Modified lotus Chassis

dsacks6 · 08-17-2006, 10:39 AM

What do you think about the modified lotus chassis they are using for the roadster.

feelthesweetbeat · 08-17-2006, 04:38 PM

Donno, hope they didnt mess up the stiffness/weight while modifying it. Lotus has a damn good engineering squad with alot of clout/heritage in the sports car world. I would subcontract lotus to fully develop the chassis and allow them to claim it as their own... people would feel more confident with slapping down the 100k. Actually, we should have tesla just adapt the powertrain to an elise. It would cut down NRE costs.

dsacks6 · 08-17-2006, 04:59 PM

I see your point about cutting down costs by just using elise platform and body perhaps but the problem is that the elise looks unsophiticated but fun imho. Also They need a fresh look and something unique that doesnt give the impression that it was made in some guys garage using a conversion kit or something...... ???

feelthesweetbeat · 08-17-2006, 05:14 PM

Using the elise's chassis was, i would hope, part of a trade study they performed when lotus submitted their bid. the fact that they are not using it probably means that the tesla's powertrain was too unique and what was once an optimal chassis for a petrol car, is no longer optimal for the batt powered car. The locations of mass, i can imagine, are very different in either case and the chassis must be designed for that. If i had the money to shell out for this baby, i would happily pay an extra $10k - $20k for a complete lotus designed chassis, purely based on their heritage. That would allow tesla to focus on their specialities and still cut costs (assuming that this is the first time tesla has modified/redesigned/optimized a chassis). I am not a big fan of how lotus cars look, but being a function over fashion sort of person, it wouldnt phase me too much... especially with the performance specs tesla is claiming. I do not mean to completely take tesla out of the loop on how the overall car looks. Send some conceptual drawings and let lotus do what they do best.

dsacks6 · 08-17-2006, 05:20 PM

I thought lotus did the designing of the chassis and platform just they had to meet certain specificications of that tesla gave them.??? Did they just take a lotus chassis and change it and ask lotus to build it that way?
Anyways apparently some people from lotus are working with tesla now so thats good. ;D

feelthesweetbeat · 08-17-2006, 05:30 PM

Ahh ok ok good to hear. Keep some specialists on hand as consultants. i read FAQ on teslamotors.com: "Lotus Engineering won a design contest where several design firms submitted proposals. Lotus Engineering supplied the initial chassis which was significantly modified by Tesla Motors engineers. " It made me worried that tesla was being too ambitious and believing that they could 1up lotus chassis engineers. "Hey lotus, just give us a design concept and we'll make it better". I guess i glossed over the "Tesla Motors has also hired Lotus Engineering for certain design and engineering tasks" part.

dsacks6 · 08-17-2006, 05:33 PM

I plan to do an interview with someone at tesla so i'll ask about that. 8)

tonybelding · 08-17-2006, 10:16 PM

Although it wasn't mentioned in the Tesla blog, I would speculate that the Roadster is probably closer in several ways to the new Lotus Europa S than to the Elise.* The Europa S is a slightly larger and better-appointed (more comfy) variation from the Elise.* With bumpers.

Now here's what I found interesting. . .* *I read a comment that replacing all the Elise's fiberglass body panels with carbon fiber would cut about 200 pounds off the car's weight, but was considered prohibitively expensive.* For an electric car the maths work out differently.* Cutting 200 pounds out of the body panels means you can fit in 200 more pounds of batteries, and you can achieve that 200-250 mile range that nobody would have thought an electric car could do.* That's arguably worth the cost.

A lot of materials and techniques for building lighter cars -- like extruded aluminum frames and carbon fiber panels -- have languished because there just wasn't an economic incentive to adopt them.* It was always cheaper to simply stamp out more steel parts.* If car companies get started using more lightweight materials, they should figure out ways to automate more of the work and lower the costs.* This could be a big part of making electric cars practical for everyone.

feelthesweetbeat · 08-18-2006, 05:49 PM

Read the blogs and well, whatever car the chassis was based off of, it is now 2" longer to make room for the batteries. I also read that the chassis runners were changed from a continuous beam bent to the correct dimensions (lotus) to actually cutting and bracketing the runners in the correct shape (tesla design). Ease of manufacturing decreases the cost and the supposed 2" door lowering improves getting and out of the car, but it also puts more potential failure points into the design, ableit the points wouldn't be a high risk failure point. It does increase mass and the frequency modes of the chassis could change dramatically with this design change (aka changing the chassis stiffness). I wonder how much money this really saves in manufacturing the car. beam bending has been around for a looong time. Really, I dont mind the difficult egress in my current cars and im 6'3". If it affects the handling to drop doors 2" then im against doing this.

I agree with tony on the fact that manufacturers should start using higher tech materials. I believe most manufacturers agree with this too, they are just taking their time to adopt it. Now, major manufacturers use lightweight materials on low risk parts such as aero parts, roofing, mirror housings, interior pnls, and i believe as the risk to using the lightweight materials decreases, they will start tooling up more parts. They dont want to buy lots of material/tooling/training only to find out that when you stress it in 3 degrees of freedom at a certain rare frequency while its raining out, it destroys itself. That, and the fact that taking longer mitigates the risk and conditions the customer to the slightly higher prices. Nobody wants to buy a 3 series that one year is 50k and the next its 65k. but if its 50k, then 53k, then 57k then 60k...(increasing faster than inflation) people might take better to that thinking that inflation is the cause. meanwhile spreading the adoption costs (tooling/training/procurement) over multiple model years.

The tesla does have carbon fiber body panels.

savuporo · 08-28-2006, 12:45 AM

Using a ready chassis and powertrain from ICE car is clearly not optimal for EVs
Witness Bollore's BlueCar
http://www.autoblog.com/2006/03/08/b...ready-to-roll/
http://www.batscap.com/en/actualites/

The car is basically designed around the batteries and powertrain, not the other way around.