Franken-Rex idea

[Vince-HX]

So I have this crazy idea. Well, I have alot of crazy ideas

Anyway, I might be acquiring a Crx from a coworker for pretty much free. It has some rear end damage and the frame is a little bent so I thought why not use the front half of the chassis for the high mileage three wheeler I have wanted to build for awhile.

I have a complete ninja 250 for the drive train. The 250 engine is rated @ 36hp@ about 12,000 rpm and 18ftlbs @ 9,000 rpm and it only had 5,000 miles on it.

I'm thinking the whole rear end from the doors back will be cut off and a BT/teardrop will be fabricated to take its place to save some weight and add a little aero. Of course a cage will need to be build to properly support the whole thing and build the rear motor/swingarm mount off of.

A sprag/overrunning clutch would need to be integrated into the drivetrain for proper P&G with Eoc.

I also have a MegaSquirt that doesnt have a home yet.

So you guys think I might have a chance to hit 100mpg with the Franken-Rex?

Money would not be an issue with this project, already have everything

[TrikeKid]

Why the sprag clutch? I realize you can't shift a motorcycle into neutral as easily as a car, but it would be long before your glide is over, or you could simply hold the clutch disengaged. I have a feeling you're going to be putting a lot of strain on that little 250 motor pushing that much weight, they're not exactly a rocket ship in bike form.

[metromizer]

that CRX sounds like a good candidate for a pusher trailer.

Hmmmmm.... imagine a barely street legal CRX with a 600hp turbo'd B18, being pushed to the race track with a CRX pusher trailer getting 40mpg. Once at the track, you just unhitch the pusher (that also carries a small tool box, aluminum floor jack and your slicks), you race for the day, kiss the trophy girl, take home the purse and smiles all around. If the unthinkable happens and engine breaks, heck, you can still push it home!

I have the same desease, I think too much

[Vince-HX]

Not a rocket ship but they pull off low 15 second quarter mile times

About the weight, i think i would be able to get total weight around or under 1000 lbs. On my other 250 with me and another person (about 700 lbs) it could still get up to 80 pretty quickly so i dont think another 300 lbs with much better aero would hurt that much. Think fully stripped, no dash, aluminum plate floor, and the stock engine bay would house just a gas tank instead of a motor and tranny.

The sprag clutch would just make p&G + EOC so much easier. I was thinking about using a hand clutch on the gear shift lever and it would suck having to hold it for long periods of time.

[mrmad]

It would be cool to try this, but I think you might go through Ninja clutches pretty quickly. Plus the Ninja 250 is a pretty high revving high performance engine, I think you'll be having it screaming just to drive around which probably would hurt mpg. I would think a larger twin motorcycle that was tuned for less rpm might get better mileage.

[Vince-HX]

with the sprag I think I could get away with only using the clutch for starting out in first so that may help with the wear a bit.

Last year I put over 12,000 freeway miles on my 250 and pretty much raped it everyday and still got 55mpg. And I'm thinking this will be pretty much be only used for in city driving as the ultimate P&G machine. I dont know if it would be able to compete with honda's leanburn technology for steady highway cruising.

And thats a cool idea Metromizer, but why stop @ 600? A few of the guys round here have proved its pretty easy to make 800+hp But really, a pusher trailer with tools and slicks would be so sweet. I dont know if the drag racing world is ready for that kind of thing yet. Hell, just trying to convince some of these guys that taking their side view mirrors off and maybe adding skirts should help mph is rough and they are too worried about their cars looking weird


And come on, who wouldnt want a three wheeled, RWD, 14,500 redline Crx

[Johnny Mullet]

What the heck are you waiting for?

[bikin' Ed]

What about making the fwd electric? You could get unlimited mpg in town, use it as an assist when you want to accelerate faster, and once up to speed just use the motercycle pusher. Kinda the reverse of Riley's ultra mileage kit car.

[Vince-HX]

Originally Posted by bikin' Ed

What about making the fwd electric? You could get unlimited mpg in town, use it as an assist when you want to accelerate faster, and once up to speed just use the motercycle pusher. Kinda the reverse of Riley's ultra mileage kit car.

That idea did cross my mind but the greatly increased cost and weight just doesn't fit into my little plan @ the moment.

Plus I had a great idea about rearranging a few things up front to drop some major poundage and simplify the steering and suspension quite a bit. If everything measures out like i think front skirts should be no problem and the entire front end could be tube framed.

Also being converted to mid engine the whole front end can be smoothed out because there wouldn't be a need for air flow.

I def havto do this

[aerohead]

I'm thinkin' the aero loading would favor the Ninja a little.If the trike ended up the same length as the CRX,you couldn't do much better than Cd 0.23.At around 18.5 square feet frontal area that gives you a drag factor of 4.25 square feet(higher than that of the Ninja).At a 1,000 pounds,you'd have very little power reserve,as your road horsepower would be in the range of 17-horsepower at 70-mph.You could probably slip the clutch a little to get going if need be,but in gridlock on the freeway or Camelback Rd or what have you,I think it might drive you nuts.The windshield is your nemesis.The two-abreast seating amplifies the frontal area so much I've gone to an experimental aircraft canopy for my trike,and thats with 700-cc and 57-hp.I agree with you that you can probably get away with the weight,I just think its alot of air for the Ninja to push.Without the power reserve,your totally dependent on your brakes for collision avoidance,and as a motorcyclist myself,more times than not,the only way I've been able to escape situations,was to accelerate away from them.Just be careful!

[SuperTrooper]

Originally Posted by aerohead

The two-abreast seating amplifies the frontal area so much I've gone to an experimental aircraft canopy for my trike,and thats with 700-cc and 57-hp.

Is there a thread on your trike?

Pictures! We need pictures!

[aerohead]

Originally Posted by SuperTrooper

Is there a thread on your trike?

Pictures! We need pictures!

In the archives under phil knox's aerodynamic photos album there are some pics of the "hyper-minicar".Not much to look.I've married a VW front end and partial pan to a motorcycle(from fork tube back).So far its just a mockup to figure all the human factors and nuts and bolts of it all.I started a thread on it over at maxmpg long ago and have been side-tracked with other "priorities" in the meantime.I gave up on side-by-side(too much frontal area),and tandem(too long) and have settled on a solo,with enough room for groceries.The Sonnerei canopy will help shave frontal area.I will build some crumple area around the flanks,with as much plan-taper as I can get away with.The target is motorcycle weight for licensing and registration and Cd 0.12 if I can pull it off,with maybe 100-mpg.I have a 1986 Honda VT 700,H20-cooled,shaft-drive bike for power and electrics.The V-dub axle is robust if not ideal.Everything is on hold 'til I can weatherize more shop space to protect everything and get me out of the dirt and mud.The aero trailer comes this Christmas season before any more work on the mini.You can see the idea for that also in my album.It's the red Honda Insight with integral micro RV trailer in the windtunnel photo,except with the T-100.

[Vince-HX]

Originally Posted by aerohead

I'm thinkin' the aero loading would favor the Ninja a little.If the trike ended up the same length as the CRX,you couldn't do much better than Cd 0.23.At around 18.5 square feet frontal area that gives you a drag factor of 4.25 square feet(higher than that of the Ninja).At a 1,000 pounds,you'd have very little power reserve,as your road horsepower would be in the range of 17-horsepower at 70-mph.You could probably slip the clutch a little to get going if need be,but in gridlock on the freeway or Camelback Rd or what have you,I think it might drive you nuts.The windshield is your nemesis.The two-abreast seating amplifies the frontal area so much I've gone to an experimental aircraft canopy for my trike,and thats with 700-cc and 57-hp.I agree with you that you can probably get away with the weight,I just think its alot of air for the Ninja to push.Without the power reserve,your totally dependent on your brakes for collision avoidance,and as a motorcyclist myself,more times than not,the only way I've been able to escape situations,was to accelerate away from them.Just be careful!

Thanks for the great info. Some in depth was just what I was looking for. So would I be able to get a bit better Cd by extending the back a bit? I am going to have to add # least a foot to the wheelbase because of the proximity of the engine to the driver and passenger.

This also would be used as a in city driver only so speeds would never exceed 50mph. How much hp do you think it would take to steady cruise @ 45mph with a weight of 1000lbs and cd of 0.23?

There are a few benifits of the crx chassis. The ability to have a passenger, carry additional payload, safety.



I love this thing Actually your mini-car is pretty much exactly what I have wanted to build for quite awhile. One thing that has been bothering me though is safety. In the past 6 months I have been in three collisions, one major one that I should have lost my life in, and two minor ones. It would seem like a pretty hard task to make such a small lightweight car able to withstand the force of an accident without harming the driver. I had planned on making the whole frame out of chromoly and building a funny car style cage around the driver.