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Forums » Grassroots Motorsports » Auto X-Prize- Real GR efforts

  • alfadriver

    July 5, 2008 8:41 a.m. alfadriver New Reader

    Since the BS meter has been running pretty deep on the Mustang thread, how about we talk about it over here?

    Real ideas.

    Anyone know the real rules? What cycle the milage is measured on, acceration requirement? Emissions, crash, etc?

    Uber Grassroots idea.... Start with a CRX HF.

    I know my '88 was capable of 60mpg under abnormal conditions, and normally 55mpg. So a 100% increase? Yikes.

    Knowing trends (and what we are workin on), I would say smaller displacement turbo- if we can maintain ~1800-1900 lb weight, a 70hp target peak power would be decent enough. Plus 90-110 lb-ft would be good enough too. Which says we have a slow spinning enigne- the later HF motor had a 5200 rpm red line, with some key bits that were not intended to spin fast...

    Since we want torque and not speed, lets find a 1.0l Twin, turbo it lightly, and try to run as lean as possible.

    Drag reduction is pretty important, too- I would close up the front end some to keep the air going around the car, and put on a full body belly pan. Nice narrow tires etc etc.

    Not sure how far that would get, but knowing the car, I bet 75mpg is pretty realistic.

    A not so uber GRM idea.

    If currnet crash rules are part of the competition, I would start with a Elise chassis. Why? Weight, mid engine, and crash certified.

    Of course, weight is huge for economy- light = less power needed to acceleration. The Elise is the lightest current production car- so we have one that is pretty crash tested.

    Alter body to change emphasis from downforce to drag. Great chassis for that, since it's already got a flat bottom. Narrow tires will help.

    Powertain? Remember, performance isn't the idea- so one could probably do well with a 80hp, 100lb-ft engine. Not awe inspiring in any sense, but one must target needs for the program. That will give us a pretty small motor if we go light boosting. Diesel? Perhaps. Small gas DI? Perhaps- lots of good possibilities.

    I really think that it's possible to do an Elise chassied car that will get close to 100mpg under the right condidtions.

    Anyone with a spare lotus?

    Eric

  • unk577

    July 5, 2008 6:08 p.m. unk577 New Reader

    Lotus Elise/VW TDI programmed for efficiency, some narrow tires, remove wing, etc,etc.If you could get a TDI out of a Polo or Lupo (neither offered in the US) they were smaller than everything we had here would be a good start.

  • July 5, 2008 10:32 p.m. Raze New Reader

    Dude go read the ecomodders website where people are basically doing what you're describing, and then hypermiling to boot so they get crazy mileage. Also, a new mod is to do an alternator delete w/some deep cycles and solar panels to reduce engine drag...

  • neon4891

    July 5, 2008 11:08 p.m. neon4891 HalfDork

    has anyone worked on uping the hybrids? and insite starts at 70mpg, IIRC.

  • alfadriver

    July 6, 2008 8:23 a.m. alfadriver New Reader

    Raze wrote: Dude go read the ecomodders website where people are basically doing what you're describing, and then hypermiling to boot so they get crazy mileage. Also, a new mod is to do an alternator delete w/some deep cycles and solar panels to reduce engine drag...

    Dude, that's not the point.

    The point is to attempt the Auto X-Prize, which has an ultimate goal of 100mpg over a measured cycle. So "hypermiling" isn't in the cards.

    Just not sure how much one can do with an elise. But IMHO, without re-engineering an entire chassis, it's the best starting point for a real car.

    E-

  • alfadriver

    July 6, 2008 9:13 a.m. alfadriver New Reader

    Rules can be seen here- http://www.progressiveautoxprize.org/files/downloads/auto/AXP_Draft_Competition_Gu...

    Which requires a significant re-think of my base idea- the Elise only qualifies for the 2+ class, which includes 3 wheeled cars and whatnot...

    The basic rules- Tier II Bin 5 emissions. These are not too bad, unless you are dead set on diesel- that will be a big hurdle for a diesel.

    0-60 in 12 seconds. Which reduces the required peak power of the vehicle, and moves the useful power more into the typical driving cycle.

    Meet US crash standards.

    The 100mpg will be measured along with the emissions and a street driving cycle. And electric cars use a "wire equivallent"- noting that electric cars are NOT zero emissions, but whatever the power plant uses...

    To say that it will be tough is an understatement.

    I would still start with an Elise chassis- stretched to 4 passengers- ala Aston Martin's use of the basic same chassis on the Vanquish (yes, that was Lotus designed). Keep it rear engined, though- keep the heat in the back of the car.

    I'd have to ask some modelling friends to figure what kind of drag and weight would be needed so that a car could reach 100mpg. But I think one needs some kind of energy recovery system.

    Hmmmm, will be tough. E

  • ignorant

    July 6, 2008 11:24 a.m. ignorant UltraDork

    http://gizmodo.com/gadgets/gadgets/sports-hybrid-built-by-kids-runs-on-soybeans-ze...

    I'd remove the massive electric system on this car, add alittle more aero and maybe you could get close to 100 mpg with the turbo diesel..or... its a start i guess

  • ignorant

    July 6, 2008 11:26 a.m. ignorant UltraDork

    alfadriver wrote: Tier II Bin 5 emissions. These are not too bad, unless you are dead set on diesel- that will be a big hurdle for a diesel.

    can be accomplished with a urea system. more weight.....

  • alfadriver

    July 6, 2008 7:52 p.m. alfadriver New Reader

    ignorant wrote:
    alfadriver wrote: Tier II Bin 5 emissions. These are not too bad, unless you are dead set on diesel- that will be a big hurdle for a diesel.

    can be accomplished with a urea system. more weight.....

    Don't count on it. Still some negotiations in need to make urea actually legal.

    E-

  • alfadriver

    July 6, 2008 7:56 p.m. alfadriver New Reader

    ignorant wrote: http://gizmodo.com/gadgets/gadgets/sports-hybrid-built-by-kids-runs-on-soybeans-ze...

    I'd remove the massive electric system on this car, add alittle more aero and maybe you could get close to 100 mpg with the turbo diesel..or... its a start i guess

    The issue with that car (and most kits) is the crash requirement in the X challenge. Which is why I was suggesting the Elise, since it has been crash tested.

    E-

  • DWNSHFT

    July 7, 2008 8:47 a.m. DWNSHFT New Reader

    The 2009 VW TDI is a Tier II Bin 5 car and will be on sale at the end of August. No urea injection. It's a sweet motor, with 236 lb-ft of torque from 1750-2500 RPM from only 2.0 liters. Much more power than you would need for the X-Prize. Even the European 1.4 liter would be overkill. I've heard of a 1.0 liter three cylinder diesel VW; that would be close. With half the displacement, you'd see something like 118 lb-ft and 70 HP.

    David

  • ignorant

    July 7, 2008 9:02 a.m. ignorant UltraDork

    alfadriver wrote:
    ignorant wrote:
    alfadriver wrote: Tier II Bin 5 emissions. These are not too bad, unless you are dead set on diesel- that will be a big hurdle for a diesel.

    can be accomplished with a urea system. more weight.....

    Don't count on it. Still some negotiations in need to make urea actually legal.

    E-

    If It's not legal, How is MB selling "Blue tec" vehicles in the US. Major HD companies are banking on it as well. But.. I know some folks who have interest in it not being accepted. I work for them.. and they spend big money in washington.

    http://www.autobloggreen.com/2008/02/04/paccar-to-use-urea-injection-and-egr-to-cl...

  • ignorant

    July 7, 2008 9:06 a.m. ignorant UltraDork

    alfadriver wrote:
    ignorant wrote: http://gizmodo.com/gadgets/gadgets/sports-hybrid-built-by-kids-runs-on-soybeans-ze...

    I'd remove the massive electric system on this car, add alittle more aero and maybe you could get close to 100 mpg with the turbo diesel..or... its a start i guess

    The issue with that car (and most kits) is the crash requirement in the X challenge. Which is why I was suggesting the Elise, since it has been crash tested.

    E-

    If you read the story.. It's built off an accord chassis, so shouldn't be as hard as one thinks.

  • alfadriver

    July 7, 2008 9:40 a.m. alfadriver New Reader

    ignorant wrote:
    alfadriver wrote:
    ignorant wrote: http://gizmodo.com/gadgets/gadgets/sports-hybrid-built-by-kids-runs-on-soybeans-ze...

    I'd remove the massive electric system on this car, add alittle more aero and maybe you could get close to 100 mpg with the turbo diesel..or... its a start i guess

    The issue with that car (and most kits) is the crash requirement in the X challenge. Which is why I was suggesting the Elise, since it has been crash tested.

    E-

    If you read the story.. It's built off an accord chassis, so shouldn't be as hard as one thinks.

    What year? (I didn't read the article, as there is a lot of hype over being "better than the automakers" when in reality there are a number of reasons why "what can't be done" can't be done)

    The year has a lot to do with passing current standards. And if the picture was correct, this Accord had it's top chopped off, which is a rather vital part of the crash structure....

    E-

  • John Brown

    July 7, 2008 10:03 a.m. John Brown UltimaDork

    So how about this:

    1- DOHC Mazda B3 engine swap (everyone says it cannot be done but I don't buy it. If a B6 head is a B3 head and a DOHC B6 fits on a B6... well you see my thinking.) Add small turbo proper cams and injectors.

    2- Festiva 5 speed transmission.

    3- Light weight flywheel.

    4- Megasquirt PnP

    5- Body of a 1988 Ford Aspire

    6- Aspire suspension bits

    7- 10lb 15" wheels

    8- 185/55r15 tires

    Mix and season generously

  • ignorant

    July 7, 2008 10:08 a.m. ignorant UltraDork

    I'd start with a honda civic VX drivetrain, swap it into a 4door. Strip out add aero modes...

    I wonder if there is a way to tune the lean burn vtec in the vx with chrome etc.

    http://www.cleanmpg.com/cmps_index.php?page=garage

    looks like the vx is already to 76mpg hypermiling and folks are getting over 100mpg out of an insight

  • ProDarwin

    July 7, 2008 10:43 a.m. ProDarwin Dork

    Find transverse drivetrain vehicle that has a low CD. A FWD car would likely be better than the lotus for this application as cooling is a major issue. Cut down weight so with stock drivetrain its <2000lbs.

    TDI motor + prius electric motor + 6 spd manual. Ridiculously long gears. Basically almost any time you accelerate, the electric motor would be engaged. Very low # of deep cycle batteries. Super aggressively programmed regenerative deceleration... maybe even 2 different sized electric motors for a wider efficiency range. I'd actually like to take the TDI motor and cut 2 cylinders off of it. A ~950cc diesel parallel twin

  • Junkyard_Dog

    July 7, 2008 12:19 p.m. Junkyard_Dog Reader

    Maybe its been done but how about a Prius drivetrain with Li batteries in an Elise? Since a Toyota already lives there I'd think its a no-brainer. Might not win the X-prize but would be interesting to see nonetheless.

  • GameboyRMH

    July 7, 2008 1:03 p.m. GameboyRMH Dork

    Meeting US crash standard and emissions standards would be tough to do grassroots-style...but I'd go with something CRX HF based. First thing, it would be stripped of everything, including the engine.

    The first thing would be to add tubular braces running along the floor of the car that come up to triangles in the front and rear (Like this |___/_| )which should brace it enough to get in the right ballpark for US crash safety standards. Next, strip it out down to a wet weight of about 1400-1500lbs. It's a CRX, it should be easy. Switch glass for lexan where legally possible, change body panels to fiberglass where possible. Next, X-brace the roof, cut off the roof panel, install a solar panel. Slam it and install an underbody wing. Next, the body gets streamlined into a true jellybean.

    As for the engine, a 2008 R6 600cc I4 coupled to a CVT. The engine is computer controlled, and instead of conventional cruise control or an automatic pulse-and-glide system activated in a similar manner, it has a cruise control system that adjusts the engine mixture once it reaches the right speed. It would save fuel without the drivetrain wear, belches of unburned fuel from rev-matching, and soccer-mom-scaring side effects.

    As for electricals, the roof solar panel charges a lithium battery and all the lights are LEDs. Active vents control airflow through the radiator, sliding vents that shouldn't need much power to move at speed. The AC system diffuses air through all areas of the car, and is automatically controlled so that it comes on mostly under engine braking, giving a fairly constant temperature even though operation is intermittent.

    Something like that should meet all the requirements.

  • ProDarwin

    July 7, 2008 1:27 p.m. ProDarwin Dork

    Most of the above ideas are good, however an R6 motor just doesn't have the cams for good fuel economy. You'd need something capable of operating at a much lower RPM and higher throttle position. An engine from a 600-650 ish Cruiser would be a much better choice.

  • alfadriver

    July 7, 2008 1:44 p.m. alfadriver New Reader

    I think it's reasonable to think that one could modify a CRX to meet crash- would be tricky, and may need some exotic materials, but it should be possible.

    The problem is the class you run in- the +2 class has much fewer vehicle standards to meet, so you'd be competeting against cycle cars that barely have a crash requirement.

    The tough part would be to find a decent ~2000lb 4 seat car.

    As for the lean cruise- that one may be tough to really do, too- the rules did say that they would do remote testing on the course, so doing lean cruise would be pretty obvious (and hard to meet T2B5 w/o lean NOx trap). The NOx traps do work, and work really well- so one can't say it's not possible, just tough.

  • John Brown

    July 7, 2008 2:01 p.m. John Brown UltimaDork

    Why again is LPG/Propane not used in automobiles more?

  • John Brown

    July 7, 2008 2:34 p.m. John Brown UltimaDork

    Can someone wh has access to a Miata head do me a favor? Measure the minimum diameter of the combustion chamber.

  • Jensenman

    July 7, 2008 2:44 p.m. Jensenman UltimaDork

    Heck, just get one of those Chevy Sprint (?) (3 cyl turbo Metro),

    strip the interior and redo with aluminum or composite seat(s),

    do a custom cam for low end grunt,

    MegaSquirt the thing for adjustability,

    all the usual speed tricks like freeflow exhaust,

    Lexan instead of glass where possible,

    Fiberglass hatch and hood,

    low drag calipers,

    skinny hard tires,

    lower friction wherever possible (use gear oil instead of grease in the wheel bearings, 20 wt engine oil, synthetic tranny lube etc),

    and dust off a spot on the shelf for the trophy.

    John B: like alcohol, LPG/propane has less energy than gasoline, meaning the engine has to burn more to do a given amount of work.

  • alfadriver

    July 7, 2008 2:44 p.m. alfadriver New Reader

    John Brown wrote: Why again is LPG/Propane not used in automobiles more?

    Convienency (filling stations), and space (fuel tanks use trunk space).

    Outside of that, they are both great fuels.

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