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-   -   Converting C4 bilstein shocks to coilover? (https://www.corvetteforum.com/forums/autocrossing-and-roadracing/2343998-converting-c4-bilstein-shocks-to-coilover.html)

87L98Z52 06-02-2009 08:34 PM

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!!:lurk:

Vector Vette 06-03-2009 01:08 AM

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.

Mojave 06-03-2009 02:42 AM


Originally Posted by Vector Vette (Post 1570311013)
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?

87L98Z52 06-03-2009 08:37 AM


Originally Posted by Vector Vette (Post 1570311013)
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!!:cheers:

ghoffman 06-03-2009 08:55 AM

I would call Randy at DRM if I were you. They have everything you will need.

87L98Z52 06-03-2009 09:10 AM


Originally Posted by ghoffman (Post 1570312679)
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.

BrianCunningham 06-03-2009 10:06 AM


Originally Posted by ghoffman (Post 1570312679)
I would call Randy at DRM if I were you. They have everything you will need.

:iagree:

87L98Z52 06-03-2009 10:19 AM

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?

87L98Z52 06-03-2009 10:30 AM

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

87L98Z52 06-03-2009 05:27 PM

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!!

ghoffman 06-03-2009 05:40 PM

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
http://www.vansteel.com/_custom/part...00%20copy1.jpg

Mojave 06-03-2009 05:45 PM


Originally Posted by ghoffman (Post 1570319187)
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
http://www.vansteel.com/_custom/part...00%20copy1.jpg

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?

ghoffman 06-03-2009 06:00 PM

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 knobs 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!

Mojave 06-03-2009 06:02 PM


Originally Posted by ghoffman (Post 1570319418)
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 knobs 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?

ghoffman 06-03-2009 06:10 PM

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.

Mojave 06-03-2009 06:17 PM


Originally Posted by ghoffman (Post 1570319551)
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...

ghoffman 06-03-2009 06:24 PM

Exactly, but not everyone needs that either.

Mojave 06-03-2009 06:29 PM


Originally Posted by ghoffman (Post 1570319749)
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.

ghoffman 06-03-2009 06:39 PM

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.

Mojave 06-03-2009 06:43 PM


Originally Posted by ghoffman (Post 1570319907)
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. :thumbs:


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