LocostUSA.com

Hello Locost world:

I stumbled across this forum in my searches for an idea that I thought was 100% completely unique. A close friend of mine races motorcycles, and he has a few Yamaha R1's in different states of repair. We have always joked about putting an R1 motor in a go kart. There was a point about a month ago when we both agreed to pull the trigger and make this happen so I began searching, as well as talking with some friends that race karts. They gave me some specifics of what I needed to find, and I went through the vast land of the internet searching. My only conclusion was that what we actually needed to get in the form of a rolling kart frame must have been made from pure gold because they seem to be very proud of them.
Back to the drawing board. Hey lets just build a frame out of tubing and drop the motor in that? Its got to be a never been done scenario right?? I went back to searching and came across this forum. Well as it turns out this is not a new fad at all, and I find that a bit disappointing, but the knowledge and experience on this forum is bountiful, so I will turn here for my build help..
A little back story on me. I live in the coastal area of North Carolina. I have auto crossed for years in my high horsepower 2006 Mitsubishi Evo with great success. I have also attended a few track days at VIR and Summit Point. In the winter of 2013 I decided that I wanted to compete in ChumpCar, so a few friend went in and we built a 1994 Acura Integra to compete. The car is done now, and we have been attending track days and autocrosses with that since June to shake the bugs out. It will debut in the VIR ChumpCar event in March 2015.
Our plan with this build is a tube frame, mid engined, Yamaha R1 powered BEC. My buddy already has all the motorcycle parts, the motor and tranny, the ecu, the dash, and all the fixings. I have purchased a 1993 Mazda Miata to use as a donor car. From the Miata we plan to use the front and rear suspensions, the braking system, and the steering system.
This leaves us with essentially the frame itself. Honestly, Blue Devils build is almost exactly what I envision our car to be. There are a few minor tweaks I would like to make, but thats pretty much the ticket. viewtopic.php?f=36&t=4970&hilit=blue+devil The problem is that I have no idea how to use CAD, I have no idea how to stress test anything in a computer. I can cut and weld with increasing efficiency, but putting it on paper is where I am having the problem.. Does anyone have any advice here? I have everything in my head and it all makes sense. Normally just running with it and making it happen seems to work ok, but this is on a whole different level.... Help would be much appreciated!!!!

Thanks
Jeremy

"Just build it and they will come."

You don't think they had CAD most of the years they were building cars do you?

Post away and everyone here will help you.

_________________
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.

Jeremy,

pencil and paper most of the time in my world

just arrange all the components in the places they will be in the car including the driver, then fill in the gaps with some tube but remember there are a lot of examples out there of exactly what you intend to build so study them, ask questions and proceed with caution, you will find that the car designs itself.

there are several dune buggies with R1 power, this may be an option if you want a mid engined setup and it gives you reverse.

_________________
this story shall the good man teach his son,
and chrispin chrispian shall ne'er go by,
from this day to the end of the world.
but we in it shall be remembered.

Build it out of 1" square tube with the tubes joining in nodes, it'll work just fine.

Having driven a handful of Se7ens, I don't know if I'd use Miata suspension or not. I'm pretty dang happy with live axle in my R1 project. Makes the build simpler IMHO.

_________________
Too much week, not enough weekend.

OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

Blood Sweat and Beers
http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216

Things to remember when drawing a frame from your imagination. ..
Long unsupported beams twist and flex.
Boxes go out of square (twist).
Loads in the middle of a beam cause the beam to flex.
These are "bad things". We called it the fifth spring effect when I was younger, early Mustangs were notorious for twisting up like a pretzel without a frame rail brace, an export brace AND a Monte Carlo bar.
Load paths work best when they distribute the load across multiple tube junctions. It's harder to bend a bundle of sticks than it is to bend a single stick.
One of our guys ( I don't remember who) built a miniaturized frame (in scale) using heavy solid wire so he could "see" how things went together.

There's also something called the "Golden Ratio", basically 1.62-1. .. It's useful in that the wheelbase-track ratio should be close to that for most applications, going to less than 1.54-1 makes a car rather twitchy at high speed but it will have a faster steering input response on a tight track than one with a 1.7-1 ratio. On the other hand, a 1.7-1 ratio will be smoother on a high speed track.

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"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

Hey Jeremy, welcome. yup BECs are a well-done thing. you should defintely take a look at SCCA D-sports racers, because motorcycle engined racers have been a part of that world since the 1970s.

_________________
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.

Hi Jeremy, welcome aboard, and remember that the giants on whose shoulders we stand did not have CAD.

As you can see, you'll get lots of support here--you've come to the right place. All I have to add is...

1. With an original design, Build Then Measure is often the quickest way to get the fiddly bits right (such as diagonal braces).
2. Wood is cheaper than steel, and if you have a table saw, you can make a lot of 1 x 1s for not a lot of money.
3. If you have a cement floor, sidewalk chalk is a handy layout tool for the early stages of chassis development.

_________________
Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

Pro Tips right there

_________________
Too much week, not enough weekend.

OOPS I did it again
http://www.locostusa.com/forums/viewtopic.php?f=35&t=17496

Blood Sweat and Beers
http://www.locostusa.com/forums/viewtopic.php?f=35&t=15216

Welcome Jeremy! Glad you found us. Plenty of useful stuff in a Miata. I think the spindles and brakes are useful parts of the Miata, but the actual suspension arms and especially the sub frames are less help than you would think. Once you build your frame to connect to the sub frames, you might as well just build it for the suspension arms and by the time you weld the frame you'll be OK for the arms. Much of the arms can be sourced anyway.

Building some mockup stuff from wood is a sensible thing to do. You can make little gussets from 1/4" plywood and screw things together.

You'll get a result that will put almost anything your going to see at an event to shame... Plus strong and reliable, not something you have to feed brake pads and tires every weekend.

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

This is amazing!! I am humbled by everyones response and willingness to help... Kinda makes a man feel at home...

Currently I am building an MDF build table with a 1x1 square tube frame, and adjustable feet. My plan is to mount it to sawhorses, and then rebuild and upgrade my current iRacing sim rig with the same 1x1 16 gauge square tubing that I will be building the car out of. It will give me some more time to familiarize myself with the way the metal behaves. Once this is complete I will begin mocking up the BEC build.

The miata platform for a donor was the choice we made because its a proven platform, both in this scenario as well as in miatas themselves. There is a plethora of aftermarket and salvage yards parts to choose from, and to be honest I just picked up the donor car for less than the tab from a good night at the bar... I certainly won't look that gift horse in the mouth....

I have done much reading and research before making this initial post. I have recently familiarized myself with the Golden Rule of Ratios, and done a bit of math. The track width on the Miata is 55.5 inches, and the stock wheelbase is 89.2 inches for a ratio of 1.607. To get to 1.618 with the same track width, we would stretch the wheelbase to 89.80 inches. What you're suggesting is that going shorter than 1.618 would be beneficial in tight turns and technical courses?? This would explain the Ar-i-el At-om 3 with a track width of 63 inches and a wheelbase of 92.3 inches which gives a ratio of 1.465... This build will be strictly for Autocross, and maybe some track days if we feel it is safe enough. With the main focus of the car being autocross maybe I should look at a smaller ratio, in the 15-1.55 area?? What do you think??

As a matter of fact, I was in the market for a good DSR car, or even a Radical, but I couldn't bring myself to spend that kind of money.. Maybe this will scratch that itch...

Well back into the garage to hopefully finish this build table so I can move onto the sim rig, and then onto the car!!!

The Brits are the experts on BEC's. Check out http://www.locostbuilders.co.uk/ . Also check out the Sylva R1ot http://www.riotcars.co.uk/index.php/rio ... re=default Russ

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You meet the nicest people in a Locost Se7en.

Welcome Jeremy15!

I've recently found this site myself a couple months ago, and it has been invaluable in building my mid engine locost inspired car. There is a wealth of experienced folks here who have helped me along the way from Tube Miter Programs to gussets for engine mounts, and welding tips which I didn't think of. I've found most folks around here to be of a rather older and mature crowd, in which the technical discussions are thought through with reasoning and good judgement, instead of worthless pissing contest of who is right and wrong which unfortunately occurs frequently on many other sites.

Also, there are several designs which I have stolen ideas from (such as KB58's Midlana and Kimini), as well as most of the Locost7 book chassis, and rear end tube layout of mjalaly. I'm going to continue to do so until I arrive at a Patent infringement.

Your miata donor car is a great choice for obvious reason. As per parts availability for miatas in salvage yard, I suppose this varies depending on areas, but in South Texas it's VERY slim pickings. (But salvage trucks and SUV's are a dime a dozen.)


As told to me by others: Enjoy the Journey.

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There is no such thing as mechanical failure, only a lack of attention to detail.

HEY NOW!!! I been accused of lotsa stuff over the years, but "Mature" and having "Good judgement" ain't one of 'em! Sir, I resemble that remark and will ask you to keep a civil tongue in yer head!!!

Yo Jeremy!
Well, as usual, I got here late and don't know what's going on... Welcome to the forum! Coastal Carolina, huh? Where-abouts? I'm an ol' North Carolina boy my-own-self, from Anson County originally. Are you one of those folks that say "Hoiy Toide"?

Yep, you need CAD... "Cardboard Aided Design". I used the box my new dinner table came in, and drew at 1:1 scale. It beat doin' all that pesky math! Actually, there was a pizza box first. Me and James ate the pizza and discussed this whole insanity. At some point the box got sacrificed to 'splain something. I think that was the first time we discovered disappearing Sharpies... But I digress.

Random thought-- An MDF table in Eastern NC is gonna be short-lived, unless it's in some kind of climate controlled building. The humidity gets to the MDF over time. It'll probably last the time it'll take you to build a frame, but keep an eye on it.

Designing a chassis is kinda complicated, but it ain't rocket surgery. You can do it. Read, listen, learn... There are lotsa guys here that have "been there-done that" and can help ya along. And if you want a BAD example, just google "Team Slotus"

Go Wolfpack!

JDK

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JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

Wait, you mean that box with a picture of a table we eat off of - actually has a table inside?!?

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Hey Jeremy, sounds like you're on the right track.

even though I( work on a very powerful CAD system daily, I am hear to say that CAD is not necessary.

Gonzo's 1:1 scale cardboard layouts are a very effective methodology, and even small scale pencil sketches.

as far as your parts selections, I will also add my vote for ditching the MX5 control arms front and rear, and building your own out of tube. they'll be a whole lot lighter than factory parts.

the miata front spindles and rear uprights will actually be a bit heavy for the kind of car you're looking to build - which should come out about the same (or similar) in weight to a Legends/Dwarf racer, but on the upside, since the brakes on Miata are sized fror a 2200lb car, your 1000-1200 lb machine will have killer stoppers.

it has been my experience that in scratch-building, mimickry gets you far along the path quickly and can show really good results without doing a ton of math or science.

are you thinking front, or rear engine?

_________________
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.