Cal Club Autocross Forums

Stumbled upon this thread

I have no idea how the 500 (and/or Abarth equivalent) would fare on the AutoX course, but mine could be made rather quick by tuning out the classic understeer inherent to road cars.
All I know is that it demands a low ride-height, very stiff springs, and shocks to match.

On the road, though the car is HIGHLY prized everywhere in Europe, and Lebanon (I literally see tens of 500 every day, here), I'm still out to lunch on the benefits of owning one in the US.
First, the US mentality is very different than the Europeans, second, roads are large, lanes are large, distances are long. The car is best suited for a city commuter, although I absolutely enjoy my weekend early morning drive to the hills on flowing switchbacks, before parking to start my road bicycle climbs. Yes, a road bike fits inside the Fiat, as long as you remove the front wheel. I do it every weekend. For that alone, and for its fuel economy, it's a kick-ass combo.

I love my Abarth Esseesse, and personally would not part it for any other commuter, today. It's a perfect complement to my Vantage V8.

John, the Solo safety folks use the rollover data that they can obtain for the majority of production vehicles, which is published by the NHTSA. Prior to around 2010, that was the static stablity factor. Around 2010, the NHTSA stopped providing SSF data, and changed to a mysterious "rollovery probability" rating. So although the criterion may be based on voodoo, it is actually quite up to date. If you don't like the NHTSA's voodoo, you're going to have to propose a viable alternative to get the discussion started.

The Abarth is not taller then wide ... does that mean it automatically is acceptable to run in CST ?

58.7" tall by 64.1" wide .... the Abarth is 15 mm lower then the regular model. About the same ground clearance of our ITA Miata

In fact it looks like the regular 500 is wider then tall also.

http://www.media.chrysler.com/dcxms/ass ... _Specs.pdf" onclick="window.open(this.href);return false;

regular Fiat 500: http://www.edmunds.com/fiat/500/2012/fe ... specs.html" onclick="window.open(this.href);return false;

http://money.cnn.com/2004/06/14/pf/auto ... /index.htm" onclick="window.open(this.href);return false;
http://wot.motortrend.com/2012-fiat-500 ... 44769.html" onclick="window.open(this.href);return false;

edited after researching more

The NHTSA published rollover probability is 14.5% for the Fiat 500. The cutoff in the Solo rules is 14.0%.

Marshall, where did you get the data on CG height? That could be a good resource for the SAC.

+1

If we could find a creditable source for CG's, SSF becomes roll your own (no pun intended)

John Stimson wrote:The NHTSA published rollover probability is 14.5% for the Fiat 500. The cutoff in the Solo rules is 14.0%.

Marshall, where did you get the data on CG height? That could be a good resource for the SAC.

i'm updating my previous post now that i've had time to do 5 more mins of research...
EDITED after even more research...
credible source for data:
http://www.nhtsa.gov/cars/rules/rulings ... html#a_ssf" onclick="window.open(this.href);return false;

"SSF is too simplistic. SSF ignores tire properties, suspension compliance, handling characteristics, antilock brakes, electronic stability control, vehicle shape and structure (post-impact rollover), and tripping factors (tires)"

The above quote from NHTSA addresses why SSF actually may have greater utility for our usage...particularly the part I've highlighted...we need a basic mathematical expression of the physics, not a probability based on changeable factors, to baseline what is reasonable for Solo and what is not, imho. The biggest issue with the new NHTSA standard is that it is based on a J-turn type of manuever with stability nannies enabled...which will undoubtably be turned off in an autocross environment, right?

When I said "creditable (is that even a word? I did mean "credible", thank you!) source of data", I specifically meant true CG, to be able to calculate SSF...which is the number we need, I believe.

Or maybe just an Official Tester (The Stig?) who will drive every new car, on whatever this year's uber sticky tire is, past the limit.

Does the 500 have to be "certified" before the lowered Abarth can be considered?

Mako Koiwai wrote:Does the 500 have to be "certified" before the lowered Abarth can be considered?

Interesting that the two links to spec sheets you gave show both cars with the same 4.1" ground clearance, despite the Abarth shown as 1.1" shorter.

Mako Koiwai wrote:Does the 500 have to be "certified" before the lowered Abarth can be considered?

Nope. But, the Abarth also has average track width less than height, so ex new data, it can't currently be classed

No 500, yet all the other "B-Spec" cars can run?

Yet, the older Toyota Yaris was allowed? As I recall, It's taller and narrower.

Michael Wood wrote: The above quote from NHTSA addresses why SSF actually may have greater utility for our usage...particularly the part I've highlighted...we need a basic mathematical expression of the physics, not a probability based on changeable factors, to baseline what is reasonable for Solo and what is not, imho. The biggest issue with the new NHTSA standard is that it is based on a J-turn type of manuever with stability nannies enabled...which will undoubtably be turned off in an autocross environment, right?

When I said "creditable (is that even a word? I did mean "credible", thank you!) source of data", I specifically meant true CG, to be able to calculate SSF...which is the number we need, I believe.

the Roll over risk % is mathematically derived from the SSF. that is combined with the useless j-turn test to come up with the stars. Likely why they dropped showing both the ssf and the roll over risk as it is redundant and confusing for the general pubilc.

Marshall Grice wrote:

Michael Wood wrote: The above quote from NHTSA addresses why SSF actually may have greater utility for our usage...particularly the part I've highlighted...we need a basic mathematical expression of the physics, not a probability based on changeable factors, to baseline what is reasonable for Solo and what is not, imho. The biggest issue with the new NHTSA standard is that it is based on a J-turn type of manuever with stability nannies enabled...which will undoubtably be turned off in an autocross environment, right?

When I said "creditable (is that even a word? I did mean "credible", thank you!) source of data", I specifically meant true CG, to be able to calculate SSF...which is the number we need, I believe.

the Roll over risk % is mathematically derived from the SSF. that is combined with the useless j-turn test to come up with the stars. Likely why they dropped showing both the ssf and the roll over risk as it is redundant and confusing for the general pubilc.

I think what you're saying is right, about the need to manage the message to the public. Unfortunately, we can't see the data we need any longer, as a result. You think relying entirely on the assimilated roll over risk % works? You might be surprised at some of the cars that pass/fail the proposed 14% threshold...

Michael Wood wrote: I think what you're saying is right, about the need to manage the message to the public. Unfortunately, we can't see the data we need any longer, as a result. You think relying entirely on the assimilated roll over risk % works? You might be surprised at some of the cars that pass/fail the proposed 14% threshold...

http://www.nhtsa.gov/DOT/NHTSA/Vehicle% ... 5-0114.pdf" onclick="window.open(this.href);return false;
go to page 18 of 36 and you have the EXACT equations used to calculate the rollover risk percentages as a function of SSF and including the dynamic test results...or not.


...WINNING!

and running the numbers for a SSF=1.3 you get a roll over risk rating of 13.9635%. so uh I guess the fiat 500 does not meet the rules for stock class afterall. haha

so at 14.5% rollover risk, the fiat has a SSF=1.285. To get the car to have a SSF=1.3 (and thus be legal for stock class per the solo rules) you'd need to lower it .25".

certainly seems like a borderline case here, why not just let it run?

The 500 is a Dog ... the Abarth is another, lower animal. Not a Mini or Civic fan ... but I think the Abarth is kinda of cool. Round ... I guess I like round ... doesn't get much rounder then my Previa!

Waiting for the BRZ first ...

Mako Koiwai wrote:Not a Mini or Civic fan

Let me take you for a ride next practice ;)

Oh I use to drive Henry's Twin Charged, 270 hp Mini but I'm not really a fan of the Look.

This one on the SM Fwy 2 day is kind of interesting ... What is it ?!

Mako Koiwai wrote:This one on the SM Fwy 2 day is kind of interesting ... What is it ?!

MINI Coupe - http://www.mini.com" onclick="window.open(this.href);return false;

Will Kalman wrote:

Mako Koiwai wrote:This one on the SM Fwy 2 day is kind of interesting ... What is it ?!

MINI Coupe - http://www.mini.com" onclick="window.open(this.href);return false;

Me no likey. Looks like some out-of-style b-boy with his cap on backwards.

BMW design is hit or miss... This missed.

This past week I had a gig doing test drives for Chrysler/Fiat at the Calgary Car Show (new cars).

As it turned out, I was happy to find out I was assigned the Fiat 500 with the sport pkg (stiffer springs, shocks, raspier exhaust, 6-speed auto with Sport mode....manual would've been nicer but ... etc.).

In any case, I spent a considerable amount of time in it with up to 4 passengers (some of them quite large .... as in big/tall people) and I did not notice that the car was overly tippy (unlike the outright scarey characteristics of an Aerostar I rented a number of years ago).

The test loop was fairly low speed (max. about 50 mph for the lead foots) however I had the opportunity to take it to the dealer for some minor service and, of course, wandered out on the freeway to see what it was like .... a little over 70 mph, hit some bumps (purposely) and shook the steering wheel while going over them to see if I could unsettle the chassis. It was very, very surprisingly composed! Just steer it exactly where you want to go no matter what the road surface is and it goes there ... no bobbling. Amazing I thought!

Furthermore, it struck me that this is just a really, really fun little car to drive ... which was a very common comment from drivers and passengers throughout the week. It would be a real shame not to be able to autox this baby.

I wonder if Fiat/Chrysler would consider giving us some center of gravity data to evaluate. I bet they would have that handy since the design would surely be done on CAD software which more than likely calculates this.

For Fiat this, of course, could result in more sales and sales exposure etc.

Mike?



Reijo

I don't have a bone in the great stock class tire debate. I really don't have any interest in "stock". But it seems to me that the best argument the street tire religion folks can make is that the future of automobiles is the B-Specs. We're going to start looking more like Europe with $6 gas and huge increases in CAFE standards. The reason we can't run a car like the 500 is really only because we have to wonder what happens when slap Hoosiers on stock springs. I'd be arguing that this is the reason stock should be on streets.

But we all know that Corvettes and Vipers and Rustangs and such all thoroughly suck on streets so, create Stock and Super Stock. Stock is the low horsepower classes currently in stock. Super Stock takes the high powered classes currently in stock. Stock runs streets. Super Stocks runs R's.

Easy Peasy..... Don't make it hard. Now the new EuroTrash micros can run.

}:) }:) }:) }:)