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Weight savings....what else?

Discussion in 'Gen 3 Prius Accessories and Modifications' started by jialideel, Apr 13, 2011.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    Note that the Prius is fairly front heavy (sth like 62/38) so you would want weight reductions near the front of the car so as not to upset the balance. (unfortunately, the two things I can think of that are heavy are the rear glass panels on the rear hatch and the spare tyre on a steel donut but you already said you don't want a tyre repair kit).

    What about body panel replacements? Can a bodyshop fabricate those panels (e.g. front fenders) out of aluminium or does it require a lot more skill? Also, the doors are steel. Perhaps consider replacing them with aluminium panels too. A polycarbonate, fixed moonroof may help shed a few pounds (I would think the polycarbonate panel, rubber seals and fabric sunshade would weigh less than the same sized steel roof panel)
     
  2. jialideel

    jialideel New Member

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    Good ideas, Tideland. Thanks. I definitely want to keep a spare onboard for practicalities sake, but I will most likely purchase a fifth volk to help knock some of the weight off of the doughtnut. I wonder if the doughnut weighs more than the stock 15's...

    As far as the glass goes, I would definitely be open to a lighter alternative (plexi?) but again...there's only been mere speculation as to whether the equivalent panel in plexi would be in fact lighter or heavier than the status quo.

    The body panels are definitely an opportunity to drop some serious pounds. I am going to look into the aluminum option. I would love to see somebody offer them in CF like they do for the Lotus...at a tremendous expense of course...but that would be the ideal set-up. Again, having said that the funds are there, I would do CF wherever possible on the car (save the wheels...don't trust the integrity)...but it's so hard to find custom fabricators who do this kind of scale WELL.

    Thanks again, Tideland.
     
  3. HI MPG

    HI MPG Active Member

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  4. billnchristy

    billnchristy Active Member

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    Look up Crawford race cars and Riley. They build tube frame GT cars for Grand-am and have complete bodies of CF. Ain't gonna be cheap but their cars look like the real deal which is hard to do on a tube frame.

    [​IMG]
     
  5. BrettS

    BrettS Active Member

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    I spent quite some time working with my GEN III model III smartkey locks to enable the system to work on the passenger door and the rear hatch. There's another thread on here that details my efforts, but I can reply to some of your questions, at least.

    Disabling the system will not be a problem. On your model III only the driver's side door handle is enabled and the handle contains the antenna and the touch sensors. If you remove the handle and disconnect it from the system then no harm will be done and everything else will continue to function normally. You will still be able to lock and unlock the car with the buttons on the remote and the interior smartkey sensor will still function so you can start the car with the existing push button.

    Relocating the sensor may be an option as well and I can at least give you some background to help get you started. First, you'll need to find somewhere to locate the antenna that's currently in the driver's side door handle. It has a very short range (maybe 3 feet from the antenna) and the signal won't travel through metal, so wherever you put it you need to make sure that the signal can still reach a key in someone's pocket or purse. As far as the touch sensors go, there are two sensors on the door handle. One on the back of the handle that triggers the unlock function, so when you grab the handle the door unlocks a fraction of a second before you pull the handle to open the door, and one on the top and bottom of then handle that you can touch to lock the doors.

    I'm not entirely certain how they work, however I can tell you this... when the lock or unlock sensors are triggered they simply bring a contact from the certification ECU to ground. If the key is detected by the antenna (technically the key detects the antenna, but it's easier to think about the other way around) and one of the contacts is grounded then the doors will lock or unlock. So, assuming you can find a good place for the antenna, you can add one or two buttons to the exterior of the car and easily tap into the existing system.

    Relocating the existing touch sensors may be possible, however, the doorhandle is plastic, so I'm not sure how they would work on the metal body of the car.

    Feel free to reply here or send me a PM if you have any more questions about this. (If you do reply here and I don't respond, feel free to send me a PM too as I might forget to check back here)

    Good luck,
    Brett

    PS... hi from another central Floridian:)
     
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    You're welcome.

    IIRC, the spare is definitely heavier. Just take the spare out, jack up the car and take one of the wheels off. I think you'll be pleasantly surprised at how light the alloys are.
     
  7. mainerinexile

    mainerinexile No longer in exile!

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    Remove the two outside mirrors and mount rear view cameras on each side, with a little view screen on each side inside the car.
     
  8. SlowTurd

    SlowTurd I LIKE PRIUS'S

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    spending $$$$$ to get $ back makes no ¢
     
  9. xs650

    xs650 Senior Member

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    It makes sense if taken as an expensive form of entertainment. Custom CF panels will cost around $100/lb saved. The Prius already has some light sheet metal work, it will be difficult to take lot of weight out of it.
     
  10. jhinsc

    jhinsc Senior Member

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    Mac, I love your brutal honesty. I concur with your thoughts here. After making all the mods and running a test, we won't ever know for sure how much the mods contributed to the mpg increase versus the very eco-friendly driving style that will be used to gain the highest possible gain to prove a point. My best advice for anyone pursuing this is to make sensible mod's and drive appropriately for high mpg's. If everyone would just drive sensibly and increase their current mpg's by 10%, hybrid or not, just think how the price of gas would be affected if total usage went down by 10%!
     
  11. Corwyn

    Corwyn Energy Curmudgeon

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    It makes a lot more sense than spending $$$$$ to lose $$, which is what most mods on this site do.
     
  12. Tideland Prius

    Tideland Prius Moderator of the North
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    touché
     
  13. Tekdeus

    Tekdeus Shifted to Green

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    Regarding tires, it's not just weight but the rolling resistance of the tread compound. Check out this Tire Rack test video with the Prius:
     
    2 people like this.
  14. sipnfuel

    sipnfuel New Member

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    Well the easiest and most practical mods mentioned so far definitely are the CF Hood, swapping 15" wheels, changing to the best 15" LRR tires with overinflation, lowered suspension, removal of spare and addition of flat tire kit (along with mini 12v compressor). The benefits will be small, at best.

    I think if you can do the active grill shutters, it will give you the single biggest mpg improvement overall.
     
  15. biggus

    biggus Junior Member

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    Have a look at how BMW with the M3 csl and Porsche do their lightweigt versions of everyday models

    In the E46 Csl Bmw did some of the following replacements/improvements

    Lighweight Glass
    Carbonfibre roof skin
    Plastic bootlid (trunk lid in usa)
    Removed radio speakers etc
    Removed air con ( not practical in Florida )
    Replaced seats with carbon fibre tubs and deleted side airbags because side racing bolsters in racing seats were deemed suitable replacement . these seats are very comfortable in practice if your not too portly, nice suede cloth.
    Replaced exhaust with thin walled titanium tubing.
    Replaced air intake with carbon fibre
    Replaced bumpers and REINFORCEMENT bars with carbon fibre

    Additionally
    more extreme versions got door pull chords instead of handles
    Removal of electric windows and repalced with simple winders
    Practically on the Prius you could do the following.
    12v battery could be repalced with lightweight racing battery prob save as much as your wheels.

    Personally;
    I would remove the rear hatch door hinges and struts and weight these, i think there could be major weight savings to be had here by replacing the whole lot with a plastic and plexiglass replacement with no effect on crash safety.

    When i was building race cars based on road models there was major savings on the shell to be made by sandblastign and removing all seam sealer and painted on/stuck on sound deadening material

    Good luck with your project, its something i would like to try.
     
  16. cwerdna

    cwerdna Senior Member

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  17. jialideel

    jialideel New Member

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    Tekdeus....thanks for the informaiton on the tires...good stuff....it looks the Michelin Energy Savers will be the weapon of choice.

    Sipn...can you explain the 'grill shutter' strategy (how the vehicle is modified, how it works, when to use it, etc.) I'm not quite clear on this idea...

    Biggus...what does 'lightweight' glass consist of? Plexi? Also...are there any disadvantages (from performance/reliability perspectives) of a lightweight racing battery?

    PS...I talked to Seibon as someone had suggested a few posts back. They have no idea if their CF hood is lighter than the stock aluminum, but they 'think' it is :rolleyes:. They are also coming out with another hood model...they are calling it VS2 (no pics yet, of course). It will feature a function air dam that is supposed to boost hp.
     
  18. sipnfuel

    sipnfuel New Member

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    Check out the Active Grill Shutters on the upcoming 2012 Ford Focus, or the active grill shutters on the 2011 Chevy Cruze ECO.

    For the Prius, you may have to custom fabricate the shutter. Then you run a temperature controlled relay that activates a variable actuator to open and shut them. Or more simply you can run a spring and cable to a stepper motor.

    I don't know the actual mechanism. Perhaps you can order the Cruze ECO part and modify it to fit the Prius (call it the Frankenprius).

    An easier mod might be a some kind of rubber tubing than fits in between the slats, that inflates or deflates with air pressure. You could take the mechanism from an air suspension kit.
     
  19. andino

    andino Senior Member

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    You wanna shed weight. Switch to lexan windows. That's what race cars use. But you have issues with easy scratching and hazing from daily use and they're not road legal.

    Could also switch to carbon kevlar racing seats and remove the rear seats. Get a company to make dry carbon versions of the front fenders, hood, doors, rear hatch. That'll lose a lot of weight. Easiest way to shed weight though is through the wheels but since you already picked up te37s, you're probably good to go there other than choosing a light tire.
     
  20. nickfromny

    nickfromny Member since 2007

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    Improve MPG
    1. Inflate stock tires to 52f 50r till the tread is gone, then buy Bridgstone Ecopias. Go to a 13" light wheel with airplane rubber(very light and good at speed), that will also lower the car. Use the areo covers or get some.
    2. Remove all lose gear and spare tire + jack, tools.
    3. get ti cat back exhaust, this will be a 30lb+ saver.
    4. Install drilled out brake rotors or ti drilled out rotors all around if poss.
    5. Remove sway bars, car won't corner but those are heavy.
    6. Light weight racing Radiator with ti cap.
    7. Ti Oil Cap.
    8. Remove exhaust heat shield.
    9. Cut hole in hood to vent extra heat, cover hole with black screen from hardware store.
    10. Remove insulation and dynamat.
    If you do the shocks make sure they are lighter.
    You should be able to get down to 2,800lbs before spending over $2,500
    Keep us posted on weight and the gains.