your guess on the z/28 1/4 times and mph

[2cnd chance]

Originally Posted by Bhobbs

Then that's my guess.

Good guess.

[Fraxum]

3,750lbs, 450-60 at the wheels, having to shift into 4th, I would say 12.1-2 with a great driver and air. 11.9 with DRs and some luck. Plenty of lightly cammed LS3s near this weight with this RWHP running slower than this.

Driver, practice in the car, and DA are the keys. The other night at Atco there was a ZL1 struggling to get into the 12s. I have seen GT500s in a similar struggle.

[z28chuck]

I only have 411hp at the wheels and I can push these times...I think you're calculations are a little off...

A fellow ECC member has 410 to the wheels / stock gears and turned 4 different runs @ 11.9 in 1 night.

Sorry, but your guess is waaay wrong.

Originally Posted by Fraxum

3,750lbs, 450-60 at the wheels, having to shift into 4th, I would say 12.1-2 with a great driver and air. 11.9 with DRs and some luck. Plenty of lightly cammed LS3s near this weight with this RWHP running slower than this.

Driver, practice in the car, and DA are the keys. The other night at Atco there was a ZL1 struggling to get into the 12s. I have seen GT500s in a similar struggle.

[Fraxum]

Originally Posted by z28chuck

I only have 411hp at the wheels and I can push these times...I think you're calculations are a little off...

A fellow ECC member has 410 to the wheels / stock gears and turned 4 different runs @ 11.9 in 1 night.

Sorry, but your guess is waaay wrong.

We shall see. We are all guessing. I am not saying there are not 5th gen exceptions with great driving and careful drag track mods with a lot of time at the track. DRs, gears, skinnies, shift lights, etc. But we are talking stock Z/28. Most of the faster 5th gens it seems to me are automatics. We might be a year away from knowing about the Z/28.

Also keep in mind the Z/28 will not be set up for Drag Racing optimal weight transfer with alignment, sway bar resistance, and shock valving. And if the Z/28 has the same basic 1LE suspension, wheel hop may also be a problem. Which makes me wonder what axles and diff the Z/28 will be using. The 1LE set up is what should be standard on all LS3s. But I see a thread already where a 1LE has smoked its axle or diff. Isn't the ZL1 diff too heavy?

I hope to race a Z/28 some day. But I will lose. I am where you are at the wheels (400+) and can't get past 12.8@112 on stock tires. I need the good driver mod. Can you show me what my car can really do?

Oh and I was supposed to guess MPH too so: 12.1 @ 114.

[Norm Peterson]

Without track prep . . .

Originally Posted by tangosix

12.4 ET

This, at ~115 mph with 500 HP and 500 ft-lbs

Originally Posted by Bhobbs

What would a 3,760 lb, 540 HP car run in the 1/4 mile?

I'm thinking 12.1 at around 118.


Norm

[OldScoolCamaro]

Originally Posted by JusticePete

You read correctly!

..between the lines perhaps, but for those who may not be able to distinguish the lingo of it all would you be able to clarify that further Pete? It's stated they are fully adjustable DSSV dampers, now,...are they being fully adjusted by Chevy engineers using algorythyms with an electronic ECM based system that can not be altered or adjusted by the owner, electronically adjustible by a switch as in the ZL1 MRC, or are they mechanically adjustable?

[JusticePete]

Originally Posted by OldScoolCamaro

..between the lines perhaps, but for those who may not be able to distinguish the lingo of it all would you be able to clarify that further Pete? It's stated they are fully adjustable DSSV dampers, now,...are they being fully adjusted by Chevy engineers using algorythyms with an electronic ECM based system that can not be altered or adjusted by the owner, electronically adjustible by a switch as in the ZL1 MRC, or are they mechanically adjustable?

DSSV dampers calibrated by Chevy engineers.

The Camaro Z/28 is the one of the first production cars fitted with race-proven, spool-valve dampers. Compared to a conventional damper that offers only two-way tuning for bump and rebound, a spool-valve damper allows four-way adjustment to precisely tune both bump and rebound settings for high-speed and low-speed wheel motions. The wider tuning range allowed engineers to dramatically increase the damper stiffness on the Camaro Z/28 without a significant change in ride quality.

[OldScoolCamaro]

Originally Posted by JusticePete

DSSV dampers calibrated by Chevy engineers.

The Camaro Z/28 is the one of the first production cars fitted with race-proven, spool-valve dampers. Compared to a conventional damper that offers only two-way tuning for bump and rebound, a spool-valve damper allows four-way adjustment to precisely tune both bump and rebound settings for high-speed and low-speed wheel motions. The wider tuning range allowed engineers to dramatically increase the damper stiffness on the Camaro Z/28 without a significant change in ride quality.

....exactly. That's the press info, but....heres my question. How is the adjustablity accomplished and by whom? Sometimes the obvious flies right past me and over my head....<a bit daft perhaps I am???> GM pre-calibrates the DSSV dampers, and there is no adjustabilty by the owner I take it? Thank you once again for all your support and information, your are truely a foremost asset for us Camaro enthusiaists!

[JusticePete]

Originally Posted by OldScoolCamaro

....exactly. That's the press info, but....heres my question. How is the adjustablity accomplished and by whom? Sometimes the obvious flies right past me and over my head....<a bit daft perhaps I am???> GM pre-calibrates the DSSV dampers, and there is no adjustabilty by the owner I take it? Thank you once again for all your support and information, your are truely a foremost asset for us Camaro enthusiaists!

GM engineers pick the valve rates. The damper is built. You have zero ability to change anything. The DSSV design allows a greater range of tuning between the high speed and low speed circuits.

Low-Speed Control

Low-speed shock movement is defined as shaft speeds that are between 1 to 10 inches of movement per second. These lower speeds are mostly associated with suspension movement caused by chassis roll and possibly chassis dive at turn entry where the sudden loss of speed is moderate. The low-speed control dictates much of the handling side of the shock design and racetrack performance gains related solely to chassis balance and weight redistribution.

Each shock has a piston mounted on the end of the shaft, and one or more small holes in the piston allow fluid inside of the shock to flow from one side of the piston to the other. The size of the "bleed" holes regulate how quickly the fluid will flow back and forth, and that is how the different levels of resistance are created for low-speed control. All low-speed adjustments on shocks built with that adjustment capability work by changing the size of the bleed opening to control the amount of flow.

High-speed Control

As we experience the greater velocities of shaft movement, we go into what is called high-speed control with shaft velocities from 10 to 25 inches of movement per second. The types of suspension movement that cause the higher shaft speeds in our shocks are: 1. bumps or holes in the racing surface (creating very high shaft speeds); 2. the driver stabbing the brakes on entry and hard on the throttle on exit; or 3. a sudden change in banking angle such as transitioning from banking onto the apron of the racetrack.

The piston mounted to the end of the shaft also contains a valving mechanism that allows the fluid to flow through slots designed into the piston. These valves consist of disks that open as the pressure increases due to more rapid shaft movement in either compression or rebound. These disks are used to control the damping rate associated with higher shaft speeds.

Shock Absorber Tech from Circle Track Magazine

The tech is cool, but not a game changer, IMO.

[Norm Peterson]

Here's a few comparative graphs that may give a little wider understanding. As far as we're concerned here, it's the shapes of the plotted curves that matter, not the force values or the application (car) that they were taken from.

"Progressive" damping (purple lines on page 2) - will make up for poorish body control damping with a harsh ride. Linear (which as shown in red is actually mildly digressive) at least gives you a bit more body control.

The slope of a line at any given point is another indication of how much damping exists, separate from the vertical axis force value.


Pete - Bob Bolles has to be talking from a pure race car perspective. Just about every other reference I've seen that even mentions high vs low speed damping talks about the low speed range of interest being about 3 ips. Even 50% critical damping (for grip/handling) at 10 ips sounds just plain harsh from the point of view of anything reasonably streetable. On the linked graphs, 10 ips is about 70% of the way out to the maximum horizontal scale of 35 cm/sec and long after the high speed circuits have opened.


Norm

[JusticePete]

Originally Posted by Norm Peterson

Here's a few comparative graphs that may give a little wider understanding. As far as we're concerned here, it's the shapes of the plotted curves that matter, not the force values or the application (car) that they were taken from.

"Progressive" damping (purple lines on page 2) - will make up for poorish body control damping with a harsh ride. Linear (which as shown in red is actually mildly digressive) at least gives you a bit more body control.

The slope of a line at any given point is another indication of how much damping exists, separate from the vertical axis force value.


Pete - Bob Bolles has to be talking from a pure race car perspective. Just about every other reference I've seen that even mentions high vs low speed damping talks about the low speed range of interest being about 3 ips. Even 50% critical damping (for grip/handling) at 10 ips sounds just plain harsh from the point of view of anything reasonably streetable. On the linked graphs, 10 ips is about 70% of the way out to the maximum horizontal scale of 35 cm/sec and long after the high speed circuits have opened.


Norm

Circle track race cars to be exact. I use CT articles because they are clear and concise, not for a specific vehicle or value.

[OldScoolCamaro]

^..thanks Pete for taking the time to share that DSSV info with us, very much appreciated. I have a better handle on how it functions and how they may intend to set it up. Thanks Norm as well...

[ParisTNDude]

Yeah, the Z28 is more prone to track use, but certainly the first magazine tests will be on the drag strip and skid pad. For the road course guys, I wonder if they think there are no quarter mile long stretches on their favorite road course? I would certainly want to know how fast it could make the trip. Besides, the 1/4 mile magazine tests are the standard (right or wrong) for determining a new cars power output. I think the Z28 will do well in the 1/4 mile, certainly would put a grin on any stock SS guys face!

I'm guessing close to 12.0@118

[Norm Peterson]

There are plenty of 1/8, 1/4, and even 1/2 mile stretches in the road course world.

But we tend to hit them at anywhere from a 40-roll on up, beginning with some gear other than 1st, so standing start times and differences between them tend to lose a lot of meaning.


Norm