Cross Coilover Initial Review

[Clap135]

Originally Posted by vividracing

Nobody is blaming anything. In fact, we have all made suggestions. And you need to compare apples to apples. That is a video on Skunk2.

Want me to post emails where dan is directly blaming my ride height to the noise?

Who cares if those are Skunk 2 coilovers. Its the same principle. Shock travel is fixed on both systems, you do not loose shock travel when you lower the car....esp when you are running more preload than standard.

[Victory Road]

Originally Posted by Clap135

Ive thought about this for some time now, but ruled it out due to fact of how violent it is. It is not just a noise, this is felt through the car and gets better the stiffer i got on the shocks and the more preload I run, however it does not go away, just gets better. I will try the zip tie test this weekend, however im 99 percent sure the springs are not stiff enough for the amount of travel the front of these coilovers have.

just as a disclaimer. I am not trying to get in between you and Vivid's current issue. I am trying to help you alone.

The difference between a 8k and 9k spring should not make the difference between bottoming out and not bottoming out in my experience. The only thing that is puzzeling is you saying it gets better with the stiffer shock setting. That should make it worse with my "noise" theory. I'm really interested to see the results of the "ziptie test".

[vividracing]

If your ride height was set to load, then it is possible to bottom out on the bump stops. With the Porsche 996TT, customers were running Bilstein PSS9 coilovers and setting them to GT2 specs. They would bottom out and hit the bump stops because of the ride height. There is 2 ways to adjust ride height: 1 you can do it the wrong way from the spring perch which is really just sag (motocross riders will understand), or 2 done from the lower shock body. The reason I say you must compare apples to apples is not all coilovers have the same type of ride height adjustment. JIC has a lower bottom bracket for the front that allows you to thread the shock absorber in and out. With that being said, you can probably lower the coilover as far down as possible, but the you can see underneath the rubber boot, the bump stop from the shock travel is limited. So yes ride height can be a problem if set to low.

[Clap135]

Originally Posted by frank@WSTO

just as a disclaimer. I am not trying to get in between you and Vivid's current issue. I am trying to help you alone.

The difference between a 8k and 9k spring should not make the difference between bottoming out and not bottoming out in my experience. The only thing that is puzzeling is you saying it gets better with the stiffer shock setting. That should make it worse with my "noise" theory. I'm really interested to see the results of the "ziptie test".

trust me i appriciate your advise, however if i go out right now and set the fronts to setting 1, ill probably put a strut through the strut tower.

[Clap135]

Originally Posted by vividracing

If your ride height was set to load, then it is possible to bottom out on the bump stops. With the Porsche 996TT, customers were running Bilstein PSS9 coilovers and setting them to GT2 specs. They would bottom out and hit the bump stops because of the ride height. There is 2 ways to adjust ride height: 1 you can do it the wrong way from the spring perch which is really just sag (motocross riders will understand), or 2 done from the lower shock body. The reason I say you must compare apples to apples is not all coilovers have the same type of ride height adjustment. JIC has a lower bottom bracket for the front that allows you to thread the shock absorber in and out. With that being said, you can probably lower the coilover as far down as possible, but the you can see underneath the rubber boot, the bump stop from the shock travel is limited. So yes ride height can be a problem if set to low.

pss9 are not the same, at least not the bmw ones. Shock travel on the CC coilovers is fixed. Btw i have a track ready r6....like i said, i understand how suspension works. Shock travel is NOT affect with ride height on this system...dear god. Think about what you are saying, then think about what i mean when i say shock travel is FIXED, aka i does not change.

[vividracing]

Here are some photos of the coilover I just went in back and dissassembled. After forwarding the link to this thread to the owner of JIC, everyone is confident you bottoming out has nothing to do with spring rate, its not possible. I suggest you get a measurement from the bottom of the spring perch to the top of the bottom bracket or post a picture here. As I just saw on the seperate coilover, if you lower the shock using the bottom bracket, you come very close to the lower spring perch. Thus you need to raise the spring perch putting more preload on the spring. The shock travel is not endless and inside that gold shock body is a bump stump. If the spring perch is to loose and the sag is set this way, you will bottom out. If the coilover is lowered to the point where there is barely anymore room for travel, you will bottom out. But nobody here has seen a picture of your shock to see approximately what your setup is.

Jon the owner of JIC said it might be the upper strut top as well. Again I hear the same thing on the front right side when I hit a big bump. I mean BIG like a rain gutter in the street. As you can see by the other picture, the upper spring collar is very close to the strut top plate when tilted all the way. Please show us a picture of how your camber plates are in from the top. Dampening really will make a difference here as dampening is how fast or slow the shock reacts when compressed. I would also take a look at the upper spring perch and see if there is any wear. In this case, it might be hitting the camber plate. If NONE of the follow persists, then the noise is probably, and this has happened before, in your strut top monoball. That monoball can loosen up if not tighten and then have play. Jon at JIC said they would replace this. You can also send your coilovers direct to them for inspection at no charge.

Here is a picture of my setup, please post a picture so we can compare approximately.

Front


Rear


Camber Plate Position

[Clap135]

ok, ill go jack the car up. Im running -2.5 degrees of camber, but ill just post the pics. Give me like an hour

[vividracing]

The camber wont affect anything unless the adjustment from top is so far in that the upper spring perch is hitting something. Let us know, we are ALL here to help.

[Clap135]

unfortunatly, i cannot get the dust boot up to reveal the shaft with the sping on the coilover. I dont know what these pictures are going to show you but i took pictures of the sag im running, the camber plates, and the top perch near the plate. Your perch seems agled, mine has an equal distance btwn the plate all around the strut.

excuse the FILTHY car, i was forced to apple picking and driving the car on a grass/dirt road, that was wet...im still pissed about that lol.

[Clap135]

the only problem that i see is that the bottom of the spring (the part that lays flat on the perch is/was hitting the first full coil) I'm not sure if its doing it, or if it was doing when i was running insane amount of preload.

After i saw the pics i reliazed the spring could be hitting, however i cleaned off all the spots that appeard to be hitting and it was just dirt, no signs of contact anywhere (aside from the flat bottom and first full coil, which you can see in the picture.)

[vividracing]

Put your camber to 0 degree using the upper mount, go for a drive under the same routine you do where you here the sound, tell me if you here it again. That is the simple thing to do. If you still here and want to know if it is the shock bottoming out or the upper mount bearing, raise the front end using the bottom bracket about 1/2inch. Repeat the above. Make sure to use black marker on both previous settings so you can go back to them. From the look of it, ride height and spring settings look ok. Mine is set at probably max 1 degree, but most of it was adjusted using the lower OEM adjustments.

I am more then happy to help and will gladly go delete my other posts.

[Clap135]

Originally Posted by vividracing

Put your camber to 0 degree using the upper mount, go for a drive under the same routine you do where you here the sound, tell me if you here it again. That is the simple thing to do. If you still here and want to know if it is the shock bottoming out or the upper mount bearing, raise the front end using the bottom bracket about 1/2inch. Repeat the above. Make sure to use black marker on both previous settings so you can go back to them. From the look of it, ride height and spring settings look ok. Mine is set at probably max 1 degree, but most of it was adjusted using the lower OEM adjustments.

I am more then happy to help and will gladly go delete my other posts.

dan, sean, adam, rob...whoever this is. I have tried everything aready. Raise the car, slam the car, setting 1 through 15, camber, no camber, even positive camber, pre load, no preload, insane preload....the biggest change was getting rid of the run flats and putting spongy snow tires on. However with preload set in the Tight, but movable position, and setting 1-4ish, the car bottoms out hard. More preload helped, stiffer settings helped, however it got to the point of driving a wheel barrel. Final setting are as pictured, f is set at 10 i believe, rear is set at 6 or 7.

I would advise you guys too dump the 8k spring and run a min of 10k f. If i went through cross i probably would have gone 12f/14r rear, but who knows if the valve the shock for that.
To those that dont know the story, i am not arguing 8k vs 9k, i believe 9k wont make much of a difference, however this was just simply one the issues that i had with vivid, thats why it was mentioned.

[Clap135]

what your take about the coils hitting each other at the bottom perch?

this picture shows it

[vividracing]

This is the Dan, the owner. If you still have the noise no matter the suggestions I have made, then it is your upper strut top. Oddly enough if 3 of us are experience a similar noise all with different ride height and alignment settings, it points to that. Based upon how your strut top looks in the picture, it would make me feel better for you to knock it to 0 and try it again. If you would like to remove the coilovers and send them to JIC to inspect and replace if damage, they will do this free of charge. But it is obvious if you have done all of the above and you still have the issue, that is is not dampening, height, or spring comparison. The 12/14 would be 1 hell of an aggressive setup for a street car and you would want to make sure for track events you have a matched RCompound tire. If you want to swap out the springs, let us know.

I run the 8kg/12kg setup on my 997TT and the only reason you go that stiff in the rear is because of the engine. Track guys in Porsche will run a 10/14kg and that is stiff. We are here to help and if you want us to assist in a product inspection, we will do so. Wish you the best.

[Clap135]

If the spring is compressed to a length shorter than the limit length, the actual stiffness of the spring increases significantly above the theoretically determined stiffness valid in the field of compression to this length. At the same time, the critical speed decreases (see [4.34]) and this also increases the risk of mutual hitting of coils in operation. Due to these reasons, a compression spring (even during a test or installation) should not be squeezed to a smaller length. This results in the condition for the design of the spring that the length of the spring in a fully loaded condition [4.22] is greater than this limit length.



hmmmm seems like my theory is getting stronger and stronger guys....

[vividracing]

the coil flat part should be resting on the spring perch, the 1st coil should not hit the spring perch however. Is there scraping or visual damage it is touching? This could be the case too?

[Clap135]

Originally Posted by vividracing

This is the Dan, the owner. If you still have the noise no matter the suggestions I have made, then it is your upper strut top. Oddly enough if 3 of us are experience a similar noise all with different ride height and alignment settings, it points to that. Based upon how your strut top looks in the picture, it would make me feel better for you to knock it to 0 and try it again. If you would like to remove the coilovers and send them to JIC to inspect and replace if damage, they will do this free of charge. But it is obvious if you have done all of the above and you still have the issue, that is is not dampening, height, or spring comparison. The 12/14 would be 1 hell of an aggressive setup for a street car and you would want to make sure for track events you have a matched RCompound tire. If you want to swap out the springs, let us know.

I run the 8kg/12kg setup on my 997TT and the only reason you go that stiff in the rear is because of the engine. Track guys in Porsche will run a 10/14kg and that is stiff. We are here to help and if you want us to assist in a product inspection, we will do so. Wish you the best.

the spring coils are hitting, meaning we are over the limit of the spring when hitting bumps. Running 14k rear is not insane in a car that tends to understear, it will rotate the rear, which is what i want. I've run crazier custom GC coilovers/koni combo on my sentra autox car. The car weight 26xx and change, most of the weight was on the front and rear spring was 950lbs... Trust me if you have the strut valved right, you wont notice it.

[Clap135]

Originally Posted by vividracing

the coil flat part should be resting on the spring perch, the 1st coil should not hit the spring perch however. Is there scraping or visual damage it is touching? This could be the case too?

there are indentations btwn the flat coil and the frist rounded coil. The srping is too weak...

you have two options to fix this...longer springs, which will decrease height adjustment, but it will spread the load more across the spring, or stiffer spring rates. No other solution that i know off. If any of you track guys know of something better, let me know.

btw the difference btwn 8-9k is roughtly 60 lbs.
for those that are curious.


k lbs
16 = 896
15 = 840
14 = 784
13 = 728
12 = 672
11 = 616
10 = 560
9.0 = 504
8.5 = 476
8.0 = 448
7.5 = 420
7.0 = 392
6.5 = 364
6.0 = 336
5.5 = 308
5.0 = 280
4.5 = 252
4.0 = 224
3.0 = 168
2.0 = 112

keep in mind that the way our rear suspension is set up does not make the spring rates equal to what they are. 12k spring rates, are more like 7-8k spring rates....dont ask me to do the math for you, just trust me

[vividracing]

You are getting into more of a custom setup then 1 off the shelf. If you would like to send them in, JIC will go through them and custom valve and switch the springs rates for you free on my dime. Just let me know.

[vividracing]

Originally Posted by Clap135

If the spring is compressed to a length shorter than the limit length, the actual stiffness of the spring increases significantly above the theoretically determined stiffness valid in the field of compression to this length. At the same time, the critical speed decreases (see [4.34]) and this also increases the risk of mutual hitting of coils in operation. Due to these reasons, a compression spring (even during a test or installation) should not be squeezed to a smaller length. This results in the condition for the design of the spring that the length of the spring in a fully loaded condition [4.22] is greater than this limit length.

hmmmm seems like my theory is getting stronger and stronger guys....

Not sure where that came from, but yes there is a difference between linear and progressive springs and why some setups use tender or aka helper springs. I would clean that lower spring perch off and coil, but a tab of grease on the coil, drive it, see if it hits the spring perch. I am going to post here some pictures of other coilovers on different cars so you can compare the bottom spring perch. Each one of these cars have been from our Project Builds Here some of these cars have been beat the piss out of on serious road courses, some only daily driven, but the ones with JIC have always been there standard spring rates and I have never had an issue with.

Apologize in advance if some pictures may or may not help.

[Clap135]

Originally Posted by vividracing

You are getting into more of a custom setup then 1 off the shelf. If you would like to send them in, JIC will go through them and custom valve and switch the springs rates for you free on my dime. Just let me know.

I do not believe this should be a custom set up. The car bottoms out with normal street use, where the stock suspension did not. I know this is not your fault are you just carry the parts, just letting you know that a custumer should not alter a product just to make it work right, not a product that runs 2 plus k. If these were megan coilover or some other knock off crap...fine, but not Jic/cross. KW is another one that has a shit spring design. Should of went with kline lol. The suspension was not designed right imo. How long does this offer stand for? Instead of taking everything off, i rather try a longer or stiffer front spring that i can just swap in in 30 min without having any down time. Either a 12k same lenght spring, or a 10k longer spring (if this is even possible)

btw didn't you post in your GB thread that you guys reported zero noise or odd things with these? And now you have 3 cars that are experiencing this out of the blue?

[m3bs]

Originally Posted by Clap135

I am not the only one with this problem. Not everyone lives on glass roads. Hell even the OP has experienced bottoming out.

How did all of this wind up in my thread?

If you will go back to my original post, I also said that the stock suspension bottomed on the bumps in question.