# Coilovers and Eco?



## FatKidsCruze (Sep 2, 2011)

From what I've found Pedders and DGR both offer coilovers for Zlink suspension Cruzes. I have also READ these options will fit an Eco, but have not been able to confirm. So I got curious this weekend and climbed under the rear of my 12 Eco, to confirm what I believed, we ECO's have a spring and shock separate from one another. 

So in theory just get coilovers and then remove the factory spring and shock and place the coil er in the shocks' location... Problem one is there is not room for clearance of the spring if it were over the shock, didn't get measurements but unless the spring is just barely bigger in dieter than the shock it will not fit without major cutting and welding. Second problem is the kits listed above require the use of your factory top hats well since we Eco owners do not have coilovers in the rear we have not top hat there...

Does this mean the ECOs are shall we say short in terms of a coilover option or am I completely mistaken/overlooking something? If the first is the fact then would it be possible to sell a kit with rear lowering springs and shock, with fronts being fully sleeved height/damper adjustable (height would be my concern as the car won't be tracked and even if it is not often enough to necessitate those adjustments.

Anyone with info please help our fellow Eco owners out. ISM, TurboTech do you guys have any answers?


----------



## osiris10012 (Feb 4, 2011)

the ls and lt cruze also have the spring and shock separate(no rear struts). i am pretty sure our suspension components are the same except for the z link and the fact that your springs drop the eco a .5 inch over the ls and lt. insanespeed and ttr can answer all the questions you have.


----------



## FatKidsCruze (Sep 2, 2011)

Oh well then these questions/concerns also apply to LS and LT trims as well.


----------



## Mofolicious (Jun 19, 2011)

I had coilovers on my S40. Same type of suspension set up, basically. 



















I'm having a hard time finding pics of the set up online. I don't think I took any of mine either. The adjustment collar sits under the spring. I found mine to be a serious PITA to adjust, since the collar sat too low in the spring cradle.


----------



## Mofolicious (Jun 19, 2011)

Almost forgot I had this pic. Maybe it might help a bit. This is the rear of the P1 platform (S40, V50, C30, Mazda 3, and I believe the european Focus)










I've only looked under the rear of my car once, and that was when I was test driving it before buying. Hopefully I'm not incorrect about the similarities. Even so, I think that answers most of your questions. I don't recall how the rear damping was set up, if at all. I know the fronts were accessed at the top of the shock.


----------



## FatKidsCruze (Sep 2, 2011)

Thanks Mofolicious, that does answer my questions on a viable solution. Now if only a company would offer a quality set.

Coming from the Honda scene and unfamiliar with anything non coilover lol.


----------



## TravsCruze (Aug 4, 2011)

i would be very leery of using shock/dampener mounting locations for coil overs. These mounts are NOT meant to be load bearing. Dampeners are meant to do one thing, dampen the oscillations of the springs which only requires a fraction of the strength that the spring mounts require. You might be fine and never have an issue out of them, but you might just as easily break off a mount. 

Even i wouldn't do this mod.

Run your springs and shocks separate as it was designed, or build a set up that allows you to use the location of the current spring perches. Since that area is reinforced.


----------



## NBrehm (Jun 27, 2011)

I'd be willing to bet since the cruze has available coil overs that the body side of the mount is identical on both cars. Either way it has very large shock bolts on the top and bottom so I don't think in this particular case you will have to worry about breaking something


----------



## SlowBoost (Jul 26, 2011)

Mofolicious said:


> Almost forgot I had this pic. Maybe it might help a bit. This is the rear of the P1 platform (S40, V50, C30, Mazda 3, and I believe the european Focus)
> 
> 
> 
> ...


There shouldn't be any similarities at all between these vehicles and the Eco Cruze. All those listed are independent rear. Even the trailing arms are evident in that pic. Not that much different than the US Focus since 1999. That's why I am not terribly certain why a torsion beam is a cost saving measure. The Focus I bought new back in 2004 was $10k brand new and they were able to put independent rear suspension on that...


----------



## InsaneSpeed (May 7, 2011)

The DGR coilovers have been tested on an ECO, they fit. We carry them in 2 options, street and race, we recommend the street as the race is very stiff. We did not test the DGR's on our ECO, we were contacted by a DGR customer that did a test fit. We are still waiting on ours due to the unusual spring rate we ordered with custom valving, we also told them to take their time due to winter is fast approaching and they won't be installed until spring, I personally have to drive our Eco this winter, that was not the plan. 
I am still waiting on pictures of the install. 
Later
Steve


----------



## limited360 (May 6, 2011)

InsaneSpeed said:


> The DGR coilovers have been tested on an ECO, they fit. We carry them in 2 options, street and race, we recommend the street as the race is very stiff. We did not test the DGR's on our ECO, we were contacted by a DGR customer that did a test fit. We are still waiting on ours due to the unusual spring rate we ordered with custom valving, we also told them to take their time due to winter is fast approaching and they won't be installed until spring, I personally have to drive our Eco this winter, that was not the plan.
> I am still waiting on pictures of the install.
> Later
> Steve


Pics of the install would be solid... waiting on some pics installed before I pull the trigger.


----------



## FatKidsCruze (Sep 2, 2011)

limited360 said:


> Pics of the install would be solid... waiting on some pics installed before I pull the trigger.


^THIS

Thanks ISM that makes me happy to hear, cuz I think just lowering my ECO just enough for the top of the tire to start tucking will really complete how the car should look in my eyes.

On a side note, 6k & 4k seem really soft for this car's weight. A lot of the OTS rates for aftermarket Honda coils are 8k&6k and most of those older civics/integras only weigh ~2500lbs 2800 at most. Do you think the "race" setup at 8&6 will be too much for a DD, I like my ride to be nice and tight but still a little give.


----------



## JusticePete (Oct 6, 2011)

Does this count?


----------



## boats4life (May 28, 2011)

FatKidsCruze said:


> Thanks ISM that makes me happy to hear, cuz I think just lowering my ECO just enough for the top of the tire to start tucking will really complete how the car should look in my eyes.


Amen! I would LOVE to see mine on the edge of tucking...


----------



## JusticePete (Oct 6, 2011)

FatKidsCruze said:


> ^THIS
> 
> Thanks ISM that makes me happy to hear, cuz I think just lowering my ECO just enough for the top of the tire to start tucking will really complete how the car should look in my eyes.
> 
> On a side note, 6k & 4k seem really soft for this car's weight. A lot of the OTS rates for aftermarket Honda coils are 8k&6k and most of those older civics/integras only weigh ~2500lbs 2800 at most. Do you think the "race" setup at 8&6 will be too much for a DD, I like my ride to be nice and tight but still a little give.












With traffic like this, looks frequently take precedence over function with Asian coilovers. We find 6kg coils front and rear to work quite well on the Cruze. When the rim size increases and the sidewall decreases it impacts ride quality as much or more than the coil and damping rate. In the end it all depends on how you plan to use your Cruze.


----------



## Skilz10179 (Mar 22, 2011)

FatKidsCruze said:


> On a side note, 6k & 4k seem really soft for this car's weight. A lot of the OTS rates for aftermarket Honda coils are 8k&6k and most of those older civics/integras only weigh ~2500lbs 2800 at most. Do you think the "race" setup at 8&6 will be too much for a DD, I like my ride to be nice and tight but still a little give.


I was thinking the same thing about the 6k / 4k spring rates. My S14's coilovers springs are 8k / 10k and the car only weights about 2750. Most coilover companies sell additional springs with different rates for about $50 a piece.


----------



## NBrehm (Jun 27, 2011)

Skilz10179 said:


> I was thinking the same thing about the 6k / 4k spring rates. My S14's coilovers springs are 8k / 10k and the car only weights about 2750. Most coilover companies sell additional springs with different rates for about $50 a piece.



If you are talking spring rate, it must ride like a tank with those springs, but handle like an F-16. It all really depends on what you want. Every time I see a Honda bouncing around with .25" of suspension travel because the springs are so stiff all I can think of is how annoying it must be on any drive over a few miles. My Trans Am had 350# springs in the front and 275# springs in the back, was a 4000 pound car and handled great and rode nice. Unless there is a different way of measuring spring rate those numbers seem knock your teeth out high to me.


----------



## boats4life (May 28, 2011)

I think the 4k/6k springs would be perfect for the Cruze, stiffer than stock for better handling, but not so stiff that it'll knock your teeth loose with every bump.


----------



## FatKidsCruze (Sep 2, 2011)

NBrehm said:


> If you are talking spring rate, it must ride like a tank with those springs, but handle like an F-16. It all really depends on what you want. Every time I see a Honda bouncing around with .25" of suspension travel because the springs are so stiff all I can think of is how annoying it must be on any drive over a few miles. My Trans Am had 350# springs in the front and 275# springs in the back, was a 4000 pound car and handled great and rode nice. Unless there is a different way of measuring spring rate those numbers seem knock your teeth out high to me.


Actually the reason you see those guys bouncing more than a 25cent rubber ball is they are riding on shotty eBay coilover sleeves with crazy unknown rates and stock shocks... However with a properly valved and matched threaded body coilover from a quality company provides a stiff and sporty ride without being over bearing.

I have 8k/6k and used to be running 205/45/16 (3.63in sidewall) and it actually seemed soft compared to my old Crx had thicker tires and softer rates. Just my experience, I'm no suspension guru..


----------



## TravsCruze (Aug 4, 2011)

Nicks numbers are more realistic. a 4k lb spring rate means it would take 4k lbs to compress the spring 1 inch. So if these cars were perfectly 50/50 front to back and right to left. Your only looking at 750 lbs over a wheel. And they probably have 6 inches of total droop and they ride right in the middle of that roughly. So they are probably more in the 250 lb range. Since it would take 750 lbs to compress the spring 3 inches to the middle point. 

In the real world, the back really isn't that heavy so it's probably more like just under 200 lbs spring rate and the front is more like 275-300 lb springs


----------



## FatKidsCruze (Sep 2, 2011)

6kg/mm is approx 335lb/in
4k is 223 lb

Ok so based on what you're saying, my Eco weighs 3061 and probably has 60/40 weight distribution that's roughly,1836 over front wheels and 1224 over rear.

So at 6k/335lb it would droop 2.75 inches and same for rear at 4k
Or at 447lb(8k) droop at 2.05 front and 1.83 rear... 

If we say 3in droop is stock, street rates would be 9.5% stiffer f&r and race would be stiffer by 46% up front and 64% in the rear...

So in conclusion Street version should provide a slightly firmer yet stock-like ride quality. The race version will be noticeably stiffer and may be irritating while daily driving, but perform well on spirited jolts or weekend track visits. Thanks for the discussion guys, this thread is turning out to be very informative for me.


----------



## TravsCruze (Aug 4, 2011)

haha.. i've never heard them being done in kg/mm.. thats a first. So this is informative for me as well!!


----------



## JusticePete (Oct 6, 2011)

The conversion from kg to pounds is Xkg x 55.88 4kg x 55.88 = 223.5 pounds to compress the coil 1"


----------



## bartonmd (Jun 30, 2011)

What you guys also have to remember is the different kinds of suspension... Our springs are basically a 1:1 ratio of movement with the wheel travel, but if you go the coil-over direction, mounted to the shock mounts, our shocks actually have more travel than our wheel has... i.e. they are farther away from the pivot point than the wheel is, so the spring travels more, but acts more heavily on the wheel movement than the spring force.

Looking at the picture of my ECO's suspension, below, without measureing, I would say that the shock is probably 30% farther away from the pivot than the wheel is... This means that the shock moves 30% more than the wheel, which means the spring only has to be 77% as strong as you want the wheel to act...











Compare this to a Civic rear suspension, which is a more standard independant setup, where the spring only travels ~75% of what the wheel travels, so the spring has to be 133% as strong as you need the wheel to act...











So if you want the wheel on both cars to have a 6Kg/mm ("6k") spring rate, the Civic needs a 7.98k spring, and the Cruze needs a 4.62k spring...

High School Sophomore level geometry... Worst case, HS Junior level physics...

Mike


----------



## bartonmd (Jun 30, 2011)

FatKidsCruze said:


> 6kg/mm is approx 335lb/in
> 4k is 223 lb
> 
> Ok so based on what you're saying, my Eco weighs 3061 and probably has 60/40 weight distribution that's roughly,1836 over front wheels and 1224 over rear.
> ...


Must also consider the free length of the springs, and the preload still on them at full droop/extension... The ride height would/should be about the same (or lower on the "track" springs), but that is controlled as much by spring free lenght, and therefore preload on the extended strut assembly, as it is about spring rate...

It's not that anything you said was really "wrong", but there's just more to it than that...

Mike


----------



## FatKidsCruze (Sep 2, 2011)

Thanks for the additional info, like I said no suspension guru just trying to figure out which version of coilovers would be best fit my car. I'm glad there are some intelligent answers going on in this thread, its a nice change from what I'm used to in other forums I've been on in the past.



TravsCruze said:


> haha.. i've never heard them being done in kg/mm.. thats a first. So this is informative for me as well!!


Kg/mm is extended for "K" listed by most manufacturers



JusticePete said:


> The conversion from kg to pounds is Xkg x 55.88 4kg x 55.88 = 223.5 pounds to compress the coil 1"


I used .0179 as the conversion factor, 4K/.0179=223.46. After reading Travs post I did some calculations based on the weight of the car and estimated that the rear would compress 2.75 inches roughly solely based on weight. However, as stated by some others there are other factors that play a role in how far the springs are compressed by the weight of the car, such as shock travel and geometrics in the design.


----------



## TravsCruze (Aug 4, 2011)

FatKidsCruze said:


> Kg/mm is extended for "K" listed by most manufacturers.


I normally only deal with AFCO and their spring rates are in lbs. But thats good to know about the other companies.


----------



## JusticePete (Oct 6, 2011)

Spring development is frequently done at the OEM level in kg and then converted to lbs. Metrics make life easy. The most graphic example is in ride height. LF 503mm RF 507mm the differencee is 4mm. LF 19.8 inches RF 19.96 inches Difference .8 inches Ack Too Much Work!

The primary coil rate is determined by the material and wire diameter. The ID of the coil diameter factors in to final rate as does the spacing of the wind / number of coils. i.e. a 62mm ID coil of 8mm high silicone wire that is 200mm tall with 7 coils would be higher in rate when measured in the load cell compared to the same coil spec with only 3 coils. Please excuse the graphic exaggeration.



















The winds just past the coil upper and lower eyes are tighter than the more open winds in the middle of the coil. Long story short, the rate of the coil is one factor in the ride / handling equation. Equally important are unsprung weight, vehicle weight and motion ratio. These must be matched to the existing OE supplied damper as well as jounce travel and the design of the bumpstop.

Additional consideration must be given to how the coil is wound i.e. hot wound or cold wound. While a rose by any other name may still be a rose a spring is never just a spring.


----------

