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Monaco Dreamin'
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I could really care less what it's made of, it weighs almost a quarter-ton more than my Exige.

Still going to test drive one though...
 

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Less is Better
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This will seem obvious to say it, but the weight of the car is ultimately dictated by it's size and content, no matter what the materials of construction. Why is the steel Cayman lighter than the aluminum Evora? Why is the F1 600 pounds lighter than the P1? Why is the steel 911 400 pounds lighter than aluminum Vantage? What's in it and how it's made. Comparing just the weight of the tub of the Elise and 4c obviously isn't enough to find out why one weighs more.
 

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Lotus Elise 111s - 11,000 Nm/deg (source: The list: Torsional Rigidity | GermanCarForum)

Alfa 4c - 14,500 Nm/deg (source: http://likesu.fiat.it/resources/lectio/files/Lectio_Catania_Presentazione_Ing_Montuori_4C.pdf)

Assuming the numbers above are correct, then the 4c is stiffer than the Elise. At the same weight, the 4c seems to outperform the Elise. But, does the 4c drive as well?

I never know which engineer to trust in these types of posts. Who's the judge of which poster is correct?
I wonder if the roof of the 4c is load baring?

Side note, I actually went through structural engineering classes. I can tell that Thomasio did too. The other two, doesn't seem like it.
 

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first off- lets compare apples to apples. you can't buy a street legal new lotus elise or exile in the us. so there is not such thing a 2,000 lb lotus vs a 2,500 lb alfa. there is a 3,000+ lb lotus to compare it to if you like.... (although id say a bit different cars)
Bingo. If you're comparing cars no longer made, then Elan and Europa owners look down on porky Eliges with disdain.
 

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I wonder if the roof of the 4c is load baring?

Side note, I actually went through structural engineering classes. I can tell that Thomasio did too. The other two, doesn't seem like it.
Thanks. Yes, I am a degreed mechanical engineer (BSME). But, "ordinary" ;) folks have great insight too...
 

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Discussion Starter #27
Lotus Elise 111s - 11,000 Nm/deg (source: The list: Torsional Rigidity | GermanCarForum)

Alfa 4c - 14,500 Nm/deg (source: http://likesu.fiat.it/resources/lectio/files/Lectio_Catania_Presentazione_Ing_Montuori_4C.pdf)

Assuming the numbers above are correct, then the 4c is stiffer than the Elise. At the same weight, the 4c seems to outperform the Elise. But, does the 4c drive as well?

I never know which engineer to trust in these types of posts. Who's the judge of which poster is correct?
The 4C link you posted illustrates a process to repair the carbon fiber sill. Do you think insurance companies will opt to repair the CF tub or declare it a total loss?
It's clear the 4c has a less likely chance of being declared a total loss because it follows the traditional body panel system paradigm. It has REAL front and rear "bumpers" that look easily replaced unlike when the Elise's clam gets squashed.
 

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Yep I got the chance to drive one, I enjoyed it a lot. I don't understand the need to debate unknown or semi-confirmed specs when "how" the car drives counts for more in the long run. At least I would think to most people the bottom line is how well or poorly it drives, handles, to me that's what counts not the damn metallurgy but whatever, everyone's gotta fight about something.

To me the 4C felt like an "updated" Elise. Still pretty raw in the handling and feel, but with some nice trim and accessories that made it more livable if you had to drive it for extended periods.
 

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first off- lets compare apples to apples. you can't buy a street legal new lotus elise or exile in the us. so there is not such thing a 2,000 lb lotus vs a 2,500 lb alfa. there is a 3,000+ lb lotus to compare it to if you like.... (although id say a bit different cars)

so your left to coampare it to.... a porsche? a bra/fr-s thingy? some other under 3k lb coupes that are quick handling. so not too much in the market there.

you can't even really compare it to a kit car - since a kit car is side stepping all the regulations that add a lot of weight into the Alfa.

so lets be factual here. isn;t the alfa the "lightest / fastest / cheapest" production sport coupe in the US?

and its a carbon fiber tub - whats not to like?!
Excellent thoughts.

Also, the Elise/Exige would not have existed in the USA but for the federal exemptions that were allowed. Bumper height requirement, etc.

I think that those who own an Elise / Exige are lucky to have them, as there isn't likely to be another vehicle like it unless the stars align again.

The Alfa is built to a new set of rules, to be certain.
 

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Yep I got the chance to drive one, I enjoyed it a lot. I don't understand the need to debate unknown or semi-confirmed specs when "how" the car drives counts for more in the long run. At least I would think to most people the bottom line is how well or poorly it drives, handles, to me that's what counts not the damn metallurgy but whatever, everyone's gotta fight about something.

To me the 4C felt like an "updated" Elise. Still pretty raw in the handling and feel, but with some nice trim and accessories that made it more livable if you had to drive it for extended periods.
How was the transmission? Did it make you miss the manual or were the paddle shifters enough?
 

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How was the transmission? Did it make you miss the manual or were the paddle shifters enough?
In "manual" mode I thought the tranny was decent, does the auto-blip of the throttle upon downshifting and upshifting seemed smooth. I did miss the plain ol' stick and wish that it came with one.
 

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I still don't understand why the CF tub isn't significantly lighter than
the Elige's AL tub.

This has yet to answered. Does the Elige's 150lb "tub" include the passenger
compartment and the front suspension pick-up points, steering rack et al.

US safety standards ruin our fun.

-Robert
The answer to that depends on a whole host of factors, a couple of which have not been mentioned:

1) While composite structures can provide higher strength/weight than metallic, the major advantage is typically more in marketing than engineering.

2) The reason for this is that metals are MUCH easier to quantify than composites. I can go to lowes and buy a piece of 6061-T6 bar stock, and am guaranteed that the strength, hardness, density, and stiffness are within a couple of percent of book values. Even more so, I can weld, glue, or bolt several of them together and have very high confidence in the performance of the assembly.

This is completely untrue for composites. Composites by definition are not a 'bulk' material, so the fiber orientations, core materials, weave types, etc are all critical to determining the strength of the resulting part. Even more important, processing has a huge effect on the performance of composites. If a slightly different resin is used, or the fibers are not quite wetted all the way, or cure temp is a few degrees off, the difference in performance of the resulting part can easily be 10-20% off, or even much more.

3) Composites are also MUCH harder to design when it comes to deformable crash structures and energy absorption. This is for the same reasons as above: a metal will bend, fold, and tear fairly predictably because it has the same properties throughout. A composite can do any of those things as well, or the plies can separate, or it can pretty much disintegrate without absorbing much of any energy at all.

The end result is that while it is possible to design a composite tub that is much lighter than a metallic one for the same performance, it isn't easy to do it. When you're talking about a low priced sports car without huge sales volume, the easy way out is just to over-design it to be roughly the same weight as a metallic chassis, but with the marketing advantage of carbon fiber.
 

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Discussion Starter #35
Is a 2-eleven stiffer than a FED Elise/Exige?
The 2-eleven does not have the tub cut-out
to ease ingress/egress.

If so, it may be stiffer than the 4C.


-Robert
 

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Gents

I find this post very interesting, because much of your very well-informed inputs, and your light-weight engineering passion, are great. But this is a big deal, as it turns out that execution is about far more than the simple spec's on paper....

This original post was about the 4C vs Elise! I have driven both in anger, on race tracks, and can report back to any of you who may be interested.

I desperately wanted to love the 4C. A new Italian, with a lusty little motor, and a light weight / stiff tub; what could be wrong with that?

Well, it turns out, a lot...and much of which, that the advertising-dependent media will not reveal to us. Yes, Car and Driver will tell you about this in a few years. When the car is not so fresh in it's marketing cycle. Sorry, but until then, the car is great.

On to the truth, the brakes on the 4C were frustrating to balance on edge, but much more importantly, was the turbo lag of the car, which was forever frustrating when you're in the middle of a corner! World Champion Walter Rohrl has commented very vocally on forced induction vs. the merits of normally aspirated.... and he's completely right! Even when you're a gifted World Rally Champion, even then the moron's amongst us can feel these shortcomings!

I'd far rather drive a less powerful, normally-aspirated car on a road course, than deal with this...it was too much,.............. and then too little,............... and then too much. I wanted to love the 4C, sincerely!........... but I couldn't. The 4C just didn't earn it. The track credentials were clear.

In retrospect, normally-aspirated cars are MUCH easier to drive. For the mere mortals driving them, which might include some of us...
 

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Don't lump superchargers into your disdain for FI vs NA. (not that they are perfect either).

Not that I've driven very many turbos, even less so on track, but when driven competently, in anger, my understanding is that you are always in the boost and this isn't actually much of a problem with a WELL-TUNED engine/induction system. For instance, I believe the 12c doesn't have such problems on track.
 

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THanks for the great review Gilles1982. Had a gut feeling here. So when you lift for a corner to brake, there is that lag even at high rpm's if only long enough to unsettle car. Even on the Eliges, that 2nd cam could make car twitchy in high speed , at the limits situations , but predictably so. Fiat/Chrysler has been pumping big advertising dollars at all the rags.....hummm... wonder how long before all the nuances of the Hellcat and its excess girth! Bet they can't keep brakes on it like the old Audi RS6's.
 

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so true, the "fickle" media. remember how Road and track proclaimed the Elise as basically god on earth and best sports car ever ia buying one!! . ...then 2 years later, they were like "this car sux so bad we excluded from out shoot out and its in last place, ...crap car ...why would anyone buy one"

despite that paid for magazine advertising, or lack thereof - it is, in fact, an epic sports car! however, the first year / generation elise had many issues, bad lift in the rear (and crashes to prove it) that required lotus to reengineer the rear of the car (diffuser and suspension set up) oxidizing alumn, inability to get in and out with a top on, and so on. over time - the bulk of the initial Elise issues were "fixed" and it solidly became "one of the best sports cars in the world" and then we got a further developed variant in the US.

the 4C in a new chassis, new car in model year one... id say - compared to the the elise in year one, Fiat nailed it and this car is only going to get "better".

and as we pointed out - the 4c meets (not exemptions) federal regs, and new generation regs as well.

fiat has said pretty clearly that the weight increase is due to 1. additional chassis material to meet federal crash standards 2. standard content on federal cars.


what could be wrong with that?

Well, it turns out, a lot...and much of which, that the advertising-dependent media will not reveal to us. Yes, Car and Driver will tell you about this in a few years. When the car is not so fresh in it's marketing cycle. Sorry, but until then, the car is great..
 
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