Turbo sled help

yukonrider · Feb 8, 2017

Getting a bog, or backfire on my 14 pro with silber turbo. Running pump gas, 5psi, 71g with an almond spring at 6200 feet. Sled has a 3 inch track and RKT pistons.

Sled will pull 8200 RPM, but sometimes if I let off the throttle and go to get back on it right away it will pop, and feel like it's bogging. Sled also started to do it at full throttle at random times.

I'm not really sure what to look at as the cause. Was told I shouldn't need to mix in av or 110 at this elevation at 5psi. Was told that I was probably hitting the Rev limiter, but I'm not sure because it doesn't happen constantly. Also I've never seen over 8200

TPS and TSS are checked and in spec. Power valves are clean, cannot replicate the problem on a trail, only happens in deep snow high throttle situations.

Ideas? Right now my questions are: if it was pre det, the sled should show an engine code, or flash det as its happening correct? Doesn't do that.
I feel like it's possibly a helix issue and the motor is getting loaded too hard down low with the 3" track so when I go from full throttle to off to full again the turbo doesn't have time to spool and the sled can't turn the weight (but I don't know what I'm talking about).

Spiderman · Feb 11, 2017

Search my thread under polaris turbo...most likely drive belt slipping and hitting limiter

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kgra · Feb 11, 2017

Unfortunately it's most likely the tuning. Lots of discussion in the turbo section over the last couple years. There areas that are a little lean and some that are a liitle rich. Heavy load on the motor makes it happen especially in the 6500rpm area. Det doesn't always set a code. Worn Primary wieght bushings can cause a jam during back shifting, in turn creating a ton of extra load making the tuning problem much more evident.

SRXSRULE · Feb 12, 2017

Most of the time when you get a popping sound its from a lean condition. That popping is also very hard on the reeds. I'm guessing its a Tune issue, have you checked the plugs to see if they look lean? Eric

Phat Cat · Feb 16, 2017

Im having the same problem with my 2013 Pro RMK Turbo. But I am running a MTNTK turbo kit. I even tried a different tune that has been proven good. When I get home from work I am going to tear my sled apart to see if I can find the problem. I will be checking reeds, clutches, Exhaust valves, new plugs, wires and caps, will check for any visible boost or exhaust leaks. Please keep us informed if you find the cause of the problem and I will do the same.

Phat Cat · Feb 16, 2017

How can we ask to get this moved to the Polaris Turbo section?

yukonrider · Feb 18, 2017

Sorry for the lack of an update. I blew a driveshaft while out testing solutions. Just got it fixed so hopefully today or have more updates. I am convinced it is a clutching issue, I don't think Silber would put out a bum tune. That said next ride I am going to put a go pro on my bars looking at my tach so I have a video for you guys.

So far I tested adding and removing the magnetic weights
Results as such:
Started out evenly weighted at like 72grams. 3 magnets in each hole. Moved 2 magnets into the toe hole from heel, got WAY better. Added a magnet to the toe hole, better still but a little high on Rs. Added a magnet to the middle hole because toe hole was full, and it basically ruined the sled. Boggy mess. Then I blew my driveshaft. So my final setup was 5, 2, 1 magnets. What does this mean?

Octanee · Feb 18, 2017

My turbo pro seems to be stuttering, if i hit the gas hard, 2 things for me, it's either a: detonation, or b: over Rev. I know. My clutching is off, I'm getting it dialed in, when I got the sled it deff was trying to shoot for the Rev limiter easily. Now maybe it's revving too fast, but also still trying for 8400 rpm. The one time it stuttered it threw a det code. I was told if it'd revving too fast that it'll do that.

kgra · Feb 19, 2017

Octanee said:
My turbo pro seems to be stuttering, if i hit the gas hard, 2 things for me, it's either a: detonation, or b: over Rev. I know. My clutching is off, I'm getting it dialed in, when I got the sled it deff was trying to shoot for the Rev limiter easily. Now maybe it's revving too fast, but also still trying for 8400 rpm. The one time it stuttered it threw a det code. I was told if it'd revving too fast that it'll do that.

Add octane or lower your boost. 8400rm is ok. 8600 is too high.

mt.sledder · Feb 19, 2017

Just to eliminate something simple try a set of new plugs gapped down to 20 thou. I have seen it help.

Octanee · Feb 20, 2017

kgra said:
Add octane or lower your boost. 8400rm is ok. 8600 is too high.

It's clutched correct now and I haven't any issues any more. 8000 rpm for my normal riding elevation and if i go up a bit I can compensate with the boost T.

snowcheck163 · Feb 20, 2017

same problem in my 15 pro with a Dobeck. figured it was just the piggy back system. ill try the weight thing tho. same magnet set up. 7psi, race fuel, at 6-10000ft.

Octanee · Feb 20, 2017

snowcheck163 said:
same problem in my 15 pro with a Dobeck. figured it was just the piggy back system. ill try the weight thing tho. same magnet set up. 7psi, race fuel, at 6-10000ft.

Try the weights, just keep an eye on your rpm, when you pin it does it spike to 8400 or higher rpm then pull back? i know the gauges on my 2012 dont update that fast, like once a second so it can be hard to see the spikes when you pin it then let off. mine was, now it just goes to 8,000 or so, 8100 and no spikes.

I my self am not a fan of the dobeck box, if you ever feel a bit adventurous try the boost it XIC fuel controller, amazing box, full unlimited control and options between fueling, rpm trim, and elevation trim, truly a turn key and go solution. my pro has their kit on and no gauges on it, i just pull and go, runs great all day so far minus the initial clutching issue for my elevation which is now fixed.

snowcheck163 · Feb 23, 2017

I'm fairly pull and go on my dobeck besides the "boot up" time when I first start the sled before a pull. Re-clutched my sled. Realized I messed up and my weights weren't the same.... Don't do clutches in field kiddos! But have a huge demo ride for the shop Sunday so I'll get to test it then.

Phat Cat · Mar 13, 2017

I am in Revy right now and rode for the last 2 days with my sled running excellent. I tore my sled apart before coming out here looking for what might be my problem. I checked my reeds and they were good. I did find that a hose clamp on my boost tube was a bit loose and also the exhaust donut on the pipe / turbo connection was damaged. Also replaced my plugs with BR9EYA plugs gapped to 20. So I would say my problem was a boost leak or the exhaust donut.

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Turbo sled help

yukonrider

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kgra

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SRXSRULE

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Phat Cat

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yukonrider

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