When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Thanks for the part numbers. If you do get the spring rates, please share.
@JRRZR1 Got the Z06 rates from Speedway. Higher than I expected and certainly way more than the advertised 30% over Z51 rates. As a sidebar, I got a Z06 front sway bar,, looks to be smaller than base sway bar. I have no idea about the rates though. Z06 uses base car rear bar as well.
We were mislead by most publications of the z06 stiffness related to the z51. Those numbers were actually ride frequency increases which scales with the square root of lumped effective stiffness. Here are numbers measured by paragon performance:
We were mislead by most publications of the z06 stiffness related to the z51. Those numbers were actually ride frequency increases which scales with the square root of lumped effective stiffness. Here are numbers measured by paragon performance:
You sir are correct. For some reason a read spring rate. That said, I saw those Paragon numbers and wondered why the difference in spring rates as compared to the Speedway numbers. I wonder if the Paragon rates are at a specific number of inches?
'The Z06 also has stiffer springs with a 35 percent higher ride frequency, which may sound like a lot, but Holder says Chevy was able to use stiffer springs without compromising ride quality thanks to some of the unique characteristics of the mid-engine platform.'
You sir are correct. For some reason a read spring rate. That said, I saw those Paragon numbers and wondered why the difference in spring rates as compared to the Speedway numbers.
'The Z06 also has stiffer springs with a 35 percent higher ride frequency, which may sound like a lot, but Holder says Chevy was able to use stiffer springs without compromising ride quality thanks to some of the unique characteristics of the mid-engine platform.'
I think the difference is simply that they are variable rate springs and they took measurements at different points or maybe one did an average and the other did a single point? Just speculating.
I think the difference is simply that they are variable rate springs and they took measurements at different points or maybe one did an average and the other did a single point? Just speculating.
I wondered if they'd be so kind to comment a bit?? I'd like to know. @paragoncorvette
We were mislead by most publications of the z06 stiffness related to the z51. Those numbers were actually ride frequency increases which scales with the square root of lumped effective stiffness. Here are numbers measured by paragon performance:
I know this is up on their website, but I find it very hard to believe. The base C8 is 180 lb/in ft and 217 lb/in rear. The Z51 is 226 lb/in ft and 263 lb/in rear. The Z06, can it really be 3 times the spring rate in front and then a significantly lower rate in the rear? A higher rear rate is very common in mid engine cars. Something seems not correct.
I know this is up on their website, but I find it very hard to believe. The base C8 is 180 lb/in ft and 217 lb/in rear. The Z51 is 226 lb/in ft and 263 lb/in rear. The Z06, can it really be 3 times the spring rate in front and then a significantly lower rate in the rear? A higher rear rate is very common in mid engine cars. Something seems not correct.
My guess is they are using active damping to compensate for the lower stiffness during certain compression events (assuming those stiffness numbers are correct). I don't know what those events might be, but I've done a lot impedance control in robots and you can certainly get an active damper to act like a spring during compression by making the damping rate a function of position and velocity of the damper if you've got the bandwidth and control authority. I don't know if those dampers are capable though.
My guess is they are using active damping to compensate for the lower stiffness during certain compression events (assuming those stiffness numbers are correct). I don't know what those events might be, but I've done a lot impedance control in robots and you can certainly get an active damper to act like a spring during compression by making the damping rate a function of position and velocity of the damper if you've got the bandwidth and control authority. I don't know if those dampers are capable though.
After a few phone calls and some time on google with what others posted here, this is what I learned. The Paragon numbers for Z06 seem to be a little high compared to the posted numbers from the Speedway measurements. Hyperco actually made the measurements for Paragon, and they certainly know what they are doing – they are a leading international supplier of racing springs.
The Z51 numbers posted on the Paragon web site agree pretty well with the OEM numbers. OEM Z51 are 226 lb ft and 263 lb rear. Paragon is 300 lb ft and 270-350 lb rear and claim to be 30 % stiffer spring rates than OEM. So pretty reasonable agreement considering they are progressive.
Josh Holder of GM claimed 30 % higher ride frequency for Z06 and 8 % more for Z07. Many web sites have claimed 30 % stiffer spring rates, but Josh Holder specifically said ride rates and this seems to definitely be the case. As mentioned above ride frequency scales as the square root of the spring rate (actually wheel rate). Assuming motion ratios and sprung corner weights are largely unchanged, a 30 % stiffer ride for the Z06 vs Z51 would yield around a 400 lb front spring and 460 lb/in rear. The reported values of 700 lb front and 443 lb rear by Paragon and 655 lb front and 445 lb rear by Speedway say that the rear is around 30 % stiffer ride frequency but the front spring rate changed by much more.
My guess is they did say they kept the same rear bar but went to a softer front bar – maybe a lot softer? Also, new wheels and perhaps offsets may have changed the motion ratios. It would be great if someone knew or estimated the motion ratios, then we could compare wheel rates and ride rates, but I guess you need accurate info on the sway bars as well.
After a few phone calls and some time on google with what others posted here, this is what I learned. The Paragon numbers for Z06 seem to be a little high compared to the posted numbers from the Speedway measurements. Hyperco actually made the measurements for Paragon, and they certainly know what they are doing – they are a leading international supplier of racing springs.
The Z51 numbers posted on the Paragon web site agree pretty well with the OEM numbers. OEM Z51 are 226 lb ft and 263 lb rear. Paragon is 300 lb ft and 270-350 lb rear and claim to be 30 % stiffer spring rates than OEM. So pretty reasonable agreement considering they are progressive.
Josh Holder of GM claimed 30 % higher ride frequency for Z06 and 8 % more for Z07. Many web sites have claimed 30 % stiffer spring rates, but Josh Holder specifically said ride rates and this seems to definitely be the case. As mentioned above ride frequency scales as the square root of the spring rate (actually wheel rate). Assuming motion ratios and sprung corner weights are largely unchanged, a 30 % stiffer ride for the Z06 vs Z51 would yield around a 400 lb front spring and 460 lb/in rear. The reported values of 700 lb front and 443 lb rear by Paragon and 655 lb front and 445 lb rear by Speedway say that the rear is around 30 % stiffer ride frequency but the front spring rate changed by much more.
My guess is they did say they kept the same rear bar but went to a softer front bar – maybe a lot softer? Also, new wheels and perhaps offsets may have changed the motion ratios. It would be great if someone knew or estimated the motion ratios, then we could compare wheel rates and ride rates, but I guess you need accurate info on the sway bars as well.
I was able to find pretty good data on motion ratios for a Z51 which I believe are the same for Z06. The motion ration data is for both the springs and sway bars. Then I found sway bar rate data from AFE for a Z51. This turned out to be very interesting. I am not an expert in this, but I believe the following is done correctly and takes account of the sway bars and spring rates to get the actual wheel rates and ride frequencies.
Front motion ratio is 1/0.6 = 1.66 and MR2 = 2.77. This is approximate but based on direct measurements (off the web) of the front lower wishbone configuration. The motion ratio includes a reduction for the shock mount to upright offset and a reduction for the shock/spring mounting angle. The sway bar motion ration is more like 2 and MR2 = 4.
Rear motion ratio is 1/0.8=1.25 and MR2 = 1.56. The rear sway bar motion ratio is 1. So the front and rear motion ratios are very different and the sway bar differences even larger. The rear motion ratio is 1 for the shock/spring to upright offset because the shock mounts directly on the rear upright, but then you need to account for the significant tilt of the spring.
The front sway bar is 480 lb/in (for a Z51) but the wheel rate for the sway bar is 120 lb/in and the total front wheel rate is about 365 lb/in for Z06 (using the Z51 front bar values but this is incorrect because we have been told they used a softer front bar with the Z06) vs 201 lb/in for the Z51.
The rear sway bar rate is 300 lb/in and the wheel rate is 300 lb/in. The total rear wheel rate is 583 lb/in for a base Z06 vs 468 lb/in for a Z51.
The above can be used to estimate the ride frequencies. The interesting thing is how big the bars are and how much they affect the actual wheel rates and therefore ride frequencies when the car rolls in a corner and when an individual corner hits a bump. On my formula race car I believe the sway bar rates are much smaller relative to the spring rates. So the effects from the bars preventing roll and stabilizing the platform in a corner vs the smoothness in ride feeling vs the lack of effect bars have on forward/rear weight transfer is interesting and something the Corvette engineers seem to have thought a lot about.
The reported values of 700 lb front and 443 lb rear by Paragon and 655 lb front and 445 lb rear by Speedway say that the rear is around 30 % stiffer ride frequency but the front spring rate changed by much more.
My guess is they did say they kept the same rear bar but went to a softer front bar – maybe a lot softer? Also, new wheels and perhaps offsets may have changed the motion ratios. It would be great if someone knew or estimated the motion ratios, then we could compare wheel rates and ride rates, but I guess you need accurate info on the sway bars as well.
The Speedway numbers at 2" of compression look a lot closer to the Paragon/Hyerco numbers for sure. I sure wish I knew how those Paragon number came about. I did send Paragon an email but there response was basically the chart as posted here so no closer to knowing how those number came about.
The bars I've researched, rear bar on the Z06 is the same that's on the base C8, not the larger Z51 bar. Z51 uses the base bar in front. I ordered and received a Z06 front bar as well. The Z06 front bar is 1" in diameter. Based on my research the base front bar is 30MM so I'm assuming the Z06 front bar is softer. Haven't swapped them yet but willl.
Lastly, I did a bunch of reading yesterday and got the feeling that sway bars didn't matter for ride frequencies. Is that not the case?
The Speedway numbers at 2" of compression look a lot closer to the Paragon/Hyerco numbers for sure. I sure wish I knew how those Paragon number came about. I did send Paragon an email but there response was basically the chart as posted here so no closer to knowing how those number came about.
The bars I've researched, rear bar on the Z06 is the same that's on the base C8, not the larger Z51 bar. Z51 uses the base bar in front. I ordered and received a Z06 front bar as well. The Z06 front bar is 1" in diameter. Based on my research the base front bar is 30MM so I'm assuming the Z06 front bar is softer. Haven't swapped them yet but willl.
Lastly, I did a bunch of reading yesterday and got the feeling that sway bars didn't matter for ride frequencies. Is that not the case?
I have the Z07 springs on my Z51 and my butt dyno says they are 35% stiffer than the Z51 coils. They were shorter than the Z51 coils as I assume they don’t compress as much due to the stiffness. They are a little more than a 1/8 thicker in diameter than the stock coils. I did not want to go with the Paragon because they lower it a full inch, which I found was too low, I was scraping every driveway when I tried it that low.
The big tricks is going to be flashing the Suspension Control Module with the Z07 software, I believe the modules are the same part number. But I believe it talks to the cars CAN software to confirm the vin, not sure how to get over this issue?
This is just my personal experience for what it’s worth.
The Speedway numbers at 2" of compression look a lot closer to the Paragon/Hyerco numbers for sure. I sure wish I knew how those Paragon number came about. I did send Paragon an email but there response was basically the chart as posted here so no closer to knowing how those number came about.
Paragon told me Hyperco made all of the spring measurements. Hyperco said they are progressive and confirmed they made the measurements and made the springs exclusively for Paragon. It might be hard to get the actual set of values from Hyperco- and from your Speedway values it sure looks like they reported about 2 inch values.
Originally Posted by gtpvette
The bars I've researched, rear bar on the Z06 is the same that's on the base C8, not the larger Z51 bar. Z51 uses the base bar in front. I ordered and received a Z06 front bar as well. The Z06 front bar is 1" in diameter. Based on my research the base front bar is 30MM so I'm assuming the Z06 front bar is softer. Haven't swapped them yet but willl.
It would be great if you could get the actual rates for the Z06 bars.
Originally Posted by gtpvette
Lastly, I did a bunch of reading yesterday and got the feeling that sway bars didn't matter for ride frequencies. Is that not the case?
I think there is some misinformation on the web when you look at this. The ride rate when both wheels on an axle move together is determined by the spring rates. When only one wheel is moving, then clearly the sway bar is being activated and therefore contributes to the wheel rate and ride rate. Going over curbing at a racetrack significantly effects one side of the car and therefore will have a big effect from the sway bar on the "instantaneous" wheel rate and ride frequency. A lot of imperfections, transitions, large bumps on the street effect both wheels similarly and then the instantaneous wheel rates and ride frequencies are mostly due to the springs. Mid corner both the sway bars and springs contribute. So a lot of the feel on a street is more spring driven and bars can be useful at making the ride feel softer in a lot of circumstances yet still work well to control vehicle roll. Because sway bars only activate some of the time, dampers are usually tuned more for the springs then the combined system.
12-12-2023, 11:39 AM
