I was trying to confirm the spring rates on my front coilovers. from what I can tell, they have "550" and another, two digit number engraved into the end of each spring. I was looking with a mirror LOL. But it looked something like the picture below. I assume they are 550lb/in springs. Does this sound right? They only say Hyperco on the outer coil.
Also, I have a set of Ohlins springs: 47010-31/100c 432. From what I can find, -31 = 9.68k? That would be surprising, as I was told they were 11k when I bought them. Though, it may help explain why my car is acting so weird.

 

Older hyperco springs were engraved at the ends on an exposed flat from the powdercoat. Its super fun trying to decipher it after theyve seen some weather... I find myself taking a known spring and rate, then measuring the spring to plug into a rate calculator on both, and going with the error of the known to apply to the unknown. Not an exact science, but works to confirm MFG rate. Spring tester would really come in handy though.

Newer Ohlins springs has the rate in a lighter blue on the spring so you can actually read it. I assume the purpose to hide the rate is to keep your competition from knowing. The new style is quite subdued without having light to view.

 

I googled that Ohlin's part number and found a post from a VERY credible and might I add VERY attracted fella. Take a look here: https://www.evolutionm.net/forums/ev...l#post11459117

Long story short that should be a 10k spring.

And Hperco is usually pretty easy to decipher. It's a random number, which refers to the OD, I use 2.5" springs and wanna say they use 18 for that, then length followed by the rate. Or you could look at old catalogs and see if anything of this is true as its usually pretty easy to back into it with a few known specs relative to the part number.

 

Okay. Thank you! I looked at my notes and the rear was sold to me as a 10k, not 11k as I mentioned before. That makes me feel better. When I was Googling the Ohlins spring, I kept finding it was a 9.68K spring, which would suck because I think the front is 9.8k. Lots of problems here LOL:
I thought the front (Hyperco) spring was 9k and the rear (Ohlins) were 10k. If the F is 9.8k and the rear 9.68, you can see the problem. Still.... having 10k, as you say, in the rear and now finding the front is 9.8k (I need to stop letting people "help" me with this car LOL), that could explain why my car handles different than it used to. I used to run 8k/10k and it handled great but rolled more than I wanted. I went to a 9kF/10kR to see what would happen. Since then, the car hasn't really done what I wanted. I planned to go to 11kR as soon as AST confirms the shocks can handle it. Now that I see I'm basically running 10k/10k no wonder it drives weird LOL
Add to that the drama of my rear diff.

I think my fix will be:
Swap my 11k springs to the rear. If valving is inappropriate, I'll go back down to 8k/10k
Order another Weir 12-plate (I know. They suck. But I don't have $750 to have TRE do my diff, right now, and he doesn't sell his Max Lock kits).

That should get the car back to how I had it before, when it was a blast to drive. I'll put the new trans in and be good to go. Stoked.

**edit. To confirm, the "-31" on the spring does not mean it's a 9.68k spring, as per this chart?

http://forums.pelicanparts.com/uploads/springchart.jpg

 

I would find some used OEM clutch plates that aren't worn out instead of wasting more money on the weir stuff.

 

I've been looking for months, nothing. Either nobody keeps them around after swapping, or they are holding onto them. I've checked shops, FaceBook, PM peeps on this site, etc. Weir is, literally, the most cost-effective option, for now.

 

FWIW, once upon a time I was asking a guy from RE Suspension (Hyperco reseller) why Hyperco didn't just have the numbers on the side of the spring like Eibach, since it would be so much easier. He said that the reason they didn't do that and probably wouldn't ever do that, was so that circle track guys would be able to hide their spring rates from their competitors SRS BSNS!

 

 

As I posted above, the new ones do have them. Its a darker blue on the lighter blue. Most my older hypercos have rust that basically covered up the rates. I now need to get them all rate tested cause Im almost guessing whats what.

 

Ohlins or Hyperco?

 

These are hyperco springs. I try to use only hyperco or swift, but have a few eibachs cause they offer higher rates in the 2.5" springs.

 

haha i just rotate my springs to the inside if i want to hide the rates. i guess the beauty of racing in a mixed GT class is that im literally the only person running a CT9A chassis so it doesnt really matter hahaha

 

Could I get clarification on as to why you state that? I've never heard/read about anything negative with Weir.

Thanks!

 

Kaj already had one set fail pretty quick. I know of others with similar experiences.

The clutch plates have no oil grooves in them, so it's hard for oil to get in them for lubrication. They wear out quick or overheat and break the tabs off.

 

Email from AST:

"Valving is for 6K front 4K rear and the window is 3K up or down from those and you wount need a revalve."

Not sure if the previous owner had them revalved when rebuilt. I assume he did, since I am definitely over 7k in the rear but the dampening is decent.
So...Still not sure what I can run. Will swap springs and test.