Page 1 of 3 123 LastLast
Results 1 to 10 of 24

Thread: 450-452 subframe - Converting a Roadster to electric power

  1. #1
    Join Date
    Dec 2015
    Location
    Cambridgeshire
    Posts
    6

    450-452 subframe - Converting a Roadster to electric power

    Hi,
    I've just joined Smartz. I hope my question isn't offensive to petrol heads .

    My question is, is the 450 rear subframe exactly the same as the 452, I'm looking for the whole rear subframe with suspension, drive shafts and gearbox so that I can convert to EV. There are very few 452 frames on ebay so I wondering if I can buy a 450 and use that?...

    I'm looking to do a conversion to run full electric, I've owned my Roadster coupe for 4 years and love the handing and looks. I've also leased a Nissan Leaf and loved the power you get from a standing start, (I also got the chance to have a go in a Tesla model S which is in another league). But.. the worst thing about the Roadster is the lack of power from a standing start, it can be almost embarrassing at times.
    I think the answer is to make the Roadster electric, I only do 30 mile round trips at most so don't need much battery and once you've owned an electric car you know that charging is free almost everywhere and no car tax (for now). I bought the motor (AC35, same HP but more torque) , controller, switches and cables from ebay a year ago but with young kids never had the time to get on with it, but rather than dismantle the engine etc and be without the car I think the best thing to do is to buy another subframe, build up the electric version over time and swap it out once it's all up and running. It won't have the top end but should leave most cars standing at the lights.

    So my questions are;
    Will a 450 subframe fit a Roadster?
    Is anyone breaking a Roadster and have the parts I can buy?
    I will also need an old clutch plate to use the spline from, does anyone have a used clutch plate I can buy (none on ebay)?
    I've seen a couple of conversions on youtube but very little detail, has anyone here thought about doing it/done it?
    Last edited by crispy; 28-12-2015 at 11:14 PM.

  2. #2
    Join Date
    Oct 2013
    Location
    Swindon
    Posts
    200
    Only difference on a 450 subframe is that it has a roll bar but otherwise exactly the same
    I have a used clutch that you can have for 55 delivered
    2001 Jaguar XKR 100
    2003 Roadster Coupe Bluewave Brabus SB2
    2002 Ex Fortwo Pulse


    Smart,Mercedes & Jaguar Diagnostics

  3. #3
    Join Date
    Mar 2010
    Location
    Hampshire
    Posts
    1,985
    I know of 4 failed attempts to convert Roadster to EV but as yet know of zero successful conversions.
    So good luck with this...
    ==============================
    2004 Roadster-Coupe SB2 Brabus
    2005 ForTwo Brabus Numeric
    2014 Skoda Yeti 4x4 DSG
    ex 2002 City Coupe 600cc Pulse
    ex 2003 City Coupe 700cc Passion
    ==============================

  4. #4
    Join Date
    Apr 2009
    Location
    Ecosse
    Posts
    3,787
    What do you intend using as transmission between motor output shaft and drive wheels?

  5. #5
    Join Date
    Oct 2014
    Location
    Essex
    Posts
    304
    I have a 450 rear subframe, drums and with bilstein shocks collecting dust.
    Follow the Hayabusa powered Smart Fortwo build here

    YouTube Video's Here

  6. #6
    Join Date
    Nov 2007
    Location
    BANCHORY
    Posts
    3,402
    Here is a link to ClubSmartCar with conversion of a 450 to electric. Interesting read.
    http://clubsmartcar.com/index.php?showtopic=23469
    Drives a Smart Cdi - 65 to 85 MPG

  7. #7
    Join Date
    Nov 2007
    Location
    BANCHORY
    Posts
    3,402
    Nice video here:
    https://youtu.be/eSOCvnaIFKE
    Drives a Smart Cdi - 65 to 85 MPG

  8. #8
    Join Date
    Dec 2015
    Location
    Cambridgeshire
    Posts
    6
    Thanks for all the information, really handy to know that the 450 subframe is the same. The fact that there have been many failed attempts makes it sound more like a challenge so I'm really keen to make sure this works. My biggest issue is time as I'm sure it will take longer than I hope or expect.

    The plan is to use the AC35 motor I have coupled straight to the standard gearbox and use the drive shafts etc just as they are, there are more losses but it's the quickest way, spec changes dramatically depending on voltage but at 144v it will do 120Nm from 0-5000RPM but I would only run at 80v to start with as the controller I have is limited. Ideally I'd strip out the gearbox and fixed in gear (so I'd be interested in anyone with a slightly duff gearbox) but to start with I'll keep the ability to change gear as I'm not sure of the best ratio yet, perhaps using 2nd and 5th would give me the best range with low for fast pull away and a high gear for lower rev top end, although the motor will rev to 8000RPM but the torque falls off quickly then. Using the standard gearbox should mean I only need a simple coupling and face plate and that will be the mechanics done although I might make use of the standard radiator and a water jacket for the motor for cooling, I could also water cool the controller heatsink. Alternatively I could use the side ducts for forced air cooling and make the nose more aerodynamic?!.
    In theory I have the high power hardware I need with only batteries to sort out, day one I'll use car batteries and when I know it all works I'll go for li-ions as these are the main money commitment. The unknown bit is what I need to do to link in as much as possible with the current control system, I plan on making a controller to try and replicate revs, temp and battery level to work with the existing system so I can use the standard gauges but not sure how many other sensors I'll need to replicate. The plan is to strap as much as possible to the subframe assembly, then I can 'simply' unbolt the old one and slip in the new one, may cut the loom so that I can unplug with a simple big connector (or two). A friend suggested I could turn the existing subframe with engine into a charging trailer!, sounds like a plan.

    Thanks for the link to the 450 conversion, oddly I've only been looking for roadster conversions but I guess there is little difference, that acceleration looks great.

    I'll probably set up a webpage for the build and give all the details of the mechanics and wiring and if I build a controller, probably an arduino based one, I can supply details to anyone who might be interested.

  9. #9
    Join Date
    Oct 2014
    Location
    Essex
    Posts
    304
    Sounds very good, there's always going to be a lot of unknowns with these sorts of conversions.

    One other thing also to look at is the brakes, there will be no vacuum produced by an engine so the brake booster won't work Plenty of 12v kits out there though to pull sufficiently to make them work as they should.

    As for RPM, take a look at the original RPM sensor, they're around 20-25 and you may be able to mount it to your electric motor to make the dash happy.

    I'll certainly be following the build!
    Follow the Hayabusa powered Smart Fortwo build here

    YouTube Video's Here

  10. #10
    Join Date
    Apr 2009
    Location
    Ecosse
    Posts
    3,787
    Quote Originally Posted by crispy View Post
    but to start with I'll keep the ability to change gear as I'm not sure of the best ratio yet, perhaps using 2nd and 5th would give me the best range with low for fast pull away and a high gear for lower rev top end,.
    I think you need to investigate how these gearboxes work. Shifting on the fly without the engine and its supporting electronics is very likely impossible.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •