Transmissions, Horsepower, and can I make my ‘86 500 faster than a ‘13 eSS race bike

So the past few weeks ago I ‘d had a few different things I have been musing about, and then I realized they all were related.  I am just going on one of my musings here, so if you see something not right, feel free to speak up.

Anyway, I wrote a post that went up a few weekends ago comparing the Empulse R to the Zero S 11.4.  Lots of comments were written, and I was corrected many, many times.  You should check it out.  This coming after I recorded my post interview musings about why you elmotos should have a transmission, which I then re-recorded because you hear me babbling on enough.  That all came after a thought I’ve been mulling over about whether or not I could build my ‘86 VF500F Interceptor up enough to beat a track prepped Empulse TTX or 2013 Zero S, which followed the past few months were I am beginning to think that horsepower actually is a completely fair way to judge elmotos to ICE bikes.  They’re all related, trust me.

Lets start with my old ‘86 VF500F Interceptor as a point of comparison.  Why my old 500?  Well, I’ve owned one before and know it well, and really some of its performance numbers put it in line with the current line up of Lightweight class of motorcycles.  Even though at the time, it was the class leading middleweight.  It will also help to show how far modern bikes have and haven’t come in the past almost 30 years, and hopefully also give a better frame of reference to compare electric motorcycles too.  That, and I can’t resist poking at both Brammo’s and Zero’s eSuperStock teams.  So, back in 1984 when the 500 Interceptor first came out it was claiming 68hp and 31 ft-lb of torque at the crank, which when tested translated to 53-54hp, and 26 ft-lb of flat torque to rear wheel on the dyno.  It was also running 0-60 in 3.9 seconds, with 1/4 miles runs in the 12.66 to12.67 range at 102 to 105 mph.  Top speed on what Honda claimed was the most aero bike of the time was 122 (recorded by a magazine), but gearing was supposed to be good for 127 at the 12,00rpm redline.  125mph is what most 500 owners seem to agree with.  The weight one moto rag claimed, with a half a tank, was 432lbs; while another got 447.5lbs with a full tank.  So basically lets say 30 lbs lighter than an Empulse, but about 80lbs heavier than a ZF8.5.  Again, Zero has a big weight advantage, and that’s with the 500 running narrower tires than even the Zero.  Something we are missing are hard numbers from the electrics.  No magazines have published actual weights, 0-60 or 1/4 miles times, much less actual top speed.  Also, neither Brammo or Zero are claiming 0-60 or 1/4 miles times.  When pressed around the May release, a sub 6 second 0-60 time was mentioned.  But Zero is claiming a top speed of up to 95mph, and Brammo of over 100mph, but reports are about 105mph on the R, and 110mph on the TTX.  If 0-60 times are that far off, both bikes are seriously going to need that immense torque (40/60ft-lb from the Empulse and 68ft-lb from the Zero) to even be in the same neighborhood of the old Interceptor.  Top speeds are already 20-30mph down and then to think 0-60 time would be almost 2 seconds off of bikes that all have identical peak hp?  Well, Honda claimed 68hp on the 500 at the crank (yeah right) but the 54hp (or 40kW) peak power Brammo and Zero are claiming are at the “crank” so we have yet to see what they are putting to the rear wheel (props to BRD for putting the Red Shift on a dyno almost first thing and posting it!).  The Zero should have much less loss than either a gas bike or the Brammo at the wheel where they don’t have a transmission.  Either way, the 500 should have an edge in rear wheel horsepower, but will be lucky to have half the torque of either bike, and really closer to a third.  So how does a bike with maybe just a bit more horsepower and a fraction of the torque have such a top speed advantage, and probably 0-60 time dominance?  I really don’t know, and I suspect here in lies they key to understanding the difference in how ICE and electric motors work in motorcycles.  But I can’t help but think some of it has to do with RPM.  The 500 makes it’s peak at 11,000rpm with a rev limit of 12,500rpm, the Empulse at 8,200rpm which is it’s rev limit, and the ZF11.4 at 4300rpm with a rev limit of 6,200rpm.  In the ICE world rpm limits are becoming a very easy yet effective way for governing bodies to control speeds and even fields in racing.  A modern 600cc supersport revs to 15,000 rpm and makes just over 100hp at the rear wheel.  But to compare apples to apples, at 11,000rpm they are all making about 85-90hp on the dyno, so clearly there have been some improvements along the way.  Following this rabbit hole for a second, if you compare the 1984 review and testing of the 500 Interceptor by Cycle magazine, and the numbers from the 2011 supersport shootout did you’ll find little has changed in many ways.  First the bikes only weigh about 20lbs less with full tanks.  The old Cycle article quotes 50mpg, but with my old wore out 500 that was 35 city 50+ highway, and I was hitting reserve at 120 miles while in town.  Then the Cycle article lists 142 miles before hitting the reserve, which they claim got you another 47 miles.  It seems hitting the highway I’d get 180 out of a tank.  The modern 600s were getting 145 to 160 miles out of a tank, and mpg in the low 30s.  So they go just as far with bigger tanks and hence suffer in fuel mileage.  Braking from 60 the 500 had all of them beat by at least 2 whole feet, at 121ft, but I’ll declare that a wash.  So the new middleweight sportbikes don’t brake any faster (well, from 60mph), don’t go any further, get worse fuel mileage, and only weight 20lbs less.  So how are they better?  In short, horse power.  Peak power, as I said before, is just over 100hp and peak torque is up to either side of 44ft-lb, ranging from 10,100rpm, to 11,800rpm with the 500 getting it’s at 10,500.  There is a physics lesson in there somewhere I am sure.  What this does for you is drop your 0-60 times 2/3 of a second to low 3s, takes 2 whole seconds off of your 1/4 mile times while you run through the trap 25mph to 30mph faster, and 40mph higher top speeds!  Ohhhh.  What is a lot harder to quantify is chassis, suspension, and tire development which really has been as significant as power developments.  I would do this with lap time comparisons, but I can’t find any to compare.  Clearly, no matter what they say comparing these bikes to 600 4-cylinder sport bikes is not particularly realistic.  The electrics will pull harder in all the places outside the meat of the 600s , but they are pulling harder on much taller gearing and running out of rpms much sooner.  A better class to compare them to is the lightweight class, or apparently women’s bikes.  Huh?  I’m talking bikes that are either 650cc twin cylinders, or of similar performance.  My 500, because of it’s age, would be in this class and modern 400cc 4 cylinders.  However, the comparison did of these bikes was labeled, “2012 Women’s Street Bike Shootout.”  Hey, don’t get mad at me, I’m just the messenger.  I guess this means the marketing folks tout the new electrics as women friendly.  Jay Leno says that back in the day when electric cars were popular, they were most popular with women because of the ease of use and minimal maintenance.  Really, the article could just as well be labeled “Beginner Bike normal sized American’s Shootout.”  Come, on, like a CRB250R is a good bike for a 6’ and 200lb dude.  Anyway, if you still think I’m trying to innuendo that the electric bikes are for girls, then you know where to send the hate mail.  Mean while I look forward to Brian and Kenyon not returning my messages anytime soon [sigh], or maybe some good ol’ smack talk.  Anyway, this test included a BMW F800R, Ducati Monster 696, Kawasaki Ninja 650, Triumph Street Triple R, and Yamaha FZ6R.  So that is three twins (one V and two parallel) ranging from 649cc to 798cc, a 675cc in-line triple, and a 600cc in-line 4.  So all of these engine types are known for their torque, accept the in-line 4.  However, all of these bikes are also in a street fighter configuration much like the Empulse and Zero S.  Those two really do fall well into this category.  And really, so doesn’t my 500.  0-60 times range from 3.71 to 4.45 seconds.  1/4 mile times range from 11.91s @ 118mph to 13.23s @ 102.9mph.  Weights vary from 414 to 477 pounds.  In that respect the 500 and Empulse would be in very good company, while the Zero would crush everyone with its small weight numbers.  Horsepower though, hits the rear wheels and three bikes are from 64 to 68 hp, while there is 74hp, and 95hp as the outliers.  These ponies all coming anywhere from 8,200 to 9,900rpm, with the Triumph again being the serious outlier at 11,800rpm.  Torque is all over the place going from 39 to 52ft-lb of peak torque, and coming in anywhere from 5,800 to 10,100rpm.  Here’s something to note.  The Ducati is lighter by 30lbs, has 15 more horse power and 20 more ft-lbs of torque, but 2 less cyclinders that make peak power only 1,500 rpm sooner and a rev limit of 9500rpm, and runs 0-60 .5 seconds slower, as well as the 1/4 mile .6 seconds slower than that 500 did back in 1984.  The electrics and my 500 would be way down on HP.  My 500 would be way down on torque, while the electrics would have the run of the place in that respect.  But by the numbers my 500 is in the game, even against the 2012 FZ6 4-cylinder.  WTF?  This should give you some insight into why pigeonholing certain bikes into certain performance categories is a bit useless, and maybe why you should take articles from the 80’s with a grain of salt.  Really want to throw a monkey wrench into the works?  Put 10 different riders on all the bikes at a track day and watch any hope of congruency fly straight out the window.  By the way, these bikes are priced from $7,499 to $10, 840.  But with their peak torque being all but constantly available, I think the electrics would make short work of all of these bikes anywhere over 20 or 30mph, accept for the Triumph which would only be very nervous in the twisties with the Empulse probably either a head or right on its tail.  And I suspect the BMW would be keeping their taillights in sight wondering where those damn American bikes came from. 

And now, after all that, it’s time for transmissions.  Here’s the deal, no one knows better than Brammo how much you have to compromise with a single speed transmission.  They have done it on their race bikes for 2 years now, and won championships doing it, being way down on power compared to other American teams.  I would even go so far as to say they would know better than Zero.  When you only have one gear and maybe 60kW/80hp, gear ratio goes from important to absolutely critical.  A friend of the blog and guest on my round tables Michael Beatty (@protomech) made a simple chart showing 0-60 times and top speeds attainable given a certain amount of power.  This isn’t particularly scientific but is based off of his 2012 Zero ZF9’s weight and performance. 

Here’s a set of hand-wavey top speed / acceleration tradeoffs, given a single speed transmission and ~400lb bike weight:
20 kW, acceleration: 6s 0-60**, 50 mph top speed (2010-2011 Zero X)
20 kW, top speed: 10s 0-60, 90 mph top speed (2012 Zero S)
40 kW, acceleration: 4s 0-60, 85 mph top speed (2013 Zero FX)
40 kW, top speed: 6s 0-60, 105 mph top speed (2013 Zero S, 105 mph gearing)
80 kW, acceleration: 3s 0-60, 100 mph top speed (600 class power, traction limited accel)
80 kW, top speed: 4s 0-60, 140 mph top speed
120 kW, acceleration: 2.5s 0-60, 140 mph top speed (1000 class power)
120 kW, top speed: 3s 0-60, 170 mph top speed (basically Lightning’s race bike)
You can see there’s only a small time difference in acceleration between the acceleration and the top speed gearings once you get to 80 kW.
A typical sportbike is about 3s 0-60. I think we can do a bit better than that with electrics.

There’s something else you have to consider too, torque aint’ everything.  Torque really is what you should be going for but if you don’t have enough to pull the gear fast enough to keep up with that high reving high horsepower engine, it’s useless.  Elmotos have gobs and gobs of torque forever, but at low rpm it takes a lot of amperage to pull a big gear, and that is asking an awful lot from low voltage (100V-ish) low power (40kW/54hp) system.  More so from the controller and batteries than necessarily the motor.  So while you will have a bike that pulls like a freight train once it is moving and has inertia on its side, getting off the line like any of the ICE bikes mentioned so far, and in similar times isn’t possible while keeping a decent top speeds without a transmission.  In 2011 Brammo was running basically a 60kW/80hp (maybe) motor in their race bike.  But as Brian said recently in my interview with him, they are using a high voltage (350V+) system (and typically with high voltage come higher rpm and less trade off in gearing).  So lets assume a 4.5 to 5 second 0-60 and a top speed of 130mph-ish.  But we know they used a different gear ration at each track, so for each track these numbers changed.  Heck tire size affected their lap times by keeping them from the optimum final gear ratio.  I agree with Michael, at about 80kW/107hp you start to lose the need to compromise.  To compete with my 500 and the other light weight bikes there is no need for a transmission to run similar 0-60, 1/4 mile, and top speeds.  But, it might still be a hard draw on current and batteries at that point.  Also, that is power that is right in with the 600cc supersport bikes.  They are running low 3 seconds 0-60 with top speeds of over 160mph.  To match that performance you need a transmission to match the 0-60 times, and reach the top speed, and make life on your controller and battery pack easier.  Lets look at the 2012 Zero S.  Using the generic chart above, at 95mph top speed we are looking at 0-60 times in the 5 second range.  For a motorcycle, that’s slow, especially one that light that wants to be taken seriously.  And I have reservations it will be that quick off the line.  I just read the opinion from apparently the only other person to have ridden both 2013 machines, and apparently there is still some initial sluggishness off the line by the Zero.  This person said the 2013 Zero’s motor was a monster, but you could still feel a bit of hesitation, while the Empulse will kick off the line harder.  I feel this is for three reasons: 1) current draw, 2) gearing, 3) beginner rider friendliness programmed in.  It’s a pain really, because all the reviews of the bikes say these things accelerate like superbikes once at speed, and really that’s where you need it and where it is an advantage.  But the American market is driven by numbers and, to a certain degree, for a reason.  0-60 times of 5 or 6 seconds and top speeds of 95mph to 105mph is a poor showing if you want to be taken seriously as a motorcycle that just happens to be electric.  The Zero’s biggest asset is it’s light weight and, as far as I can tell, it’s magic motor.  Seriously, an air cooled motor with a size 4 controller shouldn’t be such a beast, much less be that light.  But the numbers aren’t jiving.  Even if the bike pulls like a GSX-R1000 after 25mph it’s still going to hit top speed before the 1/4 comes up and probably not post a particularly impressive 1/4 mile time.  Irregardless of the Zeros performance the Empulse had damn well better see better than 6 second 0-60 times.  With a top speed of 100mph, you’d think we’d see 0-60 times in the 4 second range.  But with only 8200rpm, 54hp, and 60ft-lb of torque, I think even that is a tall order without putting some serious hurt on those batteries.  I am actually really curious about the gear ratios within the Empulse’s gearbox.  My 500 has I’m sure faster 0-60 times, a much higher top speed, and way less torque with the same amount of power.  Because of this I suspect the Empulse has a really close ratio gear box, and wonder why it wouldn’t be wider.  I’d like to see an Empulse where if you nail the throttle off the line 1st gear is low enough that it floats the front wheel with just enough power allowed out of the batteries without straining the pack or controller, and the rest of the box spaced out so that 6th gets you that 105mph top end.  If it does that and still doesn’t put in a sub 4 second 0-60 then I give up.  Here’s another reason for a transmission.  Wheelies.  Yes, the FX will wheelie all day long, but it weighs less than 300lbs and is not a proper sportbike.  People can argue all day long that electrics have all this kind of power and don’t need transmissions, and they add too much inefficacy, and single speed is so easy to use, and blah, blah, freakin’ blah.  But numbers don’t lie, and under a certain power level, they are necessary to be competitive with gas bikes.  Clearly, via the EPA’s range tests, they aren’t that inefficient.  Although, they do appear to be heavy. did a review of the Brammo and asked if it needed a transmission.  They complain that they didn’t understand what gears 4-6 were for while riding through the twisties.  Well, I don’t remember using those gears in the twisties on my bikes either.  Maybe 4th on my 500.  Really you could say the same thing for any of the sport bikes they have ridden on the same roads.  It seems a silly argument to me now that I’ve thought about it a while.  You have to dance on the shifter for those ICE bikes, where the Empulse don’t have to, you are just rewarded if you do.  It’s simple, with a transmission there is less need to compromise.  You get you acceleration and top speed.  Until powerful, high voltage bikes like the MotoCzysz, Lightning, or even Empulse RR hit the streets, transmissions will be quite useful.  Not necessary, but useful.  Really this argument is no different that  whether one should get a VFR1200 with their DCT (automatic) or regular manual transmission.  Harder edged riders chose the manual every time, where folks who either want an easier, smoother, or in some ways more pure motorcycling experience will take the DCT.  I get scoffed at by doing this comparison, but read the reviews of the DCT and of people going on about their experience with a single speed elmoto, and you may be eerily surprised by the similarities.

Now, back to my 500 and onto horse power.  I know, “enough already,” but bare with me.  What has become clear is that either Cycle magazine was horrible at timing back in the day, or Honda got a lot of performance out of a small package.  Bikes with more power and less weight are slower in the numbers.  Some of this has to do with how fast the motors spin up, which is where I think the 4 cylinders have an advantage.  They can spin up faster and higher achieving more horse power and acceleration.  But with that comes a smaller power band and reliance on the high revs to pull you out of a corner rather than torque.  It seems to be a trade off that pays.  I have read every review of the Empulse and 2013 Zero S that I know of, and something started jumping out at me.  Everyone comments on how hard the bike pulls but they all still say it feels like a lightweight twin power wise.  In my last interview with Shelina she mentioned that Eric Bostrom the Empulse RR was wheelieing like a liter bike out of the corners at the track, but putting in 600cc lap times.  And, more so than piston engines, electric motors can spin up really fast due to the lack of and kind of inertia or friction needed to be overcame.  A’la Atlas’s highside at the first round of 2012.  Mark Miller will want to talk about the torque, but he’s never been allowed to pin the throttle, so . . .  Torque is great but power is power.  So it appears that in the case of the RR even with a whole lot of torque 130-150hp still nets you performance similar to a 130-150hp gas bike.  The flat and instant torque curve is an advantage because it gives you all or almost all of the torque on demand at any rpm, which makes accelerating out of corners a whole lot easier and faster.  I chased a buddy on a Buell in the canyons one day with my VFR.  He shot out of the corners like no one’s business, but any kind of straight and I was amazed how fast I reeled him in.  I maintain that torque with out power to take advantage of it, is all but pointless.  Also, there is a reason racing exhausts sacrifice torque for hp.  Electric motors deliver tons and tons of torque, and pretty much constantly through the entire rev range, but there is no substitute for (horse) power.  So I conclude that comparing horse power numbers is not irrelevant at all.  That brings me back to my 500.  Now my bike is an ‘86 and I finally found the numbers on it.  There is a wider and flatter torque curve with the sacrifice of 1ft-lb of torque, and 2hp.  Also the motor is still making power at the rev limit of 12,000rpm, unlike the ‘84 500 where peak power came much earlier at 11,000rpm and then fell off.  Everyone in the review seemed to like the later motor revision better.  The bike did seem to gain weight as it weighted in at 459lbs with a full tank, and the 1/4 mile time slipped to just over 12.7 seconds.  Since I now officially believe power is representative, I think my stock 500 might just be quicker than these two bikes in the motor department.  I know 0-60 will turn out to be quicker, and top speed is already a know 20mph faster.  We don’t know what these bikes are putting down to the rear wheel yet, so my 500 may very well have a power advantage.  On the track the 500 would jump off the line harder, but the Zero and TTX will be running hotter maps and that may make a significant difference.  In that case the full exhaust and carbs for the track, what I have (had depending on what’s happened back in Maine) will do the trick nicely.  I don’t think over 60hp with a big jump in torque is out of the question, not to mention the loss of 20 to 30lbs just in exhaust, and the loss of all of the street gear.  So jumping these guys off the start and getting to the first corner is pretty much a given.  But while the 500 “Miniceptor” was really well known for it handling, it’s no Empulse.  I think a horsepower track like Willow Springs would give my 500 an advantage, but over at the Streets of Willow, it might just succumb to the superior chassis of the Empulse, lightweight of the Zero, and corner exit launching torque of both.  Give me $1500 and I can bring 500’s suspension into the modern era, as well as upsize the wheels so I can put on some serious rubber.  This would at least help fend off the wolves at the apex.  I think my darn near 30 year old bike would put up a heck of a fight and be in there depending on the course.  But it would be really close with the elmotos modern chassis, light wieght, and course selection being the difference.  But any kind of straight and these bikes will find out first hand just how mean even a little 500cc V4 sounds at full song.  I went into writing this post thinking a track prepped 500 would walk the elmotos, and if it ended up with a 10+hp advantage it just might just be able to pull away.  But I now walk away thinking it’d be a right ding-dong battle.

The bottom line is we need professional press to ride both and get some real data numbers, and throw these things in with the likes of the middle weight street fighters, and Women’s bike shoot out, and even supersports and liter bikes, and see just where the performance stacks up; range and price be damned.  Those things we know are coming with time and we can’t do a darn thing about it, but wait patiently.  Performance, though.  That we can mess with right now.

3 thoughts on “Transmissions, Horsepower, and can I make my ‘86 500 faster than a ‘13 eSS race bike

  1. At low speeds (so 0-60 times) the battery is not really a factor because battery current draw is low (motor current is high). 0-60 times are controlled by the controller and the gearing. Sometimes the motor can be a little, but not with the Empulse or Zero. Top speed will be harder on the batteries because that is when high battery current is needed. The motor might be an issue, but that depends mostly on it’s efficiency and cooling at top speed.

    The Brammo transmission can’t really be spaced any more (I heard this somewhere). There are limitations with gear sizes and how far each gears ratio can be apart, too far and the controller can lose “control” of the motors speed or potential for overreving on an down shift. It can also start to cause a lot of wear on the gears when shifting. I’m pretty sure they have 6gears to keep the ratios close enough.

    “Also, there is a reason racing exhausts sacrifice torque for hp” – Doesn’t make any sense. HP = Torque X Speed. Engine RPM doesn’t change and Torque decreases, HP can not increase. I disagree it’s all about torque. That’s why Brammo has a transmission to increase wheel torque, not wheel HP.

    0-60 times is about having as much wheel torque as possible and being as light as possible. This is done with gearing (limited in a single speed) and motor current (limited by the controller). Top speed is limited by having the right amount of wheel torque at a given wheel speed and aerodynamics. First limit is gearing, second limit is motor heating, third limit is battery current delivery, fourth limit is controller heating.

    1. “’Also, there is a reason racing exhausts sacrifice torque for hp’ – Doesn’t make any sense. HP = Torque X Speed. Engine RPM doesn’t change and Torque decreases, HP can not increase. I disagree it’s all about torque. That’s why Brammo has a transmission to increase wheel torque, not wheel HP.”

      In an ICE engine torque is most definitely not constant, so your equation is right but your application is not. You can have an exhaust that is tuned for more mid-range and end up with a higher peak, but because that peak torque is lower in the rev range and not in the high rev range the result is lower peak hp. Tuning the exhaust for more torque in the top end when multiplied by the rpm results results in more peak hp, but as almost all engines lose torque as the revs approach the redline it results in less peak torque. So, it makes perfect sense.

      Why would having a slightly more spaced out 6 speed ratio wear out faster? I’d imagine even if it was spaced out a bit more it’d still be within ratios that can be found in production motorcycles.

      Thank you for clarification on the amp load on the batteries.

      Really beginning to think it is a lot more about rpm.

      1. Ok I understand you on the exhaust bit. The exhaust isn’t sacrificing torque, it is relocating it in the rev range. But yea peak power may be sacrificed because the torque is more important. I don’t know a lot about exhaust systems and without the clarification, that single sentence did not compute for me.

        When you shift you are slapping two gear teeth together that were just spinning around with no load on them. The higher the difference in teeth of one gearset that greater the force is on those teeth (unless you make both gears bigger). This causes extra wear. The higher the difference in ratio from one gearset to another (ie second to third) the more larger jumper there is in torque/rpm. Unless you rev match perfectly there will be inertial energy absorbed by gears themselves.

        I haven’t studied multispeed transmissions themselves, but I took a class on gears and tooth loads and all that good stuff. The wear is not going to be too significant. There are inherent limits of specific gear ratios and ratio jumps that can be used in a transmission.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s