Coilovers...DANG are they LOUD!

[SHOfun 93]

Well I have had the coilovers in the car for about a week now, and all I cans say is AVOID ROUGH ROADS with them at ALL COSTS. Maybe I got too stiff of springs (650/350) but my sho pops and creaks now like no other unless the car is on smooth road. I have checked all the pinch bolts, etc and I still get a popping/clunk from the rear when I go over even the smallest bumps and I think it is because the spring moves back and forth trying to get "seeded" in the housing.

Oh well, the price you pay to grip the road. I was just wondering if there were ways to quiet them down a bit? shrug

 

[blewbyu]

Jeremy, When I investigated going that route, I got the spring rates, and I do not recall them beign anywhere near that high.
Also, The rear spring, or any for that matter, should not be loose in a seat, or anywhere. It should not be able to slide back and forth. That will cause major problems in a sticky situation. Just my .02, hope all goes well, and post a few pics, I went SS, but love to see those even lower than I. Craig

 

[shojuan]

SHOfun 93:
Oh well, the price you pay to grip the road. I was just wondering if there were ways to quiet them down a bit? shrug

Maybe get on the phone with Scott Patterson and discuss it with him. Perhaps he could give you some good ideas of how to track down all those NVH gremlins that have reared their ugly heads. Word on the streets is that Scott really went to town nixing all the little NVH gremlins in his SHO. That's something I want to seriously get after when all my suspension goodies are installed. Problem with these cars is they were never all that tight to begin with. I think the idea is to pretend that you are a Toyota Q/A engineer and your job is to spend a few days figuring out where Ford went half assed, lol!

 

[olympic]

Yeah, 650lbs/in is really stiff. But it's the price you have to pay if you want the car to ride low. Maybe the springs are coming right off of their perches over bumps? Those stiff springs won't compress much with the weight of the car on them so you wont have alot of droop travel before the spring is fully extended and loses contact with the upper perch.

 

[sdpatt]

I wish I had taken the opportunity to ride in Jeremy's car on the Austin Run that we just completed. It sounds as if something is not assembled or installed properly. The springs should never be allowed to become unloaded - they should always be captured in compression by the mounting on the struts/shocks. If the springs are becoming unloaded and able to move with a full extension of the strut, they are not assembled properly.

On another note, a hard ride does not necessarily equate to good handling. In fact, excessive spring and strut rates can cause the tires to loose contact with the road in rough surfaces - a suspension's failure to keep the tires on the ground.

 

[N.Pinto]

olympic:
Maybe the springs are coming right off of their perches over bumps? Those stiff springs won't compress much with the weight of the car on them so you wont have alot of droop travel before the spring is fully extended and loses contact with the upper perch.

That does sound to be the problem in question. It is quite common on coilovers. The one way I know to combat this is the use of "helper springs". These are smaller springs, up to 2 inches, with very low spring rate. These keep the spring seated in its perch and have no affect on suspension characteristics.

I had looked into these a few months ago and think they were about $100 or so for 2 perches and 2 springs.

There are a LOT of spring options out there. You should check out Eibach.com they have some good introduction information there.

 

[olympic]

That's exactly what I have for my coil-overs. Small helper springs with a 2 way perch to hold them together with the real spring. They have a real low spring rate since I can compress them flat by hand. Here's a pic, you can see the aluminum perch about 2/3 of the way up and the helper spring on top:

I probably wont use the helpers on the front since the car is much heavier on that end and is less likely to raise up enough to lose contact with the spring.

 

[sdpatt]

If the strut at full extension can unseat the coil springs then there is a design deficiency in the coilover arrangement. The helper spring is just a band aid to the fact that the main coil cannot extend far enough to allow the strut to cover its full range of motion without becoming useless. That would mean that at larger extension distances that the spring is no longer supporting the weight of the car. A large *** hole or bump in the road that causes the strut to fully extend would create a situation where the spring is not touching at both ends. That should not be allowed to occur. I am very surpried to see that situation with an expensive suspension component.

 

[AutoSHO]

I think the reason they do that is because if they were to use a full length spring, it would be very hard to adjust the ride height. It would also have quite a bit of coil bind with a spring that long. The helper springs are a very common design, although they may not be the best answer.

 

[olympic]

I can see it happening quite easily. Most of the guys running 600lb/in(or higher) front springs are using 6" springs. And the strut has about 6" of travel. So unless your desired ride height occurs with the lower perch threaded right to the top of the collar(unlikely), the strut can extend farther than the spring, thus dislodging the spring from the upper perch. The helper spring just acts as a go-between in this situation to keep the real spring aligned and seated, and prevent any rattling noises from occuring.

Same thing goes for the rear springs. By my calculations, you need an 11-12" spring back there to accomodate the travel of the strut. Anything smaller and the coils will bind before hitting the bumpstop or the upper perch will dislodge before hitting full droop travel. Most SHO coilovers I've seen on this board are using 8-10" springs in the rear.

The helper spring is not wound out of round steel, it's wound out of flat steel. So when it's compressed, the coils fit perfectly together and shouldn't affect performance. Mine came with the kit I bought so I'll probably experiment a bit. If everything is quiet without them, I'll just leave them out.

 

[gmorrell]

sdpatt:
If the strut at full extension can unseat the coil springs then there is a design deficiency in the coilover arrangement. The helper spring is just a band aid to the fact that the main coil cannot extend far enough to allow the strut to cover its full range of motion without becoming useless. That would mean that at larger extension distances that the spring is no longer supporting the weight of the car. A large *** hole or bump in the road that causes the strut to fully extend would create a situation where the spring is not touching at both ends. That should not be allowed to occur. I am very surpried to see that situation with an expensive suspension component.

While what you suggest would be ideal, its not always the case in the real world. In order to stay away from coil bind at full bump, the SHO suspension needs at a minimum, 10" springs up front and 12" in the rear for a coil over application. One could run 10"/12" F/R spring lengths at reasonable spring rates (about 350# front and 250# rear) and achieve factory ride height with the spring perches near their lowest, and with no helper springs. This would be the ideal if you wanted OEM ride height, but very few want this.

With my coil overs, I was trying to achieve an Eibach ride height with 500# up front and 350# in the rear, and some pretty stiff bump stops because of the shorter springs; 8" front and 10" rear. Lowering a SHO much below Eibach ride heights is only going to make the camber gain situation worse then it already is, so I don't see the point unless someone wants it for visual appeal, but to each his own.

Until you've measured corner weights, strut travel, wheel travel, spring travel, calculated motion ratios (Motion ratios on the SHO suspension are not 1, they're less then 1...), designed and fabricated a bunch of expensive parts, then redesigned a few parts because the first parts didn't work out exactly as planned, etc., I'd rather you wouldn't label a design as deficient. Putting coil overs on a street car is never easy, and in these sorts of applications, the use of helper springs is more common then you might think.

 

[SHOfun 93]

Well I'm glad I got some input on this subject while away at Big 12 Referee camp!

Another note, the person who installed my coilovers has done coils before for other cars, (imports etc...) so he installed them the way they should be. One note, when I put my hand under the rear where the noise was occurring, I could move the rear spring back and forth like it was losing its "seed" on the top and bottom of the housing. That is where I believe my clunking is occurring. rant

 

[sdpatt]

I'll change the reference of "deficiency" to "compromise," but it is still a design problem that must be dealt with.

Jeremy, is sounds like there is a spring locator missing from that moving spring that is not allowing the spring to seat properly.

 

[gmorrell]

sdpatt:
I'll change the reference of "deficiency" to "compromise," but it is still a design problem that must be dealt with.

Sorry Scott, I didn't mean to dis you on that.
The reality of making 2.5" diameter coil overs work on a street car is chock full of compromises, especially when you're converting a strut suspension. SLA suspensions are much easier to convert to coil overs. While it would be ideal to maximize bump travel (and minimize the chance of coil bind) by using longer springs with the lower perch further down on the strut tube, this isn't possible with the SHO because of how close the tire and wheel are to the strut and the interfering accessory brackets on the strut tube. You're simply stuck with short springs which have a spring travel that can be several inches less then the available strut travel.

I have some pictures of my coil overs, I need to activate my photo album account and post them here. There's about 2 years of spare time engineering that went into these, and I finally have them on the car.

 

[FordLover]

Even my SHOshop linear/tokico setup would 'step out' in a high speed turn situation when I'd hit a bump. It was surprising enough to bother me a few times, I still think heavy suspension mods are best for smooth track use. My ATX 4x4 stance is good enough for me for daily use, and downtown 'urban offroading'.
-Martin

 

[1fastsho]

well it is a racing set up. any coil over that is "designed for street use" isn't a real coil over set up in my opinion. my car didn't have the niose problem and this is the first I have heard of any of our sets to have noise.

my car out handled a modified miata, and while my car is pretty stiff I do not feel it is overly stiff. there are comprimises of course, but it is a racing design...coilovers in general.

Jeremy if the car is loaded ie hte wheels on the ground you should not be able to move the spring. if you can then there is something wrong.

 

[SHOfun 93]

I guess I need to rephrase that..I had the car jacked up doing the fuel pump, and that was the only way I could get access to the spring. I was trying to "recreate" the clunk I was hearing when going over bumps to see what it was, and to check the tightness of all the bolts, etc that were on the car.

My question is this. Should I crank down the springs a bit more? They can take more turns, it is just that the shop that installed them wouldn't go any lower due to the camber being away from zero.

Also, how do I turn them lower, and keep track of the turns? I really haven't dealt with coilovers before..

 

[1fastsho]

marked the lower perch and kept track of the revolutions.

 

[SHOfun 93]

thanks Shawn. Would it hurt to have a little negative camber a bit? I mean not "terriblly ricey" but go a bit lower?

 

[1fastsho]

it shouldn't hurt as long as the toe is correct.