Koni Adjustable Shocks & Struts Follow-up

[scottherbert]

Originally Posted by rice eater

I need you to help me out with some of the rear shocks if they work out for you. I can send you the cash or go through your contact if you want. Just let me know.

I just installed them -- took about 30 minutes. They are about 3/4" to 1" shorter in total length than the stock shocks -- but SCCA allows 1" + or - for stock class cars. So I had to put a jackstand under the rear axel beam and gently lower the car down to align the lower bolt hole. So far, they seem to work just fine. I've set them at the mid-point for rebound stiffness so they're probably a bit stiff for regular driving, but I'll find out.

Here are several sources for these shocks:

1st Koni direct: http://www.koni-na.com/display.cfm?m...ubmit=Continue

Remember, it's for the Chevy Cobalt -- the Koni part number is: 8040 1364Sport -- $306.

Here's another commercial, slightly more expensive site: http://www.cobaltperformanceparts.co...34a812ca992ab0

This one's $319.99

Finally, the place I got mine -- an Ebay store: http://cgi.ebay.com/ebaymotors/05-07...spagenameZWD1V

This is the SOHi performance store: $285.60 -- and that includes free shipping.

I haven't heard from my Koni contact yet...

Scott

[Pierre]

Originally Posted by scottherbert

I just installed them -- took about 30 minutes. They are about 3/4" to 1" shorter in total length than the stock shocks
Scott

Shorter in both extension and compression?

Pierre

[scottherbert]

Originally Posted by Pierre

Shorter in both extension and compression?

Pierre

Extension. Compression appears to be the same. I've been driving them around and am already impressed with the additional road holding in fast turns and very aggressive slalom-type moves.

I've measured the struts. The top bolt is 1/2" in diameter and the typical top bold on a Koni cartridge is 5/8" -- so most likely the spring top cap will have to be drilled-out 1/8". Otherwise, the strut external diameter is 2" -- to I'm pretty sure a Koni cartridge that it 1.71" in diameter ought to fit...

I guess we'll have to wait and see.
Scott

[rice eater]

I have lowering springs, do you see any conflict with having them and using the rear shocks? They are the eibach's, and they are a bit stiffer.

[scottherbert]

Originally Posted by rice eater

I have lowering springs, do you see any conflict with having them and using the rear shocks? They are the eibach's, and they are a bit stiffer.

If I recall correctly, the Eibachs are about an inch (maybe 1.4") shorter than stock. The Koni rear shocks are also about an inch shorter than stock -- but the compression limit appears to be, if anything, less than stock -- in other words, I doubt very seriously that you'd ever be able to compress these all the way to their limit, particularly with stiffer springs. I suspect the Koni's would work great -- if for no other reason that the ability to adjust rebound would help you smooth out the heavier spring rebound from stiffer Eibach springs.

In my opinion, these would be a great choice!

Scott

[rice eater]

Sweet, I'll be ordering them monday.

[scottherbert]

I did some additional measurements on the struts -- and I looked-up the two rebound adjustable strut cartridges Koni lists on their performance sheets.

As close as I could get -- the Redline struts measure 22" at total extension, 15.1" or 15.2" at total compression (a total of about 6.8" of stroke), the strut body measures about 13+" of length, and the top bolt is 1/2". Koni lists a high performance cartridge that measures 21.26" at total extension, 15.24" at total compression (6.02" of stroke), the specs state that 13.07" of strut body to support the cartridge, and it has a 5/8" top bolt. Koni needs 1.71" of internal room and the Redline strut body measures 2" of outside diameter.

Bottom line: it seems to me that Koni has a cartridge that would be about 3/4" shorter in extension that the stock strut (with a little shorter total stroke) and there will be a requirement to bore-out the spring top plate by about 1/8". I can't think of any reason why there shouldn't be a Koni strut cartridge that fits our strut.

Koni does state that they don't provide a 'generic' top bolt for the 5/8" top on their cartridge and that the buyer needs to specify the desired thread pattern and bolt for the specific application. Here's what Koni lists as options:

THREAD & PITCH
M48 x 1.50
M48 x 1.00
M51 x 1.25
M51 x 1.50
M52 x 1.50
52.8WW

Any thoughts out there? I'm a bit out of my league with THREAD & PITCH.

Scott

[NoRemorse]

Originally Posted by scottherbert

I did some additional measurements on the struts -- and I looked-up the two rebound adjustable strut cartridges Koni lists on their performance sheets.

As close as I could get -- the Redline struts measure 22" at total extension, 15.1" or 15.2" at total compression (a total of about 6.8" of stroke), the strut body measures about 13+" of length, and the top bolt is 1/2". Koni lists a high performance cartridge that measures 21.26" at total extension, 15.24" at total compression (6.02" of stroke), the specs state that 13.07" of strut body to support the cartridge, and it has a 5/8" top bolt. Koni needs 1.71" of internal room and the Redline strut body measures 2" of outside diameter.

Bottom line: it seems to me that Koni has a cartridge that would be about 3/4" shorter in extension that the stock strut (with a little shorter total stroke) and there will be a requirement to bore-out the spring top plate by about 1/8". I can't think of any reason why there shouldn't be a Koni strut cartridge that fits our strut.

Koni does state that they don't provide a 'generic' top bolt for the 5/8" top on their cartridge and that the buyer needs to specify the desired thread pattern and bolt for the specific application. Here's what Koni lists as options:

THREAD & PITCH
M48 x 1.50
M48 x 1.00
M51 x 1.25
M51 x 1.50
M52 x 1.50
52.8WW

Any thoughts out there? I'm a bit out of my league with THREAD & PITCH.

Scott

M48 means that the Maj. Dia (the largest diameter of it) is 48mm. That's like 1 7/8".. which is not really possible... that is REALLY freaking big

[rice eater]

I am sure once they see our strut, they will have a solution in a week or two. This isn't rocket science. And they are about the best in the buisness.

I don't know about you, but I have no problem with opening up some holes if need be. It beats the alternative of cutting the tower and welding in a new one.

Now lets talk camber???

[scottherbert]

Originally Posted by rice eater

I am sure once they see our strut, they will have a solution in a week or two. This isn't rocket science. And they are about the best in the buisness.

I don't know about you, but I have no problem with opening up some holes if need be. It beats the alternative of cutting the tower and welding in a new one.

Now lets talk camber???

I have lot's of experience with camber -- keeping in mind that I'm staying within the SCCA stock class rules. First, in the 2007 rule book, SCCA specifically disallows the new steering knuckles for the Redline and Cobalt SS -- so save yourself some money and DON'T buy them. (It seems that they're needed and allowed for actual road racing -- a few hundred miles at racing speed -- not an autocross.) SCCA also disallows the after market camber adjustment bolts -- two things not to buy (I've used camber bolts on SL and SC2s).

SCCA does allow "filing" (grinding, drilling) the lower knuckle bolt hole on the strut itself. It's in the GM maintenance manual and is considered to be a 'maintainence' item -- and it's legal. I had this done on mine at the dealership (but it's easy, you could do it at home). I 'can' get more than 3 degrees of negative camber with this modification -- I run the legal 2 degrees of negative for SCCA racing, and I keep it a less than 1.5 degrees of negative for street driving. I also have the front-end set with 1 degree of toe out (helps turn-in and keeps more of the slick on the ground during a turn).

The down-side: If you don't close attention and 'flip' your tire mounting periodically, it's pretty easy to wear through the inside of the front tires in a relatively short period (I corded the inside of stock tires in less than 15,000 miles running 2 degrees of negative all the time -- I didn't flip them when it was needed). I even flip my Hoosier A6 slicks periodically to get even wear -- the outside wears on them... And the toe-out makes direction changes very quick, and it takes very little effort to change direction -- works great on an autocross course.

Scott