internet racers. Lol
As far fuel mapping, can you blame them for being conservative.

 

[Brock]

Wow, great work Brock. Can't imagine time put in on this. Sure to benefit many. And like you said not all sleds may have same problems but give many place to start looking.

In my opinion I'm surprised we don't see more these problems. I mean 160+ hp from 800cc!! Mass production, electrical component variances, weather conditions and like you said internet racers. Lol
As far fuel mapping, can you blame them for being conservative.

A lot of time yes. But some things need to get figured out.

Like I said earlier, Polaris team tips covers probably anyone that thinks they have issues and don't know what there looking for and speculating. I would say over 90% of guys fall into Polaris team tips that think they have an issue. A very small amount have problems and the internet chatter/ speculating and hearsay makes guys think they have a problem. Just Google a symptom of headaches, 3 clicks later your clinically dead and this puts things into people's minds. ( get it?).

Now, these sleds that are proven down on hp have symptoms. Fouled plugs, bad gas mileage compared to other good ones, erratic idle(ski tips wobble bad), stalls going into reverse, oil spatter in belly pan from bad y-pipe to pipe seal, runs poorly compared to others.

This issues are compounded by things, meaning.
If your tps is way off it makes sled run rich and foul plugs(tps higher then 4.39 WOT.tps base higher then 0.713 volts),this sends signals back to ecu, then ecu add's fuel and maybe some timing, this can cause poor top rpm because to much unburnt fuel going through pipe, compound this with bad sealed pipe, bad pipe, bad muffler/can,bang!! We have lower rpm up top and could be intermittent. That's only one way.

Has anyone checked crank position sensors yet??? It states right in the service manual" Poor engine performance" if out of parameters.

I suggest people that think they have an issue. Take it to your dealer. Get them to hook on digital wrench and test every component that it has capabilities too. I did this, there's good problem solving in the dw. It tests tons of components.

I have more ........

 

[Brock]

I forgot to mention the seal of pipe fitting to muffler. Seems this one has a bit of an oblonged hole from factory from a bad weld to close to hole.

The distortion from this factory weld on hole is smaller then the seal Polaris provides for pipe to muffler. The hole is out of round by over a 1/16" which the hard seal can not conform too.

No seal= no proper pressure= no power.

 

[Pro116]

Great tech info.Thanks for sharing all your info.

 

[Bigfuse]

View attachment 273

You guy's may laugh at my tool and die machinist methods used(I know my best friend will,lol), but this worked.

The factory muffler on this one were the pipe meets was out of round badly from a mass produced factory weld.

I toke a caliper and measured and also used a 2 5/16 ball hitch to see out of roundness.
I used the layout blueing ink machinist method. I put white marker all around 2 5/16" ball, I inserted it in and turned with some pressure. Pulled out I could see exactly were the perfect roundness was making contact and wasn't. I then heated the areas with torch that my layout ink was showing and toke the 2 5/16" ball and smacked it to conform, did this a couple times. Wrapped emery cloth around ball hitch and turned to sand. After all this, I did the layout blueing ink method on the ball hitch and now it's leaving ink everywhere. That means it's round.
I installed seal and fits really good now.

The reason I did this is because Polaris won't replace the muffler, and it's leaking in this area. So, no seal = no pressure= no heat in pipe= no hp.

I have to admit that you were relentless in finding your problem.

 

[Brock]

Everything I'm posting has been done awhile ago and tested on dw and dyno.
Checking every component, sensor, wires,mechanical with dw and fluke multi meter has paid off.

Doing all the little things like the travel of exhaust valves, tps proper setting,cps within spec, fuel pressure, fuel sock, throttle body sync, exhaust pipe, y pipe, muffler sealed properly, etc.......

This has shown good on dyno now.

I have more, just posting as we go.

 

[Lid]

The problem with the "fade" is that it comes and goes for some like a switch for some after time riding. Common among the sleds with the fade is that they didn't do it when new it's a condition that developed over the course of time for some it was 300 ish miles others 500. Some individuals were able to pinpoint the start to just after 18 hrs. Mine started less than a quarter mile after it clicked 18hrs and it wasn't gradual it was abrubt ,not like a continuance of a wear item. When this condition occurs it had been reported that fuel milage drops by about 3 miles per gallon and oil consumption goes up. I can't say for sure about the oil but can attest to the drop in fuel milage. To somebody in tune with the engine you can hear it when it "fades" it sounds like it's in poor tune like it's rich or timing is off perhaps both. These fade sleds are not suffering from a weak engine (although some others maybe) as hen mine is operating properly it runs 8250/8300 revs quick and drag races with any other good axys it has 135 lbs of comp. wot 5 pulls. But when it changes tone(tune) it's a turd. I know this has all been posted on diff. Site not trying to be redundant just trying to start anew here without a lot of crap in mix. And because in past there have been a lot of confusion about diff. Conditions and guys thinking they have this fade issue but don't. So I wanted to make it a lil more clear here right from start about some symptoms. I can also provide a lengthy list of what will not fix it but I've yet to find a fix for it.

 

[Bigfuse]

The problem with the "fade" is that it comes and goes for some like a switch for some after time riding. Common among the sleds with the fade is that they didn't do it when new it's a condition that developed over the course of time for some it was 300 ish miles others 500. Some individuals were able to pinpoint the start to just after 18 hrs. Mine started less than a quarter mile after it clicked 18hrs and it wasn't gradual it was abrubt ,not like a continuance of a wear item. When this condition occurs it had been reported that fuel milage drops by about 3 miles per gallon and oil consumption goes up. I can't say for sure about the oil but can attest to the drop in fuel milage. To somebody in tune with the engine you can hear it when it "fades" it sounds like it's in poor tune like it's rich or timing is off perhaps both. These fade sleds are not suffering from a weak engine (although some others maybe) as hen mine is operating properly it runs 8250/8300 revs quick and drag races with any other good axys it has 135 lbs of comp. wot 5 pulls. But when it changes tone(tune) it's a turd. I know this has all been posted on diff. Site not trying to be redundant just trying to start anew here without a lot of crap in mix. And because in past there have been a lot of confusion about diff. Conditions and guys thinking they have this fade issue but don't. So I wanted to make it a lil more clear here right from start about some symptoms. I can also provide a lengthy list of what will not fix it but I've yet to find a fix for it.

What's Polaris or your dealer doing for you Lid are either one going to fix it for you or did you step up to a new one? Hope next season is better for you than the previous one was.

 

[Lid]

Dealer has been great and work with me above and beyond. We were at it every week. When had snow and still at it. Polaris started off good and had good lip service but tech support is failing miserably. Polaris has not abandond ship but are pretty much stumped and of little use at this point. They are well aware of the condition ,symptoms of of not only mine but a couple others out of shop. They just keep saying keep working with your dealer and keep up communication with tech support "polaris will fix your sled NOMATTER what" we have covered all tech support suggestions multiple times and many things they didn't even hit on. Last communication was basically if you have done all these suggestions and it still isn't right than they are at a loss and don't know what to say other than keep in touch with dealer and tech support And that it will get fixed.but since they arnt offering any further info I'm not sure how that will happen from there end. In fairness the reps have been polite and seem genuine when we speak. Also my sled has had a ton of stuff done to it clutch parts , springs , valves , relearns the list goes on and on but they have nvr bucked at anything they paid for all of it. So credit do for that. Eventually I , dealer, somebody on web , or poo will get it. I love this sled so it's kinda a mission for me. I was gonna get a 16 but have chosen to really dial this one in to how I want it. I'm confident that there is a light at end of tunnel for this. Btw. My buddy has same exact issue as mine but I've ridden over a dozen of them and all the others were fantastic.

 

[Bigfuse]

Dealer has been great and work with me above and beyond. We were at it every week. When had snow and still at it. Polaris started off good and had good lip service but tech support is failing miserably. Polaris has not abandond ship but are pretty much stumped and of little use at this point. They are well aware of the condition ,symptoms of of not only mine but a couple others out of shop. They just keep saying keep working with your dealer and keep up communication with tech support "polaris will fix your sled NOMATTER what" we have covered all tech support suggestions multiple times and many things they didn't even hit on. Last communication was basically if you have done all these suggestions and it still isn't right than they are at a loss and don't know what to say other than keep in touch with dealer and tech support And that it will get fixed.but since they arnt offering any further info I'm not sure how that will happen from there end. In fairness the reps have been polite and seem genuine when we speak. Also my sled has had a ton of stuff done to it clutch parts , springs , valves , relearns the list goes on and on but they have nvr bucked at anything they paid for all of it. So credit do for that. Eventually I , dealer, somebody on web , or poo will get it. I love this sled so it's kinda a mission for me. I was gonna get a 16 but have chosen to really dial this one in to how I want it. I'm confident that there is a light at end of tunnel for this. Btw. My buddy has same exact issue as mine but I've ridden over a dozen of them and all the others were fantastic.

I know in the past that Polaris will buy back problem sleds from customers, which I personally think that they should do with yours.

 

[Bigfuse]

The problem with the "fade" is that it comes and goes for some like a switch for some after time riding. Common among the sleds with the fade is that they didn't do it when new it's a condition that developed over the course of time for some it was 300 ish miles others 500. Some individuals were able to pinpoint the start to just after 18 hrs. Mine started less than a quarter mile after it clicked 18hrs and it wasn't gradual it was abrubt ,not like a continuance of a wear item. When this condition occurs it had been reported that fuel milage drops by about 3 miles per gallon and oil consumption goes up. I can't say for sure about the oil but can attest to the drop in fuel milage. To somebody in tune with the engine you can hear it when it "fades" it sounds like it's in poor tune like it's rich or timing is off perhaps both. These fade sleds are not suffering from a weak engine (although some others maybe) as hen mine is operating properly it runs 8250/8300 revs quick and drag races with any other good axys it has 135 lbs of comp. wot 5 pulls. But when it changes tone(tune) it's a turd. I know this has all been posted on diff. Site not trying to be redundant just trying to start anew here without a lot of crap in mix. And because in past there have been a lot of confusion about diff. Conditions and guys thinking they have this fade issue but don't. So I wanted to make it a lil more clear here right from start about some symptoms. I can also provide a lengthy list of what will not fix it but I've yet to find a fix for it.

Almost sounds like a wiring issue. Got to admit it sure is an elusive problem.

 

[Lid]

It's sure is fuse. It maybe but I think somewhere it's an input that is causing the ecu to detune the sled at times. To many coincidence with it my buddies did exact same thing within a minute of mine (18hrs) everything my sled did his would do within a few miles. For example when mine first exhibited the condition I told him and that I had just broke 18 hrs. He stated he was at 17 hours and his was fine which it was I rode it myself nxt day he called me said he broke 18 hrs and his sled went south I rode it that night and he was right same exact condition. Who knows. I do know that I and dealer have been working hard on it and I applaud You , Brock and the others that don't have problems but still are working to help others out. Props to you guys. ! Oh poo told me they won't buy it back they are gonna fix it. I asked what year that will be taking place. Lol. They laughed too.

 

[Bigfuse]

It's sure is fuse. It maybe but I think somewhere it's an input that is causing the ecu to detune the sled at times. To many coincidence with it my buddies did exact same thing within a minute of mine (18hrs) everything my sled did his would do within a few miles. For example when mine first exhibited the condition I told him and that I had just broke 18 hrs. He stated he was at 17 hours and his was fine which it was I rode it myself nxt day he called me said he broke 18 hrs and his sled went south I rode it that night and he was right same exact condition. Who knows. I do know that I and dealer have been working hard on it and I applaud You , Brock and the others that don't have problems but still are working to help others out. Props to you guys. ! Oh poo told me they won't buy it back they are gonna fix it. I asked what year that will be taking place. Lol. They laughed too.

I don't doubt that they are working on it. But like I said it sure is elusive. I honestly feel for you as like you say the sled is a blast to ride.

 

[Brock]

Welcome lid.

Let me ask you this.

What are your thoughts on all I've posted?

What are your thoughts on the new Polaris team tips just issued?

 

[Lid]

Thanks Brock. Well I'd like to thank you for all the efforts first ! I've read most of your input (I think) and I like it. The tps changing with heat is interesting for sure. I had peramaters issues with mine and that's been remidied (at least at shop temps and stand running) but I haven't taken it out really put the heat to it and recheaked it hot I will have to do that. I personally feel that the issues you are finding would be more in line with a remedy for what I would refer to as a low rpm sled or poor performing sled. Not so much a fader. Equally as important just different. For those of us who know how pipe temp effects flow, state of tune etc. that poor fit and leak is also valid and I will be addressing that fit although I really don't have a ton of oil coming out despite the 20 or better times that pipe has been on and off. But that doesn't mean I have a good seal so I will take care of it. I do have to say I don't believe poor pipe fit is related to fade as it can switch back and forth between state of tune with very little change to heat being put into pipe. For example you can ride for 20 miles with no issue then it pops up you can maintain the same throttle input and load on sled and have to switch again. You can also do wide open throttle passes of 1000 or more feet in fade turn around make pass and no fade turn back around and fade again. As a side point I have ridden on average 17-20 miles before fade shows up BUT when it was -20f I've gone 40 miles before it showed up. When it starts it usually stays in that condition and gets worse until max rpm sets in at around 7600. It may spike a lil higher but that's fairly accurate. This same sled also runs 8250-8350 when not in fade. Towards end of season it changed to a more light switch condition where it would change throughout the ride without warning instantly back and forth. Again you can here it even at idle.i can go on and on about this LOL. As far as team tips there is no magic in those very basic info that average tech should know some points more valid than others but again more directed towards low rpm sleds. What I think the problem is is that low rpm sleds are much more common with more common and tradition issues worn belts ,clutch heat etc. if polaris actually had a fade sled (A) they didn't ride it enough to exhibit condition (B) they did and the length of riding wasnt adaquate for them to see the work they did was for not as the condition will reoccur. (C)they simply didn't have a fade sled. If they did and rode it say. A hundred miles it would be crystal clear to them that this is a seperate condition. I believe they put a total of 70 miles on the sleds over approx a week. That is not enough and only a snapshot of what was going on let alone not enough time to varify a fix. As far as he weight drop (at elevation ok) I call bs. We know they need more not less. My sled has no problem with more weight when running properly. I'm 260 ish without gear and when correct my sled will pull the. 68 up to 8300 in the high 30s easily. Anyway again I appreciate your work and effort and see value in your findings keep em coming ! Tech tips. Ehhhhhhh not untrue Just so -so.

 

[Brock]

Thanks Brock. Well I'd like to thank you for all the efforts first ! I've read most of your input (I think) and I like it. The tps changing with heat is interesting for sure. I had peramaters issues with mine and that's been remidied (at least at shop temps and stand running) but I haven't taken it out really put the heat to it and recheaked it hot I will have to do that. I personally feel that the issues you are finding would be more in line with a remedy for what I would refer to as a low rpm sled or poor performing sled. Not so much a fader. Equally as important just different. For those of us who know how pipe temp effects flow, state of tune etc. that poor fit and leak is also valid and I will be addressing that fit although I really don't have a ton of oil coming out despite the 20 or better times that pipe has been on and off. But that doesn't mean I have a good seal so I will take care of it. I do have to say I don't believe poor pipe fit is related to fade as it can switch back and forth between state of tune with very little change to heat being put into pipe. For example you can ride for 20 miles with no issue then it pops up you can maintain the same throttle input and load on sled and have to switch again. You can also do wide open throttle passes of 1000 or more feet in fade turn around make pass and no fade turn back around and fade again. As a side point I have ridden on average 17-20 miles before fade shows up BUT when it was -20f I've gone 40 miles before it showed up. When it starts it usually stays in that condition and gets worse until max rpm sets in at around 7600. It may spike a lil higher but that's fairly accurate. This same sled also runs 8250-8350 when not in fade. Towards end of season it changed to a more light switch condition where it would change throughout the ride without warning instantly back and forth. Again you can here it even at idle.i can go on and on about this LOL. As far as team tips there is no magic in those very basic info that average tech should know some points more valid than others but again more directed towards low rpm sleds. What I think the problem is is that low rpm sleds are much more common with more common and tradition issues worn belts ,clutch heat etc. if polaris actually had a fade sled (A) they didn't ride it enough to exhibit condition (B) they did and the length of riding wasnt adaquate for them to see the work they did was for not as the condition will reoccur. (C)they simply didn't have a fade sled. If they did and rode it say. A hundred miles it would be crystal clear to them that this is a seperate condition. I believe they put a total of 70 miles on the sleds over approx a week. That is not enough and only a snapshot of what was going on let alone not enough time to varify a fix. As far as he weight drop (at elevation ok) I call bs. We know they need more not less. My sled has no problem with more weight when running properly. I'm 260 ish without gear and when correct my sled will pull the. 68 up to 8300 in the high 30s easily. Anyway again I appreciate your work and effort and see value in your findings keep em coming ! Tech tips. Ehhhhhhh not untrue Just so -so.

I have many questions.

I want u to keep an open mind. No one wants to read I tried everything and nothing works. Just so were on the same page.

as u can see in the pic, it's a vernier caliper.
Can u measure ur actuator cable closed and pull to full open while on sled??

 

[Lid]

The sled isn't in my hands right now. But in semi near future I believe I can make that happen. I nvr said I've tried it all I think at one point I said I could provide a list of the things that I know for sure won't fix it so as to not have anybody on a wild goose chase. For example I changed ecu and no change at all. So with that info nobody need to waste time on that angle. Also reset breakin timer using digital wrench to the last stage of break in that also made no improvement. Ya I def. Want to be on same page I'm a very posative guy when it comes to this stuff so if it comes off that I'm not or a defeatist it's just getting lost in translation of posts. Context etc. and yes I know what a caliper is. Lol. You don't have to dumb it down for me Ive got a long history in motorsports. But how to get those smiley faces and stuff seems to be eluding me also.anyway I'd be happy to provide as much info as I can I've got a lot of time and test time Into so probably can provide a lot of details.

 

[Brock]

Good post Brock .... and a heckuva lot of effort on your part. The frustrating part is that the "fade" word is being used for too many people out there. I think Lid hit the nail on the head ... there's low RPM sleds, and there are others that are hit like a light switch. And there's no denying you're find on the CVT system is the culprit on some sleds. Chatting with a few of the Polaris guys from Medina, the Team Tip is really a guide more than anything. It's giving dealers the right troubleshooting steps, and if it fixes any customer that's awesome. The bigger goal is to provide some guidance and prevent a "let's try this & throw this at it" mentality. But I think the sleds like Lid's, or a guy I know in my home town that has a legitimate fade issue, the fix is still out there. The guy I know may be lucky enough to have his sled on the way to Polaris for their own analysis ... waiting to hear back from a couple people.

Great thread

Thanks Bontz