Anyone make SE36 legal solid trans and motor mounts? I've found 13mm lower, 15mm lower, 5mm lower, etc... but none at stock height.

I am considering making them up, depends on the demand as to the production run. We've been making them for E-30's and E-36's for awhile now.

James Posig
JMT TrackCars
#231 GTS 2

Contact Vorshlag, they are making solid engine mounts.

Bimmerworld - that is where mine are from, under section Engine / Performance / Solid Engine/Transmission Mounts - E36/E46

-Tom

Bimmerworld - that is where mine are from, under section Engine / Performance / Solid Engine/Transmission Mounts - E36/E46

-Tom

Those aren't SE36 legal though.
"Engine mounts are 5mm shorter and transmission mounts are 1mm shorter than stock"

and the rules say "Motor & transmission mounts may be replaced with aftermarket parts of alternate material, but must be the same height as stock. Solid mounts are allowed."

edit: I just saw that they also offer (but don't include) spacers to raise the motor to the required height.

Those aren't SE36 legal though.
"Engine mounts are 5mm shorter and transmission mounts are 1mm shorter than stock"

and the rules say "Motor & transmission mounts may be replaced with aftermarket parts of alternate material, but must be the same height as stock. Solid mounts are allowed."

edit: I just saw that they also offer (but don't include) spacers to raise the motor to the required height.


They did include - came with mine originally a year or so ago. :)

Dang - and I was going to accuse you of not reading...

-Tom

Kina OT, but what would be the purpose of shorter mounts? Just to drop the CG a bit?

I was wondering the same thing, particularly since no one is lowering their differential a commensurate amount. Not that a few mm matters so much in driveline alignment, but ....

-tammer

stock mounts will squish somewhat so the solid ones are often made shorter to be equal to the compressed stock mount height.
cheers,
bruce

Kina OT, but what would be the purpose of shorter mounts? Just to drop the CG a bit?

The Vorshlag (www.vorshlag.com) mounts are stock height. I just installed them 2 weeks ago in my BSP/SM/STU solo car.

The Vorshlag (www.vorshlag.com) mounts are stock height. I just installed them 2 weeks ago in my BSP/SM/STU solo car.

I have had a set here for a few weeks now. I am going to drop the front subframe and reinforce it, a GOOD idea when running solid mounts. Turner makes a really good kit for this.

is it bad to run solid trans mounts and how bad is the vibration i want to run scca next year and have all the supseniosn mods aswell as m3 mounts but i want a stiffer trans mounts but i do drive my car every day still

is it bad to run solid trans mounts and how bad is the vibration i want to run scca next year and have all the supseniosn mods aswell as m3 mounts but i want a stiffer trans mounts but i do drive my car every day still

VERY bad idea to use solid mounts on a daily driver, unless you are willing to crawl under the car and check for subframe cracks every morning.

UUC sells them and is a club racing sponsor

Go to www.uucmotorwerks.com and search for part number ENGMT-RACE-1

"Engine Mount - Racing version

This part is intended for race cars only and is not recommended for street car use.

To meet the demanding needs of racers, the new urethane engine mount features a hybrid design sharing features of standard rubber mounts and solid metal racing mounts:

High-durometer urethane bushings are stiff enough to provide nearly flex-free support, yet still absorb some amount of vibration.



Virtually eliminates flex and bushing separation from powertrain rotational forces (especially with high-powered cars).



Direct-fit design with correct anti-rotation nub ensures hassle-free installation on any 1992-2005 3-series, M3, Z3, and Z4.



Stainless steel hardware.

FITS:
E46 1999-2005 M3, 330, 328, 325, 323
E36 1992-1999 M3, 328, 325, 323, 318
all Z3
all Z4"

I wouldn't consider the UUC or Vorshlag mounts to be solid...I would assume that Techno is referring to aluminum mounts.

I wouldn't consider the UUC or Vorshlag mounts to be solid...I would assume that Techno is referring to aluminum mounts.

The UUC mounts are far from solid.

The Vorshlag are pretty freakin' close. They use a bolt through design with a delrin "spacer".

The Vorshlag are pretty freakin' close. They use a bolt through design with a delrin "spacer".

If it bolts through, what's the point of the delrin? It doesn't seem like it would dampen any vibrations since they can simply pass through the bolt.

Edit: Nevermind...I see the reason on the Vorshlag website:
"Class legal for SCCA Street Prepared and Street Touring (metal content not increased)"

The UUC mounts are far from solid.

The Vorshlag are pretty freakin' close. They use a bolt through design with a delrin "spacer".

"Solid" as opposed to "oil filled" like OE mounts.

If a 1-piece mounts is made of any continuous material, whether it is aluminum, delrin, urethane, or other - it's still "solid".

As for the design of the high-durometer (hard) urethane UUC mounts, the principal concept is that they give the benefits of a metal mount (metal is illegal for SE36) but do not have the vibration-induced other-component loosening/damage issues that are understood with aluminum.

We designed these mounts to be 100% legal for classes such as SE36 as they are a true "bushing" material and stock height, no spacer required. In fact, the actual shape of the bushing itself is cast from a genuine BMW part, so the profile is 100% exact.

http://www.uucmotorwerks.com/RACE/EM-RACE-1_300.JPG (http://www.nexternal.com/uuc/Product410)

Also pictured above is our bolt-through urethane race transmission mounts, the perfect match for the urethane engine mounts. The bolt-though design is practically unbreakable in normal use as the extension stress is only on the hardware and mounting points, not on the bushing material. We've been putting these bushings on many extreme turbo cars that were shredding standard mounts from powertrain rotation relative to the chassis.

Hope this helps!

(metal is illegal for SE36)

False.

L. Motor & transmission mounts may be replaced with aftermarket parts of
alternate material, but must be the same height as stock. Solid mounts
are allowed. Aftermarket transmission mount stiffening devices are
allowed.

"Solid" as opposed to "oil filled" like OE mounts.

If a 1-piece mounts is made of any continuous material, whether it is aluminum, delrin, urethane, or other - it's still "solid".

By that definition, I guess they could be considered solid; though the term solid is more commonly used in reference to all metal mounts.

False.

L. Motor & transmission mounts may be replaced with aftermarket parts of
alternate material, but must be the same height as stock. Solid mounts
are allowed. Aftermarket transmission mount stiffening devices are
allowed.

My bad... I was thinking of the suspension and brake bushing sections of the rules which were prohibiting spherical bearings and requiring "bushing" material. Nevertheless, the other benefits and comparison remain accurate.

- Rob

By that definition, I guess they could be considered solid; though the term solid is more commonly used in reference to all metal mounts.

Well, not really - delrin mounts have always commonly been referred to as solid also. It's better to simply clarify exactly what materials are being talked about.

- Rob

My bad... I was thinking of the suspension and brake bushing sections of the rules which were prohibiting spherical bearings and requiring "bushing" material. Nevertheless, the other benefits and comparison remain accurate.

- Rob

They don't require "bushing" material, whatever the hell that is supposed to mean. They require that the bushing not allow movement in more than one axis. That does not even remotely eliminate metal designs.

They don't require "bushing" material, whatever the hell that is supposed to mean. They require that the bushing not allow movement in more than one axis. That does not even remotely eliminate metal designs.

Just to clarify....since Rob threw "brake bushings" into his comment....per section 4.B. of the rules: "Brake calipers, caliper mountings and bushings, and rotors must be as stock for the model and year of the car"

I know this isn't a thread about brake bushings, but that got thrown in there a couple of posts back, and then someone could misinterpret your post as saying metal brake bushings are legal, which they're not.

They don't require "bushing" material, whatever the hell that is supposed to mean. They require that the bushing not allow movement in more than one axis. That does not even remotely eliminate metal designs.

Wherever CR rules say "bushing", they mean bushing. This is the core of the frequent confusion within CR rules. Along with, "if it doesn't say you can do it, it usually means you cannot." We've clarified that metal mounts engine mounts are legal. Whether they are ideal is another question altogether.

S.Laing's post above clarifies further regarding other metal replacement limitations.

- Rob

Just to clarify....since Rob threw "brake bushings" into his comment....per section 4.B. of the rules: "Brake calipers, caliper mountings and bushings, and rotors must be as stock for the model and year of the car"

I know this isn't a thread about brake bushings, but that got thrown in there a couple of posts back, and then someone could misinterpret your post as saying metal brake bushings are legal, which they're not.

100% correct.

Wherever CR rules say "bushing", they mean bushing. This is the core of the frequent confusion within CR rules. Along with, "if it doesn't say you can do it, it usually means you cannot." We've clarified that metal mounts engine mounts are legal. Whether they are ideal is another question altogether.

S.Laing's post above clarifies further regarding other metal replacement limitations.

- Rob

Suspension bushing material is free, Rob. That means metal bushings which allow movement in only 1 axis are legal. Those bushings which are not free are explicitly noted.

Vendors who misinterpret rules have been a common source of "confusion" as well.

In fact, the actual shape of the bushing itself is cast from a genuine BMW part, so the profile is 100% exact.


the stock bushing *compresses* a small amount when the weight of the motor is on it. Does this replacement mount mimic the stock height of a loaded or unloaded motor mount?

Suspension bushing material is free, Rob. That means metal bushings which allow movement in only 1 axis are legal. Those bushings which are not free are explicitly noted.

What the...? No confusion, exactly as I posted, exactly from the rules - no spherical bearings. That's all I posted about suspension.

- Rob

the stock bushing *compresses* a small amount when the weight of the motor is on it. Does this replacement mount mimic the stock height of a loaded or unloaded motor mount?

The small amount a new OEM bushing compresses is part of the entire "additive tolerances" of powertrain positioning - meaning at the manufacturer level.

However, as they age and weaken, that's when they compress a lot more. Same thing with transmission mounts.

CR rules would not be using old, worn-out bushings as the comparitive specification. I think that would be a universal understanding. To follow the rules, the height of the aftermarket mount (regardless of material) would match the original's measurement, and it should be assumed that only a new mount would be accurate for measuring. All new mounts are the same height. No two used ones are the same as the compression varies by age/mileage.

- Rob

The small amount a new OEM bushing compresses is part of the entire "additive tolerances" of powertrain positioning - meaning at the manufacturer level.

However, as they age and weaken, that's when they compress a lot more. Same thing with transmission mounts.

CR rules would not be using old, worn-out bushings as the comparitive specification. I think that would be a universal understanding. To follow the rules, the height of the aftermarket mount (regardless of material) would match the original's measurement, and it should be assumed that only a new mount would be accurate for measuring. All new mounts are the same height. No two used ones are the same as the compression varies by age/mileage.

- Rob

I believe that to be the case, as well. It does not make sense to use any measurement other than that of a new, unloaded, factory mount. I'd love to see someone argue differently. Besides, if the point is to get the drivetrain lower in the chassis for a competitive advantage, and that's why the rule specifies "stock height", a solid mount at a height equal to an unloded stock mount will ALWAYS end up keeping the drivetrain higher throughout it's useful life, because it will never compress as much.

I believe that to be the case, as well. It does not make sense to use any measurement other than that of a new, unloaded, factory mount. I'd love to see someone argue differently. Besides, if the point is to get the drivetrain lower in the chassis for a competitive advantage, and that's why the rule specifies "stock height", a solid mount at a height equal to an unloded stock mount will ALWAYS end up keeping the drivetrain higher throughout it's useful life, because it will never compress as much.

So you build an aluminum core mount with a spongy/soft outer casing and a bolt-through design...unmounted it's stock height...mounted is 10mm lower.

What the...? No confusion, exactly as I posted, exactly from the rules - no spherical bearings. That's all I posted about suspension.

- Rob

No, you said metal was illegal. It's not. Sphericals are not the only metal bushing in the world.

Still looking for a definition of "bushing material" in the rule book...

So you build an aluminum core mount with a spongy/soft outer casing and a bolt-through design...unmounted it's stock height...mounted is 10mm lower.

You gotta point, there...:help EDIT...although I've never seen such a thing on the market.

No, you said metal was illegal. It's not. Sphericals are not the only metal bushing in the world.

I cited brake parts.

4. Brakes
B. Brake calipers, caliper mountings and bushings, and rotors must be as
stock for the model and year of the car.

"Stock" bushings are not metal on these cars. They are rubber.

Hopefully clarified in full, moving on.

Still looking for a definition of "bushing material" in the rule book...

Let me know when you find it.

- Rob

I cited brake parts.

4. Brakes
B. Brake calipers, caliper mountings and bushings, and rotors must be as
stock for the model and year of the car.

"Stock" bushings are not metal on these cars. They are rubber.

Hopefully clarified in full, moving on.



Let me know when you find it.

- Rob
As stock means STOCK. If bushing material is free, that's totally different.

So obviously you don't run these on a daily driver. How about a track only car that gets driven to and from the track?

I mean will ANY street usage be putting it at risk? Or just frequent driving?

Street usage compared to track usage isn't the issue...the issue is that you must check them constantly to be sure the subframes are holding up and not cracking.

Street usage compared to track usage isn't the issue...the issue is that you must check them constantly to be sure the subframes are holding up and not cracking.

Gotcha... but I assume that you're more likely to crack the subframe to begin with if you're slamming the car over pot-holes, cracks, etc, on the way to the track than you are going in circles on relatively smooth pavement.

I think the subframe issues mostly arise from constant vibration and stress rather than a pot-hole type situation. It's more of a fatigue thing.

I think the subframe issues mostly arise from constant vibration and stress rather than a pot-hole type situation. It's more of a fatigue thing.

I think my solid motor mounts are the reason for my broken motor mount arm that has led to so many money shifts of late. Hopefully, we'll have it solved with the new arm and some better motor mounts. :)

The small amount a new OEM bushing compresses is part of the entire "additive tolerances" of powertrain positioning - meaning at the manufacturer level.

However, as they age and weaken, that's when they compress a lot more. Same thing with transmission mounts.

CR rules would not be using old, worn-out bushings as the comparitive specification. I think that would be a universal understanding. To follow the rules, the height of the aftermarket mount (regardless of material) would match the original's measurement, and it should be assumed that only a new mount would be accurate for measuring. All new mounts are the same height. No two used ones are the same as the compression varies by age/mileage.

- Rob
I noticed quite a bit of "compression" after iniital contact on my M3 motor mounts when replacing the destroyed motor mounts in my 325. Upwards of a 1/4 inch.

I would assume that the "the mounts must retain the stock height" bit would mean that if you put in brand new OE mounts, measure the height of the engine versus the subframe, then replicate that with a solid mount, you are good to go.
If i were a tech inspector, that's what I'd check. I'd make a block of wood that "just fits" between the oil pan and the subframe with stock mounts. If the engine is too low and the motor is on solid mounts, then no good.

I have the UUC engine mounts in mine and older style TME's with the cups. One of my TME's let go, half of it came unbonded. Rob told me he would replace them free no questions, great customer service! BUT i told him I would just cut the top and bottom off and mount them like his new race bushing..

Mounted with a bolt the suckers increase the vibration a large amount. I would hate to have solid aluminum mounts! My driveline does not move! I have to run it on the dyno when my new UUC ceramic puck clutch gets here, KIA M5 clutch at 4k under boost:( I would bet the driveline has little if any movement on the dyno under fullpower.

The Engine mounts are MASSIVE!! I had a pair I got from Ireland and after seeing the UUC mounts I sold them and got the UUC ones..They are stiff as crap! If you want to errrr semi not be legal in a stock class you could coat the UUC mounts in tool handle rubber and then get a box of dust and "weather them" Not that I have ever cheated in stock class SCCA autoX:D

I'm prety happy with mine. They work great and stiff should move enough to not break off mounts..There is a compromise you need to be safe and not be overly stiff..

The Vorshlag Competition Motor Mounts (http://www.vorshlag.com/motormounts.php) are legal for SE36 and other classes (such as some within SCCA) that allow alternate bushing material but not solid metal units. Made with a Nylon-6 bushing material insert they are FIRM, much more so than poly motor mounts, but do provide a tad more vibration isolation than a purely solid mount. We caution people with street-only BMWs that "these motor mounts are not for everyone", as their name implies.

We have been running them on some street driven cars, and it's only from the good graces provided by the inherent balancing of the straight-6 that allows them to be used on the street. :) They do have added NVH at idle but this goes away completely above 800 rpm - you'd never know they were there. Air Con and LTW flywheels exacerbate this low RPM vibration, but everything still smooths out above idle. Regardless, they do "fix" the sloppy shifting of some BMWs, and remove money shift concerns.

http://www.vorshlag.com/images/catalog/products/motormounts_8_thm.jpg (http://www.vorshlag.com/images/catalog/products/motormounts_8.jpg) http://www.vorshlag.com/images/catalog/products/motormounts_5_thm.jpg (http://www.vorshlag.com/images/catalog/products/motormounts_5.jpg)

This "fix" really works, and when combined with stiffer transmission mounts (we use and recommend UUC tranny mounts (http://www.uucmotorwerks.com/html_product/tranny_mount/index.htm)) allows for rock solid shifts with 100% confidence. We've been running these continuously on a street driven E36 M3 for 6 months (one of 3 prototype cars, which include a modified E36M3 track car and a Supercharged ProSolo E36M3 with 315 tires) with no issues, and have sold ~30 sets since we released them October 1st. They work on both E36 and E46 models.

And now back to your regularly scheduled thread...

The Vorshlag Competition Motor Mounts (http://www.vorshlag.com/motormounts.php) are legal for SE36 and other classes (such as some within SCCA) that allow alternate bushing material but not solid metal units. Made with a Nylon-6 bushing material insert they are FIRM, much more so than poly motor mounts, but do provide a tad more vibration isolation than a purely solid mount. We caution people with street-only BMWs that "these motor mounts are not for everyone", as their name implies.

We have been running them on some street driven cars, and it's only from the good graces provided by the inherent balancing of the straight-6 that allows them to be used on the street. :) They do have added NVH at idle but this goes away completely above 800 rpm - you'd never know they were there. Air Con and LTW flywheels exacerbate this low RPM vibration, but everything still smooths out above idle. Regardless, they do "fix" the sloppy shifting of some BMWs, and remove money shift concerns.

http://www.vorshlag.com/images/catalog/products/motormounts_8_thm.jpg (http://www.vorshlag.com/images/catalog/products/motormounts_8.jpg) http://www.vorshlag.com/images/catalog/products/motormounts_5_thm.jpg (http://www.vorshlag.com/images/catalog/products/motormounts_5.jpg)

This "fix" really works, and when combined with stiffer transmission mounts (we use and recommend UUC tranny mounts (http://www.uucmotorwerks.com/html_product/tranny_mount/index.htm)) allows for rock solid shifts with 100% confidence. We've been running these continuously on a street driven E36 M3 for 6 months (one of 3 prototype cars, which include a modified E36M3 track car and a Supercharged ProSolo E36M3 with 315 tires) with no issues, and have sold ~30 sets since we released them October 1st. They work on both E36 and E46 models.

And now back to your regularly scheduled thread...

I've been considering these motor mounts, but several folks have told me that they are concerned about the Nylon inserts rather than something with a bit more proven track record for race use. Can you provide me with more information about the Nylon?

I've been considering these motor mounts, but several folks have told me that they are concerned about the Nylon inserts rather than something with a bit more proven track record for race use. Can you provide me with more information about the Nylon?

I'd be interested to hear the reasons for choosing Nylon-6 over Delrin.

I've been considering these motor mounts, but several folks have told me that they are concerned about the Nylon inserts rather than something with a bit more proven track record for race use. Can you provide me with more information about the Nylon?

The material used in our motor mounts is Nylon-6 - feel free to Google it, there is tons of data. :)

This material is very similar to Delrin (proven in motorsports), and is used in many similar applications in various industries. It was chosen by our lead Engineer based on his own past experiences with Delrin, Nylon-6 and other plastics. Most importantly, Nylon-6 has a significantly higher melting point than either Delrin or Polyurethane - important when you hang out near an exhaust header.


http://en.wikipedia.org/wiki/Nylon_6
http://en.wikipedia.org/wiki/Delrin
http://www.polymerprocessing.com/polymers/PA6.html
http://www.machinist-materials.com/comparison_table_for_plastics.htm
Nylon-6 melts at 491°F
Delrin melts at 347°F
Polyurethane melts at 284°F



Cheers,

TMost importantly, Nylon-6 has a significantly higher melting point than either Delrin or Polyurethane - important when you hang out near an exhaust header.

I just spotted that in a comparison table and had an "ah-ha" moment as to why Nylon-6 was chosen over Delrin.

The material used in our motor mounts is Nylon-6 - feel free to Google it, there is tons of data. :)

This material is very similar to Delrin (proven in motorsports), and is used in many similar applications in various industries. It was chosen by our lead Engineer based on his own past experiences with Delrin, Nylon-6 and other plastics. Most importantly, Nylon-6 has a significantly higher melting point than either Delrin or Polyurethane - important when you hang out near an exhaust header.


http://en.wikipedia.org/wiki/Nylon_6
http://en.wikipedia.org/wiki/Delrin
http://www.polymerprocessing.com/polymers/PA6.html
http://www.machinist-materials.com/comparison_table_for_plastics.htm
Nylon-6 melts at 491°F
Delrin melts at 347°F
Polyurethane melts at 284°F



Cheers,

Makes sense to me. I have forwarded a link to this thread to the shop working on my car. Who knows? You may be getting an order for use on my car within the next few days! THANKS for the info!:)

On several topics:

The Solid aluminum engine and trans mounts we have are shorter to lower the Cg of the car as guessed - they are full-pop race parts that we have made work in several other BMW CCA classes with this modification, not a street/race part that fits the rules. These are the mounts used on our E36 and E46 World Challenge cars. We used to include the spacers (required for Prepared also...) but so many find their way onto mod cars where the spacers are trashed and since they are not cheap to make. Subframes should be reinforced with these mounts but after doing that, there are no other problems that I have seen in our years of use.

Whether you use these mounts, other performance mounts, or stock, you should reinforce the F subframe - we have a weld-on kit for under $20. I ran a car hard with stock mounts for a year and in that time, the stock unmodded F subframe completely cracked up in the engine mount area. I welded up the cracks, put on reinforcement plates underneath, and it lasted another two hard years of use.

Again, the current Vorshlag Competition motor mounts work with all E36 and E46 6-cylinder models.

Our 6-cylinder E30 motor mount (also with Nylon-6 bushing material) has been designed and is being prototyped now. This is being built specifically for Spec E30 use, as requested by several racers in that class. More news as we have the E30 prototype mounts in hand. :)

Again, the current Vorshlag Competition motor mounts work with all E36 and E46 6-cylinder models.

Our 6-cylinder E30 motor mount (also with Nylon-6 bushing material) has been designed and is being prototyped now. This is being built specifically for Spec E30 use, as requested by several racers in that class. More news as we have the E30 prototype mounts in hand. :)
Just wanted to update this post. We now have E36/46 mounts in Nylon and Polyurethane, as well as E30-6 cylinder mounts in Nylon and Polyurethane. E30-S50 swap mounts and E30 M3/S14 mounts are both being prototyped now.

E36/46 in Poly and Nylon:
http://www.vorshlag.com/cart/images/motormounts_polye36_02_thm.jpg (http://www.vorshlag.com/cart/product_info.php?cPath=1_4_26&products_id=76) http://www.vorshlag.com/cart/images/motormounts_8_thm.jpg (http://www.vorshlag.com/cart/product_info.php?cPath=1_4_26&products_id=34)

E30 6-cylinder in Poly and Nylon:
http://www.vorshlag.com/images/catalog/products/motormounts_e30_poly01_thm.jpg (http://www.vorshlag.com/cart/product_info.php?products_id=99&osCsid=0df4919c73ada67f4e8c349d86176eeb) http://www.vorshlag.com/cart/images/motormounts_e30_08_thm.jpg (http://www.vorshlag.com/cart/product_info.php?cPath=1_17_49&products_id=72)
The E30 mounts are on special Introductory Pricing until May 15th ($30 off).

The Nylon-6 bushing material has a Shoreline 70 D durometer (HARD as a bowling ball). The red Polyurethane bushing material has a Shoreline 95 A (50 D) durometer (STIFF, but not quite HARD). Both provide noticeable improvement over the OEM rubber, with the Nylon versions adding some NVH (which is amplified by a light flywheel). We recommend the Poly mounts for street driven cars.

edit: All Vorshlag mounts are built to the OEM engine mount height. OEM mounts tend to compress over time - we have seen variances from side-to-side by as much as 7mm on old, stock mounts. Our mounts... don't compress over time. :D

Cheers,

i just bought your red E36 polyurethane mounts for a strictly track car. didn't know you had the white nylon, but i assume the red will still be good enough for an S52 race engine?

i just bought your red E36 polyurethane mounts for a strictly track car. didn't know you had the white nylon, but i assume the red will still be good enough for an S52 race engine?

Yes, they are only slightly softer than the Nylon (which isn't soft). :) If you haven't installed them we can swap them out if you like.

Brian

Brian, is the polyurethane e36 mount a bolt-through design or different?

I can't decide between the UUC's or something else...

The UUC mounts are far from solid.

The Vorshlag are pretty freakin' close. They use a bolt through design with a delrin "spacer".

I touched these... they might as well be solid...

Has anybody looked at the Group N mounts from AKG?

Brian, is the polyurethane e36 mount a bolt-through design or different?

I can't decide between the UUC's or something else...

Both the Nylon and urethane mounts are bolt-through designs (I have both).

We have some Group N stuff (the ones that BMW sold for $800/pair or so) on the way that will be a fraction of the cost. Very durable and very solid, but not full solid aluminum.

Whats the consensus on bolt-through/poly for a street driven car that sees track use?