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2019 SBA 850, 2012 SBA 800, 2002 700 XCSP, 1992 Polaris Indy 500 EFI
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Discussion Starter · #1 ·
I had a '92 Indy 500 EFI I sold my buddy last winter. Replaced it with a 700 XCSP. I'm fairly new to sledding, but am curious why there aren't more EFI sleds out there? Why so many carbs? Again, limited exposure, but my EFI was flawless last year while some of my buddies had nothing but problems with there carb sleds. Might not have anything to do with it, I don't know. Just seems like an EFI would be less maintenance in general than a carb engine. Are they not as prevelant because EFI isn't as much fun to play with?

On a carb engine, how big of a difference do temperature changes make on the performance of the sled? Can you cause significant damage to the engine if you don't adjust the jetting routinely? Saw another thread talking about adding a Tempaflow. Any downside to doing this?

Trying to slowly expand my neophyte knowledge..

Thanks! :div20:
 

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I could be wrong, but most new sleds are FI due to new emissions regulations. Within a year or two, I think they ALL will be FI.
 

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Most all of Ski-Doo's and Polaris' two stroke lineup have semi direct injection (SDI, CFI). A majority of Arctic Cat two strokes use throttle body injection (EFI). Carburetors will be gone from two stroke engines with in the next couple of years I'm willing to bet. You just cannot control them like you can with an injection system. There are currently no direct injection two stroke engines in snowmobiles that I know of so far.
 

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I think cost has held back fuel-injected sleds. Lets face it, its a lot less expensive to just use carbs because you dont have all the electronic gizmos.
I think that the ever tightening emissions regulations are going to force the industry to fuel-injection. With fuel injection that make it a lot harder to tinker with the engine because the average shadetree mechanic doesnt have the software that you would need to adjust how much fuel the computer feeds the engine.
 

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The old throttle-body EFI did little if anything for emission. They were targeting ridability back then. The new EPA standards required the OEMs to cut emissions and ridability improves with it. The biggest obstacle the OEs had to overcome was getting the injectors to cycle fast enough. The four stroke only pulses half as often as the two-stroke, allowing the injector to open and close fast enough. On top of that, most four strokes (as in the automotive field where EFI was refined) don't rev as high as a two strokes. Thats why the SDI and CFI position the injectors in the transfer ports. I think as long as those two satisfy the EPA, it's going to be difficult to justify developing a DFI for the two stroke.
Just my .02
David
 
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