View Full Version : Ideas / advice / build thread for a BEC
so i got a motor , and im going to build a small open wheel car with it.
doesnt have to fit any class/requirements , just something i can take to the track for some fun.
plan on some smaller track stuff , morgan park , hillclimbs and maybe the odd run at QR , again actual racing is off the cards , because i suck at it.
engine will be 1300 suzuki , 175hp ish , it weighs 80kg.
car weight to be no more than 350 kg.
wheels are pretty much decided at 13 x 8 and 13 x 10.
dattoman is supplying the brakes , willwood calipers on 266 x 16.5mm vented , same on all corners (just varied piston sizes)
tyres , depending on whats available of course , will be 190/505 and 240/525
wheelbase will be something like 1625 wide , 2200 wheelbase (1405 f 1355 r track)
questions.
maybe use the same wheel/tyres sizes all around ? ie the 8 inch ones ?
its only a bike motor after all , i kinda fear for its dinky little clutch and gearbox.
heres a cap of the basic layout.
http://home.iprimus.com.au/rzsupra/Car/layoutt.jpg
Same wheels and tyres all round is fine and desirable with not too much power.
The only essential thing to suit equally sized wheels and tyres is that you get weight balanced 50/50 from the design stages. Much easier to get that right now than later.
As ghey as a lot of the Formula SAE cars look they have a lot in common with what you are doing.
http://www.sae-a.com.au/fsae/gallery05/pages/Deakin.htm
Billzilla
24-05-07, 09:14 PM
Same wheels and tyres all round is fine and desirable with not too much power.
The only essential thing to suit equally sized wheels and tyres is that you get weight balanced 50/50 from the design stages. Much easier to get that right now than later.
We've talked about that, and while desireable it'll be hard to do with that car. It's going to end up at least 45/55 F/R I reckon, maybe a touch more.
But I like the idea of having the same wheels & tyres front & rear, it can make life easier for sure.
damn right they're gay bigmuz , impossibly short , allthough thats the rules i guess.
i agree on the wieght bias thing , unlike those sae things , my feet are going to be inline with the front wheels about , and a heavy bike motor out back ...
i think ill stay 8 and 10 inch.
considered going inboard brakes? Less unsprung weight, brake weight closer to the COG, wheel size not a limiting factor on brake size.
You could run it off the driveshafts in the rear and run a CV setup in the front. Could also get away with 1 rotor and caliper each end which could save 10-15kg.
You should see how close you can get to a F3, F4000 or any other real racing car...then take piles of measurements of everything, piles of photos.
Then as best you can, do what they did...the people who have done this for many many years as a successful worldwide business are heaps more smarterer that the awesome power that is the PF brains trust.
Copy copy copy...but dont copy pox stuff like sports sedans which are mostly built in someones shed, probably by someone who has no more clues than PF.
I assume you have all the books on Chassis & suspension design...if not I could post them up to on the understanding that they are boomerangs:)
Billzilla
25-05-07, 11:30 AM
considered going inboard brakes? Less unsprung weight, brake weight closer to the COG, wheel size not a limiting factor on brake size.
You could run it off the driveshafts in the rear and run a CV setup in the front. Could also get away with 1 rotor and caliper each end which could save 10-15kg.
Inboard brakes are okay, but unless you have a locked diff then you never get even braking on each wheel.
Also, you lose all braking if a half-shaft lets go.
I assume you have all the books on Chassis & suspension design...if not I could post them up to on the understanding that they are boomerangs:)
Done - I've lent him heaps of good material.
by someone who has no more clues than PF.
:sad:
Anyways, I agree, but it is good to discuss WHY things are headed in the direction they are is it not?
Inboard brakes probably only pay off on something intended to go really fast, I would say this sort of vehicle that Rz is building is not really intended to run much over a couple hundred kays. With a light project like this I would think the extra weight would outweigh any benefits in terms of drag and unsprung weight. There is a point when too light is a problem imho. A bloke out West used to run a supercharged bike powered open wheeler that was the fastest non nitro/ circuit race car I have ever seen in a straight line, but it was such a handful it never saw it's potential. When he wanted to turn it round he would just lift the front off the ground and walk it round.
I think he was from Parkes? Anyone remember him hillclimbing it? Nice bloke too. He went to an SR20 n/a powered ex Formula 2 car after that.
The main basics that you probably need to consider at this stage are;
Engine offset and location
Wheelbase
Suspension style
Rear axle style and drive system.
A lot of the bike powered cars that I am familiar with use a limited slip centre swung off the side of the sprocket carrier. That is something that I think is clever and suitable to your very light car. However it takes a bit of fiddling to make it all work. This decision affects the whole back half of the car, which is why it is on my list now..
Neville Trainor was his name. The next car he ran was a C18 or SR20 powered cheetah(edit may not have been the cheetah). I think his late father built the bike engined special. I'm trying to find a pic.
Someone else remembers :D
http://www.datsun1200.com/modules/newbb/viewtopic.php?topic_id=26679&forum=2&10
Why are you not building it to class requirements? They're there for a reason (like safety) and if it fits a class it will have some resemblance of resale beyond its scrap parts.
One thing about these bike engined cars that I have noticed is that they have tons of space for an awesome wide tunnel because the tiny engine and gearbox together leave tons of space behind.. The only thing getting in the way is the rear axle chain ring. Inboard brakes would hamper the potential here too.
I'd still build it light and go hard on the downforce. With a higher power:weight you can handle a bit more drag with the additional downforce.
I'd love to build one of these :)
hotgemini
28-05-07, 02:02 PM
Buy cheap kart, fit big single cylinder bike motor/box, go to mount cotton.
so anyway , i got busy on the weekend and knocked up a table to make this thing on.
also pulled the sump to have a look at whats involved in dry sumping it , stock sump hangs way too low and known to have problems in car applications.
gears and clutch look pretty darn strong.
ive updated the first cap with the engine (actual dimensions)
just plonked it anywhere atm.
http://home.iprimus.com.au/rzsupra/Car/IMG_0015.jpg
http://home.iprimus.com.au/rzsupra/Car/IMG_0041.jpg
http://home.iprimus.com.au/rzsupra/Car/IMG_0039.jpg
http://home.iprimus.com.au/rzsupra/Car/IMG_0044.jpg
http://home.iprimus.com.au/rzsupra/Car/IMG_0054.jpg
Billzilla
28-05-07, 03:24 PM
Coolness.
Now just weld a bunch of tubes around it ....
muz : yeh drive is the first thing to look at , going to visit that pro-sport mob for some advice on diffs , halfshafts , uprights.
engine will be sitting straight behind driver , centreline will probably be dead between 12,34 cylinders for ease of mounting points.
suspension will be double wishbone all around , not decided on inboard yet though.
zac : resale ..... ah who cares , i pretty much fucked up a perfectly good supra thats no longer re-registerable , or good for any class of racing :)
some downforce in the way of ugly ass wings will suffice for this , not getting carried away with it.
hotgem : your advice was fucking invaluable :D
angels666
28-05-07, 03:42 PM
The engine looks so cute included in that first picture now! :p
Good stuff. Can't possibly imagine that that engine is too low in the sump though. How much shorter could it possibly be?
Shared oil for gearbox/ engine? Get a pic of the width of the engine front and rear mate. I have no idea what they look like these days.
I've been thinking about it a bit- Maybe you should turbocharge it mildly while you are at it? It's not like it's a huge exercise compared to the rest of the deal. Otherwise doing it later when you want/ need more stick will be hard work. I'm not talking a 300hp deal, but a little responsive turbo to blow in 4 or 6 pounds to deliver an extra 50 horses but be soft on the driveline.. If you did that at this stage you could sort the oiling system out once and for all.
Anyways, I bags having a go when it is done- I figure if you fit then I will fit easy (:D)
in the layout pic the stock sump would be touching the ground , id have to lift the engine 50mm to use it ...
yes shared oil , but they have a seperate pickup thing going on (i think , havent looked real close) so any carnage is left at the bottom of sump rather than recirculated.
turbocharging to the extent you described is well on the cards , i think 250 hp would be really nice without overstressing the driveline.
ill edit the cap with width stuff soon.
played with the drawing a bit , got the rear and top view with the engine in place.
i even chucked a turbo in for good measure.
bigmuz : that pic is with the sump removed , it extends 75mm downwards from where its sitting on that SHS.
bigmuz : that pic is with the sump removed , it extends 75mm downwards from where its sitting on that SHS.
Ahhhhhhhhhh. That makes much more sense. Is that 75mil shs?
What program are you doing the drawing in?
yeh 76mm.
drawing in garden variety autocad r14.
roadsailing
30-05-07, 10:20 PM
autocad: for when you just cant find a pencil anywhere :P
a few tips (some more obvious than others)
design your suspension first, then pickup points, then build the chassis to the mounting points.
take a look at http://www.git.com.au/~theedge/ for bike engined thing ideas, but dont copy too much, as cool as im sure these thigns are they still seem a bit agricultural to me.
see if you cna use production bits for spindles etc, might save you some headaches etc.
shineyblue : i took a look around there , seems they have come forward a bit with their buggys .... used to be fairly rubbish.
i got bored today and decided to drop by pro-sport to have a look at their cars.
http://www.pro-sportdevelopments.com.au/
grants personal car is packing a sizeable turbo on a ZX12 engine and lots of other trick bits including air shifter , looks like a fun thing to drive :)
also went out to queensland raceway to see what was kicking about and look at tyres ill be using.
ended up buying a set ill use for the build so ill know all my clearences / measurements are correct.
they will probably be old and hard by the time i finish this thing but they are dirt cheap to buy anyway , ill just put fresh ones on before its first outing.
layed the tyres and engine out on the floor tonight to the dimensions outlined on plan to get a scope of the overall scale.
http://home.iprimus.com.au/rzsupra/Car/IMG_0073.jpg
Couldn't you get second handies? Jesus! What do you mean by cheap?
What sizes?
The pro sport car is excellent. Copy that. :D But seriously it is nicely done. I think the rear end is a bit flimsy with lots of bolt on bracing, but other than tha it is pretty special. I always like a big bolt on upper half rather than lots of little bolt on braces.
http://www.git.com.au/~theedge/images/products/pircv/PIRCV%20PW.jpg
This is a simple way to do the rear end. The integral sprocket/ brake rotor is good but not for you.
muz : 190/505/13 240/525/13
yeh not sure about supporting entire rear end on heim joints , i think id rather the chassis the full length of the car.
im going to use 4130 aswell , much nicer to weld/cut than old mild steel.
probably 1 inch for the main tubes and a size down for the wishbones.
Seeing you are intending to go turbo, might be an idea to get a Falicon billet basket and do the springs while you're there - have been some reports of the upsized Radicals blowing the stockers with nasty consequences.
Too late now, some of the F3 guys will give you their discards, slightly larger rolling diameter, but good enough for a mock-up. I'd be black bagging them and keeping them well away from the tig whenever possible.
Muz, that picture doesn't work.
http://www.git.com.au/~theedge/images/products/pircv/PIRCV%20PW.jpg
tortfeaser
06-06-07, 02:26 PM
Seen the Sylva R1ot? http://www.sylva.co.uk/riot.htm Dude building one here: http://r1ot.com/
Yammy R1 mid-rear mounted, or Zetec.
ok it seems like i cant get the wheels i was looking at so im going to use a guy in melbourne to supply the raw halves and ill assemble them myself.
centres will be made from some 12mm aluminium plate i have kicking around here (dont need big heavy ass cast centres)
all inners to be 5.5" and outers 3" front and 4.5" rear.
will give me 8.5 and 10 inch wheels which are a perfect fit for the tyres.
muz : yeh something like that , ive read that the top arm should be .6 to .7 times the length of the lower arm , also from all the pics ive gathered the top arm usually has a few degrees incline towards the wheel.
gxxr : what sort of boost are these radical guys running ? i thought the stock 1300 would be fine at 5-6 pounds.
tortfeaser : no end of motorbike power cars being built is there , ive found metric shitloads of them on the net.
Ya know what? the best way to figure out the chassis basics is with paper and push pins. You can try different length uppers and lowers and see what effect they have on camber and bump steer.
Then in the end you will end up coming to the same conclusions as most guys- lower control arm horizontal at ride height, upper arm 3/4 of the length of the lower arms and inclined downwards 'enough', depending on how much camber gain you want (which in turn depends on how stiff you expect it to be in roll, how stiffly sprung full stop it is, and overall weight transfer expected (ie how heavy it is relative to how stiff it is))
Then you decide how much anti dive you think you can get away with, then make that happen within constraints of caster/ camber bumpsteer, then try and buidl it stiff.
Then that's it. Simple hey :D
The Radicals I'm thinking of are the ones taken out to 1500cc odd, probably comparable power wise to a low boost turbo.
If you achieve your weight aims, still equivalent to two fat pricks pillioning on the standard bike with about four times the contact patch.
Can't remember the specifics, don't think you were running bodywork or aero. If that's the case, FF practice from a few years back at least seems to have front track quite a bit wider than rear - guess that will come down to your weight distribution - anyhow, just another thing to ponder.
damn , replys i never saw ...
muz , theres fair dinkum a million variables i know , im going to half-ass guess at most of it in the hope it works "ok"
its going to be fairly light car and moderatly stiffly sprung , i do want a bit of compliance for bumpy roads , plus my back isnt really all that flash.
i want pretty light steering so ive been thinking about caster and kingpin inclines a bit , want to put forward some starting numbers ? :)
gxxr , track is another thing , i reckon my plans are within 100mm of where i think it should be.
im going to make a good effort at weight distribution , im making up a dummy seat / floor / pedals / engine mount that i can sit in with the motor (2 main masses) so i can find a balance point to match with the wheelbase , or attempt to.
i had the wheels turn up today , 3mm spun alloy from dale hocking dhocking@netspace.net.au
they are as planned , 5 inch inners and 3 / 4.5 inch outers.
http://home.iprimus.com.au/rzsupra/car/IMG_0149.jpg
angels666
10-07-07, 01:24 PM
Awww yay :p
Billzilla
10-07-07, 04:40 PM
i want pretty light steering so ive been thinking about caster and kingpin inclines a bit , want to put forward some starting numbers ? :)
HTFU, and 2.3deg castor and 7deg KPI.
Pete: were hte outers expensive?
We have some 13 * 10's and want to get some new outers for them to make them 13 * 8's
thanks billy bob , funnily enough my old gokart uses about the same ...
chad , they where pretty cheap i thought , bill knows a guy cheaper again but i couldnt contact him at the time , email paste :
Hi Peter,
The 3mm 5.0" inners plain unfinished are $90.00 per half
90x 4 = $360.00
The 3mm 3.0" & 4.5" outers plain unfinished are $85.00 per half
85 x 4 = $340.00
Total: $700.00
Dale
xbgs351
11-07-07, 02:47 PM
Why have you made the wheels before you have designed the suspension?
Billzilla
11-07-07, 03:24 PM
Why have you made the wheels before you have designed the suspension?
'Cause that's the proper way to do it.
a few reasons.
1/ 13 inch wheels where a given , no need for anything larger.
2/ the widths are very commonly used on cars similar to this , and tyres are readily available.
3/ the offsets could have been made anything really , my only interest was that the chosen calipers / disks fitted inside them.
4/ ive been looking at shitloads of different open wheel suspension setups and the wheels have little to no bearing on how its constructed.
if you have any input id be glad to hear it , this is all a learning process to me.
xbgs351
11-07-07, 04:34 PM
Those inners and outers look to be well priced. I wonder how much the outers would cost to have polished? I have a box full of spare centres and a stack of inners and outers, but most have dings in them.
Yes, 13" is given. Let the rice boys have there 20" wheels ;)
What cars run those width wheels? F3? Used F3 tyres are a cheap tyre option.
I would have thought that you would juggle a suitable Steering Axis Inclination along with a low scrub radius, getting everything to clear and the wheel offsets. By fixing the wheel offset you limit one of your options from the word go. For comparison my AF2's wheels are approximately 13 x 9" at the front with a 7.5mm offset, and the rear are 13 x 12" with a 1.5" offset.
From using a plumb line I get the SAI of my car at 9 degrees along with a recomended castor in the 2 to 3 degree range. The car was designed for crossplys, so I'm not sure how the steering effort may differ with radials.
not sure on polishing costs , surely not more then a couple hundred ? ill just leave them raw i think.
how have i limited my scrub radius options with these offsets ? where the suspension connects to the upright governs that , and i can make that pretty much anywhere.
Well I hope all this nonsense does not mean that the Supra won't be seeing QR again. Fuck me, love that car, awesome on the track, gives me something to aim at :p
so , ive been researching differentials a bit.
im thinking i should go with something made for the job , would save a lot of fucking about trying to convert something automotive and probably unecessarily heavy.
found a couple applications for this , starting with quaife :
http://www.quaife.co.uk/shop_images/-250_QDF7ZR.jpg
more info http://www.quaife.co.uk/Chain-drive-cars-ATB-differential
quite a nice thing , seems to be just a sealed version of their ATB centres , sprocket bolts straight on.
probably about $1500 AUD landed , which sounds pretty good.
a even better thing is the "TPE" , this time american made:
http://home.iprimus.com.au/rzsupra/BASIC_NO_BRK.jpg
http://home.iprimus.com.au/rzsupra/DSCN1957.jpg
more info http://www.tpe-inc.com/prod01.htm
pretty cool , lets you have the sprocket and chain "outboard" unlike the quaife which would be centrally driven.
at $2756 USD though it can get fucked.
richy-rich , this thing should make the supra look stupid , to the tune of 3-4 seconds a lap hopefully.
i will get the old beast going again though :)
xbgs351
13-07-07, 10:07 PM
not sure on polishing costs , surely not more then a couple hundred ? ill just leave them raw i think.
how have i limited my scrub radius options with these offsets ? where the suspension connects to the upright governs that , and i can make that pretty much anywhere.
If you can get the upright to fit within the wheel, you should be right.
I found many people run the vlsd from a pulsar gtir the nissan r200 diff. I'll post some photos of what I am doing with my diff. probly a small 4 pinion diff will be indistructable and mini lsds are not that hard to find aftermarket. to keep all the oil in the diff I sealed for life bearings with rubber seals and a external vent. to keep the oil (sump oil is good enough for a mini diff) you spin a light alloy can.
To fit the sprocket I carefully cut off the ring gear from the mini diff (it's one part) used lots of coolant and some sharp tools some parts you might need a tool post grinder to get through the tough case hardening. once you get past that I machined a step to seat a sprocket
i was thinking about enclosing a small lsd centre for the job.
i guess a convential clutch lsd would do the job , i just like the idea of these ATB things , very similar to the torsen type diff afaik , should be very little drag when cornering.
hmm , what to do.
Maybe adapt something like this http://www.eatonperformance.com/differentials/Detroit-Gearless.html
http://www.westgarage.co.uk/chaindrive/chaindrive1.html
Here is a couple of examples of what I mean, mini lsd come in all sorts of configurations from a sailbury clutch type to the Zf cam and prawl style.
thanks ppls.
ive wussed out trying to make something and ordered a quaife chain drive diff.
ive chucked the dimensions of it in autocad to have a looksee at alignment with the motor.
the engine is going to be sitting 60mm off its centreline but thats no big deal.
probably give me some room to run the exhaust on the other side.
Im thinking that your proposed brakes might not fit in the rims and they may be a little over kill. The main thing I have been told is if your brakes work then dont make them bigger(unless they are going to be lighter). The other thought for for me is (I know my clubbie is a little different) that the focus on such a small weight might be better directed towards aero. For example, I can destroy all the mx5's in my class too 100 kmh but after that they catch me down the long staights at QR even though I have better power to weight. Even still I would love to drop some weight out of my car :)
agreed i think my brakes will be overkill , ie : ill be a wreck before they are ... damn hindsight , i have bought them allready though so i might as well use them.
they are willwood 'powerlites'
rotors are vented willwood 10.5" x 16.5mm (stupid wavy type things that everyone has warned me against)
one thing they are is light though , calipers are 1.00kg a piece and the rotors are 1.72kg each , which is less than a 8mm solid.
they do sit inside the wheels with plenty to spare , even 11.00" rotors could have been made fit , but yeh , thats just silly talk and quickly dismissed.
wow! nice and light, the pads must be almost as heavy as the callipers:)
hah , the pads are pretty small , im guessing they weigh fuckall.
the 11.00" fitting thing was BS though , just checked in autocad , i have 4mm caliper clearence on the 10.5 rotor ... phew.
been throwing some random lines together in cad , just for fun.
i reckon if it ended up something like this it'd be pretty cool.
like a little f1 shrunk in all directions :D
http://home.iprimus.com.au/rzsupra/layout7.jpg
how fucking cool is this shit , gsxr1000 powered.
be fucked if im going to put that much work into the body though , uber bucks.
should be able to cover most of the curves im thinking about in sheet alloy , maybe a spun alloy nose worked into it.
http://www.stohr.com/assets/images/F1000_825.jpg
that looks very cool.
since yours has a bigger engine, it will be faster then?
i doubt it , actually im expecting to make heaps of mistakes building this , may turn out to be the most ill-handling piece of shit ever.
but hopefully not.
in that case, just hope its ok-enough that you survive to make v2 :D
Pennywise
11-10-07, 06:49 PM
hows it going?
Billzilla
11-10-07, 10:47 PM
hows it going?
He's built his HANS Device successfully.
hah!
yeh ive done 5/10s of fuckall on this , been solid busy with other work for months.
got a shitload of parts sitting about , ill photograph them all together when i get a chance.
the chassis is starting to take shape in CAD , also made a mockup alloy scrap frame to work out seating position and cockpit width as seen in above photo.
below is mk2 golf hubs and splines to be grafted to suzuki tripodes , quaife chain drive diff , calipers , pegasus steering rack and other crap.
http://home.iprimus.com.au/rzsupra/img_0600.jpg
a little detail of proposed uprights etc.
http://home.iprimus.com.au/rzsupra/untitled-1%20copy.jpg
all too technical for me
hurry up and make it go fast
so whens the 1gz v12 arriving?
and the pair of gt47s?
manzinilox
01-11-07, 03:55 PM
I've bookmarked this thread...
Rz, have you checked out http://dpcars.net/
Bloke in the states did the same sort of thing. Took him a few years, now plans to sell them with 'busa derived V8's in them. Sounds like it will be a blast, good luck!
sejanus
04-11-07, 11:00 PM
don't forget to make the seat + footwell at least 2.5 metres long you lanky bastard
xbgs351
05-11-07, 03:24 PM
What's the longevity of these bike motors in a race car? The reason I ask is that it looked like a few blew at the last AMRS round at Wakefield Park. I saw a motorbike being stripped by one of the future racers and I suspect that the bike wasn't a wrecker.
manzinilox , yes i have been following that car , hes certainly put the hours into it.
xbgs351 , very short if the oiling is left alone i know that much , do you know any details of the failures these guys where having ?
i think probably not a worthwhile powerplant in anything north of 350kgs , its going to be working its ring off ... which is why im aiming well below that.
yours will weigh less than 350kgs???
Wow!
Billzilla
06-11-07, 09:40 PM
yours will weigh less than 350kgs???
Wow!
Can't see why not - I reckon it'll be closer to 300 than 400.
I still reckon that most of the bike engined things are still not that fast until you spend $$$ on the engine. They are good but not awesome; and once you start turning them really hard and using more comp and big cams and big bores/strokes they fall to pieces a LOT.
Turbo and less revs FTW.
DeanClaxton
09-11-07, 11:03 AM
Hi Rz,
Billzilla put me onto your build. I'm in the process of designing a 2 seater trackday car, and we may be able to share ideas etc.
I have specced the same tyres to yourself, same calipers. I didnt think willwood made a 10.5" rotor that fitted the powerlites though - I assume you've bought the 0,81" powerlites?
Anyway, I started a thread on the OCAU forum, not knowing about this place. I havent got very far as yet - my build is restricted by cashflow :)
I'm designing the car in Solidworks. My thread is here : http://forums.overclockers.com.au/showthread.php?t=623101
Not sure if you need to register to view it though - probably.
I chose the Compomotive wheels, but they are expensive. I havent bought them yet, though I've modelled the offsets etc in 3d. I might consider 3 piece wheels like yourself, though not sure what it would cost to mill a centre?
I chose rims with the most positive offset with the idea being that I would get the upright inside the rim as much as possible and limit KPI and scrub to a minimum (close to zero, but maybe not quite zero) - to reduce the amount of camber change with steer.
I do like the idea of a single seater open wheeler, but I'd also like to be able to share the fun, thus the 2 seater.
Anyways, have a look in the thread if you have time - we should chat some time :) Our cars will be a little different with mine as a 2 seater, but there will also be many things that will be similar.
Dean
hullo there.
yes i got the 20.6mm calipers with the 35 and 31mm pots (f/r)
rotors are the 160-8427 which where supposed to be 16.5 mm but turned out to be 20.6 , so i just turned them down and milled the calipers to suit.
plate centres for wheels could be laser cut i guess ? , im just going to use the lathe and index head on the mill to cut mine.
buying ready made wheels is probably the simplest option if you couldnt be fucked doing all that.
scrub will be around the 50mm with these wheels , should be ok i think.
i had a look at your thread , pretty similar ideas overall , alltho i think you should fuck the passenger off , hes going to slow you down :)
wish i could get my head around 3d modelling , your at a big avantage with that :) im sticking with good old plan views.
DeanClaxton
09-11-07, 04:35 PM
Well, you;ve certainly got the tools and skills to pull it all off. I dont have access to a lathe or mill (would have to get that work done for me), and have just a small Mig welder - hopefully will get the job done when I get to that bit.
Interesting with the rotors - I thought from the spec sheet that the powerlite takes a rotor from 20.1 to 21.8mm thickness? I would have thought 16.5mm would be under size for the caliper. Have I misunderstood the specs? is it 16.5mm + the pads or something that comes to the 20.1-21.8? No - that cant be right either.
Just checked the rotor - they screwed up the table. 10.50" (266,7), .75" (16,5) <- that's a mistake as .75" is 19.05mm not 16.5 - still I would have thought it undersize still for the caliper.
Where's the best place to get the wilwood gear by the way? I was thinking of getting them from the states.
Looks like youve got a lots of goodies there - just need to hang it all together :)
The golf hubs etc - from a wrecker? Look new.
Interesting article on scrub radius here : http://www.sae.org/automag/scrubradius/04.htm though for SUV's.
With scrub radius , the less the better really, but then there wont be a lot of weight on the front anyway :) The only way youd' get any less would be to change the wheel offsets and get everything deeper in the rim - dont want to reduce the scrub by increasing KPI.
Let me know if I can help by drawing stuff in 3D for you - happy to help where I can.
Dean
no your right about the calipers , they take a 20.6 rotor with pads installed , i just didnt want the mass of a 20mm rotor so i machined them down to 16.5.
downside was i had to take the calipers apart and take a equal amount off them.
they do make a 'powerlite' to take a 8mm rotor if you want to run solids.
as far as supply i used dattoman on the forums here.
hubs i got new from a vw repair joint , they have a 100x4 stud pattern and run about $60 ea , im going to lighten the fuck out of them.
fronts will just have a bolt to clamp them in the bearings and the rear ive chopped the spline off some matching cv joints , they will be welded to suzuki tripods.
DeanClaxton
09-11-07, 05:37 PM
Ahhhh... nice! fully custom :) No dramas doing that? Went back together ok with internal tubes, brake pad retainer clip etc?
Interesting with the golf parts - I could go down that path myself as I was wanting to use the vw double row wheel bearing anyway. 4 x 100 is good with me - no real need for centrelock.
I'll be keen to see how much weight you take out of them. What model suzuki are the tripod joints from? I dont know a lot about tripods, but am guessing they are smaller and lighter than cv's.
Good stuff!
clip can move in and out a bit now but its not going to cause problems.
a cv place supplied me 4 x suzuki 1.3 manual halfshafts so ive taken the tripods off them all and will use them at either end of the driveshafts.
a bit lighter than cv's and you dont need a cv unless its a turning wheel anyway.
just trying to keep it all simple.
If you can be pharked, you can lose a bit over a kilo by turfing the VW stuff and going aluminium hubs up front. I'm always amazed at the weight in the four corners of the car.
http://www.chilli.net.au/~rzsupra/cap.jpg
thought id throw a few pics up showing what this will look like.
it really is going to be small (as you can see from my giant head) so im thinking of it as a upscaled gokart rather than a serious attempt at a open wheeler.
the chassis is 95% sorted with only minor tweaks around the suspension rocker area to be done.
theres no complex curved surfaces so its all coverable in sheetmetal.
sidepods are rather large with a view to turbocharging in the future.
all the main tubes will be 1-1/4 .049 with some 3/4 thrown in here and there.
cons :
1) i think its going to be a twitchy little fucker due to the size , but hey i learnt to drive in karts :dunno:
2) my feet are in line with the front of the tyres (apparently this means i loose my legs in a crash , bummer)
3) visibility is average due to having the shocks mounted directly above my knees = body is high at that point.
3) this is a MASSIVE project , like 3+ years at my rate.
ill put some overhead views up soon.
Billzilla
03-12-07, 05:05 PM
Shutup and build it ya poof.
go fly your pissant aeroplanes you overgrown homo.
Billzilla
03-12-07, 05:14 PM
Go and do some fibreglassing, metal boy.
Go post on a forum you two wankers.
Looks great man. Don't worry about legs- walking is overrated. :D
nice drawings - interesting comment on the losing of legs. maybe you should wear steel cap boots?
thechuckster
04-12-07, 12:37 AM
will it pass scrutineering with the pedal box (aka feet) so far forward?
10sec_rx7
04-12-07, 10:38 AM
nice work mate,
have you considered a mono shock front end?? very simple to do and will save the cost on the shocks. you dont run a front sway bar, instead you run springs on the slider for the shock which control the roll, we were getting the springs made by better springs at st marys in sydney they were only about $60 a pair from memory and we didnt have to change them much as a pre load change would often be enough to make a big difference,
the 92 van deamon FF was the car to have in the right hands and held the bathurst lap record for a long time in the hands of rodney forbes,
here is the pic of the rf92 setup
http://www.race-cars.com/carsold/vandiemn/v92016/v92016pd.jpg
10sec_rx7
04-12-07, 10:45 AM
here is a better pic, this is the 93 setup
you can see the roll springs etc in this one
http://www.race-cars.com/carsold/vandiemn/1084764827/1084764827lf.jpg
xbgs351
04-12-07, 11:11 AM
We were discussing this at the last Ozboss meeting at Wakefield Park. The general consensus was that a mono shock front end works better on the smoother European circuits than it does on rougher Australian circuits. I also believe that Dallara has moved away from the mono shock front end.
10sec_rx7
04-12-07, 11:17 AM
VD went away from it in 96 as well and the cars didnt go any faster,
it works on aus tracks just have to know how to set it up, we went 3/10's under the lap record at wakefield with a RF93 in testing so they do work and do work well when setup correctly
xbgs351
04-12-07, 12:20 PM
How about Queensland Raceway? It's real rough.
http://www.youtube.com/watch?v=rLqZoDthcNk
Billzilla
04-12-07, 02:41 PM
Hard to decouple the bump/droop & roll motion. It's much easier to setup a two or even three damper/spring suspension.
yeh looks like clean way of doing it , except id probably get it more wrong than a simple dual shock/rocker setup which i do have some idea of how to build.
xbgs351
05-12-07, 08:10 AM
will it pass scrutineering with the pedal box (aka feet) so far forward?
The feet aren't any further forward than the pictured Formula Fords are they?
actually , no.
who ever told me that was a issue was obviously wrong.
cool.
so just ordered the tubing for this , from some 'bros' at gardener engineering GC.
a grand for enough material to make everything including suspension arms , which i though was quite reasonable for 4130.
also found a place nearby with some tripod rollers to curve the front tubes.
cool.
Nah it's cool man. :D
Have you done much chromoly work? IT's awesome stuff. You just have to think small cause it is so tough.
Heat treat after welding?
i have a bit yeh , nice to weld/cut compared to mild.
how necessary is treating on light guage stuff ?
Dunno. I just wanted to hear your thoughts.
We did our drag car- I think they got it too hot/ let too much air in cause it came back black with scale. It also rang like a bell and seemed really springy after. I thought it was more of an annealing to avoid the soft areas around the welds causing problems but it seems to me that they must rush the cooling to make it a bit tougher too.
Lots of guys don't do it at all so it's probably not too important. The main thing is post heat if you aren't going to cook the whole thing after. Easy with a flame- harder to arrange with a torch. I'd think that if you avoid extremes you'd be right- ie no welding if there is a huge wind to cool it down too fast and don't weld the bottom rails hard against the heavy jig (without preheating the jig).
yeh ill just wing it and see.
the tube size im using is probably overkill anyway and its not like theres a KB hanging between the rails or anything :)
its not like theres a KB hanging between the rails or anything :)
Not yet anyways :D
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