Fast Freddy
Well-Known Member
i find it hard to believe that the % of drivetrain loss is HIGHER on a GEN 1 V-Max than my Ford GT, Viper and Corvette :confused2: :ummm:
True Horsepwer?
- Thread starter Donald02max
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OK, just so you have an idea I guess.
In your average car the engines power is transmitted in a rotational direction to the front/rear of the vehicle. So, your power goes into the crank, through the clutch, into the trans, and more or less straight out to the rear end. So, then we get to our first change in direction to the rotational energy (where it really robs power). This changes from front to back to a side to side rotation through the worm gear. Then finally it gets to the tires.
In the Vmax the crankshaft runs completely different to the front/rear centerline. If it were chain drive this would actually be ideal to have it rotate the same as the wheels. BUT, since it's shaft drive we have some issues to overcome.
So, we turn the crank, which turns the clutch, which turns the transmission. All pretty much in direct correlation to each other like the car does. BUT, we've got to get the power back to the tire. So, we add it's first 90 degree turn. Now we can finally go back to the wheel. BUT, since it's not turning the right direction for the wheel we have to do it AGAIN! So, yet another power robbing change in direction.
So, besides the weight losses a chain drive conversion makes we also free up (not make) the engines available hp to the wheel. The chain drive actually has less losses then the car at this point.
So, hopefully this will "shed some light" on why there is a lot of power loss with our drivetrain.
Sean
In your average car the engines power is transmitted in a rotational direction to the front/rear of the vehicle. So, your power goes into the crank, through the clutch, into the trans, and more or less straight out to the rear end. So, then we get to our first change in direction to the rotational energy (where it really robs power). This changes from front to back to a side to side rotation through the worm gear. Then finally it gets to the tires.
In the Vmax the crankshaft runs completely different to the front/rear centerline. If it were chain drive this would actually be ideal to have it rotate the same as the wheels. BUT, since it's shaft drive we have some issues to overcome.
So, we turn the crank, which turns the clutch, which turns the transmission. All pretty much in direct correlation to each other like the car does. BUT, we've got to get the power back to the tire. So, we add it's first 90 degree turn. Now we can finally go back to the wheel. BUT, since it's not turning the right direction for the wheel we have to do it AGAIN! So, yet another power robbing change in direction.
So, besides the weight losses a chain drive conversion makes we also free up (not make) the engines available hp to the wheel. The chain drive actually has less losses then the car at this point.
So, hopefully this will "shed some light" on why there is a lot of power loss with our drivetrain.
Sean
Fast Freddy
Well-Known Member
the chain drive conversion for sure indicates that a BIG gain in RWHP is to be had by ditchin the shaft drive. it just amazes me that it is that inefficient. it seams that the GEN-2 is way more efficient than the Gen-1 for whatever reason which i find confusing too....
donnelly317
Well-Known Member
Well I got the PCW 1260, receipts say factory stage 1 jet kit, just a normal air box w/K&N and a kicker 4-1... my dyno only say 135 at rear wheel.. I thought that should be more.. it has higher compression ration pistons too.. jon also day my mad max swing arm and kosman rear tire isn't very light... I wan 17's.
sdt354
Well-Known Member
Well I got the PCW 1260, receipts say factory stage 1 jet kit, just a normal air box w/K&N and a kicker 4-1... my dyno only say 135 at rear wheel.. I thought that should be more.. it has higher compression ration pistons too.. jon also day my mad max swing arm and kosman rear tire isn't very light... I wan 17's.
Was that dyno'd at PCW? The reson? Lots of Vmax's have been dyno'd there for comparison. I wouldn't be too unhappy with those numbers. A different carb kit might get you higher. I think the stock air box has some serious hp limitations too, in your case. Just my H.O.
Steve-o
donnelly317
Well-Known Member
Yea where ever pcw does there dynoing. Over the winter I wanna do jets with pod filters..
The gen 2 is just as ineffecient in their power losses in the drivetrain. It's a generally accepted number that 20% is the drivetrain loss. That would make a 145 hp engine like the gen 1 is rated only put out 116 which is in the ballpark.
The gen two's are only putting down 165-170 rwhp for the stock bikes. So, far less then the claimed hp at the engine.
Keep in mind not all dyno's are going to read the same. You can use more ideal settings and setups (like tire sizing and gear used) to read different numbers.
Sean
The gen two's are only putting down 165-170 rwhp for the stock bikes. So, far less then the claimed hp at the engine.
Keep in mind not all dyno's are going to read the same. You can use more ideal settings and setups (like tire sizing and gear used) to read different numbers.
Sean
Sonoran6
Well-Known Member
how about the torque? for a stock vmax
KJShover
Proud Vmax lover
78-85ish for the tq
Sonoran6
Well-Known Member
Right on. Thanks
Got to disagree with you there Sean on 2 counts.
Most every Gen 2 I've seen has made at least 170 stock. In fact the accepted average is 172. I've seen very few make under 170.
And if you accept the factory rating of 197 at the crank then a 20% loss should show around 157 -158 @ the wheel. So it seems that the either the Gen 2 driveline is way more efficient or the Gen 1 is overated at the crank.
The numbers don't lie!
tmosel
Well-Known Member
There are different types of worm gears and as such, each has a percentage of power loss. From as little as 2 percent all the way to 30 percent loss.
The ones we've dynoed don't make the 170 mark stock but again it's going to vary slightly from machine to machine. They are close but not quite there.
dingy
Well-Known Member
What do I do to help my scooter
Redid in a new Dyno thread.
Sorry
Gary
Redid in a new Dyno thread.
Sorry
Gary
vintage85
New Member
New here/know I'm late to this tread, but something is a miss so for anyone follow-up reading here's what I know: I owned an 85 in 1985, as did a friend who took his to the track on a regular basis. His stocker dyno'd at 124. something (don't remember exact number - been a long time), and in the years following (all vmax's made after 1985) (due to extreme accidents and insurance companies refusing to insure vmax's), Yamaha de-tuned all further units by changing the intake/extake somehow(rumer)... Ironically, when asked, Yamaha dealers couldn't tell you "what" Yamaha did, but it's been sort of a fact that the original 85's had the most ponies....question is, what was the actual de-tune, what is the remedy, and what are the real HP crank numbers for all the models following the 85's, which would explain the 110 - 115 rear tire numbers?
PS: Find the reviews in Motorcycle mags from the mid 80's who also dyno'd the max - all stockers were putting mid 120's on the rear tire...and slight modes to the 85's were getting some series numbers at the tracks even without chain drive!!!
PS: Find the reviews in Motorcycle mags from the mid 80's who also dyno'd the max - all stockers were putting mid 120's on the rear tire...and slight modes to the 85's were getting some series numbers at the tracks even without chain drive!!!
We've dynoed a lot of bikes of all years. The 85's do not make more power then any other year. I've run a number of different years of Vmax's at the track and there isn't any one faster year then any other.
There is no "facts" that show they make more power.
Keep in mind that the dynojet was devloped using a Vmax as it's baseline machine to set all the numbers with. So, they estimated it to be 120 rwhp and used the measured settings as that. Think of it as reverse engineering.
Here's an interesting read for you:
http://www.hotrod.com/thehistoryof/113_0603_dynojet_chassis_dyno/viewall.html
There is no "facts" that show they make more power.
Keep in mind that the dynojet was devloped using a Vmax as it's baseline machine to set all the numbers with. So, they estimated it to be 120 rwhp and used the measured settings as that. Think of it as reverse engineering.
Here's an interesting read for you:
http://www.hotrod.com/thehistoryof/113_0603_dynojet_chassis_dyno/viewall.html
85vmax
Well-Known Member
Thanks, Good read.
So, essentially, the Yamaha V-Max is the bike by which all others will be judged..Literally.
T$
ouchez
Well-Known Member
All that being said remember the the ZX14RR is flirting with 190 RWHP, STOCK ,and some 230cc less than the Gen 2 motor. Yama has to re-tune the Gen2 or it's sad sales numbers will get far worse.
Ouchez
Ouchez
sdt354
Well-Known Member
Someday I might dyno my Gen1 and would be more than happy with 120rwhp. I'm happy with the way it runs regardless.
Steve
Steve
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