Car Frame Project help

[cmamastha]

Well i started a new project for my spare time, but since im new to welding i am unsure about what material to use for the project , therefore unsure about which weld equipment to buy. The point is to build a frame more like the Ariel Atom frame. i've looked into ERW steel tube (sizes: 2.5" .065 wall, 2" .083wall, and back's support, is 2.5" .120) wall or Duralumin (an aluminum alloy which is very strong".
Therefore, the question is for those experienced which would be a better material for a frame, taking into consideration weight and security ( aprox acceleration of this project when finished 0-60 3.5-4 sec, top speed 150+ mph). and second which is a better weld process for the material chosen (TIG or MIG or ARC)

Thanks to everyone who can help. i got this frame off of the internet so is somewhat like this what i plan to build

 

[pedrobedro]

I'll go and get a piece of string to measure This is a subject of much debate and the outcome of most of them is "steel will last but aluminium will stress and crack especially under heavy use" Also the aluminium section needed to supply the necessary strength will weigh as much as steel by the time it's all reinforced and braced adequately.

 

[Sam]

Have you looked at Stuart Mills site MEV ltd sure he uses 2mm wall tube.

 

[Chris Stevens]

Well i started a new project for my spare time, but since im new to welding i am unsure about what material to use for the project , therefore unsure about which weld equipment to buy. The point is to build a frame more like the Ariel Atom frame. i've looked into ERW steel tube (sizes: 2.5" .065 wall, 2" .083wall, and back's support, is 2.5" .120) wall or Duralumin (an aluminum alloy which is very strong".
Therefore, the question is for those experienced which would be a better material for a frame, taking into consideration weight and security ( aprox acceleration of this project when finished 0-60 3.5-4 sec, top speed 150+ mph). and second which is a better weld process for the material chosen (TIG or MIG or ARC)

Thanks to everyone who can help. i got this frame off of the internet so is somewhat like this what i plan to build

If you are serious then ERW is out for various reasons, as is aluminuim tube (unless you have facilities to heat treat or are able to source 7020 in the sizes you want).

The best possible choice for this type of project is T45, which will mean you can use lighter guage tubes, that will be far stronger than ERW, and not present any problems related to elongation.

Budget for a space frame chassis like that if you can do all the welding, bending, and machining yourself, and use the proper materials, is going to be at least £1K, so is perhaps not the ideal type of thing for someone new to welding.

 

[hotrodder]

One of the problems with aluminium is that it has no endurance (fatigue) limit. While it's around a third the density of steel it's also around a third the stiffness and is locally annealed (made softer and weaker) when welded. There are some Al alloys around that 'recover' well from welding (like 7020 / 7005 as mentioned) but are harder to impossible to find. As a result aluminium bike frames/chassis tend to be quite different design wise than steel. Even then steel is often used for highly stressed areas for example the Lotus Elise uses a steel subframe for the engine/rear suspension as they couldn't stop it cracking when ally was used

Mild steel would work fine in DOM (welded tube that's then drawn over mandrel to improve properties) or CDS. Alloy steels like 4130 or T45 are stronger (no stiffer though) and so some weight can be saved. Design is going to have a bigger influence than specific steel alloy but as a gross generalisation mild steel with 0.120" wall might be replaced with say .083" or .095" 4130 depending on diameter, tube placement etc

Weld process... with mild steel MIG or TIG would be fine (Ariel atom is brazed iirc?) as would oxyfuel with TIG usually ticking more boxes regarding weld quality (control, stop/starts etc) when working with small diameter thin wall tube. Stick far from ideal. Alloy steels are trickier to weld in that the properties can be damaged by poor technique quite easily. Long way to go yet if new to welding and fabrication but i'd stick with mild steel initially- less fussy regarding welding and easier to work with than alloy steels

 

[Angusdog]

While I'm sure some people do start welding by leaping straight in, if you are at all like me then you'll need to do evening classes and a lot of practice to become sufficiently competent to construct something such as that chassis. It requires welds that actually perform, rather than just hold together.

I mean, Im sure you know this and may have already started down this track but poorly constructed home-built vehicles are why there's legislation in NZ for this very occurrence.

I'm also pretty sure that internet forums and local car clubs are going to be your best bet here as well. Although this forum's got a projects area, welding is its main focus. I'd glean all I could from this forum with respect to the welding aspect but look elsewhere for the specialist knowledge require to build a 150mpg sports car. And good luck with the project - looks like a very interesting prospect.

 

[pedrobedro]

You don't need fancy lightweight options for car chassis, mild steel is strong enough if properly designed and put together. Saving weight or choosing an engine to pull what you have is the dilemma you are faced with, you are going to need stupid bhp to reach the speeds you are looking for in an open wheeled spaceframe chassis due to aerodynamics whereas my Locost with just over 100bhp would reach 110mph and was plenty fun. Get onto locostbuilders and look at some of the builds on there for a realistic view.

 

[cmamastha]

well basically the engine comes from a ninja zx 14 its about 180+ hp and high rev. the whole issue with the weld is because i need to buy a machine, so first i need to figure out material that i will be using, then buy he machine, and like i've heard from everyone practice practice practice.. although i have a couple of friend who will b instructing me into the welding process. but i will keep on doing some research into the matter. this is a long project so any ideas that i can take into consideration now will save lots of trouble in the future. i will keep everyone interested updated. thank you so the next step is to build a scale model for the frame so ill post some pics when its done.

 

[oz.]

If 170bhp from a Peugeot 306 gti gets the car to about 130mph then I think youre going to need a bit more than 180bhp. Ok the 306 isn't the most aerodynamic or the lightest but I think you may need a bit more.

 

[Chris Stevens]

well basically the engine comes from a ninja zx 14 its about 180+ hp and high rev. the whole issue with the weld is because i need to buy a machine, so first i need to figure out material that i will be using, then buy he machine, and like i've heard from everyone practice practice practice.. although i have a couple of friend who will b instructing me into the welding process. but i will keep on doing some research into the matter. this is a long project so any ideas that i can take into consideration now will save lots of trouble in the future. i will keep everyone interested updated. thank you so the next step is to build a scale model for the frame so ill post some pics when its done.

Might possibly be an idea to learn how to weld reasonably well before looking at a project like this, as unfortunately welding isnt simply a matter of buying a machine, and then using it to build a space frame chassis thats going to handle 180bhp.....................

 

[Angusdog]

^^^ I think he's got that now Having more expertise available is the best resource and as the original poster says he's prepared to practice. A lot of the welds are going to be very similar (tube/tube of the same material) so it's probably feasible. You have the SVA test in the UK anyway don't you? Reassuring to see you can't just build a car from pipe, sling a V8 in it and career all over town.

 

[pedrobedro]

You have the SVA test in the UK anyway don't you? Reassuring to see you can't just build a car from pipe, sling a V8 in it and career all over town.

Not any more we don't, we now have the stricter and more expensive IVA

 

[steviec_lj]

Engine: Arial Atom uses a Honda Civic Type-R engine, which has been dismantled, rebored, tuned, then had a turbo strapped to the side. It produces around 250bhp. 180bhp isn't going to get you anywhere near 150mph as has been said.

Also "mates instructing you" won't help with any weld you do. You really do need to practice. I started 3 months ago, and have only just welded a wheel arch into place. I've done nothing structural, as I still believe my welds need to improve.

 

[TheJoker]

Right....

First rule is to not listen to the naysayers. "People who say it can't be done are not the same people who've done it".

Learning to weld is one small aspect of building a car. But if you can't weld, it won't happen. (if you're the one wanting to build it, that is).
You'll also need tons of tools (not only a welder), and most likely a frame jig of some sort.

The general concensus is that mild steel of high quality is easier and cheaper to use than aluminium, or lo and behold; carbon fibre. A spaceframed mild steel car doesn't have to be much heavier than an aluminium or carbon fibre one. Especially if you factor in the bang-for-the-buck. A frame that bends (mild steel) is better than a frame that cracks (aluminium) for an amateur.

Another thing; Is it a race car or street car? The rules are completely different. If it's a race car, get the rules, read through them, twice. If it's a road car get the rules for that (SVA?) and read through them, twice. And make friends with a VOSA guy.

Learn CAD, even at a basic level. If you can get hold of a CAD package that does basic stress analysis and you can master it, you'll have a lot of worries eliminated (but it's only a guide, not a rule).

Learn about suspension and car geometry. Read books.
http://www.amazon.co.uk/Build-Motorcycle-engined-Racing-Cars-Speedpro/dp/1845841239/
http://www.amazon.co.uk/Competition-Car-Suspension-Practical-Handbook/dp/1844253287/
Read more books.

Go to Silverstone Classics and take tons of pictures of existing race cars.

Don't worry about the engine. That's the least of your worries. If you built it yourself, you can swap the engine at a later date.

Personally I dream of building a car one day, but I've realised my limitations especially in time and money. My approach is to learn to TIG weld slowly at my own pace. I'm also learning milling with my ickle milling machine. One day I'll have enough dosh to buy a lathe for my garage too.

I've got a license of ViaCAD that I'm trying to get my head around, when I can't be bothered to be dirty in the garage.

I'm starting out by modifying bicycles (have a look at http://www.atomiczombie.com/ for inspiration). Then maybe I'll venture to motorcyle frames, perhaps modifying first, but one day building one. Then, maybe one day in the far far future I'll have enough time, skill, money, space to start work on a car. Perhaps.

Btw, I saw an Ariel Atom-like Kit Car today. Don't remember the name, but the guy had spent £15K on it and it had an Aprilia V-twin engine in it.

If you put your mind to it, get some tools, and spend a lot of time on the project you can do it.

But, always put safety first.

PS, to check for cracks in the frame, Porsche used a slightly pressurised spaceframe. They basically made sure that air could get around all of the tubes and they put a valve on the tube along with a pressure gauge. If the pressure gauge showed dropped pressure, the frame had a "leak" i.e crack.

 

[julieanncharters]

Engine: Arial Atom uses a Honda Civic Type-R engine, which has been dismantled, rebored, tuned, then had a turbo strapped to the side. It produces around 250bhp. 180bhp isn't going to get you anywhere near 150mph as has been said.

Also "mates instructing you" won't help with any weld you do. You really do need to practice. I started 3 months ago, and have only just welded a wheel arch into place. I've done nothing structural, as I still believe my welds need to improve.

type r engine will prob be a lot heavier than a super bike engine .
ninja or similar R1 's are producing about 180hp which power to weight is amazing.
they also produce more with mods
guys are sticking em in old minis and pull the sort of figures this guys after.
ok ya not gonna get the 150mph top end but 0-60 times are going to be mental.

i'm sure a space frame chassis like the atom ain't gonna be much heavier than a mini so should go like stink.

 

[Nomad]

Also "mates instructing you" won't help with any weld you do. You really do need to practice. I started 3 months ago, and have only just welded a wheel arch into place. I've done nothing structural, as I still believe my welds need to improve.

Sounds familiar I started mig'ing about 2 years ago (with lessons from mates then lots of practice ) - I'm now very happy to do car sill replacement, wing repairs, MOT work, gates, etc.
I still wouldn't trust myself to weld a space-frame from scratch (or anything structural - like a bike frame) and have faith that it is sound.

Good luck with the project - suggest you work out what kit you need to build the car. When you get it - practice on as many other projects as possible to get the hang of it before doing anything about the chassis

 

[mjrally]

Just to chuck my opinion in the mix..................

Id agree with what the JOKER said. If you really want to do it then, go for it, but youve got to plan, and for a project like this it is massive task, but if done correctly it can be very simple to do.

As previously mentioned your not just going to buy a welder for this project, your going to need:

CAD as mentioned, (either that or good draughtsman skills)
A welder (ideally Tig)
A massive jig, A Solid steel topped bench would be the best but a very heavy duty wooden could potentially be used.
Tube profiler(notcher), or you will be there years!
Pipe bender, or a good contact that can use your CAD to bend the tube.
A friend who has a lathe and milling machine, as ther's going to be lots of brackets and bosses required.

In terms of material, the best option is T45 steel by far as its strenght properties are really good. Also if this is used in larger diameters with thinner wall you can actaully make the vehicle quite light.


I only learnt welding about 3 years ago and do it as a hobby, and id be happy to take something like this on. So i cant see any issue if your going to practice alot upto the build why you cant do it yourself. do test pieces and try and destroy them thats the best way!

Oh and the chassis design bit is quite easy, its the suspension geomatry that sthe hard bit......... and that bit needs doing first. so getting studying!

 

[Nomad]

Some inspiration!

I thought about starting a new thread but decided to add to this existing - mods feel free to split it needed

For some inspiration about spaceframe builds, have a look at link below.
Amazing Bently speed-8, built from scratch
http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http://forum.savarturbo.se/viewtopic.php%3Ff%3D21%26t%3D21458&act=url

 

[oz.]

Would love to see more pictures of that ^

 

[Angusdog]

All that talent and he still put the steering wheel on the wrong side? I hate people with skills, time and money...