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Old 10-22-2004, 03:25 PM   #1
cboggess
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Default STi shifter slop: gauging interest

I posted this in another forum, but I thought I'd throw it out here to gauge interest. Seems lots of folks are unhappy with the amount of play in the stick on STis. Some have even gone so far as to have the bushings replace multiple times. We think we have a solution to this. Right now we are gauging interest before we go into production. Here's what I posted elsewhere:

In order to understand why this happens you have to understand how everything is put together.

First off there is a front fork off the shifter rod coming out of the tranny, and there is a second fork coming off the shifter linkage rod. Between them is a u-joint like connection. A bolt goes through each fork and through the u-joint assembly (with all its bits).

Now, looking at that u-joint connection you have to look at how it is assembled. We'll look from the inside out. Both sides of the u-joint assembly are assembled the same, only one is a little shorter than the other. Going through each side, and the associated fork is a bolt. Surrounding this bolt is a sleeve bearing. Surrounding this sleeve bearing is a flanged bushing (the ones labeled Problem Bushings). Surrounding these bushing is the u-joint housing.

Now, here is where the play in the shifter comes in:

1) There is a very small amount of space between the sleeve bearing and the bolt. That's just the way it is. In order for the bolt to slide in the sleeve bearing there needs to be some room. Although I would think that Subaru would have made the tolerence tighter.

2) After use (1000 miles seems to be the amount) the rubber bushings that surround that sleeve bearing start to compress, but not decompress. In other words they mash, but don't fully bounce back. This causes a gap between the bushing and the sleeve bearing. When we took my apart the sleeve bearing just fell out. We just stood there stunned.

3) The bushings sit between the sleeve bearing and the wall of the u-joint. Due to their compacting you get another small gap that can lead to play (although not nearly as much as the other two).

In summary there are three places where there is a gap that contributes to play - between the bolt and sleeve bearing, between the sleeve bearing and the bushing, and between the bushing and u-joint wall.

While each of these gaps is very very small when you take that small amount of play and run it up the length of the shifter you start to see some real play at the end up at the shift knob. I measure this on mine and I was getting 3/4" side to side, and 1/4" front to back.

You will also see this in the short shifter, but not as much due to the lever arm from the u-joint assembly being shorter than stock.

Now, what can you do to fix this? Well, a couple of us have been working on this, and believe that we have found a solution. Replace the bushings. Now, you could just keep going back to the dealer and get OEM ones over and over or you could just do it once and be done with it.

Currently we are running some prototypes and have gotten some great feedback. While not ALL the play is eliminated (due to the tolerences between the bolt and the sleeve bearing), we have been able to eliminate quite a bit, and what little there is left takes more effort to happen instead of the stock flopping around. Everything is much tighter, the stick centers itself very quickly, and the positive snap into place for each gear is very nice. I will note that there is a slight increase is vibration, but not enough to be annoying, and certainly not enough to make you miss shifts.

Anyway, the reason I am posting is to gauge interest in these. We are thinking about going into production with them, but would need to know that it would be worth it to the community. What are your thoughts?
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Old 10-22-2004, 04:19 PM   #2
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I think the sti's is a little different but here's a pic of the 5spd's little U-joint thing, and yes I've got about 1/4" of slop with a brand new joint & bushings.

I'm probably going to order another one, and put some nylon or metal bushings/sleeves in there.

pics
http://www.surrealmirage.com/subaru/...2/DCP_3314.JPG
http://www.surrealmirage.com/subaru/...2/DCP_3315.JPG
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Old 10-22-2004, 04:33 PM   #3
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yes, STi ones are slightly different. First off you can take out the entire core on the STi. The WRX one is a non-removable rivet on the tranny side. Also, the STi parts are a little bigger than the WRX ones.

As for what you have there I have a couple thoughts. 1) upgrade that grade 5 bolt to grade 8. I know it doesn't really carry any load, but you would get he peace of mind. 2) When you install it put the bolt in the top with the nut on the bottom so if you lose the nut you don't lose the bolt and the linkage disengages.
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Old 10-22-2004, 04:51 PM   #4
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Quote:
Originally Posted by cboggess
yes, STi ones are slightly different. First off you can take out the entire core on the STi. The WRX one is a non-removable rivet on the tranny side. Also, the STi parts are a little bigger than the WRX ones.

As for what you have there I have a couple thoughts. 1) upgrade that grade 5 bolt to grade 8. I know it doesn't really carry any load, but you would get he peace of mind. 2) When you install it put the bolt in the top with the nut on the bottom so if you lose the nut you don't lose the bolt and the linkage disengages.
???
the u-joint is removable on a WRX trans, you have to pull it off to disassemble the trans.. it's got a pin in it you push out with a punch..
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Old 10-22-2004, 05:07 PM   #5
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Quote:
Originally Posted by Safir
???
the u-joint is removable on a WRX trans, you have to pull it off to disassemble the trans.. it's got a pin in it you push out with a punch..
I agree. what I'm talking about it the fork and u-joint interaction. Instead of a bolt they used a rivet on the tranny side of the linkage assembly. You can see it on the pictures Legacy777 posted. On the STi it's all put together with bolts. How the u-joint connects to the shifter control going into the tranny is via a roll-pin also.
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Old 10-22-2004, 06:23 PM   #6
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oh that...

FWIW neither of my u-joint assemblies have any play in them that i can feel... i've shifted the transes out of the car by holding them.

the play in my car (not an sti so YMMV) is in the "rear" bushing in the linkage, that holds the "cup" in place at the bottom of the shifter, it is very soft and moves a lot.
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Old 10-22-2004, 07:02 PM   #7
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Quote:
Originally Posted by cboggess
yes, STi ones are slightly different. First off you can take out the entire core on the STi. The WRX one is a non-removable rivet on the tranny side. Also, the STi parts are a little bigger than the WRX ones.

As for what you have there I have a couple thoughts. 1) upgrade that grade 5 bolt to grade 8. I know it doesn't really carry any load, but you would get he peace of mind. 2) When you install it put the bolt in the top with the nut on the bottom so if you lose the nut you don't lose the bolt and the linkage disengages.

I plan on cutting the rivot and putting a bolt in it's place.

As for the grade bolt, I don't think that's really a problem. I put the bolt the way I did because the bolt is just long enough where it might hit the linkage/spring if I install it the other way.

I'm going to be tweaking things, which probably means new/different bolts. I take pictures and document everything when I do it.
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Old 10-22-2004, 07:03 PM   #8
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Quote:
Originally Posted by Safir
oh that...

FWIW neither of my u-joint assemblies have any play in them that i can feel... i've shifted the transes out of the car by holding them.

the play in my car (not an sti so YMMV) is in the "rear" bushing in the linkage, that holds the "cup" in place at the bottom of the shifter, it is very soft and moves a lot.
The way I determined where my slop was is I tied a string to the shifter, got under the car and pulled on the string. I could see the rubber bushing pieces flexing in the U-joint. Other way, have someone move the shifter while you're underneath.
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Old 10-24-2004, 11:24 PM   #9
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Given the lack of posts it doesn't sound like anyone is interested.
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Old 10-25-2004, 02:25 AM   #10
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Given the lack of posts, it looks to me like people are waiting to see what your resolution will be. It's just a matter of perspective. Perhaps not that many people are experiencing the problem. I haven't yet with my Subaru short shifter, but I'm lurking on this thread to see if '05 owners chime in.

I know Glenn Wallace was experiencing the same slop in his shifter. I don't know what his solution was. Perhaps making the bushings out of something like delrin?
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Old 10-25-2004, 04:01 AM   #11
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I have the same issues with my shifter and I've come to similar conclusions, except that I believe the problem has more to do with the length of the metal sleeves inside the bushings more than the bushings themselves. The sleeves are a little too long, which doesn't allow for a good fit between the raised edge of the bushing and the fork (for lack of a better term). I shortened the metal sleeve for the bushing at the shifter slightly and noticed a slight reduction in play. I'd imagine if I did the same for the rest (just didn't have time to pull the whole thing out this time) of the joints, it would go a long way towards reducing the slop.

This being said, I would be interested in upgraded bushings provided they are reasonably priced.
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Old 10-25-2004, 11:39 AM   #12
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Default Proto Results

Just wanted to add my .02 to the discussion. I currently have the proto replacement bushings in my shifter and here is what I have noticed.

I have had the replacement bushing in for about 1.5 weeks (~500 miles) and being that I don't have a radio right now... I can really concentrate on the drive. And, after driving over the past week, all I can really say about it is that it is reeeeally nice. It seems to be a large improvement over stock feel.

Interesting points/possible improvements:
-It chould just be me... but in some occasions I have found it alittle harder to find the gear that I was looking for. It was almost like I personally was looking for the slop to get it into second but in actuallity I shifted into 4th. Once I changed my shifting technique to pop it out of gear and let it center before picking a gear... that problem was solved. (It happens really fast so you really are not wasting any time.)
-When you get on it or when you are trying to go forward with little gas imput, you get a alittle vibration/movement through the shifter. My guess is that this is just a result of there being a harder bushing in place so lest vibration is absorbed.

Let's see good points:
-ease to find center. The shifter really pops to neutral. I think this is a good thing. It is quick and seems more sporty.
-it seems like once I changed my style alittle bit... it is alot easier to get into gear. again, that is probably just my driving style... not a design flaw.
-I LOVE how tight/notchy the shifter is. It makes the whole driveline feel closer to the racecar it is supposed to be. I let one of my friends drive it the other day and he was commenting on how well it shifted.

Overall I would say that it is something that should be done on all of the STis out there. These coupled with the Kartboy bushings make it an amazing shifting experience.
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Old 10-25-2004, 11:44 AM   #13
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What material are the prototype bushings made out of?
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Old 10-25-2004, 12:07 PM   #14
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Quote:
Originally Posted by supermarkus
What material are the prototype bushings made out of?
Urethane.
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Old 10-25-2004, 01:10 PM   #15
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About what durometer would you think would be optimal? In your opinion, would delrin be too noisey? I have a lot of delrin sitting around in our shop, I was thinking about doing something with it.
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Old 10-25-2004, 03:24 PM   #16
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Quote:
Originally Posted by supermarkus
About what durometer would you think would be optimal? In your opinion, would delrin be too noisey? I have a lot of delrin sitting around in our shop, I was thinking about doing something with it.
You could give Delrin a try, but in that case I would forego the sleeve bearing. I would be a bit concerned about the tranmission of noise (although it is an STi), and vibration. Our concern over vibration is why we did not do metal bearings. Our material is MUCH stiffer than what is in there stock, and yet still is soft enough to cut down on some of the vibration, although there is still a slight increase in vibes over stock. In our application we kept the sleeve bearing, and sized the new bushing so that you have to press it in, eliminating the play between the sleeve and the bushing.
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Old 10-25-2004, 05:21 PM   #17
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So something around 80-90A durometer would probably work in that situation if noise were a big concern?

Last edited by supermarkus; 10-27-2004 at 10:45 AM.
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Old 10-27-2004, 09:10 AM   #18
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cboggess,

What diameter is the outer part of the bushing, as well as the inner diameter of the hole?
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Old 10-27-2004, 09:27 AM   #19
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Quote:
Originally Posted by legacy777
cboggess,

What diameter is the outer part of the bushing, as well as the inner diameter of the hole?
You do know that this is for STi only? The WRX assembly is different sizes.
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Old 10-27-2004, 12:33 PM   #20
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Quote:
Originally Posted by cboggess
You do know that this is for STi only? The WRX assembly is different sizes.
That's why I asked the dimensions of the bushing. Have you pulled the the stock bushings off the wrx joint and comp the inner diameter of the hole to the sti?

Just curious
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Old 10-27-2004, 12:49 PM   #21
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Doesn't Kartboy already have stiffer bushings for sale?
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Old 10-27-2004, 01:03 PM   #22
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Quote:
Originally Posted by s2ktosti
Doesn't Kartboy already have stiffer bushings for sale?
Re-read this thread, these are different bushings.
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Old 10-27-2004, 01:59 PM   #23
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Quote:
Originally Posted by legacy777
That's why I asked the dimensions of the bushing. Have you pulled the the stock bushings off the wrx joint and comp the inner diameter of the hole to the sti?

Just curious
We did pull the assembly off an 04 WRX, but once we saw the rivet we decided to skip it for now. I'm not sure of the dimensions for a WRX but I do know just from looking at it that it is considerably smaller than the STi.

Additionally, it looks like the WRX has two bushings in each location. A soft one and a hard one, one smaller than the other. It may have just been how the flange was shaped, but that's what it looked like to me.
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Old 10-27-2004, 03:19 PM   #24
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Quote:
Originally Posted by legacy777
I think the sti's is a little different but here's a pic of the 5spd's little U-joint thing, and yes I've got about 1/4" of slop with a brand new joint & bushings.

I'm probably going to order another one, and put some nylon or metal bushings/sleeves in there.

pics
http://www.surrealmirage.com/subaru/...2/DCP_3314.JPG
http://www.surrealmirage.com/subaru/...2/DCP_3315.JPG
IMO solid Teflon bushings would be the best!
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Old 10-27-2004, 04:12 PM   #25
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Quote:
Originally Posted by Undepelo
IMO solid Teflon bushings would be the best!

Yeah I'm probably going to do something like that.
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