Welcome to the North American Subaru Impreza Owners Club Friday March 29, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
Click here to visit TireRack
Brakes & Suspension Forum sponsored by The Tire Rack

Losing traction? Need new tires?
Click here to visit the NASIOC Upgrade Garage...
Go Back   NASIOC > NASIOC Technical > Brakes, Steering & Suspension

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 09-17-2020, 05:40 PM   #1
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default Please help me fix the clunking of my Tein Mono Sport CO's on a 2011 STi

Hey all. I read the stickies, did searches, Googled it, etc. My back is getting sore from taking my wheels off and putting them back on, so I'm looking for some help before I go take more cracks at it.

I got this 2011 STI a week ago that has a lot of suspension mods like Eibach sway bars, Cusco strut braces, etc., including Tein Mono Sport coilovers. He had it lowered a bit more than I wanted, so I took the wheels off and took a look at the Teins.

There was no spring pre-load on them. The springs were loose with like an inch of play. This seemed wrong to me, so I did some research. Some people say it's fine and the "suspension will settle". Others say you need pre-load on the springs. Logic would tell me preload is good so your springs don't clunk around or get off-center (if possible). I'm a complete newb since I've only had 3 WRX's with zero suspension mods on them.

Tein has no online instruction manuals, unfortunately, so I watched some youtube videos and it seems pretty simple. I went ahead and put quite a bit of pre-load on all 4 CO's, like at least an inch, which did raise up the car. But this resulted in loud clunking, especially from the fronts.

I then found another video that says to put 4mm of preload (the thickness of the spanner wrench), so I did that on all 4 CO's. The fronts didn't clunk at all, but the rears still do.

I checked the force setting and all 4 were set to max, so I turned it down 15 clicks (out of 16, so like the least "force"). The clunking remains.

I tried adding a little more pre-load to the rears, like 6mm total (~140lbs). It still clunks when I hit decently sized bumps and potholes.

I tried adjusting force up to midway. Clunks the same amount.

I swear it didn't clunk when I drove it home 2 hours from the place I bought it from.

Currently, the front has 4mm - 5mm preload and 2.5" between the bottom spring collar/seat and the jam nut (I think that's the right term). The rear has 6mm - 7mm preload and 2" between bottom spring collar/seat. The rear was at about 3" previously and had clunking about the same amount, and I lowered it about an inch using the jam nut just for experimenting.

I have not adjusted the front jam nut since purchasing the car.

Before I take all the preload off the springs and/or raise the rear via jam nut a couple inches, I was hoping for some input from someone with an STI and these Teins.

What could possibly be clunking as the suspension rebounds? It definitely seems like it's on the rebound, not the compression. It's not a loud clunk, but it's definitely pretty easy to trigger and is super annoying now that I am listening for it all the time.

Thanks and sorry if I'm missing something obvious.
* Registered users of the site do not see these ads.
snake2332 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 09-17-2020, 08:10 PM   #2
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

I don't understand how my left rear and right rear coil-overs are different.

I tried to get them adjusted to max height. In the left rear, I loosened the jam nut and threaded the shock out as far as I could. It started to get wobbly like not enough threads were in the jam, so I threaded it back into the jam a few threads. Overall I extended it about 1.25". However, when putting preload back to 6mm, the gap only changed from 2.0" to 2.5". Not sure how that math doesn't add up. I put more preload on it, 10mm total, and set the car down. The car is raised about 1.5" from doing this. Okay...let's go do the right side.

On the right side, I started doing the same thing. I threaded it out of the jam about an inch, then set preload on the spring but the gap was like 3.25". This math made sense but didn't match the left side. Also, on the right side, if I preload the spring and twist the shock into the jam, the preload loses tension and eventually there is none. On the left side, if I preload the spring and thread the shock into the jam, the preload remains intact, as expected. It's like the top of the shock isn't attached to the spherical joint or whatever at the top of the coilover. If it was, then the preload would remain and threading it into the jam would bring the jam up, not bring the shock and coil down.

Do the left and right sides vary like this? Is that even possible? This is seriously hurting my brain and my back.
snake2332 is offline   Reply With Quote
Old 09-17-2020, 08:13 PM   #3
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

Also, I measured from top of jam to top of coilover where it bolts to the car on both sides and it was 10.0". The gap between bottom spring nut and jam nut is 2.625" on both sides. 10mm of preload on both sides.

However, the right side is almost 1" lower when measuring gap above tire.

I'll go check out the top of the coilovers after I take out the trunk liner. Something seems broken or amiss.
snake2332 is offline   Reply With Quote
Old 09-17-2020, 08:36 PM   #4
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

I think the clunking is gone now. Seems odd that I have to have it near its highest extended setting for that to be true, but whatever. I'll put some miles on it tomorrow though I want to get the right rear of the car lifted to match the left, even though the coil overs measure the same in every regard.

I guess this is my own personal journal. I'll post some pics later.
snake2332 is offline   Reply With Quote
Old 09-18-2020, 07:26 PM   #5
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

Still majorly confused about the rear coil-overs. It seems no matter how far into the jam I put the shocks, the ride height is the same and about .75" difference between left and right. I can change the jam by over an inch and the ride height won't change, despite the same 8mm preload. Still trying to wrap my head around this but it defies logic and physics. The front COs work as expected, but the rears don't. If I screw the shock down into the jam, somehow the spring preload goes away, maybe because the shock is pushing down. Then when I lower the car, the shock goes back in? Yet why and how can the height not be changing when I am threading it in and out of the jam by 1" - 2"?

I gave up trying to measure anything because it doesn't make sense. Now I'm just trying to get the rears to the same height. I went to the right rear since it seemed to work as expect, threaded out the shock about .75", made sure preload was 8mm, put the wheel back on....car rides like .2" LOWER somehow. WTF?

Does someone have the Tein manual for this unit? I've searched all over the internet and can't find a PDF of it.
snake2332 is offline   Reply With Quote
Old 09-19-2020, 05:15 PM   #6
brecks
Scooby Specialist
 
Member#: 435142
Join Date: Nov 2015
Chapter/Region: MWSOC
Location: Commerce Twp, MI
Vehicle:
2004 STi
Java Black Pearl

Default

Quote:
Originally Posted by snake2332 View Post
Still majorly confused about the rear coil-overs. It seems no matter how far into the jam I put the shocks, the ride height is the same and about .75" difference between left and right. I can change the jam by over an inch and the ride height won't change, despite the same 8mm preload. Still trying to wrap my head around this but it defies logic and physics. The front COs work as expected, but the rears don't. If I screw the shock down into the jam, somehow the spring preload goes away, maybe because the shock is pushing down. Then when I lower the car, the shock goes back in? Yet why and how can the height not be changing when I am threading it in and out of the jam by 1" - 2"?

I gave up trying to measure anything because it doesn't make sense. Now I'm just trying to get the rears to the same height. I went to the right rear since it seemed to work as expect, threaded out the shock about .75", made sure preload was 8mm, put the wheel back on....car rides like .2" LOWER somehow. WTF?

Does someone have the Tein manual for this unit? I've searched all over the internet and can't find a PDF of it.
Well, your preload depends on your spring rates and ride height. I'm not positive about Tein, but most coilover manufacturers suggest you start with preloading the spring the thickness of the spanner wrench (as you've done) so that's where I'd set it and forget it, unless you're corner balancing or doing any sort of performance driving. For ****s, you can measure the length of the compressed spring and make sure the lengths are approximately even.

Since most coilovers use linear springs, your preload shouldn't change much but the ride height. If, for example, one corner of your car weighs 800lbs, and you have 800lb/in springs, that spring with no preload will compress 1" when you set the car down on its own weight. However if you have the preload at 1", then set the car down, the suspension will not compress at all. It would take an additional 800 lbs to have the spring compress another inch.

This is likely why you're having trouble getting the ride height dialed, because you're adjusting the spring preload and the ride height. On top of this, the clunking may be the struts letting you know they're shot. With no preload (as you said you found the rears) the strut compresses more than it should, and could've been riding on the bump stop.
brecks is offline   Reply With Quote
Old 09-19-2020, 05:19 PM   #7
brecks
Scooby Specialist
 
Member#: 435142
Join Date: Nov 2015
Chapter/Region: MWSOC
Location: Commerce Twp, MI
Vehicle:
2004 STi
Java Black Pearl

Default

Quote:
Originally Posted by snake2332 View Post
I don't understand how my left rear and right rear coil-overs are different.

I tried to get them adjusted to max height. In the left rear, I loosened the jam nut and threaded the shock out as far as I could. It started to get wobbly like not enough threads were in the jam, so I threaded it back into the jam a few threads. Overall I extended it about 1.25". However, when putting preload back to 6mm, the gap only changed from 2.0" to 2.5". Not sure how that math doesn't add up. I put more preload on it, 10mm total, and set the car down. The car is raised about 1.5" from doing this. Okay...let's go do the right side.

On the right side, I started doing the same thing. I threaded it out of the jam about an inch, then set preload on the spring but the gap was like 3.25". This math made sense but didn't match the left side. Also, on the right side, if I preload the spring and twist the shock into the jam, the preload loses tension and eventually there is none. On the left side, if I preload the spring and thread the shock into the jam, the preload remains intact, as expected. It's like the top of the shock isn't attached to the spherical joint or whatever at the top of the coilover. If it was, then the preload would remain and threading it into the jam would bring the jam up, not bring the shock and coil down.

Do the left and right sides vary like this? Is that even possible? This is seriously hurting my brain and my back.
Also, this is telling me that you're spinning the spring assembly on the shock, and the shock isn't moving at all. Sometimes you need to unbolt the lower mount from the hub to adjust the ride height


Last but not least, each corner of your car (likely) weighs a different amount, so to get the heights exact, the threading on the coilovers might not be the same side to side. Since I take it this is just a street driven car, here's what I would do:

1. Set preload the SAME on all 4 coils. Thickness of the spanner, don't change it.
2. Make sure your lower mounts are actually spinning the strut, not the spring assembly. Sometimes this requires unbolting as mentioned above.
3. If threads are seized, that is a whole different story.. but if not, you should then be able to set ride height side to side ONLY adjusting the height of the strut, NOT the spring preload.
4. Profit??

Last edited by brecks; 09-19-2020 at 05:24 PM.
brecks is offline   Reply With Quote
Old 09-21-2020, 12:59 AM   #8
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

Thanks Brecks. I am still confused by the behavior of the left rear unit, but I've got the ride height pretty close on all 4.

I was making sure the shock was turning as I adjusted it. I don't see how the spring can compress when I am doing this since it should only be threading in and out of the jam. And then when I put the car back down on the ground, even though I made sure it had 6mm or 8mm of pre-load, I can immediately jack up the car and that spring will be loose with half an inch of space above it. None of the other 3 units do this, so I'm confused big time, haha!

I spent all day wiring in my subwoofer, dash cam, radar detector, and removing the 4pt harness that I didn't mess with the suspension, but I'm going to tackle it again. Thanks for the input and glad to see I'm not being completely stupid.

How is it Tein doesn't have instruction manuals on the internet? Kind of mind-blowing considering how many coil-overs they sell.
snake2332 is offline   Reply With Quote
Old 09-21-2020, 08:08 AM   #9
Norm Peterson
Scooby Specialist
 
Member#: 498642
Join Date: Mar 2019
Chapter/Region: Tri-State
Location: our wrx IS the family sedan
Vehicle:
'19 WRX Ltd 6M dgm
'08 Mustang GT (the toy)

Default

When you change the ride height at one corner of the car at a time, you're changing the wheel load at all four corners of the car, and the car will shift the ride heights around until it finds its own balance. At least the ride height measurement checking needs to be done on a flat, level surface.

This is complicated somewhat by the sta-bars, which work against making side to side adjustments. You should probably be making your ride height adjustments with the bars disconnected at the ends, and reconnect them afterward. You may need adjustable endlinks to get them to fit up afterward without having to force the bar to fit the last bolt/stud into position (if you have to force the bars, that'll change the side to side ride heights).


Norm
Norm Peterson is offline   Reply With Quote
Old 09-21-2020, 10:39 AM   #10
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

Thanks Norm. I did have the rear tower bar disconnected through all of this, but not the front, and I was doing it in my driveway that has a slight grade. I'm going to try in my garage instead and disconnect both. I also kinda figured that altering 1 meant it would shift weight around on the other 3, but thanks for confirming that. Once I get all 4 corners having the same distance to the ground with equal pre-load, I'm going to leave it alone and get it aligned, hopefully with camber and toe adjustments.
snake2332 is offline   Reply With Quote
Old 09-21-2020, 11:40 AM   #11
Norm Peterson
Scooby Specialist
 
Member#: 498642
Join Date: Mar 2019
Chapter/Region: Tri-State
Location: our wrx IS the family sedan
Vehicle:
'19 WRX Ltd 6M dgm
'08 Mustang GT (the toy)

Default

Sta-bar = short for stabilizer bar = "anti-roll bar = what most people (incorrectly) call a "sway bar".

Those other bars might have a minor effect, but if they're bolted down solid it'd be minimal. A little front to rear downhill slope probably won't matter much (you could end up with a tiny amount of rake on flat ground).


Norm
Norm Peterson is offline   Reply With Quote
Old 09-21-2020, 02:33 PM   #12
snake2332
Scooby Newbie
 
Member#: 173313
Join Date: Mar 2008
Chapter/Region: RMIC
Location: Missoula, Montana
Default

Oh okay, ya this car has Eibach "sway bars" on it. Maybe I'll jack up the rear of the car and unbolt that if I can't get the corners all equal.
snake2332 is offline   Reply With Quote
Old 09-21-2020, 04:56 PM   #13
Norm Peterson
Scooby Specialist
 
Member#: 498642
Join Date: Mar 2019
Chapter/Region: Tri-State
Location: our wrx IS the family sedan
Vehicle:
'19 WRX Ltd 6M dgm
'08 Mustang GT (the toy)

Default

You really should disconnect both bars. Any preload on the front bar will show effects at the rear as well as at the front.


Norm
Norm Peterson is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 04:37 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.