Strut/Spring question.

[SASHO91]

Ok, i know that the other side of this has been beat to the ground.... Another thing that caught my attention was a member stating that the eibachs actually had a lower spring rate than stock... now, i dont think that was the case, but i would like to clear that up...

Now for the question....
Ok it is a known fact that if you put Intrax/Eibach Springs on a stock style strut, that it will become a pogo stick on wheels....
But what if you did it the other way around, assuming you have good/really good stock springs.... putting stock springs on Koni's....

maybe this has been disscussed before... but i really didnt want to search through all of the Spring/Strut threads for this akward question....

 

[Shoaz]

Both the Eibachs and Intrax are quite a bit stiffer than stock springs (roughly 2x). A stock strut will be pretty underdamped with either.

 

[Sh03d]

What about stock springs and Konis or Tokicos? I think that was the question.

 

[Dave Kegel]

Both the Eibachs and Intrax are quite a bit stiffer than stock springs (roughly 2x). A stock strut will be pretty underdamped with either.

This is not necessarily true. There are a coupe of things to consider. First, there is a pretty wide range of stock spring rates. Depending on your spring code, the Intrax/Eibachs can be quite a bit stiffer, or not so much. The second thing to remember is that stock springs have a linear rate while the Intrax/Eibachs are progressive. So, while the aftermarket springs may have a compressed rate that is 2x stiffer (again, depending on your stock rate) than the stock rate, they're certainly not 2x stiffer at the stock ride height.

Dave Kegel

 

[Shoaz]

So, while the aftermarket springs may have a compressed rate that is 2x stiffer (again, depending on your stock rate) than the stock rate, they're certainly not 2x stiffer at the stock ride height.

And the damper isn't doing much at rest ride height. As soon as the suspension goes very much into bump, which is frequent under normal use conditions, the rate goes up so quickly that, IMHO, anyway, you're going to suffer from the underdamping pretty quickly.

I've got Intrax on my silver car now, after moving the 500/350 lbs/in front/rear coilovers to the other car. Under bump it feels at least as stiff as the coilovers were, but the lower initial rate definitely takes the edge off.

 

[NotSoSlowSHO]

What about stock springs and Konis or Tokicos? I think that was the question.

yes, this was the original question. They would work fine But I would not want to keep a soggy pair of stockers in there, if everything is torn apart already.

 

[SASHO91]

which is why i was asking that.... my stock springs are still very firm, and are NOT sagging, at all(actually the rear rides higher).... i dont know if they were replaced before i got the car...

I wasnt sure if that would work or not... running a really good stock spring with koni's... or even tokico....

were could one aquire the spring rates???

 

[Shoaz]

Here's one reference for spring rates:

http://www.panix.com/~awinbow/sho/suspension.html

The springs do age, though, so the rate when new isn't necessarily the rate now. The stiffer damping of the Koni and Tokico struts is to match the generally higher rates of the Eibach and Intrax springs. If you have stock springs you'll likely be much better off with the less expensive replacement struts that are more closely matched to the stock spring rates.

 

[Sh03d]

So it is not suggested to install Konis or Tokicos with stock springs but it will not damage them?

 

[yamahaSHO]

When I bought my '95, it had stock springs with Koni struts. I always ran the Koni's at full soft when the stock springs were still in. The Koni's held up great, then again they are a very good strut with a lifetime warranty.

I wouldn't recommend running an aftermarket strut with a stock spring as the strut will be doing most of the work. I later installed Eibach w/ the Koni's and currently have Intrax w/ the Koni's. With the aftermarket springs, I always have the Koni's turned up full stiff, sometimes a quarter less in front.

 

[SASHO91]

which is what i was going to do...
run them full soft to maybe a 1/4 ....
thanks for the info Jason.
thanks for the link Eric.

 

[SASHO91]

SHO
200/160
Eibach
150-260/
150-194
Moog Cargo-Coil
159-??/
145-??

taken from the site.....
so the stock SHO spring rates are 200/160..... does it keep that through out the compression of the spring... as they are not progressive springs....

the eibach fronts are 150-260... so even under full compression, they are only 60lbs more... and the rear are 150-194, only 34 more lbs....

or am i not understanding this correctly?
why wouldnt the koni's under a full soft, or close to full soft, work??? do you need a progressive spring with them? or does it need that 60 more lbs. of progressive spring?


hmm.. guess i need to find a 22mm FSB and 26mm RSB..... this 24-23 isnt the best of choices huh????

 

[Silver95]

So what other sturts besides the koni's are there that i could use with aftermarket lowerings springs? i know that the tokico's are done for, so the koni's are the ONLY option left??

 

[Shoaz]

There are spring charts available to match spring codes (the three letters on the tag on the OEM spring) to the specs for that spring. I just went back and looked and for Taurii the spring codes amount to either 155lbs/in or 200lbs/in for the front or 100lbs/in to about 130lbs/in for the rears.

My 95 MTX got SLO springs from the factory (a lot of the later ones did). I'm not certain that the 260/194 high rates quoted for the Eibachs are correct, but even if they are for a lot of SHOs that's a 70% increase in spring rate from when the OEMs were new, and will probably amount to about 2x or 2.5x from an old spring to a fresh Eibach.

Same thing for the rear, going from an old 100 or 130lb spring to a new 194lb spring is gonna feel pretty harsh.

You're probably not too far off that if the OEM strut valving could handle 200lb springs they might handle 260lb springs, but I think it'd still be bordering on the ragged edge of matching the spring rate adequately. IIRC the OEM struts for SHOs with stiff springs were valved stiffer than SLO struts, too, so current "Taurus" struts valved for 155/100 are likely going to be pretty weak for a 260/194 spring set.

People have done it, though, and they'll certainly bolt up without a problem.

 

[SASHO91]

Guess the only way to be certain is to try it....

if all else fails i will just go get some intraxs...
thanks for the help Eric.

So the 200/160 SHO factory springs were just like the sway bars... they threw in whatever they had laying around, huh?