Now having owned both: my F55 versus Z51 opinions
09-06-2008, 09:37 AM
#1
Le Mans Master
Thread Starter
Now having owned both: my F55 versus Z51 opinions
It seems that the debates which swirl around the great F55 versus Z51 controversy are endless and can go on forever. Everyone seems to have a strong opinion regarding which suspension choice is "the best", or even appropriate for the C6.
The thing that always amazes me about these prolonged and often heated battles, is the fact that the vast majority of the most vehement advocates of either the F55 or Z51 have never even driven the system they're throwing barbs at. "I've heard that...I've read that....I know someone who said that..." doesn't really count as firsthand experience. In fact, much of what I've read here is often based on second or third hand experiences, or simply parrots misinformation that was wrong when it was first posted.
A few on this board have actually owned both F55 and Z51 cars. Jim Schindler has, and has often posted comments pointing out the virtues of both systems. I'm now in the position of joining the ranks of those who have owned and driven both F55 and Z51 cars. I now feel that I can offer some objective comments regarding these two truly excellent suspension systems.
Let me start out by saying that my current F55 setup has been beefed up with the addition of the Z51 sway bars, so it is not a completely stock F55 system. The fact that this is a simple upgrade that only costs $200, makes it easy for anyone to do, if they choose to.
On my 2005 coupe, I must admit that I was a big fan of the Z51 package. The car handled with uncanny precision, was flat through very hard cornering, and exhibited very little dive on hard braking. Absolutely the "sports car" setup for this car. I often pulled close to 1.00 g on the HUD when I pushed it through sharp turns .. and it stuck like glue. After four years of driving my 2005 however, I also became increasingly aware of the Z51's limitations.
Although the Z51 is fairly well damped, and offers a very comfortable ride over smooth or modeartely coarse road surfaces, its performance over really rough or washboard roads was not the best. It could get very jarring, given the right...or wrong...road conditions. This was a trade-off that was not totally unexpected but, after many miles, I found I was avoiding certain roads completely.
The other issue I had with the Z51 was its OEM Supercar tires. Although really impressive when new, I found the tread wore very quickly on these tires. By 11,000 miles, my front tires were close to needing replacement, although the rears still looked pretty good. As the rubber wore, the wet performance and cold weather performance suffered noticeably. I had to be very careful starting out in first gear on wet roads, since the rear end became increasingly easy to break out. I did not, however, find hydroplaning to be an issue at all. At temperatures below freezing, the SC tires lost about half their traction. I always kept my cornering below .4 g's in the cold, although the car seemed okay as long as it wasn't pushed hard.
The coolers in the Z51 package were never a factor for me, since I did not track the car. I've often seen comments insisting that the Z51 package is only designed for track use. I disagree with this completely. It's ideal for track use, but it's really a way of incorporating GM's most aggressive handling system into what may be a 100% street car. The Z51 changes the feel of the car...the C6 feels crisper and more aggressive with this package installed, and feel is what it's all about.
So, if the Z51 is that effective, why did I go for the F55 this time around? I've always owned, and sometimes raced, sports cars. This goes back many, many years. I always value handling over everything else in a sports car. I really agonized over this for quite some time but, in the end, I opted for the F55.
This becomes a very personal decision, so my reasoning may not agree with anyone else's. First, I recognized that my local roads have gotten much worse over the last few years. These are all secondary roads, and many are badly crested, patched, and have sections that are washboard like. The Z51, in spite of its realtively tolerant ride characteristics, was becoming uncomfortable over too many of the roads I had to drive on. I needed a more compliant suspension system. Also, I grew to hate the Goodyear SC tires that are standard on the Z51 package. They stick well on hard, smooth surfaces, but have poor tread life and add to whatever harshness there is in the Z51 suspension. I didn't want to worry about changing my tires every 15,000 miles. I know many report that they have gotten 20-30,000 out of these tires, but not driving on my roads and under these conditions ... so that doesn't help me one bit.
I've now spent 1,000 miles with my F55 C6. I must say that I am totally impressed. These magnetic shocks are more compliant than the Z51 shocks, but never feel "soft." The difference between Tour and Sport is subtle, but real. I do leave it on Tour for most of my driving,, where it feels a bit softer than my Z51 did. It's as flat as my Z51 through hard corners, although it does exhibit just a bit more dive on hard braking. On the Sport setting, it's almost impossible for me to tell the difference between this and my Z51. Again, this is all based on the F55 with the Z51 sway bars installed.
The steering on my 2009 is a totally different unit, so I can't make any valid comparisons. It's quicker, lighter, and has better feedback but, I believe, that's unrelated to the suspension choice.
The gearing on the Z51 transmission (MN6) is more aggressive than on the F55. I can feel the difference there. The F55 stays in gear longer, before hitting the redline, than the Z51 did. This gives the Z51 MN6 a quicker feel through the first two gears, but by 3rd gear there is really no difference I can feel. Both cars pull strongly, can be moved just by feathering the clutch in first, and can be started in second gear.
Both the F55 and Z51 are superb setups. One is not "better" than the other. The F55 offers excellent handling, excellent ride control, and some really interesting technology. The Z51 offers somewhat sportier feel, definitely has an advantage for track use with its coolers and more aggressive MN6 gearing, but really needs better rubber to make it a complete package.
I loved my Z51, and I feel just as strongly about my F55. GM has done an incredible job with both packages, and both deserve the full respect and admiration of all Corvette owners. Does anyone know where I can buy F55 badges?
The thing that always amazes me about these prolonged and often heated battles, is the fact that the vast majority of the most vehement advocates of either the F55 or Z51 have never even driven the system they're throwing barbs at. "I've heard that...I've read that....I know someone who said that..." doesn't really count as firsthand experience. In fact, much of what I've read here is often based on second or third hand experiences, or simply parrots misinformation that was wrong when it was first posted.
A few on this board have actually owned both F55 and Z51 cars. Jim Schindler has, and has often posted comments pointing out the virtues of both systems. I'm now in the position of joining the ranks of those who have owned and driven both F55 and Z51 cars. I now feel that I can offer some objective comments regarding these two truly excellent suspension systems.
Let me start out by saying that my current F55 setup has been beefed up with the addition of the Z51 sway bars, so it is not a completely stock F55 system. The fact that this is a simple upgrade that only costs $200, makes it easy for anyone to do, if they choose to.
On my 2005 coupe, I must admit that I was a big fan of the Z51 package. The car handled with uncanny precision, was flat through very hard cornering, and exhibited very little dive on hard braking. Absolutely the "sports car" setup for this car. I often pulled close to 1.00 g on the HUD when I pushed it through sharp turns .. and it stuck like glue. After four years of driving my 2005 however, I also became increasingly aware of the Z51's limitations.
Although the Z51 is fairly well damped, and offers a very comfortable ride over smooth or modeartely coarse road surfaces, its performance over really rough or washboard roads was not the best. It could get very jarring, given the right...or wrong...road conditions. This was a trade-off that was not totally unexpected but, after many miles, I found I was avoiding certain roads completely.
The other issue I had with the Z51 was its OEM Supercar tires. Although really impressive when new, I found the tread wore very quickly on these tires. By 11,000 miles, my front tires were close to needing replacement, although the rears still looked pretty good. As the rubber wore, the wet performance and cold weather performance suffered noticeably. I had to be very careful starting out in first gear on wet roads, since the rear end became increasingly easy to break out. I did not, however, find hydroplaning to be an issue at all. At temperatures below freezing, the SC tires lost about half their traction. I always kept my cornering below .4 g's in the cold, although the car seemed okay as long as it wasn't pushed hard.
The coolers in the Z51 package were never a factor for me, since I did not track the car. I've often seen comments insisting that the Z51 package is only designed for track use. I disagree with this completely. It's ideal for track use, but it's really a way of incorporating GM's most aggressive handling system into what may be a 100% street car. The Z51 changes the feel of the car...the C6 feels crisper and more aggressive with this package installed, and feel is what it's all about.
So, if the Z51 is that effective, why did I go for the F55 this time around? I've always owned, and sometimes raced, sports cars. This goes back many, many years. I always value handling over everything else in a sports car. I really agonized over this for quite some time but, in the end, I opted for the F55.
This becomes a very personal decision, so my reasoning may not agree with anyone else's. First, I recognized that my local roads have gotten much worse over the last few years. These are all secondary roads, and many are badly crested, patched, and have sections that are washboard like. The Z51, in spite of its realtively tolerant ride characteristics, was becoming uncomfortable over too many of the roads I had to drive on. I needed a more compliant suspension system. Also, I grew to hate the Goodyear SC tires that are standard on the Z51 package. They stick well on hard, smooth surfaces, but have poor tread life and add to whatever harshness there is in the Z51 suspension. I didn't want to worry about changing my tires every 15,000 miles. I know many report that they have gotten 20-30,000 out of these tires, but not driving on my roads and under these conditions ... so that doesn't help me one bit.
I've now spent 1,000 miles with my F55 C6. I must say that I am totally impressed. These magnetic shocks are more compliant than the Z51 shocks, but never feel "soft." The difference between Tour and Sport is subtle, but real. I do leave it on Tour for most of my driving,, where it feels a bit softer than my Z51 did. It's as flat as my Z51 through hard corners, although it does exhibit just a bit more dive on hard braking. On the Sport setting, it's almost impossible for me to tell the difference between this and my Z51. Again, this is all based on the F55 with the Z51 sway bars installed.
The steering on my 2009 is a totally different unit, so I can't make any valid comparisons. It's quicker, lighter, and has better feedback but, I believe, that's unrelated to the suspension choice.
The gearing on the Z51 transmission (MN6) is more aggressive than on the F55. I can feel the difference there. The F55 stays in gear longer, before hitting the redline, than the Z51 did. This gives the Z51 MN6 a quicker feel through the first two gears, but by 3rd gear there is really no difference I can feel. Both cars pull strongly, can be moved just by feathering the clutch in first, and can be started in second gear.
Both the F55 and Z51 are superb setups. One is not "better" than the other. The F55 offers excellent handling, excellent ride control, and some really interesting technology. The Z51 offers somewhat sportier feel, definitely has an advantage for track use with its coolers and more aggressive MN6 gearing, but really needs better rubber to make it a complete package.
I loved my Z51, and I feel just as strongly about my F55. GM has done an incredible job with both packages, and both deserve the full respect and admiration of all Corvette owners. Does anyone know where I can buy F55 badges?
09-06-2008, 09:42 AM
#2
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Nicely stated, Stan
09-06-2008, 09:47 AM
#3
Team Owner
As someone who has driven (albeit not owned) all of the suspension packages as well as the Z06 I can only say excellent write-up. Very well done. After my comparisons I chose the F55 and short of buying the Z06 that I so desperately want, I will continue to choose the F55 as long as it is available. It really was a best of both worlds solution for me.
09-06-2008, 09:51 AM
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St. Jude Donor '15
"In honor of jpee"
That would be interesting, Stan: F55 badges. I think it'd be a first. I bet that guy austinmn would do some up for you. Not only would you be the first in the state, prolly (like that word? 
) first in the nation!
As to the writeup, I liked it. I do think with the addition of the Z51 sways you "swayed" the impressions tho. Not by much tho.
I also think that it would be of big benefit to all to have their car's alignment re-done early on. I had mine done at about 2500 miles. My Supercars are now at 12.5K miles. They don't look worn out, or close to it. We will see. I know I'm paying for the slightly added performance level of the Supercars and that's why it's part of the Z51 package.
I would, however, tend to agree with you re rough roads. If you have to travel consistently rough roads, the Z51 may not be ideal. I was thinking of traveling up thru the city streets of the largest northeastern US city, and just couldn't imagine those streets and my car, the Corvette. I'd just finished driving it in a luxo-barge.
It could be the Z51 is less of a compromise and less realistic for some roads/streets/highways. Re highways, I'm thinking specifically of some that I've driven in PA and MI which are ususally in bad shape. My teeth would rattle in the Z51.
Thanks for the comparo.
) first in the nation!As to the writeup, I liked it. I do think with the addition of the Z51 sways you "swayed" the impressions tho. Not by much tho.
I also think that it would be of big benefit to all to have their car's alignment re-done early on. I had mine done at about 2500 miles. My Supercars are now at 12.5K miles. They don't look worn out, or close to it. We will see. I know I'm paying for the slightly added performance level of the Supercars and that's why it's part of the Z51 package.
I would, however, tend to agree with you re rough roads. If you have to travel consistently rough roads, the Z51 may not be ideal. I was thinking of traveling up thru the city streets of the largest northeastern US city, and just couldn't imagine those streets and my car, the Corvette. I'd just finished driving it in a luxo-barge
.It could be the Z51 is less of a compromise and less realistic for some roads/streets/highways. Re highways, I'm thinking specifically of some that I've driven in PA and MI which are ususally in bad shape. My teeth would rattle in the Z51.
Thanks for the comparo.
09-06-2008, 09:52 AM
#6
Le Mans Master
Ya, but tell us how you REALLY feel.
Nice write up.
As far as badges, C6F55 and F55C6 are both available plates in your state.
Nice write up.
As far as badges, C6F55 and F55C6 are both available plates in your state.
09-06-2008, 09:53 AM
#7
Team Owner
09-06-2008, 10:17 AM
#8
Le Mans Master
Thread Starter
As to the writeup, I liked it. I do think with the addition of the Z51 sways you "swayed" the impressions tho. Not by much tho.
I also think that it would be of big benefit to all to have their car's alignment re-done early on. I had mine done at about 2500 miles. My Supercars are now at 12.5K miles. They don't look worn out, or close to it.
I also think that it would be of big benefit to all to have their car's alignment re-done early on. I had mine done at about 2500 miles. My Supercars are now at 12.5K miles. They don't look worn out, or close to it.
The OEM rear sway bar on the F55 is about the width of my pinky, so it isn't too impressive.My 2005 was aligned during the first and third year of ownership and still, the tires wore quickly. I already had the dealer check my 2009 and, sure enough, the left front camber was way out.
So far, I'm very impressed with the flexibility of the F55 system, although we may have to come up with a new name for all the F55's out there with the Z51 bars. Maybe an F51 or Z55? F55Z?
09-06-2008, 10:24 AM
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St. Jude Donor '09 & '12, '14
Z51 is all about track performance. It's not your weekend caddy.
You feel every bump and divot in the road. Steering response is excellent and the car is flat at all times when cornering and braking. In a non Z51 it was alot easier to break the backend loose. This car would take some extreme effort.
I will probably consider F55 on a future car as there is a benefit to ride comfort.
Then again I'd think Z51 is closer to Z06 then F55 - so It's all what you like to feel when driving.
You feel every bump and divot in the road. Steering response is excellent and the car is flat at all times when cornering and braking. In a non Z51 it was alot easier to break the backend loose. This car would take some extreme effort.
I will probably consider F55 on a future car as there is a benefit to ride comfort.
Then again I'd think Z51 is closer to Z06 then F55 - so It's all what you like to feel when driving.
09-06-2008, 10:25 AM
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Thank you for the great write up. I too have the F55 and am very happy.
How do you feel about the F55 stock versus the F55 with the Z51 sway bars? My car is still stock, but this sounds like an interesting change. Do you feel like you gave up anything with the change in sway bars?
How do you feel about the F55 stock versus the F55 with the Z51 sway bars? My car is still stock, but this sounds like an interesting change. Do you feel like you gave up anything with the change in sway bars?
09-06-2008, 10:34 AM
#15
Team Owner
Nice write up except that for total accuracy you'd need remove those Z51 SWAYS.What you're giving us is the Z51 SWAY/F55 COMBO write up,not the STRICTLY F55 one.
09-06-2008, 10:36 AM
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09-06-2008, 10:56 AM
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I have a set of Z-51 sway bars on order for my F55 coupe. After that write up it looks like I made the right decision. I noticed a some body roll when pushing it on some of the on ramps I use daily. As a DD I really appreciate tour mode on the roads in NJ. Sometimes I wish it had "Barcalounger" mode.