Poor-sha

There's been a fair amount of speculation on the suspension differences between a Z07 equipped car and a regular Z06 but so far I haven't seen anyone publish the details.

I reached out to a friend of mine and was able to get the details directly from the chief suspension engineer for the Corvette. As we already know the suspension on Z07 optioned cars (FE7) is stiffer than that on non-Z07 (FE6) cars. Specifically the springs, shocks, MR calibration, and stabilizer bar bushings are different from FE7 to FE6.

The front spring is 62% higher rate on the FE7 than the FE6.
The rear spring is 22% higher rate on the FE7 than the FE6.

The different stabilizer bar bushing tuning helps get the car the appropriate understeer level.

The MR shocks on the FE7 have a tighter gap which means a higher “passive” curve in addition to a more aggressive MR damping tuning.

I hope this helps folks trying to decide between Z07 or not. This also means that trying to convert between Z06 and Z07 suspensions will require quite a bit of work assuming you can even find a way to update the MR calibration.

Steve Snake Driver

Thanks. Great information to have. Think you are right in suggesting full conversion to Z07 spec would be difficult. Wonder what simpler changes like sways would achieve on non-Z07 cars. The comment about understeer level begs the question, what happens to understeer level if you switch from cup tires to regular Z06 rubber on a Z07 car?

truth.b

Op, Thanks for providing additional information. I don't know much about suspension tuning so in practical everyday terms what do the above two statements mean? Also does this mean that the Z07 equipped cars will naturally have stiffer less compliant rides on normal roads?

Steve Snake Driver

Most of the people with Z07 option that have posted opinions here have said it is not a rough ride in Touring mode. Probably the only way to get an evaluation that would be accurate for you would be to score a ride in one of each, a Z07 equipped car and a non-Z07. Hard to quantify ride quality.

Poor-sha

Most of what I posted is verbatim from the e-mail exchange so the rest below is my interpretation of his comments.

The sways are the same from FE7 to FE6, it's the sway bushing that change.

I don't really expect the change from MPSC2 to PSS to affect the balance - just the overall available grip. As far as the understeer comment I'm amazed at how much goes in to tuning these cars. Little things like the 3rd air dam on the stage 1 cars to reduce rear lift and balance the effect of a smaller splitter in front. At some point they decided the car didn't have enough understeer and a bushing change could get them their desired result without changing the sway bar. It could also be that they wanted more understeer in the more street oriented FE6 - I don't know and am just guessing.

I interpret the comment about the "passive curve" of the MR shocks to mean that there is a smaller range in which the shock will dynamically soften in response to a bump. In effect it acts like a non-MR shock more of the time than the FE6 suspension if that makes sense.

I hate guessing and could go back with follow-up questions but to be honest I'm honored they answered me the first time and agreed to let me disclose this information. I'd like to avoid bugging them if I can

The Z07 is going to have a harsher ride than a Z06 (FE6) that's for sure. I commented in my comparison of a C7 Z51 with MR shocks to my FE6 Z06 how the Z06 in tour was almost as stiff a ride as the Z51 in sport. What is harsh to you is of course entirely subjective just like how loud an exhaust is. I do know that my sensitivity to both noise and harsh ride in a daily driver has changed dramatically in the last 25 years.

Steve Snake Driver

Thanks again for the useful information. I would agree that understeer is the industry default for street cars. Perhaps some of the attendee's at events where there is access to Corvette engineers (Tudor Corvette Corrals, Museum events, etc) can use information like this to ask questions.

jdmdohcpower

I was talked out of getting the z07 by the dealer. When I ordered, (one of the first orders with kerbeck) there is no real info on the z07 differences would be. I was told it would be a harsh ride and ruin the streetability. I can say that I've driven both, mine and a z07 car. I noticed no difference in ride quality. Maybe a few bit in track but not enough to even be sure. With that said I'm really disappointed I passed on the z07. I wish I had the suspension and brake upgrades. And I did some research, it's not possible to upgrade either system due to the tuning, even if you had the parts

SBC_and_a_stick

That is very useful info. Thank you. Makes sense the front is that much stiffer. I can tell the Z07 has very good turn in for a stock car and it's very sharp in transitions. I wouldn't have it any softer.

I drive in track everywhere and lately I'm also defeating all the nannies. I only have one application for tour on my Z07. Freeways where the concrete is laid down in wave like patterns. It makes me dizzy in track mode. Otherwise tour is just wrong. The spring rate is very high for the damping available, very Cadillac like.

dvandentop

thanks for the info Sean should be in a faq at top of forum

b4i4getit

Agree. I hope the mods add this since it is good information that the dealers don't know about.

Katech_Zach

Z07 springs are massive!

RS4EVA

The tuning should be updatable, maybe just not simple, unless the hardware is different between FE7 & FE6. Tadge in fact said at the Road Atlanta press event, they had, just hours before, received some new data from the 'ring testing that they updated the cars on the track with.

I was initially bummed about passing on the Z07 as well. That being said, I think Lawdogg's review at the same track proved the Z06 stage 2 with an"unknown" Firestone alignment is a very potent track day machine. He was within a 5-6 seconds of both Milner and Pobst in Z07 A8s, in much warmer weather.

For not being a pro racer getting paid, I am comfortable with that level of performance. Also having 8k extra will pay pads and tires.

dvandentop

unless you have a gm tech insider i doubt you will be able to just flash the BCM or whatever module houses the mag ride settings with a new download.

RS4EVA

Agreed it might take some special know how, but it is just software.

Greg Quillen

because of constraints i couldnt get the Z07
hoping i can add later.. upgrade suspension.. I track the car ALOT so hopefully.. be nice especially when i put slicks on

Greg Quillen

anyway to upgrade to FE7 afterwards.. ?

Greg Quillen

62% stiffer than Z06 that already stiffer than the stiffer Z51 ..
i feel bad for the people that bought it just to drive on the street with it.. going to be a rough ride lol.. worth it for the road courses though

jdmdohcpower

It's no harsher than standard z06 when in touring

jvp

You won't be able to re-tune the MSRC. All of the other parts and pieces are swappable at potentially great expense.

Greg Quillen

With way stiffer springs it is. Shocks only do so much