[Trans Am Don]

Has anyone done any mods to address the bottoming out of the rear suspension. My car bottoms out frequently even driving solo. On a road trip with passenger and luggage it can be quite severe. I have been looking at an airbag in the rear coils but the snubber seems to preclude this approach. Any thoughts would be appreciated.

 

[Guillermo]

Try contacting some auto spring manufacturers. Many of these will make custom springs for you if they cannot find one in stock that will do the job. If you get stiffer springs in the rear only it will cause your car to understeer less or even oversteer depends on the tire grip and how much stiffer the rears are.

 

[Yves M.]

Spacer

Hi,

I have been thinking to add a half inch nylon ring between the coil spring and car. I need to look into the dimension but I have done this in the past on my Jeep Cherokee's front suspension.

Yves.

 

[Yves M.]

Hi,

I have looked at the distance between the bump cone and the body on the rear and without people in it: 1 1/2 inch which is not much. Less with me and a passenger.

I have installed a 1 inch spacer (home made using thick plastic).
Now the rear is one inch higher so the possible travel up for the
wheel is now 2 1/2 inch (about 75% improvement).

For now it works fine. I will see with time how less often the car bottoms out.
See an image in the Photos section of the HONDA-INSIGHT group.
It is a composite of before/while/after images. The file is called:
"rearlift.jpg"
At: http://photos.groups.yahoo.com/group/honda-
insight/vwp?.dir=/&.dnm=rearlift.jpg&.src=gr&.view=t&.hires=t
(need to copy/paste the second line of the link)

Yves.
P.S. You can see on the picture that the rubber cone has hit the body tube so many times that there is not paint left where there is contact.

 

[gomarlins3]

Linky no worky

 

[Yves M.]

Hi,

Try this then:
http://autos.groups.yahoo.com/group/hon ... arlift.jpg

Yves.

 

[Yves M.]

Hi,

Tried the link and this one works.
Y

 

[flunkysama]

You can also try a rubber spacer that jams between the coils. Depending on the coil spacing they can stiffen the spring without increasing the ride height (which will probably hurt MPG). They can also be easier to insert and remove.

Here's a link to one that JCW offers. http://www.jcw.com/webapp/wcs/stores/servlet/ProductDisplay?Dx=mode+matchall&productId=1116&catalogId=10101

 

[Yves M.]

Hi,

I have tried that a few years ago on an other car. There is lots of pressure on the small thing. The rubber will break in two, cut by the spring compression.

I wanted to have more room between the stopper cone and the body stub which is around 3/4 inch when two are in the car. It makes for very small bumps before they hit eachother. Now it is doubled and the ride is more comfortable. I did not want to stiffen the suspension.

Yves.

 

[speed]

Stiffen by spacer

I am looking into this problem as well, and will look at the spacer idea, but need to point something out. A spacer will raise the vehicle. It will also preload the spring, basically, if it was a progressive spring, you just removed some of the initial "softness", but the total spring rate will not change. You can see this in older motorcycles, where the preload collar is rotated. My problem is that the travel AND spring rate is just too low. I am about 225 and my fiance is about 125 (with probably 40 lbs of purse too!). It taxes the suspension, god forbid we actually use the storage areas for things with weight. A increase of about an inch with about 20% increase in rate feels about right (based on other cars I have modified). If anyone knew the stock spring rate, getting a custom wound one would be easy. Anyone???

 

[Yves M.]

HI,

I am about at the same weight situation as you. Probably more weight here (215+150+stuff).
I would not agree about the preload. It only raises the car but does not compress the spring while nobody is in the car. It is the raison it is higher by the same amount than the spacer. No spring compression modification (in relation to the "removed some of the initial softness" part)

I suppose that on a motorcycle (not sure), the spring is held to a maximum length when nobody sits, by the mechanical parts holding it. So then it is preloaded because the length is prefixed. On a car at rest, the car weight sets the height, not the shock length or oher parts

Once we are into the car, then the car is probably setting where a one 150 pounds man would be. The car is no longer higher. It was probably lower than supposed to when the lift spacer was not present.
¨
EDIT: For the total rate, the spring can now by compressed by an inch more than before so the total rate used is increased by the last inch

 

[james]

"...getting a custom wound one would be easy..."

Try a search on old threads. There was one where someone did it, maybe last fall? Gave an address for the custom spring maker...

 

[coolcat]

My Insight has never bottomed out its springs, not even with me (225 lbs) driving and my brother (275 lbs) as passenger, and a load of stuff (oh, about 100 lbs or so) in the back. I've done a fair bit of driving with this load, on bumpy roads and all, and never had a problem. In fact, I'm thinking about doing what Mitch did, getting lowering springs with a higher spring rate made. I wonder if there's really that much variation in the spring rates from the factory? Or maybe you just have really-really-really bad roads?

 

[speed]

Yes yves, you are right. Motorcycle springs have retainers that set extended length, so it results in preload. Your spacer will not change it, but I need more spring rate as well. I may still do a spacer, since the travel limitations in the back are way out of sync with the front. I hope to have a spring rate, and damping rate solution soon.

 

[Yves M.]

This is specially for Coolcat,

Please,Please,Please take the time to try and give the result on this tread, what you wrote about, I really think that all Insights are the same and Very much wish for the answer:

Like you wrote:
- Put yourself in the driver seat (225 lbs)
- Put your brother as the passenger (275 lbs)
- Put about 100 lbs of stuff in the back
- Now, get a third person to check under the back of the car with a flashlight. That person will see the coil spring. Inside the coil spring there are two things 1) a stub that is the car body 2) a rubber bumper that is attached to the wheel axel.

a) take an approximate mesure of the distance between the two (stub and rubber bumper) with the load above

b) Remove everybody from the car and the stuff (100lbs) also, no load, and mesure again the distance between the stub and the rubber bumper

Now give the result. I would expect that there is no distance (or less than an inch) when loaded. I do not remember what it was without the load, but you will provide the answer.

I thank you in advance for doing the test for me. I will see if we have similar cars.Mine is a 2000 model, and yours is?

 

[speed]

I am close to having a replacement rear spring from Eibach picked out. With the wide selection they have, a custom wind is not required (custom = more cost). My rapidly upcoming wedding and customers airplane and engine requireing reassembly has slowed me up, but I should have the spring speced out in a week or so. Eibach was very helpful in supplying the formulas and springs they stock. The next issue will be finding a shock with increased damping to match, Insight a VERY short shock. I do not plan to change the fronts, at least initially. The rears are way unbalanced, and the fronts may be just fine as is. Loading the car adds far more to rear loading anyway. It's true this will increase oversteer, but I like a FWD with that, nice change from understeer (if you know how to drive, lol). This can be balanced somewhat with replacement of front stabilizer bar bushings with hard urethane, gives quicker increase in roll resistance. Again, I am intrested in suspension load ability for normal driving, not full race handling. I am pretty happy with the basic handling considering the cars purpose.

 

[Yves M.]

Refresh, Any update from Speed, Coolcat?