Anyone use the Polyurethane version of this? Or should I stick with the OEM rubber?

BTW I have the Polyurethane upper.

 

Boxers or briefs ??


No really.

Rubber is stock, sloppy, similar to original, wears out sooner, gets the job done and less possible vibration transmitted to the vehicles body.

Poly, hard, almost no give, keeps the component in the proper alignment under harsh conditions, lasts nearly forever, may transmit more vibration to body.

You have to decide what it is you are looking for and what if any trade offs you are willing to make.

IMHO, I wouldn't even consider the rubber if mine needed replacement but I've seen threads of people who can feel the difference and don't like the vibration. I've read threads where people who bought the poly have gone to rubber so it does bother some people enough to replace their new good part.
One of my first repairs was to install a poly upper engine mount bushing because I bought mine with it hanging out. I pressed the original one back in and a month or two later it was out again. Went with IPD's poly and I've had no problems.

 

If you are referring to the mount that Kiss posted, then yes I have had the iPD poly version. I liked it but my daughter didn't much. It sends vibrations through the steering wheel at idle and low rpm's. If you try it and don't like it, I may buy it from you. I plan to get one soon.

 

Hey, I was here first and I'd buy it off him (at a deep discount since they are sooooo bad!).

 

I don't get it? What exactly is the advantage of having the engine (more) solidly mounted to the sub-frame and more closely coupling the driver to the engine vibrations?

 

Stock engine, normal driver it isn't a problem going with the stock rubber. In fact it makes more sense as it's a more comfortable and economical route.

Modified engine and or aggressive driver and the engine and transmission start to move forward and backward pulling on different mounts depending on if accelerating with the engine or decelerating using the transmission. These components, if soft can allow the engine and or transmission to shift so much they can seize the shifter linkage or use up all the play where you can't shove or pull the shifter far enough to get it into gear. In the case of manual clutch linkage you might not be able to push far enough to disengage.

You don't want to increase the vibration felt inside the car it's just something most people are willing to compromise on if they're going to modify the vehicle to go fast.

When you think of cornering you already have a tire that's going to bend and deform going around the corner, the control arms have stock rubber bushings which are soft. At the top of the strut is a rubber spring seat that centers the struts shaft in the top plate and can bend a bit then there is the engine cradle that has four big rubber doughnut bushings that also bend under extreme cornering. There is also frame flex and the strut physically bending the tower it's mounted in. That's what a strut brace is for. Then there is the steering rack itself trying to hold that tire at the correct angle but it's mounted in rubber too.

Now you replace as much as you can with Polyurethane, Delron or solid metal and you get a vehicle that you can feel turns faster and is more precise.

So that's the deal. A lot of guys try to replace as much of the rubber as they can to get better control. It's faster to respond, it's crisper but it's also more rigid so it's likely to, almost guaranteed to transmit vibration but also give you more feel of the road.

I find it a little uncomfortable that the only option I can find for the motor mounts on the 850s are the stock ones. I don't trust the hydraulic rubber ones. In fact in most high performance engines you go with solid motor mounts, solid steel !! That or like I did with my RX-7 I went with stock Chevrolet metal/rubber mounts but added a chain on the acceleration side in case a mount breaks and the engine tries to roll over in the bay. That 454 rocks that little car bad enough with the metal/rubber mounts.

 

I have become a big fan of poly-bushings. Changed over the top and bottom torque arms this past weekend even the firewall bushing is now poly. Now seeing that they were both trashed to being with I cannot complain about the vibration. Everything feels tighter now and even I am getting better fuel economy.

 

That's supposed to be a joke, right?

 

Sorry Kfrog; no disrespect at all, but not buying it. The only benefit I can see is that they're likely stronger and therefore will last longer; especially if you're dealing with excessive HP (260+) but for 95% of us out there, I think the stock mounts are more than adequate.

There's a reason those mounts are made of rubber; in addition to passengers' comfort, it's to isolate the engine vibrations from the chassis engine mount points. Otherwise you would need much beefier solid mounts to distribute the stress evenly (as much as possible) to the chassis; else you would see metal fatigue pretty quickly...

 

No joke at all... I have no sense of humor that I am aware of.... I had always felt I had to give the car more throttle to maintain speed then i should have. Now just light pressure on the pedal and the car maintains speed. I will know over next the couple of tanks for sure.

 

"Sorry Kfrog; no disrespect at all, but not buying it. The only benefit I can see is that they're likely stronger and therefore will last longer; especially if you're dealing with excessive HP (260+) but for 95% of us out there, I think the stock mounts are more than adequate."

I agree with you on the stronger and longer and no offense taken
And for most people there is no real benefit and it doesn't justify the added expense.

"There's a reason those mounts are made of rubber; in addition to passengers' comfort, it's to isolate the engine vibrations from the chassis engine mount points. Otherwise you would need much beefier solid mounts to distribute the stress evenly (as much as possible) to the chassis; else you would see metal fatigue pretty quickly..."

The reason they are made out of rubber is because rubber is the cheapest material that will get the job done. It's a simple engineering vs cost decision that car manufacturers make daily while making compromises. That is far from being the best material and doing the best job. Rubber will give you a smoother seat of the pants experience and most people want that "boat" feel, nice and smooth.

The way car makers look at it: Volvo made 1,360,522 850s from 1992–1997. If they can save one cent on just one part that was used on each vehicle they just saved $13,605.22 and that's just one cent on one part.

I'm talking about doing modifications to a perfectly good car that 95% or more of the owners think is just fine.

If you're not a believer I can hit you with the science but in the end it's just a matter of desirability, necessity and affordability.
Chassis Engineering - Herb Adams - Google Books

And if you're still not a believer, I can agree to disagree.

 

Our cars both shifted smoother and quicker with the poly tranny mount. As for trying to make as much as possible poly... I think the road conditions in your area will help you decide what will work best for you. Some areas have long straight flat smooth streets/roads, poly would be great. Our area has lots of hills and patchy roads, poly would kinda of suck.

 

Thanks for the link Kfrog; good stuff. But he's primarily talking about suspension components. No argument there; think we can all agree that spongy suspension components impact handling. But I thought we were talking about engine mounts? That was my main point.

And you make a good point about cost being a factor; like you said, whatever a company eventually manufactures is always a compromise of some kind.

I can also see in extreme high performance driving situations, not having the engine/drivetrain assembly move at all in relation to the chassis is probably a good thing.

But again, IMO, for most drivers out there (including enthusiasts) the primary benefit I can see to harder engine mounts is longer life of the engine mount itself.