Urethane Upgrades

[Aptyp]

Preamble: I wrote this for our local forum, which has a diminishing amount of e30s as of late, so I thought I'd transfer it here for all e30 meatheads to have an input. Don't forget that this was written for local guys, so businesses I used are the ones that I could get parts from the same day. Entire write-up is based on my own experience with all my e30s over past who-knows-how-many years.
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As I was saying before, one of the most important first upgrades to any car is suspension.

In e30 this could never be more true. With the youngest models approaching two decades on the road, it’s not only an upgrade, it’s a necessity. Twenty year old rubber is in no shape to withstand high performance driving and stock parts may cost you as much as performance upgrades.

Luckily, e30 has such a rich motorsport history, that there’s abundance of performance parts available. Title of this thread suggests urethane is the way to go, but you may also consider derlin components. I recommend urethane (polyurethane). Replacing rubber with rubber just makes no sense. It’s a matter of time until you’ll have to do it again, and urethane is cheaper and easier to replace than rubber, you’ll see why.

Let’s go over what’s supposed to be replaced:
Control Arm Bushings (CABs)
Trailing Arm Bushings (TABs)
Rear Subframe Mounts (because you love projects and hate life)
Rear Shock Mounts

That’s it. Sway bar bushings are pointless to replace, unless they are gone. I don’t mean too-far-gone, I mean physically not there. Strut mounts, if replacing, you may as well get camber plates. Differential mount isn’t on the list, because e30s came with amazing solid rubber diff mounts. They are indestructible, and the same ones are not available from dealer anymore. New ones have holes in them like CABs, (e36 z3 type) and they allow more play (and tear differential out). When you replace subframe mounts and diff is one of the locations where subframe is hung, wouldn’t you want o stiffen that location as well? That’s up to you. This really covers all you’d need to get your e30 for holidays.

Where to get and how much to pay?
Korman Autoworks: for people who like picking up their parts and don’t mind paying a little extra. Great quality parts, proven by years of successful racing. Expect to pay around $400 plus tax.

Ireland Engineering: for those of us who are stingy with their cash and do not mind waiting for shipments from California. IE does have a dreadful reputation for selling Chinese off-brands, but when it comes to polyurethane, their quality is respectable, and there are a lot more enthusiast rolling on IE parts than any other brand. Expect to pay around $322.

Turner Motorsports/AKG: They carry AKG brand, and I simply have no respect for that brand. AKG should take a slogan out of Papa John’s advertisements, and start using better ingredients for better parts. Those parts are squeaky, wear out faster, and if you look at them after they’re used for a while, you may even say they’re dangerous. Surprisingly, expect to overpay at $385.

write-in: I planned reusing AKG parts on my car when I was doing my 5-lug swap. After dissasembly, I found the reason AKG TABs squeak so much... They looked like they've been hit by hammers and inner races were no longer round. I knew inner races were a bit too light to be true, but I couldn't belive they were made from aluminum foil. I ended up having to spend money on a set of real bushing with steel inner races and proven urethane from Korman.

Bimmer World: both carry PowerFlex, world leader in urethane suspension parts. That’s about all I have to say. It’s definitely the quality that has been proven, so expect to make it rain with $418 for street and $453 for race setup.

Personally, I like saving money, so I shop around between those few to pick and choose products I want. I have a lot of respect for IE urethane, so TABs and Subframe Mounts come from them at $162. I save a little dough on CABs by buying stock e30 M3 ones. They’re solid rubber, offset AND only run at $40 per pair not breaking the bank. I get shock mounts from Turner MS or Ireland Engineering. TMS has really good mounts for $100. IE mounts have replaceable urethane bushings for only $75 and replacement bushing can be purchased at Advance/Autozone, because they’re the same as Ford/Chevy sway bar link bushings. So, my setup tends to run about $300 before shipping and special discounts.




CONTROL ARM BUSHINGS
ADDED 3.20.09
So in this edition of my Urethane Upgrade thread, lets discuss CABs. We'll rate in smileys out of 5.

To start, let's list all contenders: AKG, IE Derlin, THR, PowerFlex, Korman/BMP, stock M3.

Now let's pick them apart for what they are and what they're worth.
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1. AKG: I've scrutinized this brand, but when it comes to their cabs at their price, it's not a bad deal... One problem with them is that they're made to fit over control arm just a bit loosely, and cause squeaking. Most people fix that with heavy lubing and/or continuous maintenance. These are 75D polyurethane, basically a very durable ABS plastic. They are plenty stiff, for road and track. Quality to price, I rate them right down the middle.
Quality: :):)
Price: :):):):)

$60.00 :D:D:D
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2. IE Derlin: I enjoyed these on my last e30, but they are just about exact same quality as AKG with exception for derlin material and being less squeaky, but not squeakless. Something to remember here, is that these are made out of "delrin". Very hard, lightweight, wear-resistant, and low friction. These are quite possibly the stiffest bushings next to THR.
Quality: :):):):)
Price: :):):)
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$85 :D:D:D+
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3. THR: Superior quality, and in their competition with ebay, price has become a lot friendlier. They still are the most expensive ones, but it all depends what you expect out of your car. For 99.9% of people, these are unnecessary, but it's a "cool" factor, and they're lime-green fuh race or rice. Look at the picture, these are as stiff as CABs can get, without welding control arms to chassis. If you're spending money on these, then noise is definitely not a priority.
Quality: :):):):):)
Price: :):):):)

$189.00 :D:D:D:D+
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4. PowerFlex: another superior quality product and it's priced really well. As I was mumbling before, PowerFlex are leaders in what they do, so you really get an amazing product for a decent price. It's a two piece urethane bushing, and it's contact surface area with control arm is doubled. It is ridged and lubed like a condom, and allows inner bushing to rotate, if needed, inside of outer bushing, these don't squeak. However, Powerflex makes them out of urethane, and makes them flexible enough to put them into a daily driver, and stiff enough for performance/spirited driving. These are proven to be successful on the track.
Quality: :):):):)
Price: :):):):):)

$74.99 Offset, $64.99 Centered :D:D:D:D+
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5. Korman/BMP: I forgot the name of the actual company that makes these CABs, but here two places, where you can easily get them from... These are actually really well designed CABs and also come with special goop-lube. They are quiet, easy to install, but cost a bit more than should. What makes them quiet is their design: they do not rotate inside of the lollipop, and do not allow control arm to rotate inside of the bushing. They are made of urethane, and that allows them to twist against itself, and not let control arm slip inside causing squeaks.
Quality: :):):):)
Price: :):):)

$80.75 :D:D:D+
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6. Stock e30m3: last, but certainly not least. I love this CABs, besides being incredibly stiff, long lasting, and surprisingly affordable, the only downside is installation. The have to be pressed in just like stock ones, while most urethane ones can slide in a lot easier. I personally recommend these to everyone, regardless of what they'll be using their vehicle for.
Quality: :):):):)
Price: :):):):):)

$40.00 :D:D:D:D+
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In one of my next rants, I'll cover subframe mounts or TABs, if anyone's interested. Also, let me know, if you agree/disagree with my ratings, and whatever else you may know, that I don't.

[gearheadE30]

For the record, I have had no issues with my AKG parts after about a year on the road. The CABs squeaked, but zerk fittings fixed that. I have never heard of anyone else having issues with the parts. This is with regular autocross and street duty, but no track days yet. What was your car used for when the AKG parts were on it?

[Aptyp]

it was a spec-e30 setup and car ran a few track events, but was mostly street driven. I'll take some pics of races of AKG TABs.

Trailing Arm Bushings
ADDED 3.21.09
As promised, let's cover next topic, trailing arm bushings.

Contenders: AKG, Ireland Engineering, BMP/Korman, and PowerFlex.
I will rate them in in 5-smiley standard.
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1. AKG: I'll beat this dead horse one more time. Without reciting my problem again, I'll just say that inner races for these bushings are made from lightest aluminum possible, and are not up to par. Material is the same as CABs, which is polyurethane (AKA plastic). They are squeaky and they do cost more than they should. Adjustable ones come with stainless steel inner race.
Quality: :):)
Price: :):)

$100 standard and $200 adjustable :D:D

Here's my reason for not liking AKG...



Car was squeaking like freaking crazy, and no lube ever helped. Regardless of the way I drive, I'd expect a lot of things to fail before trailing arm bushings.
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2. Ireland Engineering: in recent years, IE changed design from single piece bushings to dual to resemble AKG. I haven't seen the new ones yet, but I really enjoyed the other ones I drove on for two years until my car got totaled. Inner race was was made of decent material, and bushing was urethane. I had them lubed with lithium caliper lube, and I never ever heard a squeak. Again, I haven't had the new design yet, but if they're anything like old ones, urethane with solid races, then these are the BEST bang for the money. (Someone please confirm that new design is still a good one, as I am rating what I had). These are reasonably stiff, and perfect for a track rat as well as a daily driver. Another bonus is that these were the easiest to install.

Update: Contacted a person with a new design, apparently new design has a lot more in common with AKG TABs these days, their rating drops for a lot of squeaks and questionable quality. Still awesome price though.
Quality: :):)
Price: :):):):):)

$52.00 :D:D:D
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3. BMP/Korman: These are great quality and are the ones I currently run in my car. Again, these aren't made by neither BMP nor Korman, but those the places where you can find them at (cheaper from BMP than Korman). Urethane with zinc plated steel inner races. For the money, these are great and a great alternative to IE.
Quality: :):):):)
Price: :):):):):)

$61.15 :D:D:D:D+
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4. PowerFlex: are available in two types, street and race. Made of the same superior urethane as the rest of their components. I'd love to have these installed now, as my first e30 did, but I can't justify spending that much money on them. I don't know what got up PowerFlex marketing department, but they have outpriced themselves out. Unless you're buying entire PowerFlex line-up, buying TABs on their own is pretty much pointless, especially since these aren't any stiffer than competition, not even race ones.
Quality: :):):):):)
Price: :):)

$139.99 Standard and $159.99 Race :D:D:D+
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Well that's that, choose wisely between PowerFlex, BMP/Korman, and Ireland Engineering.

... and now a pic on the easiest way to remove stock TABs:

8" Clamp, 36mm socket (as used for the front wheel hub), lug bolt (to get bushing started), and any deep socket to finish the job.

Takes about 10-15 minutes to get all 4 out.

Next I'll type up some info on shock mounts and subframe mounts. I'll do shock mounts first, because I know more about them. Enjoy and chime in.


Shock Mounts
ADDED 3.23.09

So this is the weakest point of e30 suspension. Stock mounts don't need 20 years to be destroyed, few of my friends were very successful destroying stock ones in matter of months. Beauty of stock ones, though, is that they are rubber and allow movement of shock with the trailing arm. Choices here are abundant, Turner Motorsports and Bimmer World sell 5 different kinds (6 if counting stock) each.

Pointless mentioning all contenders, as every vendor claims them to be their own, so we'll go by design, but I must add purpose to the rating.

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1. JTD Design: the most inexpensive solution, and is actually a solution. Not the best performance optionr high performance driving and nothing much to look at, but it's the best replacement to original shock mounts. Apparently some places sell them with life time warranty.
Purpose: :):) Street, Daily Driving
Quality: :):):)
Price: :):):):):)

$40.00 :D:D:D+
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2. HD OEM: definite attempt to repent, and not even by BMW. These ones are an alright substitution to stock shock mounts, but even these fail after a while. Allows great movement and wouldn't destroy
Purpose: :):)
Quality: :):)
Price: :):):)

$60.00 :D:D-
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3. Ireland Engineering Urethane RSM: good choice for the money. I must tell you, that IE picture look much better than actual product, but actual product come with everything in the picture. It is definitely a bang for the buck, and when installed right, it allows shock to move the same way stock mount would. It comes with reinforcement for shock tower. This is the best bang for your buck in this category.
Purpose: :):):):)
Quality: :):):):)
Price: :):):):):)

$75.00 :D:D:D:D+
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4. Ground Control RSM: great design, great performance. Design-wise, it's the same thing as a lot of other ones are, but it has a name "Ground Control" on it and in pretty GC color.
Purpose: :):):):)
Quality: :):):):):)
Price: :):):)

$97.00 :D:D:D:D
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5. Turner Motorsport Urethane RSM: same thing as GC pretty much. Doesn't have the name, but oh so pretty.
Purpose: :):):):)
Quality: :):):):):)
Price: :):):)

$99.95 :D:D:D:D
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6. AKG Polyurethane RSM: here's one product I endorse made by them. Material they use suddenly seems perfect for this purpose and they got design just right. It's very close in design of IE, but hemispherical bushings really do the trick.
Purpose: :):):):):)
Quality: :):):):)
Price: :):):):)

$100.00 :D:D:D:D+
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Well this is it without getting into spherical/bearing designs, but then we're talking about whole different price market, and purpose better be racing. I currently run IE ones, and have run them on my last three cars, but if it wasn't for buying some other parts from IE, and getting it all shipped at once, I would be driving on TMS or AKG ones for sure.

[gearheadE30]

Okay, that would be awesome. Mine don't squeak or clunk that I can tell, but I might check next time I'm under there just to be safe.

[fiftytakedowns]

This was very helpful, thank you.

[guibo09]

this is also the first time i have seen complaints about akg quality, which worries me since i have a full set of akg urethane waiting to be installed...

[LaserAWD]

I just put AKG CABs on my car. The stockers were shot when I bought it. They creak / squeak like a mofo and I've had them on and off 3 times trying different greases. I have some "good" grease coming in to try this weekend, it's recommended on many different car forums. If that doesn't stop it I'll be getting different CABs from some other company. I want to have a much firmer suspension and I like how the front end and steering feel with these but the noise is just too much for a daily driver.

[guibo09]

I just put AKG CABs on my car. The stockers were shot when I bought it. They creak / squeak like a mofo and I've had them on and off 3 times trying different greases. I have some "good" grease coming in to try this weekend, it's recommended on many different car forums. If that doesn't stop it I'll be getting different CABs from some other company. I want to have a much firmer suspension and I like how the front end and steering feel with these but the noise is just too much for a daily driver.

which hardness do you have?

[LaserAWD]

They're not the street ones, they're the harder ones. I had poly bushings in my DSM and never had a squeaking problem so I wasn't expecting these to squeak either.

[gearheadE30]

Drill a hole through the lollipop and bushing and press in a zerk fitting. That way, as soon as they start squeaking, you can relube them with a grease gun. I have to do mine about every 4 months, with no squeaks.

[LaserAWD]

The few times I've re-lubed mine has all been in the same weekend. They start squeaking again within 30 miles. I had time to look up the grease I ordered: Super Lube Synthetic Grease With PTFE Teflon 21036 It was recommended on many forums when installing poly bushings, I hope it helps. I'll know this weekend when I get back home and have time to work on the car.

[gearheadE30]

Okay. I'm using some sort of synthetic marine grease that also has teflon in it. The issue is that when you slide the bushing onto the back of the control arm, it pushes all of the grease off. The zerk fitting forces the grease to flow between the metal and the bushing.

[LaserAWD]

How do you put on a zerk fitting that forces grease inside the bushing? I thought everyone put zerk fitting on the lollipop which which just lube the outside between the bushing and lollipop and not between the bushing and control arm?

I just got back in town about an hour ago and have tomorrow off. The grease was here waiting for me so I'm going to try to get it done tomorrow and see what happens. I'll report back.

[Aptyp]

I use CRC brake caliper grease. It's lithium based, and quiets out practically everything, and doesn't dry-up. But it is like $10 for a small bottle.


Rear Subframe Mount
ADDED 3.24.09

So here's the question, how committed are you? I don't mean to your car, I mean mentally. If you feel like you should have been institutionalized the day you got your e-dirty and you have all special tools, friends, patience, and press then follow along.

Contrary to popular vendor myth, stock subframe mounts are long lasting, and you'll find that out when you'll try to remove them. As a matter of fact, you must be laying quite a bit of power and going airborn to destroy stock mounts.

There are plenty contenders here, and this is the first component that can be 100% solid: PowerFlex 80A/95A, Ireland Engineering Street/Race, Aluminum, Group N, AKG 70A/75D.

*Note: Stock e30 subframe mounts aren't solid for a reason... You must understand the way subframe mounts, and that subframe itself isn't solid. When you stomp the pedal and car jerks with all it's "mighty e30" power, subframe bows. It is designed to do so, and rubber mounts assist subframe in doing so. When subframe suddenly become solid, it starts putting all that extra stress on differential mount and driveshaft. Stock e30 differential mount is no weak-link either, so they'll handle all the abuse as long as you're not going solid. Another plus, is that rubber doesn't transfer as much road noise into the cabin, that all performance upgrades will.

Rating here will be based on quality, purpose, and price.
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1. PowerFlex: world class. There's very little to say that hasn't been said already about this brand. They make two different sets, and both are very streetable, as neither set is 100% solid. Purple ones are softer, and black ones are harder. There are a lot of members that run these, and you'll never hear a bad review of them. I've been in a few e30's with these installed, but never had an opportunity to have them installed in any of my cars.
Purpose: :):):):)
Quality: :):):):):)
Price: :):):):)

$104.99 Purple 70A and $119.99 Black 95A :D:D:D:D-
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2. Ireland Engineering: decent quality, and still for decent money. I have had both sets in my cars. I started with green/street, and ran them until my car was totaled. For my new car, I thought I'd get red/race mounts. I've been very happy with each set. I've daily driven both cars, and this mounts have been nothing but great. There are some complaints about IE, like forgetting to put top washers into boxes (some aren't capable of removing their original ones because of age). I haven't run into that problem, though.
Purpose: :):):):)
Quality: :):):):)
Price: :):):):):)

$90 Green/street and $110 Red/race :D:D:D:D-
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3. Group N: unless you're fooling someone, this is a true waste of money. They cost way too much compared everything else. Before we go any further, they cost well over $300 and are rubber.
Purpose: :?::?::?::?::?:
Quality: :?::?::?::?::?:
Price: :down:

$378 and I'd question my sanity, if I ever spent this kind of money and ranked it.
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4. AKG: I must say, they're 70A ones are perfect for street driving, and 75D are the most inexpensive solid mounts out there... but I took AKGs out. When I saw what happened to my TABs, I wasn't in a mood to keep any AKG products on my vehicle. Either way, this is another time that AKG has a good price, but inner race is made of extremely light aluminum that easily deforms. Alert: if getting 75D, get a solid diff mount.
Purpose: :):):):)
Quality: :):):)
Price: :):):):)

$90.00 either 70A or 75D :D:D:D+
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5. Aluminum: this can be had from practically every tuner, and should only be considered to be put on race cars. Solid aluminum transfers all of the road noise into the cabin, and with all the road noise comes all the road stress onto the chassis. Without proper reinforcements, you should avoid this options. There are a lot of them on the market and how different can two chunks of aluminum be?
Purpose: :):):):):)
Quality: by brand, but all are high
Price: by brand
Check out: Turner Motorsports, BimmerWorld, VAC, and practically every serious tuner that races.
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Again, please add do it, as I can only write-up what I have experience with.

[KenC]

My IE TABs squeak like a mofo.