Mercutio

You're right in that the other driver may well have been better. However, it's the best real-world example with objective numbers in an autocross environment I have. If you have better numbers taken from cars that are actually modified for SCCA autocrossing, please post them. And if the numbers you posted don't have the two cars on the same tire then it's not a valid comparison anyway.

Let's examine how the cars compare to each other when modified for SCCA autocrossing. Let's compare a B-stock RX8 vs. an F-stock CTS-V. Stock class rules say that you can use aftermarket wheels so long as they're the stock size. Both the RX8 and CTS-V have 18x8 wheels, but the Mazda has a much greater selection of lighter-weight wheels than the CTS-V does. So the Mazda will drop more rotating, unsprung mass than the Caddy will.

Tires: In stock class any tire that will fit on the stock-size wheel is legal. Stock class guys get pretty crazy here, so 295s on 8-inch wheels are common. The RX8 can fit 295s on all four corners; the CTS-V can't get 295s up front, at least not while complying with the rules. And since the RX8 rolls on 225s stock vs the V on 245s, the RX8 will gain 70mm per tire while the Caddy will only get 50mm extra in back and maybe 20mm extra in front. That's an advantage for the Mazda.

I also think you underestimate the advantages that the RX8's shorter wheelbase and shorter overall length give it on a tight autocross course.

This thread (http://www.rx8club.com/showthread.php?t=133564) has a list of BS-class weights at the 2007 SCCA Solo Nationals. The RX8s are all right around 2800 pounds; the lightest RX8 on the list is 2792 pounds. My 05 CTS-V w/sunroof was 3,802. Take a non-sunroof car and use legal tricks like a lighter battery, custom lightweight catback (the Corsa is 7 pounds heavier than stock), race tires and (custom, probably not available) lightweight 18x8s and maybe you could drop the V to maybe 3,650--MAYBE. But how can you expect the CTS-V to compete with a car that's 850-1,000 pounds lighter but rolling on the same size tires?

If you seriously think that a CTS-V will beat an RX8 when both cars are prepared to the limits of the rules then try it. Here's the 2010 SCCA National Tour schedule:

http://scca.org/contentpage.aspx?content=56

liqidvenom

iTrader: (2)

so a modded v on hoosiers lost to two stock class vehicles over 1000lbs lighter and you still assume the v will win some how?

i have driven the doors off a rx-8 at an autox. i just dont see how a v would have done as well. its like a bull in a china shop on those really small autox courses. even sports cars like c5's/c6's were putting up worst times then the rx-8 did.

the slalom and braking is the key when it comes to something like this. the v might get the the first turn faster... but normally thats the only flat out section, the rx-8 would walk away from that point.

AAIIIC

iTrader: (19)

If you're someone who's fast in whatever kind of car you drive, sure. Perhaps with a bit more seat time in the RX-8 you would realize that it's really damn hard to overcome an 800-1000# disadvantage on an auto-x course.

Which is nice and all, but isn't what this thread is about, so I'm not sure why you mention it.

Thank goodness my V goes more than 111' without breaking! That would sure make my daily commute a grind!!

Comparing the typical 700ft slalom that magazines do (100ft cone spacing) to a typical auto-x slalom isn't particularly useful. Even on R-compounds in my light(er), nimble, auto-x prepped Subaru there are very few auto-x slaloms that I can navigate at 67mph. A shorter slalom (think 45-65ft cone spacing) means the transitions are that much faster and makes the extra 800+lb that much more of a weakness.

You didn't tell Jon04CTSV, SkullV, 07CTS-V, or SoJersey05V that their comparisons were invalid, so why does it matter for Mercutio's?

That's true at the local level. Again, comparing results at the local level just doesn't mean much. The top level national drivers find the platform that works the best and develop it. Sam Strano auto-x'd F-bodys Camaros for years, winning a few Solo National and ProSolo National titles, then jumped ship in just the past couple/few years to the S197 Mustangs. He (and all the other top level FS drivers) would buy a CTS-V (rather than spending more on a new Mustang) if it were the car to beat in the class, but it just isn't.

You're implying that the V isn't competitive because there just aren't enough competing to make it competitive. You're looking at it backwards. There aren't many Vs competing because it isn't competitive.

In Stock class most of the cars are not pure auto-x cars. There's only so much you can do mods-wise in Stock, none of which would compromise the daily drive-ability of the car. I'm sure many of the top level cars get trailered to events, but I personally know and have raced with a guy who won a national championship in his daily-driver Subaru. He then sold the Subaru and bought an RX-8, which again was his daily driver, and had a couple of top 10 National finishes in 2005 and 2006.

Except it won't...

Except it's not.

Anyway, I'm sure I'm wasting my breath. This thread has evolved exactly as I figured it would even before I opened it.

adanieljohnson1

iTrader: (1)

Non the less its still a good debate... I like hearing both sides though I would still like to see some vids...

2003RC51

iTrader: (9)

Careful, AAIIIC is gonna jump on you. The C5/C6's are in Super-Stock so its impossible for the RX8 to be faster than them since it is in B-Stock.

I also agree that a super small course is a different story. I have been to many auto-x events and the ones that I went to you could reach speeds in excess of 75 mph on some of the straights. These weren't SCCA sanctioned races but it was still auto-x.


Actually, they will still be very close in slalom. Once the cone spacing goes down, so does the mph. If the RX8 was that much better in the slalom at 45'-65' spacing/lower mph it will be that much better at the 100' spacing/higher mph.


I was not responding to their posts. Where did I say that their comparisons were valid? That's right, I didn't.

Not once did I say that the V is the optimum car for an auto-x, nor did I say it will beat the RX8. I said it should be competitive.


The V is a limited production vehicle so you are going to see less of them everywhere. I see a plethora of Sub's, RX8's and Miatas all over the place. If there are more of them on the road you are going to see more of them in motorsports.


I think you are placing to much faith in how they place the cars in those classes. Sure, most of them are correct but the CTS-V being placed in F-Stock while the base CTS is placed in D-stock??? I guess that means the base CTS is faster than the V since its in a higher class? I think not.

Also, how much faster was the top B-Stock time over the top D-stock time?


So acceleration isn't important in auto-x? Ok.




The OP specifically stated a stock RX8. When he said stock I am sure he was not referring to a stock-prepped/modified RX8. Also, the stock RX8(manual) weight is 800lb less than the V, not 1000.

Now... Be sure to read this part. I am NOT saying the V will beat the RX8. I am saying it should be competitive and it will DEFINITELY not get destroyed.

Mercutio

DS is not necessarily a faster class than FS; cars aren't automatically classed by speed alone. DS is a class for fast FWD cars with good diffs (ITR, Cobalt SS, Mini Cooper S) and a few oddball RWD cars (some BMWs, Crossfire). FS is for pony cars and other large-ish RWD vehicles (G35, etc.).

At the NT I raced the Caddy at, the stock class winners, from fastest to slowest, went like this: SS (Lotus Elise), FS (Shelby GT), AS (S2000), ES (Celica), BS (RX8), CS (Miata), DS (ITR), GS (Mini), HS (Civic).

2003RC51

iTrader: (9)

Good to know, I was going off the SCCA site and it does not break down the "stock" classes like it does the "Street Touring" classes(or I could not find it).

Imp

Herro.

Are there people here that just argue for the sake of arguing? Oh, right, a car forum. Of COURSE!

I had my '05 RX8 down to 2810 lbs. Weight trumps all at an autox. While the absolute numbers of the RX8 are misleading, this is one of them 'magic cars' that the sum of the parts are greater than the whole. The 8 does auto-x fantastically. The V? Not so much.

There's this little thing called momentum that is talked about very little. Being able to keep the speed your at though a turn. All things being equal (specifically stock class rules and same national caliber driver doing back to back runs), other than the obvious weight penalty for the V, the 8 will be able to keep a higher average speed through most auto-x maneuvers than a V because it can keep its momentum from not having much weight (and conversely much less scrubbing of speed) though the turns.

It's "light in the loafers". While power and torque are wonderful things for coming out of corners and straights, getting INTO the corner and settling the car before turn in is where the V loses. While they more than likely have the same published numbers for *straight line braking* there are very few chances on your typical auto-x course to actually brake in a straight line. Most auto-x braking is trail braking, doing the minimum amount of braking to get the car to turn in... in other words, keeping your speed aka. momentum through a turn.

A car that's 800 lbs lighter, but on the same tires, will be able to keep a higher rate of speed through a turn. It's simple physics... with the same amount of grip available, but at a higher weight, the V will have to give up more speed entering the turn because that weight will want to continue to go straight *more than* the RX8 will if it *didn't* give up more.

That's just the way it works. Auto-x is a different sport where weight + grip > power. There are no straights to open up any car.... it's all about momentum and losing as little momentum as possible. The V is not a car known for changing directions (aka transition) quickly.

I can understand how you guys love your cars. They're just phenomenal sedans. Having been in quite a few, I wouldn't turn one down. But realistically, they don't have a snowballs chance in hell against an RX8 given same drivers in stock class. The RX8 has the same grip, but *much* lower weight.

--kC

Imp

Auto-x vids will show you nothing of discernible value other than a car going around some cones. You can't pick up what's happening unless you're strapped in and feeling the G's. Outside car? Cones. Inside car? Turning the steering wheel. That's all that video shows. (Unless you have it hooked up to data acquisition, then it's a different story, and you'll see the RX8 can keep higher G's and higher entrance speeds than the V.

--kC