LocostUSA.com

Hi all, I have been lurking for a bit and have few questions.

First and foremost....I don't know what I don’t know.
I'm a fair wrench, and perform most of my car and motorcycle maintenance, but have never welded, built a race car, or any car for that matter. I am sure the answers are out there somewhere, but I feel if I just ask the question instead of scouring the internet I would probably have better results.
What I think I want:
To build a relatively low cost sports car in my garage such as http://www.greatbritishsportscars.co.uk/cars/zero-race/
that is extremely fun to drive.

The requirements of this build would be:
1. To actually finish it!!
2. TAKE THE PATH OF LEAST RESISITANCE!!! (no engineering, follow what others have done tried and true.)
3. Do it as reasonably possible.
4. Have something of use/value once completed.

Admittedly, I don’t know squat about any of this, but what I am really confused about is the power train. From what little I know, I think that if I was to go with a motorcycle engine that a Suzuki Hyabusa engine might be the way to go.
I say this because I think that something in the 200HP range would be completely entertaining.
Now on to my questions:

1. Will a motorcycle transmission hold up to this, or does one constantly replace clutches and gears ect?
2. Best way to buy the engine?
3. What is the best year busa engine to get?
Until I know different, I think that I would run a shaft from the engine to a reverse gear box such as http://www.roadstercycle.com/Reverse%20 ... cycles.htm
4.But what do you typically run for a rear diff with a setup like this?
5. rear diff gear Ratios?
6. I have already been given an opinion by someone who told me to avoid this type of Engine. I would love to hear insights on why I SHOULD?

Finally, thank you for taking the time to read my post. Build me up or beat me down, I don’t care. I just want to learn about this and determine if this is a good way to go. Opinions welcome!

Welcome to the loonie bin.
Read as many of the BEC build logs as you can. That's what I did; you'll get an idea of what is involved. I built an airplane, but had no welding experience, before I started. Read, watch and practice, and you'll get pretty good at it.
As to your questions:
Motorcycle transmissions will stand up to it. It has been done many times.
Try looking for a crashed bike; you may be able to salvage some other parts and make some money back. I got lucky by finding a R1 engine complete with everything I need for $ 900. And I sold the fuel tank on Ebay for $ 250.
Don't know about the Busa, but they are a lot more money. From what I understand, they also require a dry sump, which adds to the cost. The R1 is a pretty rugged and well known platform, that's why I went with it.
I am using a 94 Mustang 7.5 rear end. Bike engines are geared quite short, so they need a tall rear end, otherwise your cruising RPM are too high. I think the final drive on a R1 is around 2.62, so I chose a 3.27 rear end. I hope that it will be a good compromise.
Why should you? It is fun to figure it all out and make it work. There are very few people who actually finish and drive a home built sports car. Even fewer with a bike engine.
Hope it helps.

_________________
Martin


My build log:
viewtopic.php?f=35&t=14520&start=0
My build video:
https://vimeo.com/143524140 password "matovid"

Thank you mgkluft.

I was looking into building a Kitfox SS 7 at one time. It started getting very difficult to justify building an airplane, so I abandoned the idea. I feel this car will present enough challenge for me right here on the ground too.
I have read the Busa needs a dry sump. I don't want that to deter me, but I am not sold on it either.
For my first build I want to be able to source what I need and assemble vs. designing and engineering things. I would rather buy a header than try to design from scratch if you know what I mean.
Where do you get headers?

The Kitfox 7 is nice, but pricey. I do like the folding wings.
Don't kid yourself about just assembling. You can't avoid designing and engineering. Not a lot of the stuff is off the shelf. You still need to adapt to your requirements. But that's half of the fun. I am fast approaching 1,500 build hours, and I'm probably only half way.
Case in point, the headers. I haven't been able to source any; even looked in the UK. There are some around for the Legends cars, but in the end, even they need modifying. Look for bonjo2's build log about that. I will make my own. It is another project within the project. But as I said, that is the fun. Mine will be 4 into 2 into 1, because I won't have the Exup valve. I found header collars and flanges at Weller Racing, the rest will be from an exhaust supplier.

_________________
Martin


My build log:
viewtopic.php?f=35&t=14520&start=0
My build video:
https://vimeo.com/143524140 password "matovid"

1. Yes, the motorcycle transmission will hold up. They've been used for dwarf car racing for years, and they subject their cars to some serious abuse.
2. Like Martin said above, I think the best way to buy an engine is to buy a complete wrecked bike. I bought a wrecked 2002 Yamaha R1 for $2200, sold the frame with title for $900, the forks for $200, the swing arm for $100, and a bunch of other small stuff. It added up pretty quick, the engine was practically free. Plus you get everything you need to make the engine run. If you buy a separate engine on ebay or from someone, the engine harness could be cut, injectors or fuel lines could be missing, etc.
3. I'm not trying to dissuade you from a Hayabusa engine, but the reason why I didn't go with one is cost. Everyone wants to put a 'busa engine in their car. They cost a premium over other motorcycle engines. You could look into the Kawasaki ZX-12 for similar performance at a lower cost.
4. It really depends what you want for ratio. You just find one with the closest gear ratio to what you need. I'm using a 7.5" 3.27 ratio rear end from a MN12 Thunderbird.
5. There's a great spreadsheet out there to calculate theoretical top speed. It is called bike_ratios.xls. If you can't find it online, PM me, I can email a copy to you. Punch in your info (a lot of it is provided), and you can decide for yourself what rear end ratio to go with. A theoretical top speed for ~100mph can lead to really high RPMs on the highway and really short gears.
6. If a lightweight engine with a 10,000+ RPM redline appeals to you, this is the way to go. BECs are certainly less streetable than a car engine, so there certainly are compromises. If you're looking for a car to cruise around in, this is not it. BECs prefer to drive around with their hair on fire. And from what I understand, they're just plain miserable on the highway.

And again, like Martin says above, you won't be able to find off the shelf headers. I made my own. They're not particularly pretty, but it was a fun exercise. Unless you buy a kit, you'll find yourself needing to do some engineering. Just the nature of building a one of a kind car. I think Westfield makes a somewhat reasonably priced BEC kit.

A Gen 1 busa will not cost as much as you think. If you plan to build a two seater, then the extra torque of a Busa or a ZX14 will be the ticket. I've raced D Sport Racers for a few years and ran a GSXR 1000 (capacity governed by the rules) and even though it screams, it does not match the busa that I have in the car I'm building (see two seat race car for street) Also if you Super charge it or Turbo it, the Gen 1 is a good platform. The only weakness are the gears, they are not under cut like the Gen 2's but the gear sets interchange if I'm not mistaken.

Cheers
Linz

Have to kind of agree with the statement that the BEC type is a balls to the wall kind of car. I have a hayabusa, been driving for a few months. It screams and is a blast to drive. Right now upgrading to a dry sump to make sure the engine stays in one piece.

I love the rapid pull with such little weight, it really moves, but for street driving, it draws too much attention and you always feel like you are revving at 8k.

All that said, would not trade mine for anything right now.. Things you need to think about

1. Reverse, its a pain, no matter what solution you put in, none of them are perfect
2. Noise - It screems, always, unless you gear it not too, but then I think you loose the value
3. When choosing an engine, choose one that several others have done a BEC with, safe bets are Yamaha R1, GSXR-1000, Hayabusa. I choose Hayabusa to get the torque. Keep in mind you will eventually want to modify, what are the suppliers that sell parts for it??? Especially keep in mind the BEC world
4. Speaking of gearing, what ever differential you choose, make sure you have a good range between 2.9 and 3.6

Hope that helps, if you choose to build one and need help with anything, just ping me...

_________________
Ali ---

-- Push the pedal on the right, the one in the middle is for wussies ---
- Link to build blog- http://BluLi7ard.blogspot.com/

One more for you list:

I got a ride in a 'Busa powered Seven and apparently because bike engines don't have flywheels, the car had this annoying habit while cruising at constant speed. It would get into a mode where the driveline (crank through to wheels) would start oscillating back and forth, causing you the occupants to involuntarily start rocking their heads slightly. If the driver got onto the gas just a tiny bit, or lifted just a tiny bit, it would go away. I didn't much care for that, in addition to cruising at 70 mph which - in his car at least - was 6000 rpm. I kept wondering why he didn't shift to the next gear, but he already had.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

Kurt, do you know if it had a guibo in it and if not do you think it might have resolved the oscillation issue?

_________________
"There are times when a broken tool is better than a sound one, or a twisted personality more useful than a whole one.
For instance, a whole beer bottle isn't half the weapon that half a beer bottle is ..." Randall Garrett

Basher, take a look at my build log. my build (while not strictly a locost, it used locost materials and build techniques) has a 1980 yamaha XS850 engine, (maybe 65-70 hp at the rear wheel?) and weighs only 905 lbs with a half tank of gas.

I drive it everyday it doesn't rain, well actually, like Nikki Lauda, "I accept 20% risk, no more!" with regards to the Prob of precip . my engine redlines at 9000, and on the highway with 3.09 rear gears I turn 4000 rpm at 70 mph. I can out accelerate any damn car I please from rest, simply because my vehicle is so light, and torque off the bottom is good. I don't have a reverser box, and now I really don't want one (for this vehicle anyway) since pushing isn't really that high effort, and it forces me to carefully consider my parking. in a vehicle this light, I now consider reverse to be a convenience, not a requirement.

don't be so quick to seek the highest horsepower, rather, look at power-to-weight. the goal should be around 10-15 lbs/hp, and this will give tyou a very lively car. strive for lightness in the build. a bike in-unit engine/transmission has the advantage of bringing drivetrain lightness to the build, and this will positively affect overall lightness. set a weight goal for the vehicle (for a street-driven locost 1200-1500 lbs is realistic) and choose the power level of the engine based on that.

its importantnto remember that many Legends race cars use yamaha FJ1200 engines, which are air cooled. this implies that an FJ1200 (which is an engine renouned for its torque) can be successfully used in a automitive application, as long as its mounted up front, and has sufficient airflow directed its way and over the cylinders and head.

best advice I can give is DON'T OVERTHINK THINGS. struggling over minor details will kill the build. expect it to take 2-4 years before you can do more than sit in it and daydream.

Also once you get going, start a build log, take and post a crap ton of pictures

have fun!

@ Oldjack - if I were to do it again, and I likely will if I'm honest, I would definitely engineer a guibo into the driveshaft on a another BEC build. the B-3 itself may get one, someday, actually.

_________________
The B-3 build log: http://www.locostusa.com/forums/viewtopic.php?f=36&t=13941 unfortunately, all the pictures were lost in the massive server crash

The beginnings of the Jag Special,
https://www.locostusa.com/forums/viewtopic.php?f=36&t=19012
Again, all pictures were lost.

The Seven was a Westfield, so that's my way around answering your question. The fact that it was a commercially available kit makes me want to think that it "should" have one but I simply don't know. I've never ridden in a car with a guibo so I don't know if that would cure it.

_________________
Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/