• Oct 17th 2010 at 6:12PM
  • 18
VST Conversions BMW bi-moto EV – Click above to watch video after the jump

Back in February of 2009, a fellow hailing from Croatia showed up on DIY Electric Car, a forum for EV builders and conversion enthusiasts, saying he wanted to build an electric that is faster than 99 percent of the ICE cars out there. After many months of trials, tribulations and design changes, "CroDriver" may have done just that. But then, what else would you expect from a guy who uses a derivation of Newton's first law of motion – velocity is equal to distance traveled divided by time taken (V=S/t) – as the name of his company. Introducing the very slick, very quick BMW bi-moto electric vehicle.

So, how quick is it? Quick enough to pull down low 12s in the quarter-mile on an airfield dragstrip. Quick enough to whoop a Tesla in a street race. Quick enough to...well, you get the idea. For Mate Rimac (his "real world" name) though, it's still not quick enough. Not yet.

The 1986 E30 323 BMW that serves as the test bed for VST Conversions has already seen its motors swapped and batteries upgraded. The current configuration features a pair of power packs using Headway cells sending their juice through a Zilla controller to a Netgain WarP11 HV series DC motor capable of pumping out over 500 horsepower at the wheels. The next incarnation should include a new battery pack, a different motor (probably) and will take advantage of a custom two-speed, zero shift transmission to help deliver some serious horses.

While we wait for more news of the latest build, we can take great solace in the fact that Mate has a talented film-making friend who has put together some excellent videos worth watching. Our favorite pair await you after the jump, along with footage of that aforementioned Tesla Roadster street smack down.

[Source: DIY Electric Car]

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    • 1 Second Ago
      • 4 Years Ago
      Hi guys! I'm Mate (the maker of the green BMW).

      I'm reading autoblog several times every day because it simply has the best EV related information and I couldn't believe it when I saw this article today! What can I say besides thanks a thousand times!

      I was driving to Munich today to visit the e-car-tech (a exhibition exclusively for EVs and EV drive components) so I didn't had the chance to write a comment earlier, I just arrived to Munich... I have brought my professional camera with me so I can share my photos with autoblog... I'm sure that there will be lots of interesting exhibits.

      Btw. We're working on a lot of things that I'm keeping off the record, the BMW is just a cool test-bed for various components.

      Best regards

      Mate Rimac
      • 4 Years Ago
      Pardon my trolling, but the author of this article should educate himself on Newton's laws. Newton's 3 laws all pertain to force and accelaration (change of velocity). The definition of speed came far before Newton.

      On that note, VST should educate themselves on the definition of velocity. The velocity is defined by 2 values, it is (1) the instantaneous speed and (2) the direction of motion. For example, a change of direction even at a constant speed is a change of velocity, aka acceleration. Speed can be defined as the magnitude of velocity, or |V|. Distance traveled over time (S/t) is the formula for average speed, not velocity.
        • 4 Years Ago
        The post at hitxp is not technically accurate when it describes velocity. Velocity is a vector. It has both magnitude and a direction. Speed is the magnitude of velocity, and has no directional component. For instance, if I say that I am traveling 55 mph, I am giving my speed. If I say that I am traveling 55 mph at a heading of 45 degrees, I am giving my velocity. Another example: I can drive my car at 30 mph in a straight line. My velocity and speed are both constant. I can then make a turn. During that turn, I can maintain speed. Speed is still constant. My velocity, however, is not. During the turn, the direction component of velocity changes. This change of velocity is called acceleration, which is also a vector, with both magitude and direction components. The direction of the velocity vector is in the instantaneous direction of the car, which changes through the turn. The direction of the acceleration vector is actually perpindicular to the velocity vector, pointing to the center of the turn. Force, by the way, is also a vector. Newton's laws describe the effect of forces between different bodies on their acceleration. The Wikipedia link is fairly good at describing it, but this concept really would really be explained better by more visual explainations, possibly found on youtube.
        • 4 Years Ago
        I am somewhat familiar with the basic Newtonian laws of motion (an object in motion etc), though I did look the Wiki entry ( http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion) over while researching this post.

        In an attempt to figure out what v=s/t was about, I came across this page ( http://www.hitxp.com/phy/cph/071202.htm) where they it can be derived from Newton's equation.

        Physics is not my forté and so I relied upon the seemingly superior knowledge of this writer. Feel free to tell me why they are wrong.

        As for VST Conversions themselves, I don't know exactly why they chose to go with the name but I suspect it was directed more by the spirit of the equation rather than the literal application of it to automotive travel.
      • 4 Years Ago
      I am stunned to see someone using the headway cells outside of electric bicycles/motorcycles. I think the reason is that they can discharge more than the thundersky's.

      This is cool as hell and is a gerat example of how technology has passed since the Tesla Roadster was produced. Those Panasonic laptop battery packs are no longer state of the art!

      And props to them for an e30 conversion. What a perfect car to do it with! I keep going back and forth about whether or not i want to convert an e30 or Porsche... this is tipping me towards e30 now.
        • 4 Years Ago
        yes it is a nice build and yes headway have a lot more power than thundersky. thundersky is really a boring cell but it's popular because it's easy to work with and the price is decent.
        it's not quite right though that this is an expression that things have improved a lot since the tesla roadster was conceived. A123 cells (or chinese DLG for that matter) are more power dense than headways and they have been around for years now and so has headway. A123's latest pouch cell is even better, just a shame that they are so bizarrely obtuse that they wont actually let you buy the cells.
        the tesla pack could be pushed to do more but they were never concidered state of the art in power density. they are quite poor at that actually, still are. they were chosen for energy density and laptop cells still rule that arena. latest panasonics have more than twice the energy by weight of thundersky and headways so if you want to make a marathon runner there is no substitute for laptop cells. if you want to make a drag racer then it seems A123's 20Ah pouch cells are state of the art and they even have quite good energy density too (around 135Wh/kg is word on the street). but you can't get them because the sales people have less than stellar minds.

        if you wanted to make a name for yourself in drag racing but can't get A123 then chinese DLG have 26650 cells that perform very close to the original A123 cells, in some ways even better iirc.
        of course they are small cells and you have to connect about 1000 of them like killacycle did with theirs.
        and of course making the car light weight helps tremendously. aero too if the cars hits high speeds at the end. if you want to go really fast then a soft heavy steel car from the past or present isn't the way to go. fiber composite chassis, no heavy disc brakes, wheel hubs, rims, tires. done right it would easily be too fast for full power road use.
        killacycle fast or even faster.

        and if you flipped the battery premise to a larger pack of state of the art laptop cells then it's easy to make it go 1000+km on a charge (at 100km/h, level road, neutral wind). and probably still do a sub 3 second 0-100km/h

        when you again and again hear me say car makers should go light weight and aero, there is a good reason. if they did they could make cars you wouldn't believe were possible. affordable electric cars that make corvettes and ferraris look like the primitive steam locomotives they are. if the less than beautiful people at BMW ever make their carbon electric car you might see a glimmer of what can be done there. although given their betrayal by not showing it at Paris, I wouldn't expect anything relevant from them.

        btw, I'm the one who brought headway cells to the attention of the world
      • 4 Years Ago
      You know, I think I understood that. Thanks.
      • 4 Years Ago
      This Whtie Zombie had it's best time so far at 10.2 sec at 125 mph.
      • 4 Years Ago
      Tesla has to go with the cells they use for cost. If they had automotive grade lions to install in there car they would not need all the complexity of 6,800 cells with a water jacket.

      My automotive application lion batteries have never exceeded 33 degrees Celsius. You should not need water to cool the batteries and you don't need water to warm the pack up.

      BMS is further complicated by having 6,800 individual cells. When the cells only number in the 50 to 200 cells for a automotive application pack, EV's will have arrived.

      Nissan, with there approx 95 cells, air cooled have it right. Mass production of EV's will not take place using 6,800 water cooled cells for each vehicle. IMO.

      Sorry for making points already made, this post was interrupted.
      • 4 Years Ago
      This thing does not stand a chance with another street legal 1972 electric datsun by John Wayland. http://www.youtube.com/watch?v=pd9hDa-JHZ8&feature=player_embedded
      1/4 mile in 10.2 sec at 124 mph
      • 4 Years Ago
      The streets will be full of these BEV conversions if the cost of Li Ion batteries comes down.
      • 4 Years Ago

      It's all about the 電気。

      • 4 Years Ago
      "Those Panasonic laptop batteries are no longer state of the art"

        • 4 Years Ago
        Good point. The batteries in this conversion are optimized for high power, those tend to have lower energy density. Upshot, good for drag racing, but the driving range is less.

        Actually, it's kind of nice that there are a variety of batteries for a variety of uses!
        • 4 Years Ago
        Oh and by the way, i have some Chinese lithium polymer packs that put the Panasonics to shame in some areas. Discharge rate is 20c on 'em which is insane! Also.. lightest cells per ah i've ever weighed. Downside? less safe and needs voltage management.

        Panasonics are still good. But i would not build and sell a car with thousands of those cells in it. Then again, in 2006 Tesla really didn't have a lot of options.. unlike today.
        • 4 Years Ago
        @Middle Way
        The thing is, even with that many cells and supposed overhead, Tesla's pack is still the best in energy density in the industry. 18650 is pretty hard to beat in terms of energy density. Also even with that many cells, the failure rate per cell is much lower than the Chinese lithium poly packs (although they have gotten better recently). I haven't heard of cell failure in a Tesla yet (although there may be some tolerance built-in for individual cell failures so that it isn't noticeable to the user).

        For a guy doing a conversion, Tesla's approach is insane, with big cells obviously being better. But Tesla has the automation to make packs with that many cells and it seems to be working well for them.
        • 4 Years Ago
        The Tesla battery pack contains 6,831 "18650" laptop battery cells ( similar size as an AA battery ), which is quite ridiculous in terms of how much weight in battery casing / wiring is used. Also, what do you do when a few cells go bad? go hunt for a needle in a haystack, that's what! or toss the whole cell group ( more likely ). In short, it's impractical and heavier than it should be. The Panasonic cells themselves are great. It's their size that is a problem.

        For reference, panasonic cells are about 0.2-0.4AH each. Headway cells can be as big as 16AH, maybe bigger than that. Thundersky seems to range from 20ah to 7000ah.

        Big honkin' cells are better for a car! Then you can have a proper BMS, far less wiring, and far less headache when a cell dies later down the road..
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