[justpete]

Originally Posted by robc1976

solid mounts = to much vibration. Already did the tranny a while back

Yep, that's because the OE mounts isolate low frequency vibration. A larger harmonic balancer is required to damp lower frequencies than the OE balancer can in order to run stiffer trans and engine mounts with negligible in-cabin vibration. Driveline windup is also mostly eliminated which puts torque to the road faster than otherwise possible. Also enables safer shifting with an MT as relative motion between the body and the trans is pretty much eliminated. Makes it possible to use a shifter without a shift carrier, the AKG DTM and CAE Ultra Shifter for example. Add a rigid clutch and lightweight single mass flywheel and slip is eliminated making it easier to accelerate harder through shift points. The price is gear rattle and audible gear whine from the trans.

[robc1976]

Originally Posted by justpete

Yep, that's because the OE mounts isolate low frequency vibration. A larger harmonic balancer is required to damp lower frequencies than the OE balancer can in order to run stiffer trans and engine mounts with negligible in-cabin vibration. Driveline windup is also mostly eliminated which puts torque to the road faster than otherwise possible. Also enables safer shifting with an MT as relative motion between the body and the trans is pretty much eliminated. Makes it possible to use a shifter without a shift carrier, the AKG DTM and CAE Ultra Shifter for example. Add a rigid clutch and lightweight single mass flywheel and slip is eliminated making it easier to accelerate harder through shift points. The price is gear rattle and audible gear whine from the trans.

I am AT

[justpete]

Originally Posted by robc1976

I am AT

I know, just pointing out what this type of engine mount enables, for search reference. The only real benefit to AT users is reduction of driveline windup which may or may not be worth the hassle.

[robc1976]

Originally Posted by justpete

I know, just pointing out what this type of engine mount enables, for search reference. The only real benefit to AT users is reduction of driveline windup which may or may not be worth the hassle.

very useful information

[robc1976]

May CANCEL the delrin order as a buddy of mine pointed out that delrins are rated at 75? This is the same as the crappy powerflex yellow? IF this is a fact Delrin is crap. I can't see how they are only rated at 75?

[justpete]

Originally Posted by robc1976

May CANCEL the delrin order as a buddy of mine pointed out that delrins are rated at 75? This is the same as the crappy powerflex yellow? IF this is a fact Delrin is crap. I can't see how they are only rated at 75?

75 what? 75D Shore hardness?

[robc1976]

Originally Posted by justpete

75 what? 75D Shore hardness?

totally missed that lol! Powerflex is "A" rated and Delrin is "D" rated. Wonder what 75D hardness is in "A" rating?

[justpete]

Originally Posted by robc1976

totally missed that lol! Powerflex is "A" rated and Delrin is "D" rated. Wonder what 75D hardness is in "A" rating?

It's the other end of the spectrum, sorta kinda...

AKG Motorsport Materials page

75D Shore is applicable to polyurethane and is about the same hardness as Delrin.

[robc1976]

Originally Posted by justpete

It's the other end of the spectrum, sorta kinda...

AKG Motorsport Materials page

75D Shore is applicable to polyurethane and is about the same hardness as Delrin.

I see, so Delrin is rated at 75D which is the same as the AKG shore.

[justpete]

Originally Posted by robc1976

I see, so Delrin is rated at 75D which is the same as the AKG shore.

Well, it's not always rated at 75D, its hardness is usually rated on the Rockwell scale since it's specifically for harness instead of durometer. Makes it hard to compare directly.

Plastic Hardness Scale

Delrin is acetal on the scale

[Stucks]

Got them in the mail today. snapped a quick pic.

[robc1976]

Originally Posted by Stucks

Got them in the mail today. snapped a quick pic.

congrats man! Hope they do you well!

[robc1976]

Got my delrins today, amazing quality!

[Seanzie]

There's some great conversation here... I got the Purple Powerflex rear subframe bushings a few months ago, and really enjoyed them. Was actually going to get the yellow ones, but they were out of stock. So, although I can't speak on the relative differences, I do really like what the purple bushings did for me.

My car is mostly stock. I have Koni Yellow's, front M3 control arms, camber pin delete, and the purple rear subframe bushings as my suspension mod list. The subframe bushings were my most recent upgrade, and I noticed that the ping-pong delay in response between the front and the rear was drastically less. It's incredibly noticeable on the track, where my car now transfers weight into corners much more efficiently. Previously, taking a turn felt like a 2-step process: transfer weight/let car settle, then work on turning & any trail braking needed. Now the process is much more seamless, and my suspension is not as easily upset since the front & rear react much closer together in time.

Who knows if the yellow would have performed as well.. but I'll never know.

justpete, you have some impressive mods there! About half of those acronyms are foreign to me though. I'm assuming that you track your car regularly, given those mods. How frequently do you hit the track?

[justpete]

Originally Posted by Seanzie

My car is mostly stock. I have Koni Yellow's, front M3 control arms, camber pin delete, and the purple rear subframe bushings as my suspension mod list. The subframe bushings were my most recent upgrade, and I noticed that the ping-pong delay in response between the front and the rear was drastically less. It's incredibly noticeable on the track, where my car now transfers weight into corners much more efficiently. Previously, taking a turn felt like a 2-step process: transfer weight/let car settle, then work on turning & any trail braking needed. Now the process is much more seamless, and my suspension is not as easily upset since the front & rear react much closer together in time.

Wow, that's the best description of how rear subframe bushings can affect corner entry on the track I've seen, very nice.

Originally Posted by Seanzie

Who knows if the yellow would have performed as well.. but I'll never know.

justpete, you have some impressive mods there! About half of those acronyms are foreign to me though. I'm assuming that you track your car regularly, given those mods. How frequently do you hit the track?

And it's not all of the mods either. Which acronyms don't make sense? Curious cuz most of the ones I see too don't make a lot of sense either.

Been to the track four times in the last couple of months, on a waiting list for mid December, waiting for registration to open for early February, not seeing much past that yet though.

[justpete]

Originally Posted by robc1976

Got my delrins today, amazing quality!

They seem expensive right up until you open the box. Just gotta see 'em in person I think.

[robc1976]

Originally Posted by justpete

They seem expensive right up until you open the box. Just gotta see 'em in person I think.

totally agree, the machine work is perfect!

[ashmostro]

Originally Posted by robc1976

Got my delrins today, amazing quality!

the worst thing about buying parts that gorgeous is that you have to install them where you don't get to see them anymore!

One thing I'm curious about is the bushing with the larger cavity - seems like with the Al sleeve it would still have a rather large gap between the delrin and the Al... is that space taken up by something else? How is the Delrin supported there?

[Stucks]

Seems like the ones rob ordered would be stiffer because they aren't solid delrin.....I see lots of aluminum there too lol. the akg 75D ones are solid delrin and don't have aluminum parts like these have. Good choice for a race cahhh!

[Fundguy1]

Let u know when you get those derlins installed and how they feel. Thx

[robc1976]

Originally Posted by ashmostro

the worst thing about buying parts that gorgeous is that you have to install them where you don't get to see them anymore!

One thing I'm curious about is the bushing with the larger cavity - seems like with the Al sleeve it would still have a rather large gap between the delrin and the Al... is that space taken up by something else? How is the Delrin supported there?

I agree, they are pretty lol! The sleeves are different sizes, 2 big and 2 small. I can't push any in they fit so tight!

[robc1976]

Originally Posted by Stucks

Seems like the ones rob ordered would be stiffer because they aren't solid delrin.....I see lots of aluminum there too lol. the akg 75D ones are solid delrin and don't have aluminum parts like these have. Good choice for a race cahhh!

how they work well!