pix on 14 pro meltdown

[yammi4ever]

have a couple logs to show good af's at wot. Sled was broken in on the trails last march, very easy just like they want. Put turbo on this summer, made a test run or two a few weeks ago when we had snow, tweaked the map and tested again. Af's looked great.


Sled ran great on a short ride Sunday, never missed a beat, probably never hit wot at all. Maybe a little boggy at .25 throttle, but cleaned up and was crisp above that. Went to ride the next day. started sled, waited til 118 on the temp and drove easy to town cracking throttle every now and then and noticed a pop, like a backfire. Looked at overflow, seemed a bit too busy for my liking, but had never looked at it before. Went on for a few more miles of ditch riding, not hard riding at all as snow was already set up. stopped in a drive way idled a few seconds temp 130 and shut off. Never started again. mag side was checked at 30 psi, it is the better looking piston. Pto side had 80 psi and looks terrible lol. Neither piston got to the second ring, so it was sill intact. Pto piston had lost some of its ring into the pipe.

Plugs look good, really too rich actually,

150 miles approx on sled, MAYBE 30 with the turbo

working with turbo kit man to see what might have caused this, but we are a bit perplexed since all signs were good.

ideas????

 

[Danny Dangles]

can you share some information about the setup?
boost?
fuel?
turbo?

that is some serious det.....crown melted right off the piston, mine looked like that after a season of running pump gas, minus the shrapnel damage...
for the record my plugs looked like that as well, im gonna say you need some octane.....

 

[yammi4ever]

can you share some information about the setup?
boost?
fuel?
turbo?

that is some serious det.....crown melted right off the piston, mine looked like that after a season of running pump gas, minus the shrapnel damage...
for the record my plugs looked like that as well, im gonna say you need some octane.....

pump gas kit, 6 psi, had fresh gas in and was a little 91 octane with mostly 93 octane during tuning runs, on the day it quit i had added 8 oz of torco just to be safe.

Would you call it detonation????, or a air to fuel issue, seems to me detonation would be more a shot peening of piston???? The one piston that looks the worst actually has square beatings in it. like a few pieces of ring got on top and did the damage. I did find 5 or 6 small pieces of ring in the pipe, so pretty sure they caused the beating on the pto side. Definite meltdown tho.


thanks

last night i got to wondering what the boost is actually running, i need to check the logs to see if it is running more than 6 like it should be.???

 

[Bacon]

You need octane. You can't run 6 lbs at low elevation on crappy pump gas. You detonated the $hit out of that motor. What setup do you have. If you are going to run that boost you will need to get rid of compression or timing or both.

 

[turboless terry]

Get some av or race fuel. Throw that toro in the dumpster. It is a joke.

 

[yammi4ever]

vipec controller

so everyone thinks it isn't enough octane???

 

[Bacon]

Did you have any gas left from last year in the sled? It's definatly a det issue. I'm surprised you couldn't hear the thing rattling like crazy. Double check what you logged for boost. I had to pull timing on mine when on and off the throttle. It would detonate.

 

[TheBreeze]

6 lbs and pump gas in Iowa? Det city.

 

[yammi4ever]

Did you have any gas left from last year in the sled? It's definatly a det issue. I'm surprised you couldn't hear the thing rattling like crazy. Double check what you logged for boost. I had to pull timing on mine when on and off the throttle. It would detonate.

very little, and it had been stabilized.

I will admit that i am not completely sure what this sound of detonation should sound like, i have researched it, and never have been able to get a good definition of it. It actually was running fine and idling fine right up to shutting it off other than a backfire occasionally. From the looks of the pistons i cannot believe it was running at all

when making a couple of the tuning runs it did make a strange noise (possible detonation???) and it acted like it lost power for a sec or two, then picked right up after letting up on the throttle. but during full throttle runs it did not miss a beat.

I would love someone to post a good clear video of detonation. A while back someone posted a vid of a run and a couple guys said that the motor was obviously detonating. Had a couple buds listen with me and we all looked at each other and looked puzzled at what they were hearing.


to figure boost do i take map minus bap and divide by 14.7 as the software does not report what the gauge shows???

 

[Bacon]

Det kind of sounds like you have a little gremlin inside your motor with a jackhammer. Once you know what it is, you don't want to hear it again. You can also get light deto that you don't hear.

 

[kiliki]

Deto For sure!
I though the poo had a det light and sensor?

 

[yammi4ever]

Deto For sure!
I though the poo had a det light and sensor?

pretty sure it does,

not sure how it works and if it stores the code. will have to read the manual to see, but since i cannot start it i cannot read it lol


I never heard a jackhammer going off in this motor for sure, but certainly could have been doing some lesser form of detonation and i didn't know what i was hearing

 

[Super Dave3]

As bad as that engine detonated, I wouldn't be surprised if you have lower rod bearing issues down the road.

 

[Boyko]

Not Just Deto

Looks like both piston crowns melted... at the exhaust port!

My guess is that you were running it to lean and maybe had a minor deto issue

With deto and a lean condition you can poke a hole in the center of the piston

Detonation can break the ring lands off of pistons, it doesn't melt the crown off on its own

You can easily meld down a 2-smoker with a long 1/4 throttle pull, happens a lot, check you logs at the low end.

Plug colors change, they have to be checked at that point and time of tuning you are evaluating

A/F reading can be off and should be validated through other means

Does your EGT get logged as well as you A/F?

There is some pretty crappy pump gas out there, it pisses me off what can get sold as premium fuel.

I am a firm believer that a AV gas mix is your best option at low boost

 

[mt.aero]

Looks like both piston crowns melted... at the exhaust port?

My guess is that you were running it to lean and maybe had a minor deto issue

My guess too.....it detonated BECAUSE it was lean. Look at the piston wash, there is so much carbon on top of the piston.

 

[Wheel House Motorsports]

Done that way to many times learning and testing.

Pretty much always getting greedy with low octane, and low elevations. WOT afr would be good, but just gets hot in the mid range and lean/deto takes it out... Done almost the exact same thing to a sled in less then 5 miles. 7 psi on pump at 3k elevation. or i was trying to. LOL

stock POO would have had the det sensor lighting up like an SOB.

what are you running for turbo setup?

 

[Boyko]

My guess too.....it detonated BECAUSE it was lean. Look at the piston wash, there is so much carbon on top of the piston.

To me it looks like most of the carbon has been burnt off

 

[mt.aero]

To me it looks like most of the carbon has been burnt off

Looks caked on if you ask me, but the pictures are a little dark. (I've been wrong before though)

 

[yammi4ever]

Little more info, agree or disagree lol. thanks for the replies from all of you by the way.

Ok after me consulting a couple guys and my turbo kit guy consulting MANY experts and reviewing the several logs they had access to it has been determined it is not detonation, but if anything pre ignition. Why is the thing we are trying to narrow down. One VERY respected polaris guru came out and said this very likely could have happened last spring breaking it in, pre turbo. All is a bit of speculation at this point, but these guys have Way more knowledge than i or most others for that matter. Bad fuel??? maybe we now know we were over boosting a bit, so maybe some of that?? fuel delivery issue or excess air entering they system somehow????? ruling some things out, and will be testing for some once sled is back together.

Turbo kit man has been doing everything to try to find a cause and solution, even sending me some stuff to help get it back together.

I was feeling like a complete idiot thinking i wasn't hearing the detonation, but now appears i was not hearing it cause it wasn't there. Deto meter did not go above dangerous levels according to log.

Hopefully this was just one of those things that happens, and when put together it will run great, but definitely will be double checking a few more things and will be keeping a eye on the fuel quality as best as i can

I purposely left out the kit company, so this couldn't turn into a bashing of him, since this, in my opinion, was not a kit issue. Any issue more than anyone adding a turbo to a two stroke anyway LOL.. Some of you have figured out who's kit it was and started ringing him with calls. That actually helped to rule some things out, so thanks for that too. There is a lot of behind the scenes knowledge on these forums.

thanks

I am no expert in this, so if i might have screwed up a explanation or two in this post sorry.

 

[Boyko]

Looks caked on if you ask me, but the pictures are a little dark. (I've been wrong before though)

More wash means its rich, or lean

Please correct me if I'm wrong

If you look at the pick below it looks like there is a carbon spot in the middle, it is hard to tell though

That spot can also be from pre ignition