Actually the more I read it I think that Wanklin is incorrect and the way I have previously stated is the correct method for the coilovers in question.

On the link I posted above you will notice that the coilovers pictured next to "Ride Height Adjustable" are a entry level set of coilovers, ie with out the means of adjusting ride height seperate of spring preload. Where the coilovers pictured next to the one just below that, "Full Length Adjustable" are like the OP's coilovers and the correct way of adjusting these is not by changing the spring preload. In fact it is to use the lock nut I had circled earlier, as to not change the spring preload.

 

The only way I could see that occurring is if the shock body (the part which contains the piston and defines the range of motion <Xmax, Xmin> of the shock) can move relative to the bottom shock mount. Or if the upper spring perch (on top of the spring) can be adjusted relative to the upper shock mount. Neither seems to be the case here.

The key concept here is that spring length/compression is determined solely by the weight on that corner of the car, and not by the position of the spring perch.

Remember, the shock at rest does not put any force on the spring.

You cannot simply "compress" a spring on one corner without affecting the weights on the other corners. Once you adjust the other corners to compensate (get the car back in balance) you will find that all your springs lengths have returned to where they were originally.

Think about that.

The range of operation of the shock is determined by the overall length of the coilover unit. This depends on the spring length (which we have determined is a set length) and the distance between the bottom shock mount and spring perch (plus a little bit for the distance from the upper spring perch to the upper shock mount).

BTW, my account name is "wrankin" (no 'L', extra 'R') - "Wanklin" is someone different. But you can just call me Bill, since that's what I sign all my posts with.

-b

 

Cgotto6 - please define "preload" for me. I think that is the term we are having problems with.

Thanks for the Tein reference. I will go do some reading.

 

Okay I think I see the confusion - if I read the Tein site corretly, then for their "full length adjustable" units the entire shock body is threaded and can be raised/lowered relative to the bottom shock mount. That is what I did not realize.

I was under the impression that the unit pictured above was only ride height adjustable (ie. the shock body is fixed relative to the lower mount).

I humbly concede the point to Cgotto6

 

Ok Bill lol, I understand what your saying however corner balancing is irelevant to this discussion. In this case the objective is to lower the ride height. This is achieved by shortening the total length of the coilover as we both can see. When we accomplish this by lowering the spring perch we can both agree that we begin to reduce shock travel, we'll just leave preload out of this at this point because our focus is the affect on the range of motion of the shock. Now, if we reduce total coilover length by the collar on the "shock body" we are not reducing travel at all. This is because the "shock body" is actually just a housing and the shock itself is welded to the collar. However if the "shock body" is actually part of the shock itself you would be 100% correct.

 

Thanks, guys. It was a great discussion. Definitely learned something here

(now out to the garage to wrench on the FC)

-b

 

Wow, I had no idea this thread would turn into such a discussion lengthy discussion, hah. I'm not even concerned about losing shock travel honestly; this car will not see serious track use and I don't care about comfort. I should be able to adapt to the lessened shock travel if I have to lower it by the springs. Though I'll likely still get a decent cross weight and align it first, as if I were going to road race or auto-x it, and write down all the settings, so I know what to put it at if it doesn't feel right after lowering it by the springs. Thanks again for all the help.

One thing I am still curious about. Is it normal for the factory coilover assembly to have no spring preload? Mine didn't...but it wasn't really "factory"; I think it might be because of the lowering springs that were on there. I can't wait to get this car aligned and drive it. Both of the rear struts were completely blown and had no rebound...after taking them out, I was able to push the piston all the way into the shock housing, without it bouncing back out

 

So I am a bit disappointed in these coilovers. The car will never be as low as I want it to with the limitation of the rear shocks. I'm not sure if this is a function of the design of the FD, or these particular coilovers.



Completely maxed out in the rear, and the fitment still looks like this...



Two whole fingers fit in the gap. Ew. And as you can see, this is with the springs dropped down, which isn't really a good idea as we've discussed. With the spring preloaded (i.e. spring meets top of the body like it should) the gap was a whole hand including thumb. Maxed out like this, there is around half an inch between the spring and the upper mount; I can hear it binding when I put the car on the ground, but it doesn't seem to bind while driving so I'm not worried. Still, this is as low as I will ever be able to go with these, unless I modify them. Which is stupid, seeing as how one of the reasons I bought these is that they're known for being able to go really, really low. The fronts are fine, they're as low as I want and have plenty more room to go. I think I'm going to try and get ahold of the manufacturer and ask if this is normal, but again, I'm not sure how much help they will be.

In reality, the car actually is pretty low. I'm just gonna need some massive rims to fill that extra gap. Sorry for the bad pictures, I'll take some more during the day.



On the plus side of all this, the ride quality of these is amazing for how stiff they are. I can't wait to push them a bit!

 

What is the ride height measured from flat ground to the fender lip? 25" to around 25.5" is usually the sweet area - read Howard Coleman's thread in the suspension section.

What is the spring length? If the height really bothers you, you can probably go with some generic Eibach Race Springs in 2.5" diameter and the length you desire.

 

Ranger, you might not be able to, but just to be sure on this picture:



Are you able to move the #1 lock nuts to where the arrow is pointing, and the threaded part of the shock body (#2) into the lower shock body more? Or are you limited on how much you can move #2 by the little bump labled with the #3?

 

Nope, can't move the threaded part of the shock body any further. It's not limited by the bump (#3) but presumably it's already all the way into the sleeve / shock body; I can't turn it any further. That's why the spanners are jammed up against eachother like that, I had to lower the spring in order to get it at a decent looking ride height. If I raise the spring back to where it should be, there's a massive gap between the tire and the fender.

Spring height in the front is 7", I didn't measure the rear but I'm guessing it's around 6-6.5". I didn't measure the ride height, didn't feel the need to since it's maxed and still doesn't look low enough. Numbers don't matter at this point, I doubt I will even corner weigh it now. I know it sounds stupid from almost any perspective, but proper damping isn't that important to me in this case, I'll mostly be drifting this car, not autocrossing or road racing it, so as long as it looks good, with good wheel fitment, I'm happy. Have not had it on track yet, just took it for a spirited drive, but it feels great like it is. I'm considering removing the bottom lock nuts...since it'll be maxed out anyway, they're not necessary. Or I might go with a shorter spring.