[gscott]

First post on the forum - like everyone - anxious for next Tuesday.

Stopped by one of the local shops that specializes in RZR and sled mods. Asked them about CVT losses. They said the stock RZR 1000 measures about 83 HP at the wheels on their dyno (may have been a HP reading corrected to sea level altitude but I forgot to ask) - they are at roughly 4,000 ft elevation. With the elevation de-rating of 3% per 1000 ft elevation the stock HP spec at the crank would be reduced from 107 HP to about 94 HP. That is only a 12% loss of power between the crank (94 HP) and the wheels (83 HP). Others have mentioned that a loss of around 30% would be expected for a CVT.

Just wondering, and looking for some other examples - hopefully with dyno measurements - of typical losses from both a CVT and a manual transmission (no torque convertor).

Starting next Tuesday the side by side comparisons will be the most revealing... but in the mean time...

Thanks in advance for any additional input.

 

[zztop]

Yes I heard the belt systems r about 29 to 30% loss n man trans is about 9 to 10% loss... Again that's what I here anyway

 

[rockitman]

The cvt itself is approximately 8%. The rest of the loss is in all the other parts of the drive train. Net gain with a manual will be probably 8% at best since the rest of the drive train is fairly similar in number of turns and bearings, cv joints, u joints, seals etc.

A manual transmission is not going to make a much lower powered vehicle into a world beater if that is what you are thinking.

 

[Deeyoh]

No, but it would make a similar powered vehicle into an ass whoopin on the cvt. The rubber band loses a lot of energy. Why do you think people have problems with belt temps and it constantly needing to be cooled. That's because it's transferring energy that could be turning the wheels into heat energy. It's a lot more than 8% difference. More like 18% difference.

 

[rockitman]

Nope. 8% loss in a cvt according to the engineers that test them.

But 8% is quite a bit.

In these vehicles the whole drive train is turning all the time when you are moving, like a 4wd truck with no unlocking hubs and then add 2 cv joints at each wheel. There is lots more loss through all the drive train other than the cvt.

Think about the difference in efficiency between a 4wd truck with an automatic without a locking torque converter versus one with a manual with a clutch as a general comparison.

If you have 100 hp and you are using 8 hp of that to heat up the belt wouldn't that create a lot of heat?

Did you ever stick your hand on a rear differential after you have been blasting down a trail for an hour?

 

[Tmesic]

Nope. 8% loss in a cvt according to the engineers that test them.

But 8% is quite a bit.

In these vehicles the whole drive train is turning all the time when you are moving, like a 4wd truck with no unlocking hubs and then add 2 cv joints at each wheel. There is lots more loss through all the drive train other than the cvt.

Think about the difference in efficiency between a 4wd truck with an automatic without a locking torque converter versus one with a manual with a clutch as a general comparison.

If you have 100 hp and you are using 8 hp of that to heat up the belt wouldn't that create a lot of heat?

Did you ever stick your hand on a rear differential after you have been blasting down a trail for an hour?

Please stop using logic and fact to make your point. The facts keep getting in the way of what people want to believe......................................................Tim

 

[squaredaway]

Please stop using logic and fact to make your point. The facts keep getting in the way of what people want to believe......................................................Tim

I agree^^^^^^^^^.

I see you made it over here Tim. from Glamis dunes. ( vmaxup) Hope to be In Glamis this season!

 

[jajl22]

The turboXp has 28% power loss from Crank hp to wheel hp. This has been proven by two companies on RZRforums.net, i believe it was Alba and Evo who posted dyno number for stock turbos but please don't quote me on that as i bounce around to a lot of different forums.

Obviously this is not strictly cvt power loss but will give you a vehicle to vehicle comparison once the YXZ's get on the dyno.

I think overall drivetrain is a better comparison anyway since the power has to go through all the moving parts, will be interesting to see just how much more efficient the new YXZ designed drivetrain is, or if it is even more efficient, I assume it will be but you know what can happen when you assume.

 

[gscott]

Thanks much for all of the input. Very helpful.

I have never been a fan of the CVT - not a sled guy and have only rented a RZR. I plan to buy ASAP but have been waiting for the YXZ.

I friend was on a group ride in Baja, came back with photos of a burning RZR 900 they had to abandon on the side of the road. They attribute the fire to an extended period of high speed running, on asphalt, that melted the belt to the point of starting a fire. Not sure if there may have been another cause - the burned hulk was left in Mexico.

My friend was riding a Can Am and also trashed a belt on an extended (10 miles plus) stretch of asphalt on this same trip.

I realize the XP has improved CVT cooling, and guys win Baja races with the CVT.

Thanks much for all the added inputs - great forum.

 

[Desertdog]

They change belts during the Baja race.

 

[jajl22]

Belt temp gauge would have helped your buddies a lot, when they saw the temps starting to rise could have backed it down a bit and then got back on it when it cooled. CVT's definitely have there place but i think the next logical advancement is in getting rid of the CVT, hence the reason the YXZ could be a game changer.

Anybody ever taken the time to Dyno a new honda 1000? wonder what the loss is through their drivetrain and DCT setup.

 

[Hotrodbanshee]

Ya git rid of the crappy belt cvt transmission.

 

[dbmachine]

You shouldn't have to buy a belt temp gauge to make sure your belt doesn't get too hot. She be designed and tested enough do that a belt getting too hot to catch on fire or explodes never happens

 

[sand shark]

Please stop using logic and fact to make your point. The facts keep getting in the way of what people want to believe......................................................Tim

LMAO!!! Don't mess with an engineer.

 

[sand shark]

They change belts during the Baja race.

Depends on the race. Some can go an entire race on one belt. I believe the Murray's have done it a few times in their turbo Maverick and Johnny just did the Vegas to Reno race, over 500 miles of racing on a single belt in his Turbo XP (that race was in 100+ degree temps). I think the manufactures are getting much better with the CVT system.

But the transmission set up in the Yamaha will give hp junkies lots of room for more hp. The only thing that will get lots of abuse is the clutch itself.

 

[NSaneturbos]

Efficiency loss is something that needs to be measured consistently. I have lots of data on the first XP 900. OEM says it made 88 HP but to the wheels only produced 68.7hp at 400 ft of elevation. If those numbers were consistently measured, you could assume that a CVT would consume about 21.7% of power output but of course, that's not on the same dyno doing the same test. As an engineer, you'd need to establish the drag on the crankshaft with the weight of the clutch, then the drag of the belt and springs, which is the only way a CVT knows how to move is with pressure against the springs, centrifugal force and helix angle. But, we also need to measure the transmission gear ratio drag, axle weight/length, wheel/tire weight/ height that also affect the output (which they do), so you can't blame a CVT for the entire power loss. It gets pretty complicated pretty quick... From an engineering standpoint, I'd say it safe to say that a CVT claims between 9-13% power but that all starts to change with weight, spring pressure, helix angle, etc.

What I can tell you, CVT's keep an engine in an optimal RPM range of operation but they are by no means efficient. They're heavy and they smoke belts.... The heavier the vehicle / more power the vehicle makes, the more belts you get to smoke. Spring pressure, alloy friction, absolute temperature, cooling efficiencies, and belt surface area become major factors in belt wear. It's a circle jerk for people who were trying to engineer a vehicle that "anyone" could drive without spending the money for an automatic transmission.

 

[rpmaddict]

CVT's definitely have there place but i think the next logical advancement is in getting rid of the CVT, hence the reason the YXZ could be a game changer.

I actually believe that the next advancement will not antiquate belt driven CVT's. What I do believe is the evolution of the sport is steel link belts, much like the auto manufactures have done with their CVT's in hybrids & such. I think that there is a market for clutch shifters and there will be a bigger market for auto-paddle shifters.

As to the HP loss on CVT's vs the output on the manual clutch, I think what gets lost in the conversation, partly because it doesnt really fit anywhere, is the ability to bring the rpm's into the torque range via the clutch. In the MX world, we call that 'feathering'. In the old school auto world it might be referenced as 'side-stepping'. Anyway, there are huge advantages (for me anyway) to have the ability to use the clutch to get more wheel spin or power to the ground. Hard to quantify that in a discussion but it is very real. That is why the clutched shifter works for me. I want. I need. I beg.

 

[jesseowen30]

Gotta take into account that not all CVT's are setup optimally, once a guy starts playing with weights and springs, and changing tires, he could really be shooting himself in the foot power wise. The 40hp loss on the turbo XP seems like a bit much, maybe the clutch alignment was off a bit or something. Just the fact that we wont have to mess with the weights and springs is a plus, Tennesee said you can start in 3rd and roost the tires, so I'm sure adding 30" tires wont be a problem. Cant wait.

 

[Flying Tiger]

The turboXp has 28% power loss from Crank hp to wheel hp. This has been proven by two companies on RZRforums.net, i believe it was Alba and Evo who posted dyno number for stock turbos but please don't quote me on that as i bounce around to a lot of different forums.

Obviously this is not strictly cvt power loss but will give you a vehicle to vehicle comparison once the YXZ's get on the dyno.

I think overall drivetrain is a better comparison anyway since the power has to go through all the moving parts, will be interesting to see just how much more efficient the new YXZ designed drivetrain is, or if it is even more efficient, I assume it will be but you know what can happen when you assume.

You are correct.
Also:
With tax, license, set up and shipping, a roof and a bumper the Rzr turbo is flirting with $30K OTD in some parts of the country.
Some dealers are asking $2k over MSRP for the Rzr.
Being outrun even by the boosted Maverick has eyebrows lifting.
That's a lot of money difference for pricey vehicles to begin with.

Plus time for a change.
Jus' my 2 cents worth.

Polaris might lower the price on the Turbo significantly soon enough.

 

[Hoseclamp]

My '12 outlander 1000 and '14 maverick Max both were a very close 29% loss at the wheels, 2,000ft elevation, forget the name, wasn't a mustang dyno. '15 xds turbos, I've read reports varying 90-94bhp, a 22.3-25.6% range of loss, mine already was modified by the time it arrived for tuning, no idea what it would of made stock. I do know very little for clutching was done with my build, a c12 belt and maybe something else, it works very well, no slipping and rpm's near peak for the cams that went in. Ride report so far from builder/tuner is "Dude this thing is fkn retarded, I want to keep it" Lol. This is from a guy that builds +300bhp renegades and outlanders, with racks and winches and runs down full race banshees all day long, so it must be good Can't comment on xp1000's.