I'm not an expert on suspension by far, but I'd say the intelligent way to get your desired height is mark the springs out in 1" increments and start low. If it doesn't look enough, go to the next mark. And do so with a full tank so you're at full weight.

But then again, you've done this before. You should know that....

 

Learning now why cutting coils doesn't work with progressive springs...

 

If the length of the cut spring end up being shorter more than one inch over the OEM, it could get crooked into its seat. Not good.
If it's much shorter, it will eventually fall out... how sweet!

It wouldn't be a problem up front where the spring has nowhere to go on a Mac Person design but in the back, it's totally independent from the shock.
So you guys with the "It's been done since springs were invented" comment, please don't quit your day job!
The cutting doesn't work in all applications...

 

Not questioning your almighty car knowlegde, Pascal, but since the weight of the car rides on the springs and not the shocks, the springs should stay in place unless you completely unload the suspension, regardless if its a independent spring/shock or a coil-over design, as in the macpherson.

Please let me know if Im mistaken so I can add to my knowledge base.

 

Doesn't the S197 have linear rate springs? I believe I read somewhere that even if you got some aftermarket "progressive" springs, the weight of the car would pretty much compress the springs to the point that they become linear...

I still wouldn't suggest cutting them though, especially if you don't even have the means to measure equal cuts! That will cause you to have different spring rates on either side of the car (not sure what this could damage, but will probably create problems when cornering/braking).

 

I'm not sure about having to completely unload the suspension, but I've heard of people with cut springs (imports, but that shouldn't really change anything) that took a pothole, or bumpy roads and that caused their springs to fall out of position.

 

I would imagine if the car bounced hard enough and extended the length of the strut farther than the uncompressed length of the spring, you could risk it falling out.

 

Cut a rear spring on these cars too short and it can easily fall out if the suspension ever goes to "full droop".

Cut it badly enough so that it's trying to bow out sideways and it will always trying to pop out. Might not have to completely unload the suspension to full droop for that to happen in this situation.

Cut them with poor enough technique and you can make the spring metal brittle and it can and will break. Then you have a too-short spring with an end that's pretty much guaranteed to be the wrong shape (plus a loose piece of spring that's either going to get in the way or fall off the car).


All that said, cutting springs is in fact successfully "do-able" - even if the springs are progressive - if you understand spring design and what to avoid doing. But if you don't even know what the questions you need to ask are, don't try it.


Norm

 

Thanks for the compliment but I think that between Norm, Sam and other folks here, they have the almighty knowledge in check...

It is not that uncommon to unload the suspension on normal driving.
So like Norms says, cut them too short and they will bail.
Don't know if you dropped your car or not but if you did and did it yourself, did you notice how easily that shorter spring goes back into place? And the OEM one isn't that hard to remove BTW...
So you don't have to cut them a lot before you get in trouble.

 

Cut springs compromise the ride integrity.
Sure it looks cool, but take a corner to fast and
the weirdness of the rear suspension could just
catapult you right into the ditch.
I personally like looks and function hence the
Roush rear springs and shocks only.

I have heard that heating them while under pressure
is the way to go to shorten an OEM spring.
It can be done using the vehicle as the pressure part.
Just heat the coils until the rear end drops to the desired
height. Done deal and you didnt even have to remove
the springs. Dont worry about the gas tank under there
as it is made of Asbestos and it fireproof.
A strap to limit the suspension travel will help
keep those now shorter than OEM springs in the seats.

Or just buy a set of $100 Roush rear springs...