triple v.s. twin - Snowmobile Forum: Your #1 Snowmobile Forum

polarisindy · 12-23-2007, 02:53 AM

I've always wondered this about a triple and a twin sled. Ok so the triple motor is going to be a little heavier than the twin but not a whole lot. So...back when manufacturers were actively producing triple cylinder 2-stroke sleds, why were they so much heavier than twins of close to the same cc and same chasis? Where was all the weight at?

kccats · 12-23-2007, 07:47 AM

Well the single heavyist part of a engine is the crank shaft! And we are only talking about less than 50 pounds! But in general a triple will need to be a bit beefier to handle the more torque and horse power! A 600 twin a few years back was only good for 110 - 115 hp the triple was 120 -125 stock! The twin could make 125hp mod, but then the triple could do 145-150? And the 800's and 1000's were even more!

**smallengineguy** · 12-23-2007, 07:54 AM

There was only 45 lbs difference between Doo twins and triples in the 90's.

Jaded · 12-23-2007, 10:38 AM

Some of the triples of the 90s were such gas pigs that they were 50 pounds heavier than the twins when you filled them with gas, as some had larger fuel tanks. My Mountain Max triple has a 12 gallon tank.

Cdndairyman · 12-23-2007, 01:39 PM

I didn't find my old XLT to be bad on fuel at all. I think it is better then a twin from the same era. Just my thought anyways. Triples also run MUCH smoother! The weight of an XLT really wasn't that out of line with the XC 600 twin. The hp was a little less on that triple though.

RoadkillSTX · 12-23-2007, 01:56 PM

Well a 600cc 2 cylinder and a 600cc three cylinder have the same amount of area in the combustion chambers.

The difference is the 2 cylinder will have 2 large pistons, while the 3 cylinder has 3 smaller pistons.
So that third piston needs an extra connecting rod, the block needs to be made larger to have a space for the third piston and the crank shaft needs to have an extra counter-balance and needs to be longer.
You'll also need a third carburetor and extra fuel and oil lines (not a lot of weight, a little more)

As previously said the largest amount of weight comes from the crankshaft.

Think of it like this... a 600 cc triple is like having 3 200cc single cylinder motors combined. Whereas, a 600cc twin is like having 2 300cc single cylinder motors combined.
Thats a pretty loose and inaccurate analogy but it helps to get you're mind around why a triple HAS to weigh at least a little more than a double.

To the guy who said the triple has better internals because it makes more power: Actually if anything the twins would need better internals because now that 115HP and the force it creates on the parts is being divided by 2, (57.5hp per cylinder) as opposed to the 125hp of a triple (41.67hp per cylinder). Again a weak analogy, but it comes down to amount of force and compression per cylinder, which is all higher per cylinder on a twin than it is on a triple.

This is why a triple is MUCH easier to pull over than a Twin of the same CC's.

EDIT: Also a triple is not necessarily going to make THAT much more power than a double. If the HP numbers I've found are correct (highly unlikely) then my 583 twin makes 102hp-104hp, the 600triple my g/f has makes 107-110.
Typical engine mechanics as well as to why a triple would win in a race. 2 cylinder has more bore=more torque+low-end power. 3 cylinder less bore but more cylinders=high-end hp.
A twin will typically be faster off the line, but the triple will eventually pull ahead due to the majority of it's power being made in the upper-end of the rpm band.

SawBlade · 12-23-2007, 05:58 PM

[quote=RoadkillSTX]

This is why a triple is MUCH easier to pull over than a Twin of the same CC's.

EDIT: Also a triple is not necessarily going to make THAT much more power than a double.

Huh!!!! ??????????

**smallengineguy** · 12-23-2007, 07:15 PM

My 98 Mach Z triple made 140 hp, the 2005 Renegade 800 twin makes 150!!!

RoadkillSTX · 12-23-2007, 08:19 PM

Quote:

Originally Posted by SawBlade

Quote:

Originally Posted by RoadkillSTX

This is why a triple is MUCH easier to pull over than a Twin of the same CC's.

EDIT: Also a triple is not necessarily going to make THAT much more power than a double.

Huh!!!! ??????????

Triple's are easier to pull over because the compression is divided by three cylinders instead of by 2. Each cylinder is easier to compress because there is less area being compressed per cylinder.
And a triple is not necessarily going to make significantly more power than a double.

kccats · 12-23-2007, 09:09 PM

Quote:

Originally Posted by smallengineguy

My 98 Mach Z triple made 140 hp, the 2005 Renegade 800 twin makes 150!!!

But SEG back in 98 what hp did they get out of the bigger twin?

I was reading about how triples could make a come back!!

Ditch hopper · 12-24-2007, 01:27 AM

Quote:

I was reading about how triples could make a come back!!

That would be aswome i love tripples they sound aswome run sooooo smooth and just scream topend cant beat that for lake running!!!!

IndianRvrShiver · 12-24-2007, 08:52 AM

Quote:

Originally Posted by kccats

I was reading about how triples could make a come back!!

......yea, but in the form of 4-strokes!!

Ditch hopper · 12-24-2007, 12:44 PM

Quote:

......yea, but in the form of 4-strokes!!

NOOOOOOOOOOOOOOOOO i hate 4 strokes there sooooooooooo slow, heavy, and ugly have a look at the apex/phazer thats a desgin only a designer could love

JL Club · 12-24-2007, 06:15 PM

i think im going to have to call bs on your compression theory. when you measure compression, your measuring each cylinder. its not being divided by the number of cylinders. if you have 3 cylinders, your compressing all of them at different intervals during the pulling of the recoil. your still compressing 130-140 psi per cylinder, depending on the motor. not to mention the more moving parts you have to get going with a tripple. another point, my buddies formula 3 700 is about the same to pull over as my zr 600, but my efi starts on the second pull, and his takes about 5-7, depending on whether or not its cold. i havent found out yet if id get beat at the top end, but i know i kick a-ss on the twisty trails. much easier to have less weight to throw around.

Jaded · 12-24-2007, 10:27 PM

Quote:

Originally Posted by Ditch hopper

NOOOOOOOOOOOOOOOOO i hate 4 strokes there sooooooooooo slow, heavy, and ugly have a look at the apex/phazer thats a desgin only a designer could love

Beauty is in the eye of the beholder. I agree the look does take some getting used to. Slow? How many of the new four strokes have you ridden? Honestly!
Yeah they are a bit heavier but I get a kick out of how some people get so hung up on the "weight" issue. Unless you're seriously competeing those few extra pounds distributed properly with good power ratio.......it all comes down to opinions 9 times out of 10. I watched a dude in 3 feet of powder this past weekend on a 1050cc Apex and that was "freakin unbelievable"! The guy riding it was like 60 years old too. He went everywhere with ease and then stopped to help his buddy get his 2006 Ski-doo 800 un-buried. Apex is my next sled after seeing that!

Ditch hopper · 12-24-2007, 10:38 PM

Quote:

Beauty is in the eye of the beholder. I agree the look does take some getting used to. Slow? How many of the new four strokes have you ridden? Honestly!
Yeah they are a bit heavier but I get a kick out of how some people get so hung up on the "weight" issue. Unless you're seriously competeing those few extra pounds distributed properly with good power ratio.......it all comes down to opinions 9 times out of 10. I watched a dude in 3 feet of powder this past weekend on a 1050cc Apex and that was "freakin unbelievable"! The guy riding it was like 60 years old too. He went everywhere with ease and then stopped to help his buddy get his 2006 Ski-doo 800 un-buried. Apex is my next sled after seeing that!

I see your point jaded

the reason i dont like four strokes is beacause like i stated i think every 4stroke out there ugly IMO, there heavy witch means there more diffcult to throw around ,aggresivly ride with, and get unstuck. I think there slow because every weekend at the lake i see apexs running agianst 700,800,900 and getting smoked each and everytime I dont even wanna tell you how they fair agianst the 1000 thats just a joke so I really dont see the advantges to the 4 stroke engine other than reliblity and gas milage but then agian many two strokes like the skidoo get equal gas milage with the 4strokes so idk to each is his own

i guess but i will not buy a 4stroke just my opnion any ways this thread is not about 4strokes its about tripples as how aswome they are

LONG LIVE THE TRIPPLES

Jaded · 12-24-2007, 11:24 PM

Agreed. However, the Apex is not designed to be a lake racer. It's forte' is powder performance. Totally different clutching.
I ride and own two Yamaha 700 triples, the first triples I've ever owned, and I can see how a guy can grow to love them. They sound awesome, (stock), long smooth power band and eye-ball peeling power!

lrnnorth · 12-24-2007, 11:48 PM

Quote:

Originally Posted by Jaded

Agreed. However, the Apex is not designed to be a lake racer. It's forte' is powder performance. Totally different clutching.
I ride and own two Yamaha 700 triples, the first triples I've ever owned, and I can see how a guy can grow to love them. They sound awesome, (stock), long smooth power band and eye-ball peeling power!

There are different packages in the apex model. He is probably talking about the short track and you the long track. I dislike four-strokes but they do have their place. I saw a guy with an apex short track with a turbo on it and that thing could fly!

It was one of the wickedest things I've ever seen. It won the open class drag in our area everything stock except for the turbo. Second was a fully modified genesis 1085 in an xc frame. There was a rumor last year before the new models came out about Polaris having a new big bore triple. One thing to remember too guys, compare apples to apples. Take a twin from the same brand the same year the same cc's. Then compare the horse power. Just think with the new technology how much hp's could they make a triple pump out?

Ditch hopper · 12-25-2007, 01:52 AM

Quote:

Agreed. However, the Apex is not designed to be a lake racer. It's forte' is powder performance. Totally different clutching.
I ride and own two Yamaha 700 triples, the first triples I've ever owned, and I can see how a guy can grow to love them. They sound awesome, (stock), long smooth power band and eye-ball peeling power!

well put man

i cant judge the moutian apex beacuse i've never seen one go! so ill still have a little fatih in em

Btw how does your tripples do in the deep stuff tripples were always knowen for topend just curious how ur sled fairs?

Quote:

Just think with the new technology how much hp's could they make a triple pump out?

I could think of a few numbers

would be aswome tho a big bore 800cc tripple with modern tech oooo man