Wass

Plenty has been written about the Z51 equipped C6. Perhaps most forum members prefer this package. However, with the present constraints on Z51 equipped C6 Corvettes, the F55 may deserve some consideration. There really isn’t much of a seat-of-the-pants difference in these two option packages. And under real world driving conditions, regardless of constraints, the F55 may be your best choice.

The book CORVETTE C6 by Phil Berg, quotes Automobile Magazine's Tim Ferris as follows: "The MR (magnetic ride or F55 MSRC) car is easier to drive on the track, but on public roads it seems slightly trampy and, personally, I preferred the Z51." The same book quotes Road & Track's Matt Delorenzo: "And out of the two, the Z51 and the MR cars, on a back road the MR system is better". It’s interesting that in this case, even the experts don’t agree. However, everyone seems to agree that the F55 option does provide the most comfortable ride. Another interesting comment in the book came from Car & Driver's Larry Webster. He said, "I think if you put the Z51 tires on an MR car, the handling would be just about equal."

I've driven both cars, and I think they are pretty close. Comments from some of the experts reinforce my opinion. The Z51 has slightly better numbers in the quarter mile, and 0-60 (perhaps by 1/10th second or so), but not enough to be perceptible while seated behind the wheel. The Z51 has options oriented more for the track, but the F55 (MR) can be an asset driving fast on normal roadway conditions.

The F55 computer system will signal to the suspension how much damping force is needed for the existing road conditions. Based on what I have read, it is the world’s fastest-reacting damping system, using magneto-rheologic shocks filled with a special fluid containing randomly suspended iron particles. These particles can change the viscosity of the fluid almost instantly, from a free-flowing liquid to a thick syrupy consistency, almost like peanut butter, according to the level of electric current sent to a magnet in each shock. The system controls the tendency of the wheel to bounce, but lets up as the wheel rolls on smoother surfaces. The system will continuously adjust shock absorber resistance, increasing when needed to control body lean when cornering, and it can prevent the front end from excessive diving under hard braking. The goal of the system is for maximum tire tread contacting the road, which will benefit safety and handling. All of this reportedly can be done in a thousandth of a second, which equals about one adjustment per inch at 60 mph.

The tires on the Z51 equipped C6 are another issue to be considered. The TireRack has a survey of 20 Maximum Performance tires. The Eagle F1 Supercar tires (Z51) rank last in wet traction and hydro resistance (hydroplaning). The 4.7 (out of 10) rating for hydro resistance is well below the next worst rated tire at 6.3 (recently posted in the Forum by DANNOV). In addition, the Supercar tires wear out faster than the Eagle F1 GS-2 EMT tires (F55 & standard C6). You can replace the Supercar tires with F1 GS-2 tires. However, the wet handling characteristics of the Supercar tires may not matter that much to drivers who are mainly concerned with their excellent dry handling characteristics. http://www.tirerack.com/tires/survey...ay.jsp?type=MP

I drive an F55 equipped C6. I live in a mountainous area with plenty of twisty back roads that are only in fair condition at best. I have about 2,000 miles on the car, and I am very satisfied with the handling characteristics of this fantastic Corvette. Is the F55 the best choice for your C6? Perhaps, when you consider the way you will be driving the car, and the road conditions you will most frequently encounter.

shopdog

The drawbacks to F55 as I see it are, higher first cost, excessive cost for replacement shocks, and the added electronic complexity of the control system.

The drawback to the Z51 package is the extra harshness over things like highway expansion joints due to the high rate shocks.

My solution was to go with the base suspension and add the Z51 sways and bushings ($160). That gives a cushy ride, but still makes the car corner flat. It is not only far the cheapest solution, it is also
the best compromise for a highway car that won't see a track, but still needs good emergency lane change and cornering ability.

Miaugi

Good write up!

My current car has F45 which I like a lot. Ordered my C6 with F55 which I'm sure I'll enjoy even more.

Now if I could just get those extra coolers and the Z51 6 speed tranny.

Wass

Great modification idea!

I have read other concerns in the Forum about replacment costs of the F55 shocks. And I remember one post about defective leaking shocks. However, Jim Mero, a suspension engineer at G.M. who led the team that engineered both the Cadillac and Corvette msrc systems has said that the shock absorbers are so sturdy and simple that they should last the life of the car. Only time will tell for sure.

Corvette Junkie

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For what I use my Corvette for the F55 was definitely hte way to go. There's a road I drive all the time that has a rise in it that I would never take at more then 45 mph in my 03 with Z51 because of getting airborne. Much like in the pic you have. With the F55 I have now taken it at 65 mph and never left the ground.

LS6v

Here's one thing that I don't like regarding the magnetic ride control:

Our Cadillac STS and SRX have this suspension and it leads to a lack of confidence in the car. While you're driving normally down a road it has a soft and compliant feel, and it's this soft feel that makes it difficult to anticipate how the car will behave entering a turn. Once you're in the turn the suspension has firmed up and improved body control but before that happens you're (I'm) not quite certain of what to expect...

I'll assume that the C6's F55 when set to "sport" is a lot firmer than the STS when set on "sport", so it might no be as big of an issue. But the variable suspension feel doesn't inspire confidence when you decide to push the car to the limit, and you're not sure how and when the shock(s) will "adjust".

Also, if you do plan on taking you C6 to the track, the magnetic shocks don't hold up to extend periods of track driving. That's why the STS-V didn't get them (The STS-V would also work the shocks harder than a C6 because it weighs about 1,000lbs. more).

V Vette

Do we know what the time frame is when "changing" F55 modes? If I am in sport mode and change the **** to tour, how soon will this happen? Thanks

shopdog

It should be immediate. The system has a response time on the order of 1/1000th of a second. Now it may not poll the switch that often, but it should still be well under a tenth of a second.

Wass

I believe the change is instant. I've tried it and I will tell you that you will not feel a dramatic change, but it is noticible. I was talking to Bob Breeding from the Corvette plant in Bowling Green about this. He told me that the change in handling charicteristics is significant between tour and sport, but it is not so much a seat-of-the-pants change. You won't necessarily feel everything that is going on with the system. Maybe someone with track experience could shed more light on this.

BIG Dave

I went with F55 this time. It's my first Vette with any kind of adjustable suspension. So far, I like it however I don't feel too much of a difference between SPORT and TOUR. I can say it's a much smoother ride compared to my C5. Maybe I'm just getting older and prefer a softer ride...

Wass

This is the kind of feedback that proves the system really works! Thanks.

Another Yellow

When making a decision on which suspension to order, don't forget to consider the fact that the Z51 will stop from 60 mph 9 feet shorter. That might come in handy someday.

Corvette Junkie

But not when everyone changes brake pads because they don't like the squeal.

Miaugi

LS WON

Check out the road test in Corvetteactioncenter.com

LS WON

The roads in my area are notoriously bad so this magnetic ride suspension will iron that out and F-55 acts as another added safety feature to keep all wheels planted on ground and will not allow the corvette to ever bottom out.

coolcat

Another BIG drawback to the Z51 package is the replacement cost of the GY F1 Super Car tires that wear out super fast. Better keep a big tire replacement budget if you get a Z51 equipped C6.

Rapid-Richard

I will gladly give up the additional tire wear for the grip. Z51 is softer rubber which has more grip. I can afford the tires and I would assume that most Corvette owner could also. This is a never ending debate and we all have our idea of which one works best. There really is no wrong answer, but I would much prefer the Z51.

coolcat

Have any forum members actually tried this? Adding the Z51 sway bars to this set-up would be frosting on the cake.

Wass

Perhaps, but I am concerned about the Z51 sway bars because of MSRC computer algorithms. The MSRC system uses specific algorithms to vary current flow to the electromagnets in the shocks which control the magnetorheological effect to provide the correct damping. This current flow is based on various algorithms developed for MSRC. I assume the algorithms were based on the standard F55 sway bars, etc. I wonder if the larger Z51 sway bars will work optimally with MSRC during all types of driving conditions considering these preset algorithms. It may or may not be problematic. It's all pretty complicated. Look at this link and scroll half way down to The Deep-Geek of MR: the "Sky Hook" Algorithm:

http://www.corvetteactioncenter.com/....php?qstId=503