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Building a Kart/Buggy
(80 posts, started )
not a frame, you'll probably have to buy tubing, unless you use an existing car body (aka excess weight).
they can't jump.
yeah i like the look of the autograssers, but i would like one of the ones with giant suspension and whatnot. if it turns out its all just a bit too expensive we could settle for autograss i guess.
Quote from oli17 :http://www.youtube.com/watch?v ... TL&videos=44ZBQ_Ltkp4 sorry to keep reposting this but its sorta what we're basing our design on. would a pickup have suspension/brakes etc like this?

Usually suspension is selfmade in such construction (double wishbones front and rear). Springs and dumpers have to be fit individually - if you are going to make really offroad machine remember that buggy would be half or more weight of donor car... thus suspension would be twice stiffer (but also with twice durability as calculated for heavier car).

I didnt know you have autograss class in UK (we have RX races here - not an oval - with modified roadgoing cars plus one small autograss type with 600ccm ca. 20bhp) - frankly I dont know why use body? It is added 150-200kg with no impact on strenght
http://www.youtube.com/watch?v=vN-fZkGKhGM
Quote from AndRand :Usually suspension is selfmade in such construction (double wishbones front and rear). Springs and dumpers have to be fit individually - if you are going to make really offroad machine remember that buggy would be half or more weight of donor car... thus suspension would be twice stiffer (but also with twice durability as calculated for heavier car).

surely it would be half?? i will give home made double wishbone a go, not sure how good it'll be. also, going back to the starting the engine with a battery and some fuel - i can't really get my head around how that would work, can anyone find a youtube video or tutorial or something of it being done.
Depends on the engine. If it's an older coil and points type ignition system then you just need a live coil and a live starter motor really, plus some fuel going to the carbs. If it's an injection engine or has an ECU etc then it's a bit harder to get it working (though it might just be a case of powering up the ECU and the starter motor again - it depends on the application in question).

The stiffness of the suspension won't change from the donor car. Springs don't suddenly get stiffer with a lighter vehicle. But it would probably be far too stiff for a buggy, where you'll want lots of suspension travel and quite a low spring rate (plus a lower damping rate)....

Making the buggy any good will be a challenge. But that's why it'll be interesting, and why not many people attempt it.
engine we were planning was either a GSXR600 engine or a CBR 929rr fireblade engine (if that helps)

also, i'll probably be coming back here to ask for help a lot, as, being 16, my experience and knowledge of this stuff isn't all that great!

edit: also, can anyone recommend any good (cheap?) books or magazines on this subject area, i'm always willing to learn stuff like this so any reading matter would be much appreciated
for the suspension, maybe look at the shocks off a large dirt bike? if they are too soft, maybe doubble them up?
Quote from anbiddulph :for the suspension, maybe look at the shocks off a large dirt bike? if they are too soft, maybe doubble them up?

2 shocks on each wheel?
Sure thing. Lots of vehicles over the years have used double shocks per corner.
fair enough, i'll have a look. would finding scrap shocks like this be cheaper than 1 decent shock per wheel? also, how much do "cheap" versions of things like the FOX shocks cost?
You'll want second hand parts of everything if you want to do it on a budget, in which case there is unlikely to be a specific cost we can tell you. You might find someone clearing their garage that has 4 perfect shocks for £10 the lot, or you might have to hunt around and buy 8 less than brilliant shocks for £20 each.......

You need to draw. First off draw a scale sketch of what you want in plan and side view, including the chassis tubes, wheel locations, steering column, engine, radiators, seats, pedals etc etc etc using your best guesses as to dimensions. Then gradually source the bits you want, either from a complete donor car or as individual parts, and put them into your drawing so that it gradually morphs from guess to reality. Along the way you will find things that can't be done due to lack of space, and will have to relocate things, but that's the joy of a project like this.

Once you have a reasonable idea of what is going where, and how each bit is joined together (i.e. try to consider coolant pipe routing, or throttle cable positions, or how the handbrake is going to be activated (if you want a handbrake), and what sort of wiring you'll need) then you can finalise the design, and start cutting/welding metal to form the chassis on to which everything hangs.

Then you start bolting stuff on, and at this point is where it becomes difficult. If you thought the first bit was hard, you ain't seen nothing yet!!!

Everything you fit won't. You will have to change stuff. Modify stuff. Rebuild stuff. Reweld parts of the chassis to accept the changes. Even once you have a rolling chassis, you're only about 10% of the way there. You need to think of EVERYTHING at EVERY stage, bearing in mind that a lot will change after every stage. Write everything down - part numbers, dimensions, drawings of modifications, costs. Make sure that you have a drawing that shows the current state of the design at all times (i.e. if you change a chassis tube, annotate the drawing)...

Have fun! Sounds like a wonderful summer project. You'll need books (no recommendations, just read up on what you need to know at the time - wiring, engines, stress calculations in trellis frames etc), you'll need tools and you'll need to not stop thinking about it until it's finished.

One of my life ambitions is to design and build a road going sports car myself (well, as much of it myself as is feasible), but I'm not clever enough yet, I don't have enough time, don't have enough money etc etc etc. I think it's something I'm more likely to attempt a decade from now.
cool, will use that as a reference. how much do you think it would cost to make it road legal and insure it if it was road legal?
Oli, if you can find any design of the buggy (I know that where popular there are quite universal designs with many mounting places) - better use it. I had detailed manual for donor car, but many parts were still on car when designing - I had many parts that werent measured properly, some mountings werent shown in the manual, so improvisation was constant part If you get a bike as donor you should have all the wiring also.

I thought autograss middle-engined with light bike engine is quite well balanced (I got real rear-engined car, so now with no mass in-front, I put there battery, spare wheel and 30kg of concrete steel - it has COG about 85% weight on rear :tilt. So now I get it with whole front body (maybe even some mounting places can be used) from a car in higher classes :doh:

Previuosly I meant that suspension is designed for dedicated mass to fit frequencies - therefore in fact springs and dumpers wont get stiffer, but suspension - yes, it would have smaller frequencies with smaller mass. Well I wouldnt dare to make moving suspension parts (I wouldnt trust its durability) so I wish you good results with your desing and job done


Those autograss buggies can be bought for 4000
You can pretty much buy the chassis / wish bones / etc for one of those buggies for ^^ said price, including the engine.

Basing your buggy on one of those could turn out pretty cheap, and you could pretty much rob the design of the chassis / wish bones / swing arms / etc from one of the buggies. Could simplify things somewhat.

BTW: they are ****ing rapid. And they also do a class 10 version, which is basicly the same thing but having 2 engines. The things fly.
Quote from samforey12345 :Those autograss buggies can be bought for 4000
You can pretty much buy the chassis / wish bones / etc for one of those buggies for ^^ said price, including the engine.

Basing your buggy on one of those could turn out pretty cheap, and you could pretty much rob the design of the chassis / wish bones / swing arms / etc from one of the buggies. Could simplify things somewhat.

BTW: they are ****ing rapid. And they also do a class 10 version, which is basicly the same thing but having 2 engines. The things fly.

Indeed, class 10 is unlimited, so as you say, twin hayabusa bike engines are not unheard of, i have also seen (and heard!) chevy v8 powered 10's over the years as well, but we are leaving out class 9 i think here same thing esentially, class 8s are limited to 1350cc, 9s are from 1350cc to 2055cc and 10s are as already mentioned, unlimited, but for me, 8s are more fun to watch, nice and competitive, my favourite saloon classes are class 3, class 6, and class 7 tho, excellent fun, class 7 fiat seicentos with twin bike engines in the boot are always fun to watch!

I used to love class 2, (im showing my age now...) but then they started letting bloody FWD cars into class 2, novas, psshhhh, but RWD escorts and toyota starlets started getting harder to get hold of so something had to change, similiar to whats happened to class 1 as well, used to be 998cc minis only, but now some other tiny fwd cars are allowed (cant remember what, small fiats and pug 106, maybe fiestas too?) because the minis are nearly all gone.
#71 - Migz
Not too sure why you'd want something like a 600cc GSXR engine?
If your making a little lightweight buggy imo that'd be just stupid.

A good friend of mine does go karting and he has a Rotax 124cc Engine in his go kart (Exact same engine from an Aprilia RS125) and his go kart would happily do over 100mph.
Stick a smaller front sprocket on it and it'll do about 90 tops but it'll get there shit quick.
I don't know what putting a 600cc engine in a little go kart/buggy would be like but im sure it'd be just too much power for something like that.
Quote from samforey12345 :Those autograss buggies can be bought for 4000
You can pretty much buy the chassis / wish bones / etc for one of those buggies for ^^ said price, including the engine.

Can you link me that? I especially interested in transmission, rear axle, differential?
I dont think there is really anything like a differential on these, well there hardly ever used to be anyway, all they used to be was pretty much the same as a bloody great oversized go kart rear axle, solid axle from wheel to wheel usually made using a pair of shafts from a FWD car (they used to use front hubs on the back of these so it was possible) and seam welding them together to make it one solid shaft, and driven by a very short chain directly from the bike gearbox, a lot of them have the rear brake disk mounted in up somehere near where the sprocket is to keep it cool.
Quote from Migz :Not too sure why you'd want something like a 600cc GSXR engine?
If your making a little lightweight buggy imo that'd be just stupid.

A good friend of mine does go karting and he has a Rotax 124cc Engine in his go kart (Exact same engine from an Aprilia RS125) and his go kart would happily do over 100mph.
Stick a smaller front sprocket on it and it'll do about 90 tops but it'll get there shit quick.
I don't know what putting a 600cc engine in a little go kart/buggy would be like but im sure it'd be just too much power for something like that.

The Aprilia RS125 is a 2-stroker, with probably about the same power as a 600cc 4 stroke engine. Difference being, the 2-stroker is bloody expensive, unreliable, and very very dirty. Having said that they give you a thrill to remember when hitting the power band xD
Quote from samforey12345 :The Aprilia RS125 is a 2-stroker, with probably about the same power as a 600cc 4 stroke engine. Difference being, the 2-stroker is bloody expensive, unreliable, and very very dirty. Having said that they give you a thrill to remember when hitting the power band xD

An RS125 has about 35hp and a GSXR600 well over 100hp. That's not quite the same!

Building a Kart/Buggy
(80 posts, started )
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