bristolguy79

Has anyone driven a C6 with the Z51 package and a C6 with the MRC? I don't plan on taking the C6 to the track or racing it in any way, just regular driving. So my question is, which feels better for regular driving situations, driving on smooth and bumpy roads? Does the MRC make bumpy roads smooth or does it not work that well? Does the Z51 package make the car feel really jittery over bumps?

SinCityJet

I have the F55, and have driven my C6 more than 2800 miles in the past 13 days. On highway driving, you'll really appreciate the Tour Setting, and if you decide you want to feel all those road groves, lane reflectors, and expansion joints while getting flatter turns, the Sport setting is just a flick away.

Most people who get the Z51 package did it for the oil and transmission coolers, the better brakes and tires, and the firmer ride, and most say they are pleased with the ride.

Another Yellow

One think to consider is that with the bigger Z51 brakes, the car will stop 9 feet shorter from 60 mph, 116 ft. v. 125 ft. That might come in handy some day.

FunDriver

Doesn't the Z51 also come with the M12 transmission (comparable to a MN6 and 3.90 rearend). That is the biggest reason that I want the package since I now have 4.10 gears and definitely want a comparable setup in my new C6. Right now, however, I'm waiting to see what the new Z06 will be like.

coolcat

For us daily drivers the downside of the Z51 pkg would be that the Supercar tires wear out a lot faster.

c2jones

I have read this, too (on this forum), but many of the reports from those who were interviewing (Dave Hill and Mike Neal) and testing the (Z51) car (as with the Hib Halverson article) state commentary otherwise:

"The brake system improvements won't be noticed on the street - well except for maybe the cute, drilled rotors - but on the track, especially in situations where you're doing laps in succession, the car stops better and more consistently as heat builds in the system."

The shorter stopping distance referenced above may have been in track situations after the heat was built up in the brakes. If this is the case, a street application to where the shorter distance would be realized (in a safety related situation) would not come into play.

c2jones

Precisely.

I have often wondered why this gets so overlooked by the Z51 faithful.

Some feel that the replacement (MSR) shocks of F55 should be a consideration (and use this as a reason not to go with F55). Well then why are the Z51 (Goodyear F1 Supercar) tires which will wear out quicker and need maybe twice the times of replacement not a cost consideration?

c2jones

This discussion has been on the board in abudance.

Please allow me the liberity of an expanded perspective:

Chief Engineer, David Hill, is fond of saying; "Z51 is for the aggressive street driver, for the occasional autocross or track-day driver who also takes the car to work, for the daily commuter who lusts for the sporting nature of America's Sports Car or even the wannabe who has gotta have the cross-drilled rotors and the F1 Supercars 'cause they look cool, but orders an automatic, heated seats and doesn't want anything close to a stiff ride."

However, Hill has also said (a few times) that as F55 technology has so few competitors, he and the whole Corvette team are very proud of their innovation and cherish this technology as a strong feature toward establishing the Corvette as a world-class sportscar taking the next generation Corvette into a new era.

A recent article:

MotorTrend – “The Suspension Dimension.” (September 2004)

“The more performance-oriented, who will likely shift for themselves and perhaps engage in autocross or track events, will want to step up to the Z51 suspension, which adds about $1500. This option used to cost $395, but the higher price represents a significant increase in content, including the larger, cross-drilled brakes, Goodyear F1 Supercar tires and revised manual transmission gearing with shorter 2.97, 2.07 and 1.43 ratios in the first three speeds.

"The Z51 is actually a touch softer than the previous package thanks to revised damping. But again, the new suspension geometry, longer wheelbase, more aggressive tires and shorter overhangs give the car quicker turn-in, better body control and higher cornering speeds.”

“While the Z51 was definitely a hoot to push hard around VIR, the Magnetic Selective Ride package ($1675) is truly the thinking man's alternative when it comes to suspension. In its normal touring mode, it offers a ride as supple as the base car's but with the added benefit of virtually flat cornering thanks to the fast-reacting shocks filled with magnetic-rheological fluid (a magic mix of iron particles and suspension oil) that, when energized by an electromagnet, stiffens the dampers to counteract body roll.

“The system has been changed to have two settings, touring and performance (as opposed to three settings last year). Unlike the previous switch, which didn't prevent the system from going into full performance mode automatically, the touring reacts much slower than the performance mode, producing a little more compliance and body lean.

"The performance mode ensures flat cornering no matter what the speed. In a way, the MSR system inspires a bit more confidence when pushing the car hard around the track — it prevents the body from becoming unsettled when the suspension loads and unloads over undulating surfaces.

"The compromise is the slightly slower turn-in. It just doesn't feel as razor sharp as the Z51 when attacking a corner's apex. The real value however in the MR system is that it nearly eliminates the surprise factor out on the open road when encountering a pothole or other unseen road irregularity.”

<End>

I would think, however, that the difference in that F1 Supercar tire alone compared to the mere run-flat tire of the F55 would be attributable to that "slightly slower turn-in." Besides, this is with maximum speed racetrack situations.

For the practical, daily driver, F55 is hard to beat.

For me (IMO), Z51 is for the "go-fast" mentality that (although being delightfully pleased that Z51 is actually quite forgiving as a daily driven car), the truth is that they don't mind the overkill if they can have the thrill of knowing their car is racetrack ready. They want the most Corvette they can have, especially in that the rotors look better, advertise what suspension they have, and the tires are considered optimum for performance. For me, for my use, the only real lure for the Z51 is the visual effect of the rotors. (Admittedly, larger, cross-drilled brake rotors make the car look more advanced and up with the times for a modern sportscar.)

[BTW, I often wonder if one could mix these packages? Z51 with F55 shocks? We're only talking about shocks, after all, right? Or, adding the F1 (or similar) tires to F55? What are the possibilites that in time, one will not have to choose, but rather, Corvette will have the best of both of these packages universal in the car? (Like Mercedes, etc, who don't offer suspension "packages"; all their cars come with ALL they can.]

The Z51 was designed to have a (slight) compromise of maximum ride comfort in trade for the tightest suspension for spirited drivers, and to ensure that those who were going to be using the car in track, rally or other racing competition had the best possible setup they could have right out of the box. (Thus the larger oil cooler (and other parts), cross-drilled brake rotors and higher performance tires [and lower gear ratio for 6spds].) However, most daily street drivers are not going to be able to bring to use the full performance aspects of Z51.

But the refined aspects of F55 are not to be taken lightly either. This mode offers Cadillac type everyday driver comfort, while adding its own very serious performance characteristics that Z51 simply cannot match. While Z51 might have a slightly tighter turn-in upon high speed (roadcourse racing) corners (which most people will NEVER test), the advantages of F55 take over thereafter. Z51 (rotors) look better and the car turns better under racetrack conditions (especially with those tires). But “spirited” driving has to account for more than looks, and it’s on the street that most of us drive our cars.

F55 eliminates the “surprise” factor and makes “spirited” driving more stable and predictable for the everyday driver who wants to go out and experiment on their car (especially on street and general road conditions of the average person) no matter what the speed and situation is. No matter what the open road or street irregularity is (like encountering an unseen pothole, indentation or fast appearing dip, bend or curve in the road), F55 is ready. Its great technology.

Essentially, F55 thinks for the driver (much like sportscars and sport sedans from Mercedes, BMW and Audi). F55 inspires more confidence for those who don’t have years of track time at Watkins Glen or Laguna Seca (or be forced to be onguard and driving concentrated like they do). On a racetrack, there are no unexpected matters to deal with. On the street? Everything SHOULD be unexpected. That’s the difference.

While Z51 is a dedicated (fixed) sport-tuned setup, the beauty of F55 is that it gives you a much broader range of suspension feel and firmness. It’s like having two cars in one, with only a turn of a button (on the fly) to make the difference.

Dedicated tight, sport-tuned suspensions have lots of examples from almost all manufacturers. But F55 sets Corvette apart. As a longtime European sportscar owner who would have never considered a Corvette before, the rules have changed. The new Corvette is demanding its place in this ultra-competitive arena.

KungFu

They should make this a sticky. This question gets asked alot.

Weasel

The drilled, larger rotors.
The lower first four gears.
Plus you still get run-flat's.
It's all good news to me n' VN4290

skfurr

What is the real story with the transmission in the Z51? I've seen it said that the first TWO gears are lower, that the first THREE gears are lower, and now the first FOUR gears...

Also, it's been reported here in the forums that the brake pads are the same on base, F55 and Z51 cars. If the rotors are larger diameter on Z51, then does that mean that the calipers are the same just mounted further out (radially) on the Z51 cars? Can one buy the larger cross-drilled rotors and the offset brackets and fit them to the base or F55 cars?

Just a thought for replacement down the road when it comes time to do the brakes anyway...

Stephen

Another Yellow

How Motor Trend could get that wrong is amazing. They are supposed to be a car magazine. The F55 has always been two settings and first made available for model year 2003. It was the original adjustable system from 1997 to 2002 that had 3 settings.

The stopping distance numbers come from Corvette Quarterly. No mention of how they were tested, just the 9 foot difference.

7 OUT

Of the 6 gears, only 4th is the same 1:1. The rest are different, others have posted the comparison on this forum a least a few times.

The reason I ordered the Z51 was because of the transmission. I believe even as a daily driver this one difference will be noticed and worth going with this package.

Dana

jvp

Same calipers, same pad (size,) which means, overall, the same swept area. Which means you're not getting any benefit from the larger rotors other than the slight chance they'll cool themselves off better.

This'll **** the Z06 purists off, but, much like the C5 Z06, the Z51's braking advantage comes from the contact patches (tires.) Not the brakes themselves.

jas

skfurr

Yeah, I wasn't planning on changing them out until the pads were gone and the stock (non-Z51) rotors were glazed or warped. I figured if I had to buy a set of rotors anyway it wouldn't hurt to "upgrade" to the larger Z51 rotors.

I've gotten in the habit of not turning rotors. If the rotors are so far warped as to require turning, I'd rather replace them. Turning them just makes then thinner and more prone to warping again.

Thanks for the info!

Stephen

Norske

All other factors the same, a larger diameter disc rotor will provide greater stopping power because of its greater leverage. The Front rotors are 13.4" (Z51) vs 12.8", giving 4.7% greater leverage. Rear rotors are 13" vs 12", giving 8.3% more leverage.

skfurr

Thanks for the clarification!

Stephen

jvp

This only works, of course, provided the pads/calipers aren't overwhelmed by the greater rotor velocity. One of the major fallacies of brake advertising is: bigger diameter rotors are better!! Well, they're not always better. If their greater velocity is too much for the calipers' clamping force, there's no advantage.

Good discussion. :-)

jas

SSkindog

Adjustable MRC shocks cant make up the performance differences that come from the stiffer sway bars and springs that the Z51 uses, can they?

skfurr

I don't know of anybody outside of the magazine corps who's spend a ton of time behind both F55 and Z51. If you believe the magazines, the F55 is not a match for the Z51 on smooth track conditions. The F55 begins to shine in uneven bumpy pavement however and can actually outhandle the Z51 if the pavement is so rough that the Z51 starts bouncing off the road. Supposedly the F55 in sport mode controls body roll nearly as well as Z51 by stiffening the outside shocks.

Anyone with real seat time in both?

Stephen