Vansteel is now selling a new kit for C4's, and soon, a similar version for C5's and C6's. We (Hardbar) designed the upper clevis, and the lower rear C4 mount and did dyno development on the shocks. Best bang for the buck you can get either in a single or double adjustable. They are 100% each dyno tested, and are 100% made in USA and cost less than the competition.
http://www.vansteel.com/index.cfm?fus ... ProductList&SubGroup=1906
[IMG]http://www.vansteel.com/_custom/partimages/CO-C4-DA-2-400%20copy1.jpg[/IMG]

Wow!

Wow - look like great pieces. But am I misreading this or is it a typo - 2 shocks included in kit?

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No, it is a full car set, 4.

QA1's Gary?

These yes, when you factor in the price point. I would not pretend to tell you that they are as good as my 8700 Penske 3 way's. But they are pretty good, better than most other adjustables on the market. They are mechanically mounted as good as the high end Penskes, they have my clevis mounts, my new lower rear mount, and have Acme threads on the aluminum bodies. I insisted that each and every one be dyno tested, UPSIDE down! Why upside down? These are a twin tube bypass shock and I found that they were not bleeding all the air out when we dyno'ed some samples. If they are not bled as well as a brake, they will cavitate, and really suck upside down (literally). This way, with the knob set in the middle of the range, it is obvious on the dyno if they are good or not. They come with first class Hyperco springs and you can get whatever rate you wish. For a daily driver that does track day duty, this is an excellent setup for $1699 complete with all the mounts.

Stupid question; What's the difference between single and double adjustable besides the obvious that one has double adjustments? Har Har

And on installation it gets rid of the transverse spring, correct? Ride height adjustable or does that make for a harsher ride?

A "double" means that the compression and rebound are independently adjustable. Yes, you get rid of the leaf springs and your ride height and street ride is whatever you wish it to be, and the tool to do that is included!

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Only if you want it too, depends what the spring rate, and what the shock adjustment is. You can get any spring rate you want from Hyperco, they make them in 50 lb increments, 600, 650 etc.
Hyperco are the best springs out there, all the racers run them from indy cars to us amatures.

I don't have the money to do this now, but I have considered coil overs for a couple of reasons. First, I'd like to get a better handling car for street and autocross events, and second to lower the car and get rid of the transverse spring.
However, I'd like to achieve this without sacrificing ride. Is this possible?

Yes!

Another Q - do these require modifying/cutting the front shock tower as some kits do?

Matthew

Doubles are the way to go.

Compression adjustment is for the street
Rebound for the track.
You can also go from street to drag.
They're the way to go if you want to be serious.

Someone can put your dual rate coilovers on these if you want right?

Here's some good threads on adjustment
http://sccaforums.com/forums/1/363190/ShowThread.aspx#363190

http://sccaforums.com/forums/2/363966/ShowThread.aspx#363966

Is it possible to set them hard enough you wouldn't need a sway bar?

That's what I'm thinking.

I worked at a race shop that ran their track cars w/o them.

I'll let you know how it works out.

I though the whole point of sway bars was to allow you to run more compliant springs.

I'm not sure why you would want to reduce anti-sway, stiff springs would ruin the car everywhere else on the track.

Because a sway bar make an independent suspension, well, less independent.

I know how one place did it, I'm working with Gary on it.

This is where I need to keep quite till things are released.

Sounds good! I'd love to hear more. I'm addicted to taking weight out of the car. Those are out of my budget for now but long term I would like them. If this new SR combo holds together awhile I'll have some spare cash.

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Don, what do you have against leaf springs? Coil-overs do not, by themselves, improve handling. They simply allow you to more accurately adjust things like corner weights and rake in your vehicle.

You can make a leaf spring car handle just as well, in fact, less than half of the C4 and C5 race cars I run with have coil-over suspensions. And the ones that have coilovers run $8000 remote resivoir set-ups - of course Gary supplied the system on Ken's car, who I think now has the most track records in NASA Great Lakes / Midwest.

These are sweet shocks, don't get me wrong, but waaaay overkill for a street car.

As as I know, no one makes a dual rate or progressive rate leaf spring.

Which is why they really make a sweet street setup as well as racing.

Get the QA1'a and some of Gary's springs for the cost of new shocks and leafs.

Well, a couple of things, or more! Yes, I agree technically that a leaf should be can be as good, but with a C4 you have:
1) No front height adjuster on the OE leaf and it is a high friction setup anyway.
2) The newest one is 13 years old so if OE, it is time for shocks and springs anyway.
3) Tires have changed alot, so new spring and damper rates are probably in order.

S0, for $1699, you get a big upgrade that will dramatically update a 20 year old car. That price includes the proper clevis mounts and the new CNC lower rear mount that nobody else has (available separately). Those cantilevered pins can and do bend even without coilovers. I think it is a pretty damn good deal for the money.