Which kit car manufacturer designs the best chassis ?

[trimix06]

Hi guys,

Yesterday I have posted a couple of comments and questions in another section regarding our electrical roadster project.
Today, I would like to have your feedbacks about the pros and cons of your favorite kit car chassis, especially about their rolling quality, behavior on the track and manufacturing.

This is to help us to identify which manufacturer we could approached to cooperate on our project.

Cheers !

[Paul Drawmer]

Sounds more as if you need a chassis designer.

[Furyblade_Lee]

Give Westfied a call. They are already building an electric one. Or try Lotus, thats what Tesler did. Totally irrelevant really what an existing car engined chassis will handle like when 500kg of batteries are added to it.

[Toltec]

MEV are always bringing out new cars and have done an electric trike. I cannot comment on how good their chassis are, but they might be interested in helping.

[spitfire4v8]

you could do worse than email sam68 off these forums, he's well up on his kit car knowledge and knows a bit about chassis and suspension too. Would be a useful contact anyway methinks.

[singlecoil]

Best in what sense?

Is cost effectiveness an issue? What other compromises have to be met?

[Kevp]

How about Caged?

They make chassis for the Pheonix - twice as stiff and a 3rd of the weight (including the roll cage) of the original chassis, apparently.

http://www.therollcagepeople.com/gallerystuarttayl...

[Hunky Dory]

Kevp said:

How about Caged?

They make chassis for the Pheonix

For Caterham too, I thought?

[Sam_68]

Kevp said:

They make chassis for the Phoenix - twice as stiff and a 3rd of the weight of the original chassis, apparently.

They're being slightly disingenuous by quoting the weight and stiffness compared to the 'original' Phoenix chassis, mind you. The original chassis was designed to be cheap and robust, using fairly heavy gauge, square section ERW tube. Sylva themselves did a 'lightweight' chassis for racing that made similar improvements.

Not that I'm having a go at Caged - they're a very competent company, but they're not cheap and I suspect that they are cost effective on fairly large production runs, only.

But I digress....

As Lee said, the effect of the weight on handling is going to be your biggest problem. Nothing that can't be solved, but I think you'd be better off with a chassis designed from scratch rather than to try to adapt something. The extra weight will mean that dynamic weight transfer will become even more critical, so your top priority will need to be to ensure that the roll centres are in the right place to suit your weight distribution and that they don't move even slightly in relation to the sprung mass.

Since you'll have a lot of sprung:unsprung weight, there might be a good case for using a de Dion rear axle, since it will give you a fairly high roll centre (hence little body roll) that can be very well located, without getting into the 'jacking' side-effects that a high roll centre gives on independent suspensions. Of coyurse, you'll have to match it with suitable independent front suspension geometry, unless you're brave enough to try a beam axle at both ends...

On a separate note (and as I suggested in response to your original thread), my personal opinion would be that you might be better off looking at a composite chassis construction, both for weight/stiffness and because it won't disolve into funny white powder if your batteries spill a bit of acid on it. And it will, in theory, last nearly forever, which sits well with the 'sustainability' ethos of an electric car. If I had the money, I'd definitely be talking to Martin Ogilvie, if I were you.

[singlecoil]

Kevp said:

How about Caged?

They make chassis for the Pheonix - twice as stiff and a 3rd of the weight (including the roll cage) of the original chassis, apparently.

I'm guessing that's supposed to read "a 3rd off the weight"?

[Furyblade_Lee]

Hmmmmm. Assuming a bare Phoenix chassis is about 60 kgs, a 20 kgs chassis would be a bit of a feat.. Must mean 1/3 off as you say. BUT whan I was in Belgium at Oracle Cars (Kit Car importer / agent) i saw a FANTASTIC Robin Hood chassis up on axle stands. It was the Lightweight version, all folded Aluminium sections. It was a genuine lightweight work of art, the only problem was two of us with our bare hands could lift it and twist it so much you could see it flex!!! Sod bolting engine, suspension and brakes to that and giving it a workout! Or a crash.

I know Fisher Furys can be specified with lightweight chassis, but I would be worried that it is designed for the lifespan of a racecar on smooth roads with a 5 year max lifespan rather than dealing with a heavier roadcar with all our potholes ect. and expecting it still to be straight after 5 years. If I was contemplating a new build, within reason the chassis is not the place to start shaving a few kilos off in the big scheme of things.

• I think Arch Motors make all of the Caterham chassis nowdays.

[trimix06]

Well, Well, well !

Thanks a lot for your paths !

Indeed cost effectiveness is one the target ! As our target is to build a low cost electric roadster in medium series, our requirements are the following :
- light and stiff so less power required for good performances hence cheaper propulsion chain
- simple and cheap tooling so metal stamping is excluded so frame chassis is the best option but needs to be carefully studied to reduce manufacturing operations, complexity and ensure a constant quality and precision... I agree this is a big issue
- excellent drive quality
- able to be EU approved

Lotus Elise chassis is great but too expensive (we are in contact with Lotus Engineering).
Lotus Electric City Car Chassis looks simple and well adapted to electrical car but I doubt that it could be adapted for a roadster ! but the disposition is good.

[LotusNova]

You could try these folks: Spyder Engineering

[Sam_68]

Spaceframe chassis are, by their very nature, labour intensive and expensive to build.

I'm afraid that if you're saying that the Elise chassis is too expensive, then you've pretty much written off the project's credibility if you are hoping to use a UK-manufactured chassis.

I'd suggest that you need to look at designing a custom chassis (probably spaceframe, to allow for low-tech construction methods), then get it manufactured by child labour in a third-world country.

[trimix06]

Sam_68, Lotus Elise chassis is quoted around GBP20k (less for huge order), it's quite expensive but I agree with you it worth it ! and this is excluded the necessary modifications to manage batteries and motor implementation.

I also agree that space frame chassis is labor and cost extensive that's why we are hesitating even we have the possibility to make them manufactured in low cost labor country but quid of quality, precision and also shipping fees and pollution !

The reason I request here some advice is because I'm pretty sure that guys here could have better idea than any car engineer used to current series IC car !

Our dream would be that this car could be manufactured where it will be bought (somehow like MDI proposes for its air cars). This is a sustainable way !

We are probably idealist but we still think we will find a suitable solution.

[Sam_68]

trimix06 said:

Lotus Elise chassis is quoted around GBP20k (less for huge order)

That's absurd, to be sure! You can buy a whole Elise for about £25K, including profit margin for the dealer, so if they're quoting you £20K for the chassis, they clearly either don't want to sell the chassis separately (contractual obligations with Tesla?) or they don't think you are serious.

You could always do what Westfield did to obtain Hyabusa engines and buy whole cars, then sell of the bits you don't need as spares?

On a general note, I wouldn't place too much faith in the design capabilities of British kit car manufacturers. Even the best (Caterham) took a someone else's design and have merely developed it over a number of years. The chassis design specifications of 'Seven' type cars are all pretty standard (in terms of stuff like geometry, weight distribution, spring rates etc), so most manufacturers simply copy what's been done before.

I wouldn't necessarily rely on them to be able to develop a decent chassis for something with completely different weight distribution, just because their existing kit handles ok.

The two exceptions that spring immediately to mind are Jeremy Philips of Sylva Sports Cars and Lee Noble (if you can track him down after his departure from Noble Sports Cars). Or there are the independent design consultants or small race car manufacturers like Martin Ogilvie and Steve Owen, if you want someone who actually understands what they're doing rather than just regurgitating established design principles, but you've got to accept that that sort of knowledge won't come cheap.

Edited by Sam_68 on Friday 7th August 12:30

[Toltec]

Sam_68 said:

Jeremy Philips of Sylva Sports Cars

There were a number of reasons I decided to build a R1ot

Jeremy has just released the Spectre so you never know he might be up for another challenge.

[andygtt]

trimix06 said:

Hi guys,

Yesterday I have posted a couple of comments and questions in another section regarding our electrical roadster project.
Today, I would like to have your feedbacks about the pros and cons of your favorite kit car chassis, especially about their rolling quality, behavior on the track and manufacturing.

This is to help us to identify which manufacturer we could approached to cooperate on our project.

Cheers !

I could put you in touch with someone who can help with chasis/geometry design, he knows and works with Lee Noble as well so even if he cant help you directly it would put you in a good 'loop' so to speak.

Pm me privatelly and I will send you the details.

[Tony427]

You need to speak with the company that makes the chassis for Lotus, not Lotus themselves.

Have a look at www.radshape.co.uk. They are based in Birmingham and are steeped in the automotive industry.

They make bonded aluminium chassis for Lotus and Morgan amongst others and do a lot of work for Bentley etc so if you're looking for light weight chassis engineering you can't go far wrong having a chat with these guys.

Cheers,

Tony

PS Last time I put work their way they ended up making the toboggans for the British Luge team. Highly adaptable engineers.

[cymtriks]

You are not really asking the right question.

"who makes the best chassis?" could have many answers-

• the cheapest
• the most easily modified
• the most accurate
• most practical (doors, boot space etc)
• the stiffest
• the lightest
• the strongest
• one that can be mass produced
• one that can easily be justified for low volumes
• etc etc...

Then all the above can/will change if you intend to race it or if you have a specific styling look in mind.

Spaceframe, monocoque, ladder frame and backbone could all be the best depending on honest answers to the above questions.

Specifically for an electric car I'd expect any chassis designed for a standard drivetrain would be very different to how you'd design one for an electric car given a clean sheet of paper.

Is your project going to focus entirely on youngish people only requiring two seats and sportscar handling and styling? You'll probably have a big low mounted rectangular block shaped battery pack behind the seat. A space frame might require a diagonal going through the battery pack to get the results and given the "experimental" nature of the project might be harder to change than the other simpler types. A backbone chassis or a ladder frame might be more suitable if you think design changes as you go along are likely.

If you want four seats then how are you going to fit them around the batteries? Perhaps an A class shaped design would suit with the battery pack going under the floor.