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fanfoy
fanfoy HalfDork
10/11/13 5:40 p.m.
Keith Tanner wrote:
Flight Service wrote: I have never understood the "let's cut up a sports car to make an old looking sports car!" A Miata donor for a Locost (other than a specific class build) seems idiotic to me. You have a sports car, but you want a sports car?
You're right, I should have restored it. After all, it had only been sitting outside in this condition for five years. Seriously, older Miatas are getting rusty. It's the same reason so many AE86 Corollas got cut up before the drifters discovered them, they were mechanically tough, cheap and rusty. Nobody takes apart a good car to build one of these. The end result performs much better than the donor car too - my Locost and my Targa Miata lap our local track at very different speeds, but they have very different ways of going about it. And the Locost was a lot cheaper to build.

With a race series as popular as spec Pinata, it's not like there will be a shortage of mechanically great, but esthetically poor Miata donors anytime soon. And it's a Mazda, so Keith is right....rust.

carbon
carbon Reader
10/11/13 6:09 p.m.

Nobody's with me on the bike thing huh? Are there reasons that I'm not seeing or is it lack of faith that the bike tranny will hold together or? We raced sprint cars with those drivetrains for years (in basically a spec class) I never saw a failure form any of our competitors. The legends series runs them in cars, so do baby-grands. The 1300s make 165ish hp to the wheels with 100lbft of torque. You run the motors mounted longitudinally and they sell a u-joint holder that attaches to the countershaft (where the front sprocket would be). the bike clutch is hydraulic so easy to plumb, the trannys are stout 6 speeds and sequential. Aftermarket and factory parts are readily available, dealer networks are worldwide. Oh and the whole deal weighs in the neighborhood of like a 150 pounds, engine, trans, wiring, charging system, cooling system, starter, everything, compact as hell too. What does the tranny weigh on most of the other options? Am I missing something? Is reverse the deal breaker on a 1000lb car? I'd love to hear some opinions before I build mine. I think I'm going to do an elan if I can find one thats reasonably priced.

Keith Tanner
Keith Tanner MegaDork
10/11/13 6:10 p.m.
in a previous post, Keith Tanner wrote: A coworker has a bike engined Seven. It's the black one from the Car and Driver article, only with a lot more mechanical work. It's proving to be more, umm, "maintenance intensive" than mine in a lot of ways, but it sounds amazing on track and is about a second quicker per lap. PITA on the street, though. No reverse and the trans really prefers hard charging over cruising.
carbon
carbon Reader
10/11/13 6:14 p.m.

What driveline is in it? What's been the maintenance issue? So I can engineer a solution when I build mine

JoeyM
JoeyM Mod Squad
10/11/13 6:17 p.m.
Flight Service wrote: I have never understood the "let's cut up a sports car to make an old looking sports car!" A Miata donor for a Locost (other than a specific class build) seems idiotic to me. You have a sports car, but you want a sports car?

I didn't want a sports car[*], I wanted to design and build a car from scratch. It sounds like the sports aspect of the car is the most important part for you. For some other people, it is the DIY part that matters.


[*] - obviously, since I'm making a street rod

sesto elemento
sesto elemento Dork
10/11/13 6:33 p.m.

Got to take into account the night and day difference in civility between a modern 1300 bike with efi and and old 900 with carbs in a car swap too though. The last 10 years have been pretty huge in terms of refinement for bikes, and 400cc's is a big deal there in terms of grunt.

bgkast
bgkast HalfDork
10/11/13 6:37 p.m.

In reply to carbon:

Good Info. I had heard concerns that bike transmissions may not be stout enough in a BEC application. They do sound fantastic and have a sequential shift going for them...

I'm using an SRT4 engine for my build. It probably weighs 3x what a bike engine does, but 400hp shouldn't be a problem.

Driven5
Driven5 Reader
10/11/13 6:37 p.m.

In reply to carbon:

In my humble opinion, sport bike engines have terrible gearing for use in cars. A super tall 1st gear, with 5 more spaced closely behind it. In addition to that tall 1st gear, you're carrying significantly more weight than the engine and clutch were designed for. But the more you gear it to be easy off the line around town, the worse highway driving gets. With a Hayabusa engine you can have 'only' a bit worse than an early Miata on the highway running 4400rpm@80mph and a 200mph theoretical top speed, but 1st gear alone will take you to 80mph and it will certainly feel sluggish at low speeds without having a shorter gear to downshift into. Using a 4.1 final drive gets you down to a much more 'normal' 45mph 1st gear, but you'll now be spinning 7700rpm@80mph with a 115mph maximum speed.

If bike engines made car like power in the 2k-3k rpm range AND revved to 10k+rpm, it would be less problematic. But high strung engines need revs and gearing to work well. Some people really enjoy driving BEC's on the street, and you might be one of them. But for many (most?) others, they are too heavily compromised to be practical for anything more than occasional street use to get to the track.

In reply to Flight Service:

Yeah...It's not like the sports car driving experience will be affected very much by a ~1,000 lb weight reduction.

carbon
carbon Reader
10/11/13 7:07 p.m.

Looking at the torque figures here, seems to me it (60+lbft) would be enough to motivate a seven at 3000rpm. For the record thats 10ftlbs more than a stock miata at 3000rpm. Stock gearing on the hyabusa allows 192mph at 10.5 in 6th with 77mph in 1st at 10.5 (redline is 11,000 IIRC), I think a reasonable middle ground could be found there. It's not a drag car, it's a car for back roads and such right?

<img src=" photo 2006BusaStockNosmoothing.jpg" />

slopecarver
slopecarver Reader
10/11/13 7:15 p.m.

In reply to carbon: Bike transmissions don't like automotive scale engine braking nor shock loading and don't have reverse. Bike Engine Builds can work but they will likely be less reliable especially when driven hard.

Keith Tanner
Keith Tanner MegaDork
10/11/13 7:22 p.m.
carbon wrote: Got to take into account the night and day difference in civility between a modern 1300 bike with efi and and old 900 with carbs in a car swap too though. The last 10 years have been pretty huge in terms of refinement for bikes, and 400cc's is a big deal there in terms of grunt.

The article is 7 years old. It has a new rear LSD end and a new fuel injected engine. CBR990, I think. The original builder made it look great, but really wasn't good at building. So some of these problems are due to the build, and anyone who wants a bike engined car will simply shrug them off. But here you go.

The biggest bike-related problem I can think of was with the kickstand switch triggering - that took a while to sort out and it was really frustrating, because it means immediate engine shutdown. I think vibration has been the source of a number of failures. There have been wiring problems from the factory connectors not seating properly, and at the last track day the plug wires wouldn't stay seated so it never ran on more than three cylinders. It's had repeated axle failures and fuel feed problems. Only one fire, though. The small battery means that there's not much reserve if the car's having trouble starting.

The exhaust tip falling off every single time the car came to the track was mostly entertainment for the rest of us.

The street manners are such that he's recently let the registration lapse, and it's now a track-only trailer queen. Since it almost always left the track on a trailer anyhow, that's not a big change.

carbon
carbon Reader
10/11/13 7:47 p.m.

We ran 4 seasons of wheelying sideways in sprintcars around bumpy dirt tracks with zero failures, plenty of shock (including some cartwheels) and engine braking. No competitors had failures either IIRC. I'd love to hear a personal experience with a tranny failure in a car, seems like lots of assumptions that they're weak because of the weight difference.

Kickstand switch is a simple splice on suzukis, 2 min fix, 2 wires, twist and tape, or solder and shrink if you want to do it right. Wiring issues being a concern is a failing of the builder, that would carry over to any swap and bike wiring is going to be the simplest of any efi swap. Axles would be a problem with any motor if a 900 bike motor breaks them, its a normal fuel pump any efi swap= same, battery doest have to come from a bike, it's a 12v system.

To original poster, whatever you do with it, good luck, I've never seen a 7 that I didn't like, no matter how it was powered. It'll be a fun adventure to build it, and it'll be fun to drive when it's done.

JoeyM
JoeyM Mod Squad
10/11/13 7:48 p.m.
Keith Tanner wrote: The original builder made it look great, but really wasn't good at building. So some of these problems are due to the build,

in his defense, the article says Chris had "a lack of experience," and that it was limited to "some modest wrenching on a Neon he used for autocrossing."

I'm sure that he did the best job he could. He learned as he went, like a lot of us are doing. I once responded to the question "Is there anything you would have done differently in the buildup"by filling an entire page with things I could have done better. I'm still going to have a major sense of accomplishment when the car finally moves under its own power.

I'm not saying that you were criticizing him; I'm just pointing out that a first build can usually be expected to be less than perfect. I suspect that this might by part of why SkinnyG is building a second locost.

carbon
carbon Reader
10/11/13 7:59 p.m.

I think its an awesome job for limited experience, just a bad example of why not to build one yourself. (no offense to Keith, he's probly got more experience with this stuff than most of us)

Driven5
Driven5 Reader
10/11/13 8:14 p.m.
carbon wrote: I think a reasonable middle ground could be found there.

For the right type of person, you're correct. If you like it, then that's what really matters.

Keith Tanner
Keith Tanner MegaDork
10/11/13 8:17 p.m.

I knew it wouldn't matter what I posted.

But the fact of the matter is that the car's been in the hands of an engineer for the last 5 years, and it still hasn't started running reliably. He knows how to read a wiring diagram, and fixing the kickstand problem wasn't just a matter of splicing two wires - it was eventually traced back to a connector in the stock harness that wasn't seating properly. Meanwhile, a car engined car doesn't have a kickstand switch.

My point wasn't that you shouldn't build one yourself - hell, I wrote a book telling people they SHOULD. But it's my experience with a bike engined car, so when you asked I shared it. If it were car engined, it may still be licensed for the street.

Chris was inexperienced, yes. He built a car that looked great and was extremely light. A bit tooooo light in some cases, but that's been sorted out now.

carbon
carbon Reader
10/11/13 8:25 p.m.

I'm glad that someone with personal experience posted what their take was. Not trying to troll, or argue, just trying to solve problems so cool e36m3 can happen for people. Good luck.

bgkast
bgkast HalfDork
10/11/13 8:43 p.m.

Keith- what brakes are you running on your car?

Keith Tanner
Keith Tanner MegaDork
10/11/13 10:21 p.m.

Dual Wilwood masters on a Wilwood pedal with bias bar. 7/8" and 15/16", I think. At the wheels, it's just stock 1.6 Miata stuff with some hearty Carbotech pads. The big secret is the bias, I have an adjustment knob right beside the shifter so I can dial it in perfectly. The fact that the car has rear weight bias with a driver in it helps as well when it comes to braking.

It's been interesting getting it back on the track after so long. It's set up to be really loose on turn-in (the light front likes to push a bit otherwise). If you take this as an indication of the overall balance, it'll oversteer through the whole corner as you feather the throttle. But if you get on the gas right after turning in, the rear digs in and you get wicked drive off the corner. Definitely different from the V8 Miata, which usually requires a bit more neutral throttle before you get back on it.

carbon
carbon Reader
10/11/13 11:01 p.m.

I found a video of a hayabusa powered caterham in traffic for those who are interested. Seems geared ok to me and doesnt look too hard to be smooth in. Enjoy:

http://www.youtube.com/watch?v=RdqQr7_uetk

Driven5
Driven5 Reader
10/11/13 11:31 p.m.

While it may not be my ideal street toy, there is at least one driver I know of on the Locost forum (olrowdy_01) that has been happily enjoying his street driven bike engined build for a few years now:

Locouki

JoeyM
JoeyM Mod Squad
10/12/13 10:10 a.m.
carbon wrote: I found a video of a hayabusa powered caterham in traffic for those who are interested. Seems geared ok to me and doesnt look too hard to be smooth in.

Stop trying to convince people (including yourself) with links and graphs. Instead, start your build thread and show us. As my favorite rapper said, "get the job done, 'stead of talkin' 'bout it"

You can power it with whatever you want. Trust me, the more ill-conceived the idea is, the more we'll like it.

Moving_Target
Moving_Target Reader
10/12/13 12:12 p.m.

That pretty much sums it up.

paulmpetrun
paulmpetrun Reader
10/12/13 1:56 p.m.
carbon wrote: I'm glad that someone with personal experience posted what their take was. Not trying to troll, or argue, just trying to solve problems so cool e36m3 can happen for people. Good luck.

I built my first 7 replica with a 2001 Yamaha R1 engine in 2001. Back then everyone said it wouldn't work, blah blah blah... It worked BRILIANTLY!

Here's my second lotus 7 build, also with a Yamaha R1 engine.

[URL=http://s118.photobucket.com/user/profeser/media/7049_zpse0b30787.jpg.html][/URL]

As for reliability issues, problems, trans issues, kickstand switch issues, etc. I had NONE! I built both cars from scratch, used the hawk machine driveshaft adapter, the stock bike fuel pump, trimmed the wire harness accordingly, and tracked the living E36 M3 out of them. As near as make no difference 5 seasons on car #1 with not one issues. I have driven them around the neighborhood, and a few back country roads. What I found driving them on the street was I tended to run in 4th and 5th gear, just so the throttle wasn't so touchy. in the early 2000's I was very heavy into 7's, had quite a few friends with Caterham's, one with a Stuart Taylor(with a CBR900 Fireblade, a few with 4age Toyota engines, and so on. The Caterhams were the fastest, but both Cats had very potent engines and ran Avon slicks. Bart( Cat 7 with a wild track only Kent based engine) and Brian(Zetec powered Superlight R) were faster around the track than me, but they both had roughly 6 or 7 times what I had in my car. And they were really only a second or two quicker around a 1.5 miles track.

As for the bike engines, they hold up just fine if you don't abuse them, just like anything else. I have really never heard of anyone destroying a trans. At least not in the group I ran with. I would build another 7 with a bike engine in a heart beat. Street or track, doesn't matter. They work extremely well on the track, and are reasonable on the street. For city traffic, well its your car, do with it what you want. Think of it this way, a Honda civic from the 90's had 100hp and maybe what 80lb-ft torque, and weighed 2400 lbs. My first 7 weighed 1073lbs with me in it on track, and the R1 engine had 130ish hp to the wheels, and 60ish lb-ft torque. More than enough, to pull out from a stop(even on a steep hill) with out slipping the heck out of the clutch, or anything strange. yes the lack of reverse is an issue if you want it on the street, and especially if your state requires it. But theres enough solutions out there now, that its not an issue. I still wouldn't spend the $$$ on a quafe reverse box or anything, still to unrealiable in my opinion.

Bottom line, its your car, build it the way you want, and just enjoy the heck out of it

Paul

kevlarcorolla
kevlarcorolla HalfDork
10/12/13 5:07 p.m.

My buddy with an R1 powered dwarf just had 2nd gear fail and ruin some other pricey bits.I've had no problems with either of my R1 powered cars and one is awd and probably 1500+ lbs with nearly 60 standing start races on it.I'm just about to start my dwarf rebuild and I picked up a GSXR1000 engine,don't expect any problems with it either with the oil pan mods.Kickstand switch is super easy to deal with,on the R1 just open up the switch and silicon the dewey that swings and trips the switch so it doesn't move.Leave it hooked up and forget about it. These guys are right about the drawbacks of a bike engine car.....if its going to be a street car.Define your use and if its to be mostly a track/autox deal than I wouldn't consider a car engine and trans.The bike powered car will be at least 300lbs lighter up front,take a wild guess what that does for the handling/feel of a sporty car.

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