Interesting? Perhaps a new approach......

[JGringo]

Unburnt fuel is from it being a 2 stroke engine and nothing else. On a well tuned one, there is little of it. But still way more than a four stroke.

Notttttt necessarily true...

4-strokes have just as bad emissions when they are carbureted. You cannot see it like two-strokes because two-strokes make a grey-colored smoke from unburned oil... This unburned oil tends to occur from incorrectly tuned or non-EFI motors and when the engine is first started... How else do sleds pass tech when 90% are two-strokes?

 

[Matt_E]

It's not because they have a pipe that's cooled by a different substance. :clown:

 

[D-Roc]

True dat matt!

 

[JGringo]

Or the fact that water is injected into the expansion chamber? :thumbsdown:

And they are two totally different animals... 4-poke's "pipe" is nothing like a 2-stroke's "pipe" which acts as an induction/'charge' system... Water injection inhibits the rebound "charge" wave occurring within the "pipe" and makes emissions worse. Are you sure that the "cooling substance" doesn't matter? ancake:

 

[Matt_E]

Or the fact that water is injected into the expansion chamber? :thumbsdown:

And they are two totally different animals... 4-poke's "pipe" is nothing like a 2-stroke's "pipe" which acts as an induction/'charge' system... Water injection inhibits the rebound "charge" wave occurring within the "pipe" and makes emissions worse. Are you sure that the "cooling substance" doesn't matter? ancake:

Ever hear of a dry pipe?

Do you know what the water injection does? (I assure you, it's not there for cooling in the traditional sense)

 

[WFO Speedracer]

Notttttt necessarily true...

4-strokes have just as bad emissions when they are carbureted. You cannot see it like two-strokes because two-strokes make a grey-colored smoke from unburned oil... This unburned oil tends to occur from incorrectly tuned or non-EFI motors and when the engine is first started... How else do sleds pass tech when 90% are two-strokes?

Simple its called e-tec look it up sometime

 

[D-Roc]

Mmmmmmm etec. These big motors need twin pipes for the even bigger power. Too bad the hulls are so small.

 

[hondamike504]

Any word on this ?

 

[Mn-Fl freerider]

Hot pipes and cold air into the intake is what makes sled motors make more power than PWCs overall. I imagine a 1200 degree pipe in a closed hull would result in 1200 degree air into the intake and without venting the temps would not stop at 1200 degrees. Etec doos are DI engines that use coated crank bearings, they are more emission friendly but do a poor job with crank lube and ultimately are still a 2 stroke as far as gov't is concerned. Sea-doo had some DI engines in the early 2000s but ultimately went to 4 strokes due to consumer choice and tighter gov't regs.
Rotary engines have great power to displacemnt numbers for sure and could result in very light weight power which is what we all want, they may be the future of the sport! Go RRP!!
Subscribed

 

[Melmack]

There is one key factor being overlooked in this discussion. First of all, the common triangle style rotary isn't really a four stroke. That is what we call them but the more correct term would be 'stroke four' or even 'stroke eight' instead. Thats because the four combustion processes hapen in one stroke. In fact, they happen twice per stroke. This is the KEY FACTOR why they burn so clean, carbureted or injection. The gases pas through two compleete burn cycles before entering the exsaust pipe. This means nearly all the bad emmission gasses are burnt clean in the second combustion process. This is why OMC spent over 70million in the 70's reaserching and racing them. Moller Industries now holds the rights to those motors and I am in the process of trying to get my hands on a prototype for my 300 project.

 

[Mn-Fl freerider]

There is one key factor being overlooked in this discussion. First of all, the common triangle style rotary isn't really a four stroke. That is what we call them but the more correct term would be 'stroke four' or even 'stroke eight' instead. Thats because the four combustion processes hapen in one stroke. In fact, they happen twice per stroke. This is the KEY FACTOR why they burn so clean, carbureted or injection. The gases pas through two compleete burn cycles before entering the exsaust pipe. This means nearly all the bad emmission gasses are burnt clean in the second combustion process. This is why OMC spent over 70million in the 70's reaserching and racing them. Moller Industries now holds the rights to those motors and I am in the process of trying to get my hands on a prototype for my 300 project.

300Rx7!!

 

[Melmack]

Dang, you stole my name for it.