ride help Qs

[turbeau]

my car is not enjoyable to drive due to the harsh suspension. I have sectioned struts in front and non in the rear. Cosmo coil overs. springs are 280 fronts and 336 rears. 205/50/15 225/50/15 tires. Stock sway bars. I think the struts are from a first gen mr2 either koni or tokico non adjustable.

 

on the freeway the car is rocking front to back. When I hit bumps on the freeway the entire car lifts off the ground, and street bumps rattle the whole car.

 

I was thinking of ordering a set of eibach springs in a street spec, 250 200? 8 or ten inch?

 

here are some pics, all are of the rear suspension, which is not sectioned. there is a 2-3" spacer in the bottom of the strut tube holding the strut up.

 

sus2 is suspension with no load, this is the top hat?

sus1 is the suspension under full load, car on the ground, twelve threads at the bottom

sus3 is the bottom collar with no load

sus8 is car on ground, does this look like it will bottom out or coil bind on bumps?

sus9 is a big bolt?

sus6 is the height i think looks good, or maybe a half inch lower

sus5 is the height of the car with the settings of pic sus8 and sus1

 

i can post other pics if they would be helpful. thanks for any suggestions

[ZT-R]

I would start by getting some tophats for the coilovers, are the stock isolators in there? if so anything over 250 spring rate your not gonna benefit from.

[BluDestiny]

That's pretty harsh spring rates. Most people That I know who section their struts go with 225F and 250R.

 

You could also try getting a taller tire to absorb more shock, or you can try getting some small helper springs to absorb shock.

[RebekahsZ]

Hey, great pictures-your car is sweet! The picture file nambes don't show on my browser, so it is a little hard to follow you. I like the lowered look in the pic that you like, so lets try to get you driving around like that, but not in misery.

 

Did raising the rear ride height improve anything? Your springs are not progressives, so that is good, they are not coil bound and are probably not the problem.

 

I think the pic you sent showing remaining travel is of the front, not the back (but I'm not positive). We need some idea of what travel is left in the REAR when the car is on its weight, but it is hard to get visibility inside the rear fender. Try taking off the rear tire and jacking under the control arm until the control arm is at the same angle as the other side (to mimic having the tire on the ground): perhaps you can see how much travel is left then. Maybe you could put some chewing gum on top of the strut and see if it gets squished? If that photo is of the rear, it ought to be ok.

 

Did you check gland nut tightness? I can't see the gland nut in any of the photos, it almost looks like the threaded collar is longer than the strut? If your strut is loose in the tube, it could explain your trouble.

 

Check your half-shaft u-joints, I can't tell for sure from the photos, but they look crooked?? That could make a rattling noise.

 

On the "top hats" I am not familiar with the way your kit is assembled, retaining the old large spring seat and a small aftermarket spring seat together. I had upper spring seats machined from billet that allowed me to retain the top insulator (the big rubber biscuit that bolts in with 3 nuts at the top of the strut tower (chassis), and to eliminate the large stock spring seat. In your case, the old large spring seat may be clanging around. Did you put the kit together, where there instructions that told you to keep the old upper seats?

 

Question: Is your ride harsh, or just noisy? I'm gonna shoot some pictures of my stuff and edit this post in a few minutes. Try to answer all my questions so I can help you.

 

Keith

[RebekahsZ]

This is my set up which I love. My spring rates are Front: 225, Rear: 250, or perhaps 275. Pic 1 is rideheight w/ 225/50/15 drag radials on back, 205/50/15 street tires BFG on front. Pic2 shows my front kit w/ car on tire on ground w/ full weight. First you will notice that I have a lot less crap inside my strut tower than you do. The shiney part at the top is a EMI camber plate assembly from BetaMotorsports-they are no longer available, but a similar product is the DP bolt-in camber plate, also from BetaMotorsports.com. Distance from gland nut to top spring seat is 3-1/2" with 1-1/2" taken up by polyurethane bump stop mounted on shock tube (I have probably twice the travel you have. I don't have pics of the back, but when I got out my flashlight, the travel is about the same-you could use lots more travel. Pic3 shows that i am maxed out on my threaded collars-since I installed camber plates, I need longer springs-I'd really like to go up another inch or so (that would give me yet another inch of travel). Pic4 shows two different kinds of bump stops; the red one came with my tokicos and i cut it in half-it was double that length, the black one is from MSA or somewhere-it is loose on the shaft and would need to be glued to either the upper spring seat or the gland nut. Pic5&6 show you what a gland nut is. You should have at least a few threads exposed when the gland nut is fully tightened-if you don't, your shock is loose in the tube.

 

What is a "top hat." I'm not sure what other people mean. I like to be more specific in my terminology. Pic 7 is a custom upper spring seat and insulator assembly that I had machined because initially I was too cheap to get camber plates. The black thing on top is the stock insulator, the shiney thing on bottom is the upper spring seat. Pic 8 shows the components of the assembly which include the stock insulator, the steering bearing, and the upper spring seat. All of this should fit snuggly together and the upper spring seat should rotate inside the insulator to allow steering function. Pic9 shows you the assembly for the rear, which has a black rubber donut in place of the steering bearing, since you steer the rear of a z-car with the throttle pedal! Pic 10 just kind of shows how you stack the assembly up. Pics 11&12 are just additional photos of my car with different wheels and tires-I can't seem to find a photo of my car with 16X8 RBRs with 225/50/16. If you want me to, I can get out my micrometer and send you simple drawings and measurements of my custom upper spring seats so you can have some milled, but if you want to skip that step and go all the way, just call BetaMotorsports and get DP camber plates for all four corners.

 

Remember to check your half-shaft u-joints: shove a big screwdriver into them and pry around-you should have no looseness.

 

Let me know how it turns out.

 

Keith

Edited December 21, 2011 by RebekahsZ

[turbeau]

Thanks for the insight guys.

All the pics are of the left rear. Non of the front.

I have raised it up and driven around. Still to stiff, springs Definetly have to be replaced. I took these springs to a shop and measured the rates. 200 250 sounds like it will be a good combo.

I think the clunking is from the struts not being tightened all the way down from the top. I sat in the hatch and had my girl friend drive around the block. I could see the top of the struts moving up and down. When I tighten the bolt on top it just spins, I think the whole strut is spinning in the tube. I tried putting a rag on the strut then hold it with plyers and tighten, but it still spun.

[ZT-R]

Thats normal for the shaft to spin when you try to tighten it. Use an impact gun in bursts on like setting 2 of 3 or so.

[RebekahsZ]

ZT-R is right-the strut rod (shaft) will always try to rotate when you tighten the retaining nut. Some brands of struts have the threaded portion cut in a D-shape that fits into a corresponding D-shape in the insulator, that retrains rotation of the strut rod and you can tighten those up really easy. My tokicos have two flat spots machined on the sides of the strut rod, but they are not a standard size, so I don't have a wrench to fit them; I will someday make one from flat metal stock that will fit (another dam_ project). In the meantime, I have just done what ZT-R recommended: use an air impact wrench to tighten them. That has become my method for loosening or tightening anything that I cant restrain rotation on, like differential flanges, etc. Tightening that nut may solve all your problems-kiss your wife for helping you! After you tighten the nut, go for another spin with your wife and see if that fixed it-you could still have a de-bonded insulator or simply an improper parts stack within the upper spring seat/insulator assembly. When you tear down to install softer springs, I think you could go with the same spring length that you have now. Call betamotorsports and see how much a set of DP camber plates will cost you. If you install them, you will be at least an inch lower just from the plate, and you could convert that extra space into available suspension travel between your gland nut and the camber plate just by raising the lower spring seat on the threaded collar. You could also get rid of the old spring seat. Betamotorsport will have to know either what brand of strut you are running, or you will have to tear down and measure the top of your strut rod so that a compatible spherical bearing can be selected.

[zero]

turbeau

 

I bought the same coilovers around 2004 back when they first appeared on ebay. The spring rates are far to high and the springs themselves are a bit on the short side, though mine came with helper springs. Those spring rates overwhelm most stock-ish struts. I kept them because I'm stubborn, but now I plan on keeping the sleeves and ordering some new 10" 200/225 springs from Summit along with some illuminas now that I'm going back over my suspension.

[johnc]

Drop the spring rate, raise the car up, put some urethane bump stops on the shock shafts, drop your tire pressure to around 29 psi. Ride harshness comes from these things:

 

1. Tire sidewall height.

2. Tire air pressure.

3. Shock compression damping.

4. TC rod bushing compliance.

[Leon]

Drop the spring rate, raise the car up, put some urethane bump stops on the shock shafts, drop your tire pressure to around 29 psi. Ride harshness comes from these things:

 

1. Tire sidewall height.

2. Tire air pressure.

3. Shock compression damping.

4. TC rod bushing compliance.

 

Those are definitely some important components of overall rate and ride comfort (especially compression damping), but the spring rate itself is the biggest contributor.

 

As John mentions, the first thing you (turbeau) need to do is drop the spring rates. Spring rate is tied to your suspensions natural frequency; as the rate increases, natural frequency (f_n) increases. You've chosen an f_n that is too high for the intended use of your car, thus the pitching, rattling and unsettling ride.

 

Your dampers are also a big part of comfort, so if you were dead set on keeping those springs then you should match them with proper damping. However, as spring rate goes up, so does the cost of the accompanying shock! Therefore, it makes more sense to drop the rate and match it with good, but less cost-prohibitive dampers.

[letitsnow]

I use 200/225 springs with bilstein dampers, the ride is firm, but pretty good. I'm not afraid of hitting some of the smoother train tracks around here at cruising speed. The 100mile round trip to my previous job was tiring though.

[turbeau]

Great stuff guys. I'm super excited to try it all out.

 

Before I can do that I have to get the car running again. There is an unknown ignition problem. I have a thread going in the engine components ignition/electronics section. Any input would be greatly appreciated.

Edited December 21, 2011 by turbeau