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Weight savings....what else?

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

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  1. macmaster05

    macmaster05 Senor Member

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    I know what you mean. Personally I'd like him to report back because I think his car will look really cool with these modifications. But I don't want him to have the wrong expectations. Too often I see people try stuff to improve mileage and it fails. Plus it's even more negligable when you consider the wide range of driving skills people have. If he's getting 46 mpg now, do you think these upgrades will be worth it? Absolutely not, learn to drive better or hypermile until you can get 55-60 mpg consistently without any of these modifications, then come talk to us and see what you can do to further improve your mileage.
     
    #21 macmaster05, Apr 14, 2011
  2. macmaster05

    macmaster05 Senor Member

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    Sorry to sound so harsh folks. After re-reading the OP, I guess my real problem is that he's spending SO much money on a look he doesn't like for negligable results. I strongly disagree with this way of thinking. Build a car you like. Don't worry about the mileage, Toyota makes these cars very optimal and anything you do to try to add to that is futile, ESPECIALLY when it's expensive and not to your taste. Had the OP said he likes the look he's going after I'd ne behind him 100%. But this is just plain stupid.
     
    #22 macmaster05, Apr 14, 2011
    1 person likes this.
  3. robby3

    robby3 Member

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    Installing RS*R 2000TI springs saves weight as they are less heavy than the stock ones.
     
    #23 robby3, Apr 14, 2011
  4. Tekdeus

    Tekdeus Shifted to Green

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    Michelin Energy Saver tires are good for 3-6% better mileage, and are lighter too. Tire pressures at 44psi can add up to 6% more mileage according to Mythbusters. Side mirror removal has been shown to improve mileage 2-3% on some cars. Engine block heater would make a noticeable improvement by warming the engine up with electricity and not gas. Lowering the car should help as it reduces frontal area slightly as well.
     
    #24 Tekdeus, Apr 14, 2011
  5. jialideel

    jialideel New Member

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    Awesome. Thanks for the counsel, Money. So it sounds as though we wouldnt even need the cameras to be road legal...although I would probably still want to do them for safety's sake.
     
    #25 jialideel, Apr 14, 2011
  6. jialideel

    jialideel New Member

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    Haha I'm open to window replacement options. However, I read somewhere that plexiglass can actually be heavier than the status quo in certain situations...has anyone tested this yet?
     
    #26 jialideel, Apr 14, 2011
  7. jialideel

    jialideel New Member

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    Mac...I want to explain my situation a little better as I think I may have confused you. This is not now (nor will it ever be) MY car. The vehicle's purchase and all of the work that I will be putting into it are being funded by a private (and nondisclosed) entity...my skills have simply been acquired for the development process. THEY have decided to tackle the task of stretching the Prius's efficiency to the max, and THEY are not concerned with the look of the car from a "tuner" perspective. They have explained to me that they do not want me to diminish the general appeal and aesthetics of the car materially, and so obviously they DONT want it gutted for that reason. As a longtime mechanic/machinist/electrician/hobbyist, I agree with you on some of your points...gutting the car's interior would certainly be a big (and arguably BIGGER) step in the right direction toward increasing fuel efficiency, but again...I am just filling an order, and this is not what is wanted.

    Having said that, I do think there is at least SOME merit to the ideas discussed so far. Working within the limitations that I have, these are viable ideas that should at least help in furthering the goal of fuel efficiency. And I will be more than happy to post results when I'm done for the benefit of the rest of the members on the site...

    But diont get me wrong, Mac...I appreciate the realist perspective. Were it my personal ride, I might go a different way myself. :)
     
    #27 jialideel, Apr 14, 2011
  8. jialideel

    jialideel New Member

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    Thanks, Robby. RS*R? Haven't come across these yet. The two that I've seen offering aftermarket options are Tanabe and TEIN. And I was wondering what the relative weight of these kits was compared to stock. Again, I'm convinced thus far that dropping the car shoul help to reduce undercarriage turbulence...now just to determine which is the best choice. Have you had any experience with these other two?
     
    #28 jialideel, Apr 14, 2011
  9. jialideel

    jialideel New Member

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    Thansk, Tekedus. This is great info. Light (or lightest) tire options were going to be one of my eventual questions. I'm in Central Florida, so no REAL need for all-weather or snow tires. Just a basic lightweight set of radials should suffice. Are the Michelin's the lightest you've come across? I've not looked into this much yet...

    PS...having said that the goal is weight savings, I also dont want to go with such a thin or "cheap" tire that risks a blowout destroying the investment haha...so the caveat to this will be "provided that safety is maintained" :). Thanks again!
     
    #29 jialideel, Apr 14, 2011
  10. jialideel

    jialideel New Member

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    I like the underbody ideas...honestly I'll need to get the car up on a lift to see what I'm working with before I can make an informed post on that subject.

    As far as the handles go, fairly straightforward. My bodyshop guy will shave them and install poppers all in one appointment. My one concern is the whole "touch-to-lock" feature that the Gen III's have in their handles...I don't know if that system can be disabled, or prefereably relocated to a different part of the car's exterior like the door panel itself. I'm inclined to think that the system works with low voltage elctrical current, and when something disturbs the voltage levels (i.e. your hand) it triggers the lock feature. If I'm right (and please...someone educate if not), then I should be able to use another exterior surface. Not sure...
     
    #30 jialideel, Apr 14, 2011
  11. richard schumacher

    richard schumacher shortbus driver

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    Well, everybody needs a hobby :_> The one thing you could do that might make a measurable difference would be to remove the seats and all other non-essential interior parts, but you've already taken that off the table. Have fun!
     
    #31 richard schumacher, Apr 14, 2011
  12. HI MPG

    HI MPG Active Member

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    Well, if you have carte blanche, then maybe you should ask Toyota to design/build some of these skeletal seats (as on the Prius C concept) for you:
    [​IMG]
     
    #32 HI MPG, Apr 14, 2011
  13. jialideel

    jialideel New Member

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    Cool pic...I've never seen that before...makes me wonder how comfortable that would even be. I have considered REPLACING (not to be confused with REMOVING haha) the front seats with racing seats...maybe carbon fiber shell to shave a few pounds. But my experience with racing seats has been that they're not extremely comfortable...and so I'm not certain that my benefactor would approve. Does anyone have any experience with these?
     
    #33 jialideel, Apr 14, 2011
  14. sipnfuel

    sipnfuel New Member

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    [​IMG]

    Why thank you. Naturally I think my ideas are the best :D

    Well if you look underneath, it's not 100% smooth. This is Rodney's car as he was mounting some aftermarket bracing underneath.

    I don't know if the exhaust needs to be exposed for air cooling, but I guess it does if Toyota did not cover it. Or perhaps that is a high temp area where plastic would melt.

    But you see those ridges & valleys in the plastic. Those are to give the plastic more rigidity & lessen vibration. This is the part where a $4 can of spray foam and some $5 aluminized tape will work really well as a light-weight and cheap mod. All the random holes can be covered with the tape easily & later punched through or removed if access is needed.

    Note models two and above will have underbody stabilizer fins that direct air to achieve better stability somehow.

    Also, people have been fashioning full flush hub cabs out of 16" aluminum pizza tins. Unless you are using the friction brakes heavily, it won't need that much cooling. Supposedly this nets a few percent gain in mileage.You could punch a few small holes in the tin if you want.
     
    #34 sipnfuel, Apr 14, 2011
  15. GSW

    GSW PRIUS POWER

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    My suggestion would be to find someway to make adjustable louvers for the front upper and lower grill for better highway aerodynamics and thermal control. Might sound strange to you, but being able to control airflow into the engine at cold outside temperatures could mean as much as 5-8 mpg or more. Good luck and I sure hope you keep us informed. :rockon:
     
    #35 GSW, Apr 14, 2011
  16. macmaster05

    macmaster05 Senor Member

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    OK...that's understandable and quite a good deal if you are not investing a dime in this. But I still think your partner is getting ripped off. "Your skills" should tell you that it's a moot project. They want to stretch the efficiency of the Prius but are not willing to sacrafice the aesthetics or norms of the car? Good luck. They'd better be using a wind tunnel at 110 mph to collect their data, because a few internet trinkets and modifications will not make a real-world difference.

    Of course don't tell them all this, you don't want to bite the hand that feeds you. Let them learn the hard way, unless your employer goes by the name of Mythbusters, then tell them I said hi.
     
    #36 macmaster05, Apr 14, 2011
  17. jialideel

    jialideel New Member

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    Thanks for the pic sipn...it seems like Toyota at least made efforts to flatten that underside as much as reasonably possible from the factory.

    I'm wondering why we don't have answers to some of the questions that were asked in old threads long forgotten (and if they have been answered then I apologize and someone please correct me) such as...

    Body panels...such as hood and spoiler are offered in CF by several suppliers to replace the factory components. Is the CF hood lighter than the aluminum hood that the car comes with? Has NO ONE purchased the CF hood and done a weight comparison yet?

    Exhaust...there are tons of posts on aftermarket kits from Tanabe to Tom's to Granador....and some say "lightweight" and some say "performance-enhancing" and every self-proclaimed authority on the forum has added their two cents of speculation as to whether the kits REALLY ARE lighter or whether they REALLY DO improve performance...but it doesn't seem that anyone's bothered to put it to the test as of yet...

    Cold-air intakes...there are pages of forum battles between the pro-K&N and anti-K&N tuners. Yet NO ONE has dyno'd the difference for fuel to air mixture changes?

    Guess I may just have to guinea pig some of this stuff myself. Just seems like some of these products have been out long enough...you'd think that SOMEBODY would've finally put conjecture to bed by now :rolleyes:.

    BTW....thank you to those who have posted some awesome product reviews and helpful information throughout the site. I dont want to sound ALL doom n' gloom as I HAVE found some helpful information here and there...between 17-year olds trying to mod their Prius's into the next Fast and Furious movie, and crotchety old men barking about we should leave our cars alone and appreciate the fact that we don't have to walk to and from...uphill...both ways...lol
     
    #37 jialideel, Apr 14, 2011
  18. HI MPG

    HI MPG Active Member

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    I can direct you to where you could purchase a CF hood for the Gen III. If you want to purchase, weigh both for differences, and then donate the CF hood for me out of charity after your research project is complete, that would be AWESOME! I would kindly accept those Volk rims also. ;)
     
    #38 HI MPG, Apr 14, 2011
  19. macmaster05

    macmaster05 Senor Member

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    Jialideel, DUMP IT, like this!

    [​IMG]

    Dang you is fast. I wanted those Volk rims when he was done too.
     
    #39 macmaster05, Apr 14, 2011
  20. Corwyn

    Corwyn Energy Curmudgeon

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    Remember that weight reductions help most for stop and go traffic, while aerodynamic improvements help for long runs (particularly at higher speeds). Perhaps you should decide which you want to optimize for.

    If you can get reasonable numbers for weights and drag coefficients, you can calculate changes in power requirement.

    P = (1/E * (1/2 * m * b * v^3 / d + 1/2 * p * A * Cd * v^3)) + r * v
    Where:
    P: Power needed to drive the car
    E: Efficiency of the engine (Prius 0.37)
    m: Mass of car in kilograms (Prius: 1317kg (Is that right for a 2010?)
    v: velocity in meters / second
    d: distance between stops
    b: regenerative braking efficiency (Prius ??)
    p: Density of air 1.3 grams / meter^3
    A: Frontal area of car (Prius: 2.16 meters^2) (2010?)
    Cd: coefficient of drag (Prius: 0.26) (2010?)
    r: Rolling resistance
    (I hope I got that right, can someone check it)

    Here is a calculator (for constant speeds):
    Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

    Or you can determine empirically with a coast down test:
    Measure the drag coefficient of your car
     
    #40 Corwyn, Apr 14, 2011
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