background info:
1988 Accord Coupe with shortened, re-valved, double adjustable Koni shocks and ground control coilovers

I know there are so many variables out there, but if someone can help me figure this out I would appreciate it. I changed my eibach coilover springs for my ground controls from the metric 180.64.61 front and 180.64.75 rear to 7" x 2.5" x 650lbs front and 7" x 2.5" x 600lbs rear. One thing that always bothered me with the rear suspension of my car was that to get my desired ride height in the rear, I had to set the perch at the very bottom of the threaded collar. This would cause the rear springs at full droop to lose contact with the shock top hat and create a 'gap'. So, when I decided that I wanted to change my spring rates I picked up a set of Eibach "helper" springs for rear. They literally, have like
no spring rate and when the car is on the ground they are full compressed and when at full droop they are in contact with both the spring and top hat. I did not raise the rear perches because problem solved, or at least the droop problem was solved. When I finished the rears and lowered the car, the rear sat even higher than it was before. I am talking about going from a pinky gap with the old springs to almost 3 fingers currently. Annoyed, I moved on to the fronts, now my front perches are about midway up the collar and the top of the springs sits against the top hat; no helper spring was ever needed. Again, I didn't move the perches and once again the car sits with about a 4 finger gap as opposed to the pinky gap with the old springs. What gives? I know I could lower my front spring perches, but then at full droop the springs will then need those helper springs. I totally get the springs will settle somewhat, but they shouldn't be that drastic of a settle!

So, I guess what I am wondering is if there is a point in the spring rate equation that a car is too light to properly compress the spring? Did I go too far and get springs that my car's weight will never be able to compress while not moving?



BEFORE





Front AFTER




Rear AFTER

 

"When I finished the rears and lowered the car, the rear sat even higher than it was before."

yes. this is what happens when you stick a chunk of metal (compressed helper spring) on top of your old spring without moving the perch.

i dunno why this isnt obvious.

and really, you dont need the helper springs. full droop and the spring loose, big deal. itll never happen when driving. and if it does, its not like the spring is going to pop off the shock. so whats the concern?

 

Thanks for the reply.

I don't think its that obvious, but there are smarter people in the world than me. It still doesn't explain the fronts being that much higher (there isn't a helper spring there). You are right, the spring won't pop off the shock, but it may not be fully
seated in the shock if that corner was at full droop. Again, there are smarter people than me so maybe I am worrying about nothing.

attached a pic for reference of this so called chunk of metal at full droop.

*edit*
Eibach lists these as helper springs, which is ironic since on my truck helper springs are something to assist with heavy loads. Eibach has tender springs, but they list those as something that would assist in spring rate.

https://eibach.com/us/c-113-products...r-springs.html

 

So there are a few things happening here.

For the Front:
You started with a rate of about 350 lbs/in on the Ground control spring and jumped up to 650lbs/in. By adding 300lbs of spring rate to each front corner and not adjusting the perches then yes, the springs are more than the car needs. You’ll need to adjust your perches down to accommodate the increased spring rate.

For the rear:
You started with a rate of about 425lbs/in and jumped to a 600lb rate. So again you have increased the spring rate by 175 lbs. per inch and added a helper spring. When the helper spring is compressed its ½ inch thick. This is essentially a ½ spacer if you don’t adjust the perches.

If you can’t lower the perches any more. You should look at going to a 6 inch main spring that will allow you to adjust the ride height and take advantage of the helper springs. The short answer is yes. You can over spring a car to the point you won’t compress the springs while not moving.

Truck Helper springs are different than a Motorsports Helper spring. Helper springs are designed to take up the slack when the car is at “Droop”. Eibach offers two helper springs. A regular, and a tall version. Tender springs are similar in design but use a thicker wire and actually have spring rate to them. They are used for spring rate tuning.

 

oh right, the change of spring rate definitely will change the height.

you have ADJUSTABLE spring perches.

adjust them.

 

Thank you Reyes for the very thorough and helpful response. This gives me a lot to consider and it may be beneficial to go with the 6" springs, particularly in the rear combined with the extra long helper spring to control the spring at full droop. In the front, I will be able to turn the perches down, but i'll lose some shock travel. I'll have to find some extended top hats for this chassis.

Again, thank you for taking the time to reply in such detail.

So....anyone want to buy some 7" 600lb springs???

 

With fixed length shocks...you lose shock travel when you lower the car...regardless of rate, spring length, etc.

But the extra rate makes the shock less likely to bottom out because a harder spring is more difficult to compress.

Extended hats will add that shock shaft travel back. But you already have shortened shock bodies. If you give the shock too much travel, the UCA will be able to contact the shock tower.

So...be careful. Measure before you do things.

Hopefully, you're using some form of bumpstop?

 

Thank you B serious for your thoughts. I do have bump stops, however, it sounds like I may be changing them out to avoid UCA shock tower contact.

 

Keep in mind that you have increased your springs rates significantly and that will effect how much of the available travel you actually use.

Take a measurement from the center of your wheel, straight up to the edge of the fender. Then put the car on jack stands, remove the wheel and use a floor jack to compress the suspension back to the same measurement. With the suspension compressed and the wheel removed, you will be able to see exactly how much travel you have available. This will at least give you an idea of how much room you are working with.

For a car of this size and the spring rates you have, during regular driving you are probably seeing very minimal movement from the strut.

 

Great suggestion and info, thank you!!

Maybe if I give a little more info, I could get some direction as to what I really should be changing.

So my intention of getting the higher spring rates was that I wanted the car to sit as pictured in the first pic, however, unavoidable highway potholes/transitions from paved to milled areas or vice versa would cause my upper control arms to smash into my shock towers. To get the desired appearance I wanted I thought getting some really stiff springs would help prevent the control arms from smashing into the towers. I have taken this car drag racing, wanted to use it at Track Night in America events, and just drive around town on the weekends; I want something that can do everything well. I know, I am asking for a lot out of 1988 Accord. With the old setup 350f/430r the car handled very neutral. In addition, It has a big front sway bar and 19mm rear bar. It is an odd chassis and the typical do you have aftermarket camber kits in front question doesn't apply to the UCAs.

Realistically, besides raising the car up, what should I be doing to stop my UCA from hitting the towers while keeping the car kind of multi-purpose? Thank you in advance, I probably should have proposed my questions and goals before even buying the springs, but what's done is done.

 

There is never a "Perfect Answer" but what you have done makes sense. But you need a shorter rear spring to set the height you want.

On my road race car i had the same issue with hitting the front control arms on the shock tower. I used an existing hole in the shock tower to mount a small bumpstop that would stop the control arm before it hit the tower.
here is what i used. I've had these in the car for about 5 years and never had an issue.
https://www.kartek.com/parts/ultra-t...lack-pair.html

 

You don't need the helper springs. It doesn't matter if there is space between the spring and the top hat when the shock is fully extended. The shock would never extend that far when driving, unless you did something like hit a speed bump at high speed. And even if you did somehow manage to separate the spring from the top hat while driving, it will just pop right back into place once weight is applied back to it. Happens every time I jack my car up and lower it back down on adjustable coilovers.

 

If you don't want to raise up the car, the only ways to stop UCA to shock tower contact are:

-Install a large, stiff bumpstop on the shocks. Shortening the shocks was a bit of a mistake if wheelwell space is an issue. Extended hats would make that situation worse.

-Cut out the shock towers.

What type of UCA do you have? Hopefully nothing with an extended ball joint...

 

So following this directive, I measured the driver side at 13 7/8" with the car on the ground. With the wheel off, I was able to compress the suspension back to that same measurement (with car starting to lift off the jack stands). Note, this is with the 650lb front springs and the perch has not been lowered.

Great link, thanks and I will definitely be purchasing a set as well as passing the info along to others. If, I were to go with a shorter spring for the rear what am I looking at for a spring rate? Would a shorter spring need to be softer since there are less coils? For example, what 6" rear spring would I go with if I revert back to the 430lb springs that were originally in the rear and put those upfront (with a larger bumpstop)? Keeping in mind I liked the neutral feeling I had before.

I agree with you that they probably aren't needed, but for peace of mind I will keep them in.

- Cutting the shock towers is out right now. If i were to go that route I would like something clean done like those welded shock tower extenders they make for civics and integras.

- As far as bumpstops go, tonight after doing the measurement Reyes suggested, I took apart my front shocks and coils and replaced the stock bumpstop that was cut in half per the Ground Control directions from when I bought them in 2002 or 2003 and replaced them with ones provided by Koni which were much harder and bigger. As far as the shock shortening, here is how that played out...When I purchased the GCs in 2002 or 03 I was running Tokico Blues all around and was slightly tucking a 205/45/16. The thing bounced like crazy. I eventually upgraded to Koni Reds (they didn't make Yellows for this chassis) and that solved almost all of the bounce, but it still left something to be desired. This was all with the OTS GC rates 350f/250r. During this time of being super slammed I never bashed my UCAs into the shock towers. Like I mentioned previously, the Koni Reds still left something to be desired. So I called Koni up and talked to someone there...Gordon? I don't know why I remember that name or if even that is the guy but anyway, after talking to him about what I wanted in terms of performance he suggested I shorten the shocks and we made the reds double adjustable and they came back yellow and I then got the 430lb springs for the rear. lol Sorry for the long winded answer, but just trying to paint the full picture.

- I am running 83-87 Prelude UCAs. They look like so..
Under the 2 bolts on the arm itself are slots that you can adjust camber. I was at one point running these arms with ingalls camber correction for them, which was like another sliding piece on the bottom side of the arm. That caused even more UCA contact and I removed them.


Just wanted to thank everyone that has contributed, I really appreciate it. I also, apologize if I am being hard headed with this!!

 

Spring rate can remain the same. The length of the spring does not effect how the spring rate works. The different lengths are offered to work in different application. So if you know the needed spring rate, buy the length that is best suited to your needs.

 

Okay. So am I correct to assume these are a low rate spring that adds height on top of your stiffer springs.... Essentially you are increasing your spring height and decreasing the rate until they are compressed back down to the stiffer spring. You will have to lower the perches more to compensate, but now your suspension will be able to travel too much due to the lower rate of the helper springs, which will cause you to bottom things out. Either hitting bump stops, or UCA's hitting the shock tower. It will ride like crap. You are much better off just having the shorter, stiffer spring and raising the perch, so the spring can do what it's supposed to and minimize the suspension travel so you aren't bottoming things out. And yes, it will ride stiff, but it has to in order to be that low.

But hey, what do I know?

 

those helper springs wont affect his spring rate or ride quality or handling. just add to the spring height in use.

theoretically they are two springs in serial, but for too small a ratio and extremely limited conditions to matter.

effectively, a waste of money.

 

i know you know what youre saying, and you are correct in this conversation but i hope nobody takes this out of context that simply shortening an existing spring *ie. cutting" does not change spring rate.

length and spring rate are dependent. so are spring wire thickness and number of coils, etc.

when eibach says they make a 650 lb/in spring rate in a 8" length, and a 650 lb/in spring rate in a 7" length, its not the same spring cut shorter.

 

Thanks Tyson for clarifying that. You're 100% right. Each spring is designed and manufactured to a certain length and rate. Cutting a spring will drastically effect the spring rate.