how will i know when im getting pre-ignition?

Octanee · Sep 16, 2011

hi guys, as title says, im wondering on this because i going to be turbo'ing my ski doo 1000 but also not sure about the pre-ignition part, and how to detect when it is pre-ignition, does the exhaust become choppy?? does the snowmobile its self run like poop and throw a code or something?, i know the sled does have a knock sensor so not sure if the computer will let you know when its pre igniting? thanks,

and yes i did use the search function to look around but don't seem to be any actual talk on this and how to detect it, thanks

sledsrock · Sep 16, 2011

Pre-detonation?

evan3000 · Sep 16, 2011

your getting the two terms mixed up, its pre ignition or detonation, google the term for an understanding of what it is. I doubt that you could every hear it but your knock sensor should pick it up, also you can check your plugs, I'm sure others will chime in with tips but my T-Xp runs so perfectly I never have to worry about it!! :lol: plus I make sure I run good fuel !!!

Octanee · Sep 16, 2011

oh god, i am getting it mixed up aint i, ok pre-ignition? ha ha, dam.... i was looking on google but i know every machine if your trying to maybe listen for it i would think it would sound different on everything??

but yeah im getting some milled domes and such, i can run 94 OCTANE from chevron here, i dont think there is ethanol in their fuel, as fast gases here in town have that warning sticker saying may contain up to 10% ethanol but the chevron dont, also planning to run about 7 pounds of boost, i want the engine to last so i touch the engine when i usually would rather then working on the engine and replacing pistons or crank every year kind of thing.... but trying to figure out on the pre-ignition so i know if its too much boost, but googling around it just tells you causes of pre ignition and what pre ignition is, im looking to hear some sounds, and how to distinguish the sound of pre ignition, youtube does not have anything either :\

byeatts · Sep 16, 2011

Octanee said:
oh god, i am getting it mixed up aint i, ok pre-ignition? ha ha, dam.... i was looking on google but i know every machine if your trying to maybe listen for it i would think it would sound different on everything??

but yeah im getting some milled domes and such, i can run 94 OCTANE from chevron here, i dont think there is ethanol in their fuel, as fast gases here in town have that warning sticker saying may contain up to 10% ethanol but the chevron dont, also planning to run about 7 pounds of boost, i want the engine to last so i touch the engine when i usually would rather then working on the engine and replacing pistons or crank every year kind of thing.... but trying to figure out on the pre-ignition so i know if its too much boost or what,

Minor det sometimes will not be picked up by sensor, Typically in Mid throttle down the trail you hear a ball bearing or slight rattle.pulled down several 860,s which had pistons hammered and never set off sensors.plug reads .wash check is the way to assure jetting is correct.Det is caused from poor jetting, bad fuel quality or high compression ignites the fuel before the plug fires. Minor det will kill the horsepower and in some cases is the cause of a sled falling off on a climb.a tuner can listen to the engine and detect this is many cases

Octanee · Sep 17, 2011

byeatts said:
Minor det sometimes will not be picked up by sensor, Typically in Mid throttle down the trail you hear a ball bearing or slight rattle.pulled down several 860,s which had pistons hammered and never set off sensors.plug reads .wash check is the way to assure jetting is correct.Det is caused from poor jetting, bad fuel quality or high compression ignites the fuel before the plug fires. Minor det will kill the horsepower and in some cases is the cause of a sled falling off on a climb.a tuner can listen to the engine and detect this is many cases

alright, and yeah the sleds fuel injected, so as far as jetting goes that wont be something to worry about as i will have a efi that senses boost so just got to adjust that lil sucker, but yeah minor detonation is not too bad but yeah would cause it to loose power, but it would for sure cause some bad issues if it started to do it sooner, but i suppose i hope i dont encounter any pre-ignition but i shall be listening for it or for something atleast

1100 · Sep 18, 2011

If i were you I would probably not try to run Husky 94 octane at 7 pounds, I would atleast go to the airport and get some 100ll avgas to start with, thinking you will have trouble at 7 pounds with stock compression heads.

badass1000 · Sep 18, 2011

He has never even mentioned what elevation he rides at. got to know that before deciding what octane is required.
I have had the detonation sensor go off on my sled several times and two other xp's I ride with and have worked on. None of them have had signs of detonation on plugs, pistons, or any thing else in the engine.

Octanee · Sep 19, 2011

well, i got a mach z head gasket on my sled, and it made my last season in the mountains suck, so my squish is too much so i lost compression, but guy i talk to, i think his name is now sled4ever? says he runs the thick gasket any how, and ill be getting milled domes from him, so that will bring compression down to like 125 psi or so he says, my compression when i last checked was like 130psi or so maybe 135 on new pistons that now have 1400 km's on them, i ride at about 4,000-8500 or 9000ft max elevation, i want to be running this on pump gas

badass1000 · Sep 20, 2011

I run stock compresion on my 08 800r. I ride 6500' and up. I unload as low as 5000' some times. just don't hold it pined on the lake or up the trail untill I get up to the area I ride.
I have a garrett 2871 turbo with a tial stainless turbine housing and a tial wastegate and bov. I ran 7lbs on premium non ethanol the first year. every once in awhile (one out of 10 rids or so) the gas station must not have got some bad gas or the premium wasnt really premium and the sled didn't run as good and the detonation sensor would go off. friends with NA xp's with pipes and heads would have problems on the same day. So I started runing one gallon of 107 mon fuel with every fill up. Last year I ran 10.3lbs of boost with a mix of 30% 107 mon fuel and 70% premium non ethanal pump. Ran great all year and no problems. Sled ran a hell of alot better on 10lbs then it did on 7lbs. I couldn't believe how much better it ran. going to try a 11.4lb spring in the wastegate this year.

Octanee · Sep 20, 2011

badass1000 said:
I run stock compresion on my 08 800r. I ride 6500' and up. I unload as low as 5000' some times. just don't hold it pined on the lake or up the trail untill I get up to the area I ride.
I have a garrett 2871 turbo with a tial stainless turbine housing and a tial wastegate and bov. I ran 7lbs on premium non ethanol the first year. every once in awhile (one out of 10 rids or so) the gas station must not have got some bad gas or the premium wasnt really premium and the sled didn't run as good and the detonation sensor would go off. friends with NA xp's with pipes and heads would have problems on the same day. So I started runing one gallon of 107 mon fuel with every fill up. Last year I ran 10.3lbs of boost with a mix of 30% 107 mon fuel and 70% premium non ethanal pump. Ran great all year and no problems. Sled ran a hell of alot better on 10lbs then it did on 7lbs. I couldn't believe how much better it ran. going to try a 11.4lb spring in the wastegate this year.

stock compression eh, as in you did not touch your domes or base gasket for squish or anything then? but that seems like it will be hard on your engine ha ha, on the 1000 atleast im told that the stock domes will cause pre-detonation so you need to have some other brand's milled out and it will fix that right up, im just looking for now to run a turbo and not worry about my engine and just have some extra power that will be fun, but usually the gas here is always good, chevron seems to always have some great gas, the turbo i found is small sadly, its like a 2861 exhaust with a 3082 compressor, But for the price im more then happy, then down the road.... ill put a nice turbo on it and really make er go,

winter brew · Sep 20, 2011

Don't depend on the sensor. I have been able to rattle plugs loose and audibly hear deto. without ever triggering the sensor. Rattly sound....go with a little more octane than you think you need to get used to the sound....drop octane and if you encounter deto. you will probably be able to feel and hear the difference.

Octanee · Sep 20, 2011

winter brew said:
Don't depend on the sensor. I have been able to rattle plugs loose and audibly hear deto. without ever triggering the sensor. Rattly sound....go with a little more octane than you think you need to get used to the sound....drop octane and if you encounter deto. you will probably be able to feel and hear the difference.

yeah i was told that if plugs get rattled loose that, that is a indication of pre-ignition, i wouldnt think that high octane is not good, i mean it can hamper performance if you got alot higher then you need, but ill be trying it on 94 octane and see how that goes, it should be fine i am sure

badass1000 · Sep 20, 2011

the fist year it had I believe a 5 hole base gasket the same as stock. I believe I put a 6 hole base gasket in it last year. I think that is the thickest stock base gasket you can get. Other then that just some stock replacement spi pistons and stock untouched head.
As winterbrew said. the stock sensor on the xp's is unreliable. I have had sleds have the detonation sensor go off with no signs of detonation at all. He has had the oposite happen.
I was wanting to leave close to stock compresion for throttle responce.

Octanee · Sep 20, 2011

badass1000 said:
the fist year it had I believe a 5 hole base gasket the same as stock. I believe I put a 6 hole base gasket in it last year. I think that is the thickest stock base gasket you can get. Other then that just some stock replacement spi pistons and stock untouched head.
As winterbrew said. the stock sensor on the xp's is unreliable. I have had sleds have the detonation sensor go off with no signs of detonation at all. He has had the oposite happen.
I was wanting to leave close to stock compresion for throttle responce.

ahhh, well i guess good your getting away with stock domes, but im looking to add power but not cut into my maintenance, so i would like to say turbo it then every 4,000 km's i would do new pistons and get a rebuilt crank, where as turbo guys that pumping out ALOT of power in them 800s, or even a turbo kit really, usually are like pistons every winter or 2, and crank for sure by 2nd winter usually, also dependant on km's

but the ski doo 1000 engine weighs 2x more then a 800 ho engine and thats just for the extra 200ccs, they are built well so running at about 7 or so psi should be fine i am sure, but i guess i will find out soon

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how will i know when im getting pre-ignition?

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