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Converting C4 bilstein shocks to coilover?

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Old Jun 2, 2009 | 08:34 PM
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Default Converting C4 bilstein shocks to coilover?

Is this the kit that is being used to convert the stock C4 bilstein shocks to coilover?
I would imagine you need a slot machined in the shock to accept the lock ring?
Who can do that?
What size and length springs are used?
Where would i get them?http://store.summitracing.com/egnsea...5&autoview=sku

Thanks fellas!!
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Old Jun 3, 2009 | 01:08 AM
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That is the kit I used on my C4. You can send them to bilstein and they will do it for you, or you can probably contact them and they can tell you how to machine the groove and could be done by a local machine shop.
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Old Jun 3, 2009 | 02:42 AM
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Originally Posted by Vector Vette
That is the kit I used on my C4. You can send them to bilstein and they will do it for you, or you can probably contact them and they can tell you how to machine the groove and could be done by a local machine shop.
Did you send yours to Bilstein? If so, what did they charge you and how long was the turn around time?
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Old Jun 3, 2009 | 08:37 AM
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Originally Posted by Vector Vette
That is the kit I used on my C4. You can send them to bilstein and they will do it for you, or you can probably contact them and they can tell you how to machine the groove and could be done by a local machine shop.
Thanks for the info!!
I see on bilsteins site under services,they list a price of $10 each for putting the groves in.Not sure if that is rite or not.

What springs did you use?
What length and rate?
Thanks again!!
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Old Jun 3, 2009 | 08:55 AM
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I would call Randy at DRM if I were you. They have everything you will need.
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Old Jun 3, 2009 | 09:10 AM
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Originally Posted by ghoffman
I would call Randy at DRM if I were you. They have everything you will need.
Randy makes some nice parts,going to buy some of the other stuff i need from him for sure!
On this,im looking to see how its done.

Last edited by 87L98Z52; Jun 3, 2009 at 10:15 AM.
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Old Jun 3, 2009 | 10:06 AM
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Originally Posted by ghoffman
I would call Randy at DRM if I were you. They have everything you will need.
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Old Jun 3, 2009 | 10:19 AM
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Again,looking to hear from guys that have done this on there own.I know there are kits out there.

Sleeve kit-$70 a piece
Springs-hyperco,im assuming about a 10"-$60 a piece

What i would really love to do is find a sleeve kit for my dbl adj qa1 shocks.
Anyone make a sleeve kit for a qa1 shock?
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Old Jun 3, 2009 | 10:30 AM
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Found this place that makes sleeve kits for all kinds of shocks.

http://shop.a1racing.com/coiloverkits.aspx

Including a kit for qa1 shocks.

http://shop.a1racing.com/cok12413.aspx
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Old Jun 3, 2009 | 05:27 PM
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OK,sleeve kit doesnt work for the direct bolt-in qa1 dbl adj shocks.The main body is too thin to machine the groove for the c-clip lock in.

The bilstein sleeve kit will work but im looking for a dbl adj shock.

Now looking into using a qa1 dbl adj coilover shock with a 2.5" hyperco spring and special mounts to bolt them to the car.
I seen in a search that hardbar made some of these brackets.
Anyone have any info on them or a qa1 coilover setup?
Thanks!!
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Old Jun 3, 2009 | 05:40 PM
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Yes, 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?fu...&SubGroup=1906
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Old Jun 3, 2009 | 05:45 PM
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Originally Posted by ghoffman
Yes, 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?fu...&SubGroup=1906
Ohh, very interesting. From their site it looks like these are QA1 shocks. How do these compare in terms of adjustability and consistency from shock to shock as the big name stuff (particularly Penske)? Do you know what spring rates they are shipping with these, and what size springs do they take (looks like 2.5")? Do they also require heim jointed sway bar end links to clear the spring?
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Old Jun 3, 2009 | 06:00 PM
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No, I do not know the spring rates they are shipping them with, but they are genuine Hyperco springs and I am sure you can get any rate you wish. They are no where near a Penske, but the cost is not there either. They are a twin tube bypass shock with a gas separator bag. The ***** do work, but work best in the middle settings. When we dyno'ed them, there were some issues, but that is why you do testing. QA-1 was VERY receptive to suggestions and are dyno'ing each and every one in this program as a final QC check. They do have nice threaded aluminum bodies with Acme threads like a Penske, which is very nice for the spring hardware, and the upper clevis is virtually identical. The lower mount is included in the $1699 price for the singles, $2299 for doubles for C4's!

Last edited by ghoffman; Jun 3, 2009 at 06:03 PM.
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Old Jun 3, 2009 | 06:02 PM
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Originally Posted by ghoffman
No, I do not know the spring rates they are shipping them with, but they are genuine Hyperco springs and I am sure you can get any rate you wish. They are no where near a Penske, but the cost is not there either. They are a twin tube bypass shock with a gas separator bag. The ***** do work, but work best in the middle settings. When we dyno'ed them, there were some issues, but that is why you do testing. QA-1 was VERY receptive to suggestions and are dyno'ing each and every one in this program as a final QC check. They do have nice threaded aluminum bodies with Acme threads like a Penske, which is very nice for the spring hardware, and the upper clevis is virtually identical. The lower mount is included in the $1699 price for the single for C4's!
As you get towards the end of the adjustment range, the adjusters do less and less to change the damping?
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Old Jun 3, 2009 | 06:10 PM
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Well, on full soft it is REALLY soft and then tapers off at the full hard position. The Penske is very linear with each incremental click being very close to the next or previous amount. The price points are in a different league though.
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Old Jun 3, 2009 | 06:17 PM
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Originally Posted by ghoffman
Well, on full soft it is REALLY soft and then tapers off at the full hard position. The Penske is very linear with each incremental click being very close to the next or previous amount. The price points are in a different league though.
I don't think anyone expects a QA1 to perform like a high end shock such as a Penske. Good shocks really kill the budget...
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Old Jun 3, 2009 | 06:24 PM
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Exactly, but not everyone needs that either.
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Old Jun 3, 2009 | 06:29 PM
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Originally Posted by ghoffman
Exactly, but not everyone needs that either.
That's one thing I have been struggling with: how much is the right amount to spend for shocks? I want to go to coil overs so I can play with springs, but $5K for shocks is unrealistic, and I'm afraid non-adjustable grooved Bilsteins aren't up to the task.
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Old Jun 3, 2009 | 06:39 PM
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That is the intention of this kit. Springs are about $80 each, so you can do exactly that. Let's put it this way, the shock is alot better than any other non-high end (Penske, Moton, Ohlins, etc) adjustable shock I have seen.
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Old Jun 3, 2009 | 06:43 PM
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Originally Posted by ghoffman
That is the intention of this kit. Springs are about $80 each, so you can do exactly that. Let's put it this way, the shock is alot better than any other non-high end (Penske, Moton, Ohlins, etc) adjustable shock I have seen.
Would that include Konis? The Koni Sport (yellows) seem to have a decent reputation.

And thanks for the information. I'm full of questions.
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