Turbo Dropping R's

Hairdryr · Oct 11, 2018

So I have read numerous posts on the Axys losing rpms. My situation differs from most of them so I thought i'd throw this out there. I bought a 2016 hold over at the start of the 17 season. Following year i had the Boondocker sidekick installed. It runs great on small climbs or just blipping around small bowls etc. The problem is when we go to areas like Tony's Grove where there are long steep climbs. As I reach the top of a long climb the RPMs drop sharply. At first I thought I was hitting the rev limiter but that is not the case. I have bumped 8500 but sled usually tops out around 8400 rpm. When it drops r's it will go as low as 7200. I've tried replacing the belt, I had the exhaust valves checked, Replaced the exhaust relays. My experience tells me it's clutching but I'm just not sure. Sled has about 500 mi, set up by Triple S Polaris with Boondockers recommended clutching. This damn thing has left me hanging on the edge of some pretty nasty situations. Ive lost confidence in the machine Any help would be appreciated.

ewanaburner · Oct 11, 2018

intake heat
install intercooler

Spaarky · Oct 11, 2018

I know some guys that ride their sidekicks pretty hard. RPM fade isn’t really any issue. Especially not that significant.

I suspect another issue....
Fuel filter?
Motor mounts?
Clutching...
Relay?
TPS??
Exhaust leak?
What’s your center section like?
Are you in ethanol or premium Mode??
What’s you water temp???

Scott · Oct 11, 2018

My first two thoughts went to motor mounts and fuel filter.
How many seconds of wfo before it drops?

kanedog · Oct 11, 2018

What are your af numbers at 8000?

Sent from my SM-G920W8 using Tapatalk

ewanaburner · Oct 16, 2018

if your clutching is working right so it loads the motor and makes the turbo
work on a long pull (loaded hard as it should be) intake heat becomes a
major factor if you have a intake temp gage check the temp the magic
number on mine is 224* a good stocker will go right by it when it hits that
temp
either that clutch it so its zingy like most of them out there then the intake
and pipe don't heat as fast because the motor is not loaded

turboless terry · Oct 16, 2018

I would put new plugs in. I've had it happen a few times. Once with a cat turbo and twice with a polaris turbo. I've even had it happen with stock Polaris. One set at beginning and one set at end of year on a stocker. Don't know why the Polaris eats plugs. Doing exactly what you are saying.

Hairdryr · Oct 22, 2018

Scott said:
My first two thoughts went to motor mounts and fuel filter.
How many seconds of wfo before it drops?

I'm not certain there, I'd say it has happened at 15 to 20 seconds of full out before.

Hairdryr · Oct 22, 2018

Boondocker has asked me to send my control module in. Going to wire it up and see if they can figure it out. I'll post findings.

Hairdryr · Oct 22, 2018

turboless terry said:
I would put new plugs in. I've had it happen a few times. Once with a cat turbo and twice with a polaris turbo. I've even had it happen with stock Polaris. One set at beginning and one set at end of year on a stocker. Don't know why the Polaris eats plugs. Doing exactly what you are saying.

I'll try this.

diamonddave · Oct 23, 2018

A drop to 7,200 RPM after 15-20 seconds of full 8,400 RPM under load?

No more fuel filter on the Axys but there is a sock on the fuel pump. Might not hurt to check the internal fuel pump assy hose.

I don't see motor mounts flexing or worn out to the point that to cause that much RPM drop.

Sounds like a control problem with exhaust valves closing while under load. Relay issue or Corrosion in the terminals, possible bad cable, hard to see without taking them apart. I would bet you hear a tone change too.

I would also check that stator connector very close, a ton of those things are burning up from corrosion from the cheap connector getting wet.

Or like the other guy said about intake heat. I could see the ECM commanding some weird stuff (closing valves or cutting fuel to the injectors) if the intake sensor starts seeing wacked out intake temps. Might be worth throwing a gauge or monitoring the return voltage of the intake sensor and comparing it with what stock temps are supposed to be.

Could try a pipe sensor from another sled.

Didn't Boondocker have a reflash for their boxes?

Sage Crusher · Oct 23, 2018

diamonddave said:
I would also check that stator connector very close, a ton of those things are burning up from corrosion from the cheap connector getting wet.

Yep the stator connection get's ugly quick...

TheBreeze · Oct 24, 2018

Where is the stator connector located?

snowracer21 · Oct 24, 2018

Was running into a similar problem last year, and chased it for a while...wasn't throwing any codes either.

Took it to the dealer and they replaced the TPS & EGT sensor... sled was 100% after...not sure which one fixed the problem, but I've heard of Polaris EGT sensors going bad.

JJ_0909 · Oct 24, 2018

If I had to bet I'd bet EGT. That year specifically was bad for EGTs.

Hairdryr · Oct 29, 2018

diamonddave said:
A drop to 7,200 RPM after 15-20 seconds of full 8,400 RPM under load?

No more fuel filter on the Axys but there is a sock on the fuel pump. Might not hurt to check the internal fuel pump assy hose.

I don't see motor mounts flexing or worn out to the point that to cause that much RPM drop.

Sounds like a control problem with exhaust valves closing while under load. Relay issue or Corrosion in the terminals, possible bad cable, hard to see without taking them apart. I would bet you hear a tone change too.

I would also check that stator connector very close, a ton of those things are burning up from corrosion from the cheap connector getting wet.

Or like the other guy said about intake heat. I could see the ECM commanding some weird stuff (closing valves or cutting fuel to the injectors) if the intake sensor starts seeing wacked out intake temps. Might be worth throwing a gauge or monitoring the return voltage of the intake sensor and comparing it with what stock temps are supposed to be.

Could try a pipe sensor from another sled.

Didn't Boondocker have a reflash for their boxes?

Yes they did. I spoke with Boondocker and sent my box in last week for a reflash. They are claiming that some of the 800's need a little more fuel so hopefully this is the fix. Interestingly, I spoke with someone at Boondocker last season while dealing with the issue. That person said nothing about needing a reflash. Not trying to bash them here, just would have been nice to get this licked last season if it is indeed the problem.

Hairdryr · Oct 29, 2018

Sage Crusher said:
Yep the stator connection get's ugly quick...

View attachment 297396

That's nasty. I'll check this as well.

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Turbo Dropping R's

Hairdryr

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ewanaburner

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Spaarky

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Scott

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kanedog

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ewanaburner

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Hairdryr

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