cv67

Wow, what a sweet looking setup, wish I had the coin .

ghoffman

The list is long, but the valving is whatever you want and not all vendors use the same thing. They are all CNC billet construction and individually tested (each) When we were at Penske last month for additional training, they told us that 1/2 of a thousand of an inch (.0005) tolerance on the piston can cause a 20 pound variation in force. The precision is fantastic, and if there is a unwanted variation, it is taken care of before it leaves the shop. When you consider that, what do you think a mass produced shock will do? They are 100% made is USA (Reading, PA), and parts are a one day Fed-Ex away. We have a new Roherig shock dyno, along with a mill and a lathe to make adapters if nescssary for testing, and offer full rebuild/revalve services, so if there is something you don't like, it is easily changed. We also have in stock a large inventory of Hyperco springs and the poly spring couplers (that we make ourselves). There are also many piston types, from specific drag racing pistons, to velocity dependent pistons, linear, digressive and so on, so even the so called non adjustables can be tuned to whatever the customer's needs are. How do you decide? That is what you are paying us to help with! BTW, the other half of this is Richard Strout at LEMD.com. Richard has many many years in this game, from driving in the old Can-AM series, factory Cobras, and was the shock guy for some VERY big name NASCAR and ALMS teams recently. His "guesses" are closer that most others' tests, trust me on that!
We have been running the dual rate on the street and track for about a 1/2 year now on a C6ZO6 and the ride is compliant, smooth, but is very hard to bottom. Our package starts out at about 350-370 lbs/in and at full bump is around 800 lbs/in. If there is a specific application you want we can do that too! Please call with any additional questions or comments.
Gary Hoffman
Hardbarusa.com
603-682-8073

Leec4ce

Brain your post real has my head spinning

If I may would like your (and any other forum members) opinion. After months of research for and the lack of replacement shocks for my car I was beginning to lean toads a coilover system for the car and just want to get some insight on the Penske coilovers.

My C4 is a 1996 CE with the F45 suspension package with the wonderful can’t find anywhere replacement shocks. With the shocks having 53K I believe it is time to do something to bring the car’s suspension back into good operating condition maybe even to a track able condition.

This Penske package you are describing and Hardbar is offering looks like the package that I should be looking to invest my time and effort into to upgrading my suspension. In reading the post there doesn’t seem to be any issues with the Penske Coilovers fitting on the car but I know something will have to be done to the electronics of the f45 system to keep from throwing a code or two. Any Ideas?

I am not looking to be the fastest C4 out on the track just some track day fun along with keeping the car in street able condition.

Thanks again for the thoughts

BrianCunningham

I'm not an F45 or FX3 expert hopefully someone with more knowledge will chime in. But I do know it can be diabled.

Here's what I found so far:

http://forums.corvettefever.com/70/1...ble/index.html

Sounds easy enough to try on your own, and it won't cost you anything or do any damage.

Just make sure the ABS still works afterwards.

95wht6spd

I think it just won't work anylonger, and you can have it programed out so the light won't come on.

If I didn't have the FX3 system and re-valved shocks, I would probably have swithced to coilovers, and still may and just not use the FX3 system (although I like it). My ride is very stiff and firm now, not good for bumps, I would love a system that is soft and smooth, but yet very firm and wouldn't move much and would not let it bottom out.

bill mcdonald

I just unplugged my fx3 and pulled the light out of the DIC.
by unplug the fx3, I just unplugged the controllers on the tops of the shocks. I acrtually removed the actuators and set the shock to full stiff.

that system is a joke.

I have rode in a C4 with the penske coil over single adjustables and it was sweet. is sailed over some really rough road onto the freeway curve ramp under a lot of throttle comming from a LPE 383.

I have been planning ever since. this is a pretty good deal considering I had a lead on just each SA penske shocks at $500.00

VenkmanP

Aren't the QA1s like this? Can your springs be used with QA1s?

C4forlife

and decided on buying the penske 8300 series remote resevoir with titanium springs. have plenty of support from the engineers currently working with GM and they are really helping out getting a package deal together.

ghoffman

No, they are not body up, and they are a different design. I cannot comment on other brands, by policy. Having said that, I think the dual rate coils can PROBABLY be used. Here is a customer review of our setup (C4 is available as well):
http://forums.corvetteforum.com/show....php?t=1835823

bill mcdonald

Brian, I just remembered something about these shocks. do the SA come in the right length for a lowered c4.

I was going to go for it then I heard the DA might have the right length for a lowered c4.

BrianCunningham

He can get whatever length you need, just make sure you tell him when you order.

BrianCunningham

I just got this email from Gary:

95wht6spd

What's the benefit of aluminum over steel, besides weight?
I would think the steel are stronger, less likely to be damaged.

CentralCoaster

And what is the point of dual springs?

Dual springs ≠ Dual rate, unless coil bind occurs on one of the springs.

Keffective = 1/(1/K1 + 1/K2) etc. Please correct me if I'm wrong. And tell my why I'd even want dual rate instead of progressive rate.

95wht6spd

I think they are using the terms interchangably.
I think they are progessive, soft at first and then get very stiff after compressed past a certain point.

BrianCunningham

The aluminum ones have the bodies threaded, which makes it easy to go to coilovers down the road. The steel ones would require a sleeve and a snap ring, this of course dictates a large diameter spring. But if you're not going to coilovers, that's not an issue.

With progressive rate springs, which is what I wanted initially, you can only vary the coil spacing, with dual springs you can vary the diameter (thickness of the metal that is) as well. It makes setting this up like pre-rate, and the cross-over point a lot easier. It's more practicle in other words.

The coil couple has a side benefit of keeping the spring from slapping the shock. The springs in standard coilovers actually hit the shock from time to time.



EDIT
This is a progressive rate spring for comparison

What happens if you like the top rate and not the bottom?
With a progressive, you need to buy a new spring hoping they stock the rate you want.
With dual springs, you just go and get a standard off the shelf spring.

But if you want if, he can still supply it.

BrianCunningham

Yes, they're doing the same thing, the duals just easier to tune.

CentralCoaster

Progressive springs don't have a fixed rate.

I don't see those dual springs getting any coil bind anytime soon.

No coil bind = fixed rate. I don't care if you're putting 6 springs in series. What's the catch? Who's getting fooled?

I don't claim to know more than a suspension engineer, but I think I know more than the average sucker.

BrianCunningham

Like I said, he'll sell you progressive rate springs if you want.

No reason to go pulling your hair out.




What's missing from that equation?



Time.


It has to do with how fast the load is applied.

The softer springs react faster the loads than the stronger ones do.

In effect the it's taken out of the equation for quick reactions, like small disturbences on the road surface.

The large spring come into play during longer events, like going through a turn.

There's no catch, or gimick, just scientific analysis.


Gary's an engineer, and so is the man helping him out.

ghoffman

The shorter spring does indeed coil bind after some distance. In developing this system, there are at least 6 things to consider. You have to get the initial rate correct, the crossover point from one to the other, the preload, the ride height, and final rate. Then you have to consider the motion ratios of each end of the car and that is very different in C4's, C5's and C6's. In rough terms, the first spring has about 3 inches of travel, and there is about 1 inch of preload, 1 inch of droop to ride height and that gives you about 1 inch of shock travel before the transfer to the final rate. Then, you have to have a velocity sensitive valving in the damper. We are well aware of the series spring equation but that only gets you about 1/3 way there. You want a seamless transfer from both to the primary spring. We are working with Hyperco and are well aware of progressive rate springs, and can get anything we want, however this is a much more flexible way of doing it and it has benefits that are non-intuitive, such as the coil coupler preventing side motion, and ease of adjustability, and no real downside.
We have every tool available (Solidworks 2007 and 2008 Pro, Cosmos, Working Model, Roherig shock dyno, spring testers, etc) and 20 plus years of structural dynamics experience, and even with those tools, it took many, many hours of tedious iterations to get it correct. This goes into the category of 1 test is worth 100 opinions, and this has required alot more than one test. I have had the entire suspension on and off so many times and have done 11 track days testing as well as several thousand street miles on this system.