Has anyone changed out their engine, tranny, and/or rear differential mounts on a 04-05 STI? The weather has been in the 90s+ and I've noticed way too much movement in my drivetrain ie: engine and tranny. If so, which products have you tried? I was thinking of the below kit:

http://www.z1auto.com/prodmore.asp?model=wrx&cat=driveline&prodid=600

Also Whiteline makes some type of rear differential bushing/mount ~$40. I don't have a pic of it, has anyone tried it and happen to have pics? I would like as stiff as possible w/out killing my daily driver. Any help would be appreciated. Thanks.

I'm installing these on my rex as we speak, along with trans, rear end, etc. The trans mount does indeed fit the sti trans, as it's the same as the 5 speed as far as the mount is concerned at least. The motor mounts look great, and I'm sure will greatly reduce if not nearly eliminate engine movement.
I'll post how well they work soon.
I had a heck of a time finding a set though, as nearly everybody was out of stock.
Oh ya, I got the whiteline diff bushings as well, again we'll see how they work out as I have yet to run them.
-Adam

1. I had the aftermarket STI Group N on my previous 02 WRX and they were fine for the first few months however got sloppy as time progressed. I'm looking for something the "stiff" and does not degrade over time. I haven't seen the Cusco mounts ( engine and tranny ) in person so I can't really make the judgement.

2. Where did you get the Whiteline rear differential bushing and much was it?

3. How long did it take you to do it, assuming you did it yourself?

Any part that has rubber in it will degrade in performance over time. Look for a part that has urethane instead as it will last much longer. I cannot remember if the Cusco ones are rubber or urethane.

As for rear diff there are two ways you can go. Outrigger bushings (try Kartboy's) and rear diff mount replacement bushings (TiC will have those out soon).

I installed the Group N engine and transmission mounts about 2 months ago, following up with the Group N rear differential mount 1 month ago. They drastically made a difference, exhibiting far less movement on/off the gas, and during braking.

Let me tell you that the single most ignored item is the pitch mount. Neither the STi stock item nor the SPT one is sufficient enough to be installed with the above three Group N mounts. There are still significant oscillations during abrupt throttle inputs and braking applications.

Matter of factly, I have contemplated going as far as as installing a solid link, similar to what you would find in an adjustable endlink for a sway bar. But noise would definitely be an unwanted by-product. So tonight, I was going to head to PepBoys and a couple of other places to see if I can locate a polyurethane bushing kit or just something from one of the cheesy offerings that they stock. I want to bore out the rearward rubber mount as the front one is pretty stiff. Take a look here: (photo courtesy of bescaredracing.com)

http://www.njdrive.com/Pictures/subaru/tech/stipitchmount.JPG

Pictured above is the stock STi pitch mount. You can literally flex that bushing with just your hand, not good enough when you are trying to control a ~400-500lb(don't quote me on that) engine/transmission from moving back and forth. I will be using the SPT unit to insert the poly bushing into as it has a much stiffer construction seen here:

http://www.gruppe-s.com/Subaru/subeng/sti_ps.jpg

The picture above is the pathetic offering from SPT, while having a stiffer membrane, has a gap on either side of that particular bushing :huh:. I gave it a chance and tried it out, only to remove it the next day due to an increase in movements/oscillations.

Stay tuned...

I thought the general concurrence is that the pitch stop does little to nothing. I have never noticed any front to back movement in my WRX engine. I drove with the pitch stopper disconnected for over a month and didn’t even know it until I took off the IC to bleed the clutch. I don’t understand what you’re trying to accomplish here.

If you don't notice any drivetrain movement, especially with stock motor mounts, you aren't driving hard at all.

I agree completely that the stock motor and tranny mounts are way too soft and that replacing these is a great mod. The pitching stopper is what I am questioning. From what I understand, this piece is designed to stop the forward and backward movement of the engine and transmission. Given the boxer engine’s design I don’t understand why you would need a more solid pitch mount then the stock one. Everyone who as upgraded the piece to a stiffer one reports very little or no difference in feel or performance.

...Everyone who as upgraded the piece to a stiffer one reports very little or no difference in feel or performance.

That's exactly my point! There isn't a pitch mount available in the aftermarket that rivals the stock STi or the SPT pitch mount. That's my basis for wanting to make a semi-solid one. I already removed the one larger rubber mount with the gaps from the SPT one I have pictured above. Tomorrow morning, I plan on taking some thick polycarbonate that I have at work, trace an outline, fill the void left behind entirely, and then drill a hole to accomodate the steel sleeve that once resided inside the rubber bushing.

Regarding the back and forth motion, anything that you can do to add resistance to a pivotal point within a suspended apparatus will decrease the reverbration of that item at the expense of transferring the unabsorbed energy to it's chassis. The rear differential mount is a huge example of how unwanted back-and-forth movement is quenched via a stiffer mount. Power is transferred to the ground much more rapidly and with less drama than before. Shifting is improved as well, but I am still looking for less movement, especially after an all-out launch and trying to catch second gear.

All in all, I hope to achieve something positive with the modified pitch mount.

P.S. It soon may be concluded that I should have just bought the Cusco motor/transmission mount set that is as solid as they come. :lol:

like i said i have yet to install this stuff but here is a link to a few pics of the cusco mounts, they weigh about 5 times as much as the stock mounts. The bushings are urethane. I'll take some better pics of them soon.
http://www.imagestation.com/album/pictures.html?id=2125566789&idx=36
-Adam

1. I thought there were just aftermarket engine mounts, tranny mounts, and rear differential bushings to reduce drivetrain movement. However there seems to be more products coming out tackling other parts. I'm trying to figure out which products make the most difference so I can take care of it in one pass.

2. TIC also has this on their website:

http://turninconcepts.com/product_info.php?cPath=1_9_11_13&products_id=9

I wonder if it makes that big of a difference. I currently use the TIC & Kartboy bushing; they seemed to be very stiff in the beginning however now there's alot a play again and it's only been 4 months. I can literally see the stick move back and forth inside the cabin when driving. :( It's just annoying as it's getting worse in my opinion.

3. I can see you points on the pitch stop and the aftermarket ones don't seem that much "better."

4. I wish someone just sold a package deal hitting all the major parts and taking care of this issue while being cost effective.

5. Do the STI's come w/ regular engine & tranny mounts from the factory or do they come w/ the STI Group N engine & tranny mounts?

Well, I'm extremely pleased to say that I have completed the modified pitch mount and it feels GREAT!!! I estimate that there is at least a 50% reduction of oscillation/drivetrain movement, and let me remind everyone that I already have the Group N engine/transmission/rear differential mounts installed.

What I did was remove the rubber bushing seen here:

http://www.njdrive.com/Pictures/subaru/tech/sti_ps_cut.JPG

Then I used a heavy-duty plastic caster wheel that I had laying around at work, similar to what you see here:

http://www.allproducts.com/sup017/broton/ml-101r.jpg

Having a solid chunk of 2" x 2" of this stuff to work with, I layed the pitch mount over the center of the wheel and traced an outline onto it, to allow me to first cut the excess and then belt sand the rest. After getting it just right I pounded it in for a tight fit, then sanded it to the width of the steel sleeve. Drilled the center bore exactly 19/32", inserted the steel sleeve... done! The result is very similar to this:

http://www.njdrive.com/Pictures/subaru/tech/sti_ps_modded.JPG

Definitely worth the hour it took me to do it.

"D" is the other side solid. I should know i got it for you...HAHA

No, it has a tiny hard rubber bushing.

1. Does the OEM rubber part on the pitch stop just hammer out?

2. I didn't think the pitch mount made "that" much of a difference as most people seemed to have ignored it. How much increase was there in NVH?

1. It must be cut out, very easy.
2. Everyone has ignored it because there isn't a better offering from the aftermarket. It just seemed obvious that attention should have been given to this piece if you are going to the extent of replacing the rest of the mounts.

1. I appreciate the quick response. I agree w/ you that people "should" replace it while doing the other noticable mounts such as the engine and tranny. I also figured that vendors would have already tried to trackle the pitch stop to gain another product line, but of course I'm wrong.

2. Where did everyone purchase the Whiteline rear differential bushing and how much?

5. Do the STI's come w/ regular engine & tranny mounts from the factory or do they come w/ the STI Group N engine & tranny mounts?

The Group N bits are upgrades for both the WRX and the STi.

1. That's what some vendor told me, I just wanted to confirm. Thanks. :D

2. Are the Cusco engine and tranny mounts better than then Group N mounts? I would think so w/ design and material differences.

in my experience, the group N engine mounts made way more difference than the group N pitch stop ever did in normal street driving. The pitch stop was the very last mod I did in terms of engine mounts on my wrx and I didn't notice a damned bit of difference. My take is that if you have $40 bucks to throw around, it won't hurt. But I can think of better things to spend 40 on for my new car.

2. Are the Cusco engine and tranny mounts better than then Group N mounts? I would think so w/ design and material differences.

The Cusco mounts likely add a lot more NVH than the Group N mounts because they have basically no give whatsoever. Considering that a few people find the NVH from Group N mounts to be a bit much (most don't mind, tho), the Cusco mounts are probably not the best idea for a daily driver. There are a couple of reviews floating around on the forums...

I didn't have any NVH issue w/ the STI Group N mounts on my previous WRX. I think I only noticed it the first three days after the install. Assuming NVH is not an issue, I infer that people would use the Cusco over the Group N?

I didn't have any NVH issue w/ the STI Group N mounts on my previous WRX. I think I only noticed it the first three days after the install. Assuming NVH is not an issue, I infer that people would use the Cusco over the Group N?

See threads:
http://forums.nasioc.com/forums/showthread.php?t=706701
http://forums.nasioc.com/forums/showthread.php?t=505624
http://forums.nasioc.com/forums/showthread.php?t=210386
http://forums.nasioc.com/forums/showthread.php?t=203124

General consensus in the threads seems to be that the Cuscos are better suited towards a race car, not a daily driver.

The STI isn't a "race car?" ;) :devil: The main reason I'm leaning away from the STI Group N was the fact that I felt that it lost it's touch a few months after the installation on my 2002 WRX. I think my only choices are either the Group N or Cusco after some detailed searches.

in my experience, the group N engine mounts made way more difference than the group N pitch stop ever did in normal street driving. The pitch stop was the very last mod I did in terms of engine mounts on my wrx and I didn't notice a damned bit of difference. My take is that if you have $40 bucks to throw around, it won't hurt. But I can think of better things to spend 40 on for my new car.

1.You have to reread the above posts concerning the pitch mount.
2.It didn't make a bit of difference because the 2005 STi comes with the Group N pitch mount, so you installed the same exact part.

If I had a chance to redo my mounts I would have gone Cusco instead of the Group N. This is my daily driver with no radio and a titanium catless Magnaflow exhaust so you can guess I really do not care about NVH.

1.You have to reread the above posts concerning the pitch mount.
2.It didn't make a bit of difference because the 2005 STi comes with the Group N pitch mount, so you installed the same exact part.


I'm quite aware of what the pitch stop does for the car and if you read my post carefully, you'll see that I never installed it on my STi. My advice is to start with the engine and tranny mounts first since they made the biggest difference.

I think I shall go w/ the Cusco and see what happens. I shall also look at the "home" modded pitch stop as I'm always looking for ways to incease drivability.

I think I shall go w/ the Cusco and see what happens. I shall also look at the "home" modded pitch stop as I'm always looking for ways to incease drivability.

Let us know how you like 'em, 'cuz I have about 30k on my Grp N mounts and they feel like they're softening up a bit. :)

It's funny how you mentioned that you noticed the Group N "not working" as it should after 30K+ miles. Mine was right around the sametime. Technically everything was good until a "certain dealer" messed up my tranny and at the end replaced the whole tranny for almost free. After getting the car back, the drivetrain just never felt solid again. It was around 30K miles too.

Does anyone have instructions for the more efficienct way to apporach the engine and tranny mounts installation? I remember seeing it somewhere but I couldn't find it through the searches and it was actually for a WRX. Anyone have it for the STI?