Corvector

F45 .vs Z51 - what's the difference ?
Are either of these the same as 'Speed Sensitive Steering" and "Road Sensitive Suspension" on a Cadillac ?
Advantages .vs disadvantages ?
Cost ?
What model years are they / were they Offered on the 'Vettes?

Looking for a nice '99 or '00.

Thanks for your help.

USA Muscle

Z51 is more of a racing suspension and has bigger sway bars and shocks plus a steering cooler.

F45 has the standard sway bars and electronic adjustible shock settings via switch on the console and no steering cooler.

Cost of F45 is about $ 1800 sticker and not sure on the Z51 but it is much less.

Mark 84ltblu

I've got the Z51 on the 98. I prefer it because of the bigger sway bars and firmer feel. I've seen a slew of the C4's with F45 that have developed problems with the sensors and they can get expensive to fix. Neither is the same as the speed sensitive suspension that is now offered on the Vette and Cadillac. Both options have been around since the C4's.

USA Muscle

I think the F45 on C4 did have some problems. I have it on my 01, it came on it and I probably won't have ordered it but it's OK. I haven't heard of too many problems with them on the C5's and, yes, it can be expensive to have work done on them. Also I've heard that the Z51 pre-C5 were very harsh rides and it has been improved for the C5's !
Hope this helps. :thumbs:

MojoRisen

I have the f45 on mine and I like it. I live down in the hills and when I'm going around all the bends I switch to performance and everything gets tighter. It feels like I'm on rails. :cool:

Corvector

Thanks very much for all the input.
Now - the difference between 'Active Handling' and 'Real Time Damping'? Or - are they the Same thing ?
And which is the 'f45' and what's the code for 'Real Time Damping' in the C5's?

BlueDragon

Whoa! Active handling and real time damping are two very different things! and F45 is not real time damping. Real time damping is only available on the new Corvettes 04s? I think. Don't know the option number for it.

Active handling is where the computer senses where you want to go with the car, and the speed and all that and does things with the brakes to get the car where you want to go. It will sense a spin entry for example and will correct for that. Active handling is also not traction control (well almost but not really it is a part of it or can be as TC deals with the acceleration or throttle control).

Real time damping is shocks only, and the car senses a tire striking an object or hole and adjusts the shocks to deal with the uneven road surface and keep the car level and stable and reduce the shock. Go to Delphi.com they have movies and everything to show RTD.

The F45 just sets the shocks to soft, firm, or inbetween and thats it!

Alphabet soup! We have TC, RTD, AH, ABS and RC.

There is virtually an encyclopedia of data on each one of these and how they work and what they do. Start with Delphi, as they are the ones that make the F45 and Real Time Damping systems for GM.

Jer

bhamvett

My window sticker states that the F45 is real time dampening.I enjoy the
F45 suspension.It handles great on the performance setting and has
a nice ride on the touring setting.

USA Muscle

:iagree: I usually keep my the middle 'sport' setting, seems to be the best for overall around town for me ! :thumbs:

BlueDragon

REally?? You must have a very new car, maybe they did put the new RTD under the F45 option number, but I can tell you for sure the old F45s are NOT Real Time Damping under any definition, I have a 98 with F45 and there is now way in hell it is real time by the new fluid system they have.

My F45 is a set it and forget it! ya pick you ride and go!

I would have thought that GM would come up with a new option number for the new RTD (magna ride) systems.

Jer

tblazec5

Hi, I have the F45 and like it, so far no problems. Does anyone know how bigger sway bars work with this suppension? I'd like a little less lean in all settings. Any recomendations?

bhamvett

You are referring to the MAGNETIC SHOCKS.I am looking at my window
sticker and it states"Continously variable real time damping" at 1695.00.
Whatever that means I don't know,but that is straight off the sticker.I
know the F45 does not have the magnetic shocks.That was all new in 2003.

:thumbs:

Bill Dearborn

Corvector,
Active Handling on the Vette is an enhanced version of the Cadillac Stabiltrack system that was introduced in the 95 or 96 model years. Also very similar to the Stabilitrack on the Escalade and Chevy Tahoes and Olds Precision Control System. The differences are in the tuning of the systems. I believe the Caddy system puts the brakes on two wheels on a side to control yaw while the Vette is a little more adept and applies just one brake or a combination. The Vette also has more manual control. The whole system can be turned off or it can be placed into Competitive Mode which leaves Active Handling but disables Traction Control.
Bill

Corvector

Hey - Some Really great information, Guys ! Thanks a lot ! This will make my "Vette Quest" all the more enjoyable - knowing what I'm talking about.

Dandy97

F45 is real time dampening. It really does adjust the shock dampening based on suspension travel feedback. I have the Z51 sway bars on my F45 and IMHO it's the best of both worlds.

C54TIM

I had Z51 Sway bars and Metal end links on my 97 with F45 shocks. It's a big improvement over the base suspension with the F45 shocks. But it is not as good in handling than the Z51 set up. Springs play and important roll in handling, the Z51 suspension has stiffer springs than the base suspension with F45 shocks. The full Z51 set up provides better all around control, and a power steering cooler.
F45 provides a nice ride for every day use, but if you really want better handling and original GM suspension, Z51 is much better.
(T1, now that’s a completely different animal).
:cheers:
Tim

BlueDragon

Yes the magnetic shocks is what I was refering to. I didn't really think of the older F45 as being Real Time Damping as the new system is. The new system is what I call RTD. At least the way I read the Delphi information. The older F45 (which is what I have) does not come anywhere close to what the new system does. yes there is a feed back loop on the older system, but it is not as smart as the new system. (At least I don't think it is)

The only thing stock about my suspension today is that I still have the older F45 shock system. Everything else has been changed. Hotchkiss sway bars and lowered to the max on stock bolts (which stiffens the ride some). I have the bump steer kit installed and a little more agressive suspension alignment. The only really noticeable effect I get from the F45 is that over rough road the lighter settings reduce some of the initial shock of pot holes and bumps but that is about it. The magnetic system does a whole bunch more, and does it faster and better.

Maybe I am being too hard on the older system, but just never looked at it as being as sofisticated as the new magnetic ride system.

Mine is a very early 98 and I do not have active handling, just traction control and the three F45 settings.

I autocross a lot, and the setup I have works great. I think lowering it gives it more of a Z51 type ride and the Hotchkiss bars with the Hoosiers really get her around the track.

I would ditch the F45 shocks for Bilstiens, but too lazy to do all that bypass stuff. Resistors, remove the module and reprogram. Maybe some day. Someone some where said there may be a kit to put magnetic shocks on older cars, but I never saw and outcome.

Jer

Corvector

Thanks Jer - that really says it all. I feel pretty confident about all this suspension stuff - what with all the most excellent feedback I've had. And - no - I don't think I'll try retro-fitting the magnetic shocks to an older model Vette any time soon. Thanks again. :steering:

robl45

If your shopping for a used vette, worrying about F45 is not really an issue, next to none of the corvettes have it anyway. I think the stats say like 5%. I saw a bunch of used corvettes and not one had the electronic suspension.

Rob

Tiger Shark

(Copy and Paste from another post I made in 2001 with comparison between '99 F45 and 2002 Z51 w/ a few recent edits.)
...
Hi. This response is going to be quite long. It's based on a reply I've given in the past on this subject.

I had the F45 in my '99, and when I ordered my 2002, I ordered it with Z51. However, don't let that give you the impression that I didn't like the F45 suspension. F45 was the right suspension for my '99, and the Z51 is the right suspension for my 2002. If I intended to use the 2002 Vette like my '99, I would definitely have ordered F45 again [Edit: or F55 if I were to buy a 2003+]. Let me explain...

I won't try to do a full comparison between the two. Instead, I'll primarily focus on the F45 suspension, since that's the one I have 2 years experience with as a daily driver. I'll also try to provide some insight into the F45 suspension for those that may be interested. Finally, I'll try to share a little information on the differences I've noticed between the two suspensions to date.

The F45 suspension implements electronic (or real-time) damping.
First off, I'd like to point out (to the people that say electronic suspension doesn't have a place in a real sports car) that the Ferrari 360 Modena's suspension system also utilizes electronic damping... and that it's standard equipment on that car. (I'll touch on this again at the bottom.)

Here's an interesting tid-bit of information I recently learned the system could do: (This was taken from the 1999 Corvette Specialist's Data Book.)

quote:
--------------------------------------------------------------------------------
It improves the use of damping to control vehicle roll in turns and adds additional damping to aid wheel control at higher lateral accelerations as well as to control body lift and dive during acceleration and braking.
--------------------------------------------------------------------------------

Also, the second generation Active Handling system now makes use of the F45 suspension (if your car is so equipped) for stability control.

Pretty cool stuff!

F45.. there are three settings/modes: Performance, Sport, and Touring.

There is a difference between the settings.
The performance of the suspension systems requires proper tire inflation (believe me... this one makes a HUGE difference in the way the system works). If the tires are over-inflated, the system feels like it's not even working.

You really notice the difference between Performance and Touring on twisties and bumpy roads. On smooth straight roads, you won't feel that much difference except that it feels a little smoother in Touring. I never used Sport, which is supposed to reproduce the feel of the base suspension. I don't believe in a compromise (medium) setting. For me, it's either performance or comfort with no in-between.

I drove with the system in Performance about 90% of the time.

I normally had it in Performance mode. Especially when I was driving really fast on the highway or on curves, twisties, entrance/exit ramps, etc.. You definitely feel the tight precision on curves. While the stock F45 car might not be as tight as a Z51-equipped car, it comes really close and it's very stable. Plus, you can always replace the factory sway bars with the Z51 bars for a relatively low price if you are so inclined.

Now for the other 10%:

When I went for a long highway cruise, I'd drive in Touring mode. If I was driving on rough streets, I'd put it in Touring mode. Long bridges ride better on Touring mode... especially over those jarring tension joints/spacers. They seemingly disappear on Touring mode.

If I was just trying to unwind and out for a smooth cruise, I'd set it on Touring mode. It does approach the feel of a nice luxury sedan, although it will never equal that feel.

This is an especially nice setting to use when you're driving that special lady out to dinner.

My last car (a sports coupe) had a very tight suspension. After about a year, it started getting really old as far as having to drive it all of the time with that hard suspension for lack of another car. I knew that my first Vette would be a daily driver for most of my ownership, so I really wanted to have the option to choose the way it handled in case I'm just not feeling like a really high performance tight ride all the time.

Back in April 2001, I took a spur-of-the-moment cruise down to Galveston and back. I have to tell you that there's nothing better than the F45 suspension for a 650 mile cruise! [Edit: except perhaps F55!!!]
Very comfortable. I was on the road about 9 1/2 hours total with about a 1 1/2 hour rest in between. (Drove the speed limit down there, but followed some really fast drivers on the way back.)

Now that I've driven with the Z51, I can say that the Z51 would not have been as comfortable, although, it would still have been a nice ride.

Here are the specific reasons as to why I equipped my two Coupes the way I did...

I bought my 1999 Coupe with F45 because I wanted state-of-the-art and I knew this Vette would be my daily driver
I never intended to lower it, change to aftermarket wheels, or race it.
I traded it in at 35980 miles in 2001 after owning the car since it was brand new in April '99.


I ordered my 2002 with Z51 because
a) I won't be driving this Vette the same way as I drove the F45 Vette, meaning I don't intend for this Vette to be my daily driver and I plan on racing this one.
b) I wanted to maximize the out-of-the-box performance potential of the Coupe (stiffer springs, bigger sway bars, etc.)
and
c) I intend to eventually lower this C5, and change to different wheels/tires (w/ different tread pattern/handling characteristics compared to the Goodyear EMTs which are what the F45 suspension is calibrated for).

It really depends on what you're looking for in your Vette. If you have the opportunity to drive one of each type (FE1, F45, Z51 [Edit: , F55]), do it. If you get to drive an F45-equipped car, make sure you drive it not just on the highway, but also on some bridges and rough roads so that you can get a good test of the system's capability. You can trust me that it handles very well on twisties in performance mode. In that setting, the shocks are basically locked down into the highest performance setting possible. So, your selling point on the F45 suspension should be how well you like the dynamic handling characteristics of the other two settings in addition to the performance mode.

The Z51 suspension is going to have better performance handling characteristics from the get-go. That's what it's mission in life is.

You're going to be limited to an extent by what you can easily do with regards to modifying your F45 suspension (depending on how much you want to keep your F45 suspension working at optimum level in all 3 modes of operation).

Once again, if you drive alot, want the option to dynamically alter the ride depending on your mood/circumstances, want the most technologically advanced Corvette suspension choice [pre-2003 F55], and are willing to pay the price... go with the F45 suspension. F45 will give you everything the FE1 (base) does, plus higher performance (than FE1) out of the box and the ability to actually get a smoother ride (by using the Touring mode) than the base suspension. If you want to do alot of modification to the suspension in the future such as major ride height changes, wheel camber changes, etc., you'll probably want to stay away from the F45 suspension unless you're okay with possibly causing the system to not respond at its optimum level in one or more of the three modes. As far as sway bar changes, you can do that without negatively affecting the system. If you decide to replace the shocks, you're basically disabling the F45 suspension, since (at a high level) the shocks and computer are what basically make the system so this would be reason not to go with the F45 option.

One last thing, I just recently noticed in my Corvette Illustrated Buyer's Guide (written by Michael Antonick - author of the Corvette Black Book) that the FX3 (forerunner to the F45) was the STANDARD suspension on the ZR1 in 1989. I find that interesting, since the ZR1 was the "King of the Hill." Again, another example of a real-time damping suspension application in a high-performance sports car.

Okay, now for a few observations of Z51.

Overall body feel: The Z51 Coupe feels much tighter like it's more solid than my F45 Coupe. (Keep in mind I'm comparing an F45 Coupe with 35980 miles to a brand new Z51 Coupe).

Straight-line Highway driving: The Z51 Coupe feels almost the same as the F45 Coupe in Performance mode. It's probably a little bit rougher, but not by much. They both feel like a sports cars!

Curves: I haven't taken the Z51 Coupe to the extreme yet on handling, but I can tell that it does have superior handling to the F45 Coupe in Performance Mode. However, they both feel like you're on rails.

So in wrapping this up, I like both suspensions, but the Z51 is the right suspension for my 2002 Coupe.

The F45 system is very cool. I think many people think it's just a high-dollar "switch", but it's really much more than that. However, if you're Vette is going to be used for pure performance situations, they're nothing better from the factory than the Z51 package (besides the FE4 suspension, of course.)
I'm curious to know if the Corvette engineers plan to implement Delco's new real-time damping system in the future which will be seen on at least one of the new Cadillacs. It uses magnetism instead of conventional solenoids.

[Edit: I originally wrote this reply in 2001 before F55 was announced.]

Hope this helps.
:cheers: