Spring Length/Shock Internals

[steve13gt]

I have a 2013 Mustang, some of you may remember all the problems I originally had with my coil-overs.. Eibach R2s.

Anyways I originally had 225 lb/in 8" long springs, and switched to 350 lb/in 7" long springs. Since the new spring was stiffer, it needed to be shorter to maintain the same ride height adjustability, well it didn't quite, car sat higher at full adjustment.

My question is that if I was to run a shorter spring yet, say a 350/6", possibly shorten the bump stop, this would allow the shock shaft to go further into the shock, will this cause damage, is there an internal bumpstop of some sort.

I am not looking for comments about handling etc, I'm not trying to slam the car, just looking to maybe lower it another 1/4 inch. Any help is appreciated

 

[steve13gt]

No suspension experts can explain this to me ?

 

[zeroescape]

Why would you cut the bumpstop?

Your trying to achieve the ride height of your previous #225 spring setup?

The car will have the same travel as with the #225 springs. The strut will be in the same position wether its a #225 or #350 spring as long as ride height is equal.

Instead of going to a shorter spring have you tried removing the helper spring? Make sure the spring remains in contact with perches at full rebound though.

 

[Vorshlag-Fair]

Yes, if you still have the included tender spring in there, remove it and the dual spring spacer and you should lower the car about an inch at the same lower spring perch setting. We make our own tender springs in 60mm ID, but don't ever use them on an S197 strut.

The tender spring on your Eibachs is useless once the car is loaded at ride height - it just becomes a spacer. It is not needed on the front suspension of an S197, and only comes into play when the car is up on jack stands or lifted off the ground for some reason. Then it keeps the spring from unseating - which itself isn't a big deal on these cars.

On a few cars we will use a tender, like the rear struts of a Subaru or EVO, that have really LONG struts that can unload the spring going into a driveway incline. We will also use a tender on some inverted front struts, due to much shorter lengths in the strut bodies compared to non-inverted. On many applications the tenders are pretty much worthless. You tend to see them on "TUV" approved strut suspensions made in Germany or for the German market, and "Eibach" .... kind of sounds German, heh. When we brought AST into the USA back in 2006 the first thing we did was remove the requirement to use tender springs, and we sold thousands of sets of coilovers that way without issue.



We used a tender on the rear of the EVO X set-up above, because without them the spring would unseat by about 3-4 inches and make all sorts of racket. That is a LONG travel shock on the rear of the car, totally unlike the solid axle on your ca.r Again, tender springs do have their place, but an S197 Mustang isn't one of them.

Don't be afraid to see 1-2 inches of "air" between the top of the main coilover spring and the upper perch with the front strut at full droop - when up on jack stands. We even machine a taper into the underside of our upper spring perches to self-align a spring when it comes down off of a lift. It might make a "sproing!" noise, but it can do that hundreds of times and never hurt a thing.

So my advice is: yank out the tender springs and try again.

 

[steve13gt]

I have tender springs which eibach calls helper springs on mine, they are even thinner than what you showed, have zero rate at all, and are not nearly as thick as the "tender" springs I have on the shelf. However I still wonder, with me going lower and lower and lower, will there be a point that the shock bottoms out internally? Or are all shocks mad in a fashion that the entire shock shaft can be compressed into the body of the shock.

 

[jmauld]

I have tender springs which eibach calls helper springs on mine, they are even thinner than what you showed, have zero rate at all, and are not nearly as thick as the "tender" springs I have on the shelf. However I still wonder, with me going lower and lower and lower, will there be a point that the shock bottoms out internally? Or are all shocks mad in a fashion that the entire shock shaft can be compressed into the body of the shock.

Take the shock off of the car.
Compress it by hand as far as it can.
Mark the shaft at that point with a felt marker
Put the shock back on the car and lower it.
Measure the distance between the mark and top of the shock body.

That's your compression travel, before bottoming out. Some shocks/struts have internal bumpstops. Some do not.

 

[Vorshlag-Fair]

I have tender springs which eibach calls helper springs on mine, they are even thinner than what you showed, have zero rate at all, and are not nearly as thick as the "tender" springs I have on the shelf. However I still wonder, with me going lower and lower and lower, will there be a point that the shock bottoms out internally? Or are all shocks mad in a fashion that the entire shock shaft can be compressed into the body of the shock.

Of course you can always over-lower any shock or strut. We will always check the total stroke vs the available bump travel at the final ride height to determine what is ideal. I like to see about 3/5ths of the stroke in bump and about 2/5ths in rebound, from ride height. The bump stop on a non-inverted strut like the Eibach is easy to see - how much room is there to the bump stop at your latest ride height?

 

[steve13gt]

Its pretty hard to tell, I need to check once its outside. My issue is it came with these huge bumpstops new for the 2011-2013 cars from eibach, I didnt like them and requested the bump stops they were previously using which bought me some clearance.