Odd question about replacing motor mounts...

[ahkenaden]

So, in the almost 15 years I've had this car, with all of the various and massive amounts of Google-Fu that I have utilized, I have never seen anyone speak on why you would want to replace motor mounts with poly alternatives.

Any opinions as to what power level one should upgrade to poly mounts? And are there more "street-car" friendly poly's than the 80+ durometer? Should a modest power bump (given my mods...intake, zero cats, Stillen dp, 3" full exhaust, 13G's+Blitz bc, 450's, Wally255, Maf-T, Fidanza/3SX aluminium crank pulley..probably some other crap that I don't remember given the 8 years since I've regularly driven it...) necessitate such a drastic increase in NVH or would a new set of OEM mounts do the job and keep me from going insane?

I recall about 5 years back putting a SINGLE Energy Suspension poly mount in my beater 95 Sentra and good lord the increase in in-cabin vibration was spectacular. That was a tiny 1.6L, I don't want to know what a 3.0L feels like...

Thanks for any input, been out of the game for some time.

Heed

[sergechronos]

I would imagine that 3SX polys (being as they are basically poly in stock mounts) are probably as soft as you get from something readily available, you could pour your own though and use whatever hardness you like. You could MAYBE talk 3sx into pouring you something more in between, although I would advise going for a ride with somebody who has poly mounts now to see the difference. The results vary from platform to platform. My 00 Mustang used solid mounts and while there was a noticeable increase in vibrations, it was not excessive and was not noticeable when the car was moving. My girlfriend's 94 Integra, was another story, felt awful at idle and could still be felt while moving.

The benefit of poly is that it moves and flexes less than rubber, but more than solids (obviously). It's less strain on the drivetrain and less drivetrain loss due to flexing and moving, and poly tends to last longer than the factory style rubber (which I believe has a fluid filling as well to dampen vibrations.)

As said, ride with someone if you can to test and see before you make a decision on it.

[Jimvr4]

The stock setup uses rubber mounts on the front and rear roll stoppers but the driver side mount and trans mount are oil filled so they reduce vibrations. I've heard front and rear could be solids without much effect but having poly for the driver and trans mounts will increase vibration. I;ve just changed mine to poly all around so we'll see.

[zel-man]

The biggest difference I've noticed are during starts. Greater vibrations and a pronounced stutter out of first gear if I don't feather the clutch right.

[kywhitelightning]

If you commit to poly you might as well go solids. NVH will increase either way, solids are a lot cheaper, and poly's will wear out. I had a set of poly's in mine for 6 years and was a little disapointed that the pins were now mobile. I now have solids and there isn't too much of a difference between the two. For your modest power level stick with stock. They are worlds more comfortable. Make sure there is a good flex section in your DP and I assume you are still on the stock 3 piece DS.

A 4 cylinder will always deliver a lot more vibrations when the engine is more solidly mounted by shear nature of the time between power pulses. I4 every 90*, V6 every 60*, and V8's every 45* of crankshaft revolution.

Jeff

[IPD]

i don't think there's a suggested HP at which you shouldn't run stockers. if the stockers are in good shape--you can probably run them on anything.

[GTOJOE]

A 4 cylinder will always deliver a lot more vibrations when the engine is more solidly mounted by shear nature of the time between power pulses. I4 every 90*, V6 every 60*, and V8's every 45* of crankshaft revolution.

Jeff

This^^^^^ Also for your mods stay stock.

[ahkenaden]

The benefit of poly is that it moves and flexes less than rubber, but more than solids (obviously). It's less strain on the drivetrain and less drivetrain loss due to flexing and moving, and poly tends to last longer than the factory style rubber (which I believe has a fluid filling as well to dampen vibrations.)

As said, ride with someone if you can to test and see before you make a decision on it.

Is anyone 100% convinced about it being less strain on the drivetrain? If anything, wouldn't it be more as you are now transferring more torque (and subsequently more vibration) through the system?

And I'm in Michigan, I think there are 4 people who's cars still run and they are probably still using stock mounts

The stock setup uses rubber mounts on the front and rear roll stoppers but the driver side mount and trans mount are oil filled so they reduce vibrations. I've heard front and rear could be solids without much effect but having poly for the driver and trans mounts will increase vibration. I;ve just changed mine to poly all around so we'll see.

Hm, this would seem to make the best sense as you'd want to decrease front to rear engine flexing (a la 3SX's "jump around" video). And it would make sense that less NVH would be heard since they're mounted to the subframe which has its own set of rubber bushings. Had no idea the side mounts were oil filled. Still learning something new after all this time!

[Ange]

yes it seems to my like it's not really nessesary to change the sides. Like said the Engine movement is mostly back and forth like seen in the 3sx video not to the sides.

What is the argument to change the side(left/right) mounts to anything other than stock?

[Jimvr4]

yes it seems to my like it's not really nessesary to change the sides. Like said the Engine movement is mostly back and forth like seen in the 3sx video not to the sides.

What is the argument to change the side(left/right) mounts to anything other than stock?

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