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Mass Reduction?

Discussion in 'Modifications' started by Jim, Sep 5, 2017.

  1. Jim

    Jim Copenworld Newbie

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    Sep 4, 2017
    Location:
    Leamington Spa
    Car(s):
    Toyota GT86
    Does anyone know how much mass you can strip out of a Copen? I've searched the forum briefly but couldn't find a thread about it.

    I'm working on a hair-brained idea of turning one into a track-day car as I like the challenge of making one fast enough to keep up with circuit traffic. I know there's scope to get the power up to around 120HP with a turbo upgrade etc. but for best effect I need to get the mass of the car as low as possible to make the most of what power is available!

    So, how low can you go?
     
  2. jez77

    jez77 Copenworld Regular

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    Jan 16, 2015
    Location:
    Brisbane Australia
    Car(s):
    2003 Daihatsu Copen
    2000 Toyota RAV4
    There was a version with a manual roof that was about 50kg lighter I remember reading.
    So removing all the roof motors would be the first step.
    Then replacing side and rear windows with Perspex or lexan would save a bit.
    Then ditching the passenger seat maybe another 15kg.
    Overall I'd think you'd struggle to loose more than 100kg.
     
  3. Salieri

    Salieri Copenworld Veteran

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    Location:
    Germany
    Car(s):
    Pearlescent White Copen (1.3 K3-VE)
    You could also take out the carpet and interior trim
     
  4. Jim

    Jim Copenworld Newbie

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    100kg would already be a huge saving on a 830kg car! :) That would take the power to weight ratio up to 92 bhp/tonne without touching the engine (80bhp/tonne standard) which a little bit more respectable for circuit use. Still a long way off being quick though...

    I did think that taking all the roof mechanism out would be a good start, possibly even welding the roof sections together into a makeshift removable hard top. Better yet turning it into a roofless speedster would save a bit more.

    I'd hope to keep both seats but swap them out for some lightweight racing seats, ~10kg per seat for race seats. I don't know how this compares to the OEM seats?

    Definitely but there can't be that much carpet to take out of a car this small! The added noise does add to the motorsport feel though. I gutted a K11 Micra a few years back and it was good fun.

    Out there question but does anyone know if its possible to put the roof down manually if the motors are removed? Most of the cheap Copens I've found have a broken roof...
     
  5. BarnsleyRob

    BarnsleyRob Copenworld Veteran

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    Feb 2, 2017
    Location:
    South Yorks
    Car(s):
    2009/59 silver Copen 1298 cc (now gone to a new home)
    Would you need to add a roll bar for track use ?
     
  6. Jim

    Jim Copenworld Newbie

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    In the long run I'd want one but to start with you don't need one. I'd look at fitting a full roll cage which would add a chunk of weight back in sadly. :( On the up side it would significantly stiffen up the body.
     
  7. Number6

    Number6 Copenworld Veteran

    Joined:
    Apr 25, 2013
    Location:
    Dublin
    Car(s):
    2005 0.7L Copen
    Stock seats are fairly heavy. You can remove the roof pump, rear cabin bulkhead and parcel shelf, strip the door cards off, pull the AC assembly and piping, strip the headliners off, center console, glovebox, carpets, tools in the boot, boot carpets, change the bonnet for a carbon fibre one.

    All that added up might get you to 100kg. You'd have to weigh everything.
     
  8. jez77

    jez77 Copenworld Regular

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    Location:
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    2003 Daihatsu Copen
    2000 Toyota RAV4
    As much as I love the Copen I'm not sure it is going to make much of a track day car. Unless your in Japan with there parts support and Kei class racing the Copen won't be competitive.
    For example the stock 2nd gen MX5 1.8 is 1050kg and 140hp or 135hp/t
    Fully modified Copen 750kg and 120hp or 160hp/t
    Mild Modified MX5 950kg and 160hp or 168hp/t

    In other words to get a Copen to match a standard MX5 you would need to strip it out and make at least 100hp. That means bigger turbo, fully programable ECU, bigger intercooler, bigger injectors and fuel pump, exhaust system, clutch. That's at least 7k here in OZ if you can do all the work yourself.

    Not trying to be a downer and I love seeing and unusual car on the race track but I've made the mistake of trying to make an unusual car go fast, it's much smarter to start with a quick car that has racing heritage and good aftermarket parts support.
     
  9. Vin Petrol

    Vin Petrol Copenworld Regular

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    Jan 21, 2017
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    Car(s):
    2004 0.7 Copen
    ECU is the sticking point for UK spec - we can't use the Japanese ones and it has to be 'bench flashed' and apparently requires specialist equipment, I've made some enquiries and I haven't found anyone so far.

    If you want a track car Copen, you're probably better off doing an engine swap to one with easier available parts. Suzuki K6A 660cc aluminium block maybe?
     
  10. jez77

    jez77 Copenworld Regular

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    Location:
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    Car(s):
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    2000 Toyota RAV4
    I'd go the 1.5ltr Yaris motor, if you have a 1.3 Copen its an easy swap
     
  11. Jim

    Jim Copenworld Newbie

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    I completely agree that the smart choice is to get something more traditional e.g. Clio 182, BMW 328i, MX-5 but I just can't get excited about having the same car as everyone else on the circuit. I'm more planning to focus on maximising grip and cornering speed as I know a Copen will never have a chance as a straight line hero.

    In terms of racing there's the MSV Trackday Trophy which has a hp/tonne class structure with the lowest class being up to 100bhp/tonne though I think it's power at the hubs so I don't know how much of the 120bhp would actually make it's way as far as the hubs. The lowest class in the follow on championship (Trackday Championship) is 125bhp/tonne which might be more challenging to achieve!

    I love the idea of trying to be competitive with a lightweight cornering focused car. Plus the cost of consumables will be much lower as it's just not going to ruin tyres and brakes in the same way as something bigger and more powerful.

    It sounds possible but only just like you say. Failing that there's always the angle grinder...

    I read something about there being someone in Germany who can flash the UK ECU, is that still the case? If we're talking engine swaps there's always bike engines...
     
    Last edited: Sep 7, 2017
  12. Vin Petrol

    Vin Petrol Copenworld Regular

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  13. Joy

    Joy Copenworld Member

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    Car(s):
    2005 Copen L800K Manual 660 cc - a right proper one
    Strip out the stock steel underbody bracing and replace it with alloy: TryForceCenter.jpg TryForceSides.jpg TryForceFront.jpg

    There is also a D-Sport option, but their side bracing is steel. Kansai Service made an alloy package, but I think it is out of production, used pops up on Yahoo from time to time.
     
  14. shane

    shane Copenworld Regular

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    Keep the roof. What you gain in weight-loss will likely be overcome by higher wind resistance.
     
  15. adatara

    adatara Copenworld Member

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    Fukushima Japan
    Car(s):
    L880 Copen; have a Honda Airwave (long Honda Fit); had Subaru Foresters
    remove the tire puncture kit, jack & tools, opening cover for a bit of weight reduction?
     
  16. Jim

    Jim Copenworld Newbie

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    10kg per wheel is a massive saving! If it was 10kg across all 4 wheels I'd believe it more, though in fairness I don't know how much the stock wheels weigh. I've not seen it done but what stops 13" wheels fitting? Do they clash with the front brake calipers? Swapping down to a set of 13"s would allow me to fit 185/60R13 tyres which are a readily available trackday tyre size. I used them on a Micra I had briefly, £50 for a set of part-worn tyres!

    Ooo that's an interesting one, could be a good few kg to save doing that. Plus the non-rusting benefit would be nice...

    Ideally I'd keep the roof as a skin but remove as much of the support as possible. Fixing it onto a cage would be an option that might help to make the addition of the cage mass neutral.

    Definitely, they would be on my initial hit list for trimming the mass down!
     
  17. Joy

    Joy Copenworld Member

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  18. Jim

    Jim Copenworld Newbie

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  19. BarnsleyRob

    BarnsleyRob Copenworld Veteran

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    Only put in enough fuel for the laps you want to do +5 %. It's nearly a kg per litre.

    Alternatively, fill it to the brim and have a blast on some decent country roads and forget the bloody track :)
     
  20. jez77

    jez77 Copenworld Regular

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    2000 Toyota RAV4
    That's a big no no. You should always make sure you have plenty of fuel in the tank while racing. The risk is running the motor lean as the fuel sloshes to one side of the tank while cornering a long sweeping bend.
     
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