Aluminium vs Polyurethane Motor Mounts
So the stock marshmallows will silence the engine. Got it.
*Standalone* they're definately good for:
1 - Excessive engine movement which also applies stress to the other supporting driveline members
2 - Twice the rear wheel hop
3 - Less throttle response (in ANY gear, with the biggest difference being 5th gear)
4 - Accelerated wearing of the bushings, and there's a LOT of em, and they're not cheap, or easy to remove and reinstall
4 - Increased transmission and driveline shock (transmission rebuilds are not cheap either - i KNOW)
6 - Making your date think you don't know how to drive your "rice rocket" as the back end of the RX-7 hops all over the place
"excessive engine noise" confusing the knock sensor ?? are you for real ?
It's obvious you have no experience with polyurethane mounts. Or perhaps you're imagining the effects of solid engine mounts on *piston* engines.
Wait...
"They ALL make excessive engine "noise" and cause false knock readings. "
So... all of us ^^^ with poly engine mounts have mis-tuned engines in your opinion.
And ALL racing RX-7's with poly mounts and other braces are not tuned according your insight...
A lot of us have a lot of experience and work on our own cars here.
Not to a dick but
i can only imagine people reading the threads on this forum wondering what's the right and what's nonsense with people posting stuff like this.
*Standalone* they're definately good for:
1 - Excessive engine movement which also applies stress to the other supporting driveline members
2 - Twice the rear wheel hop
3 - Less throttle response (in ANY gear, with the biggest difference being 5th gear)
4 - Accelerated wearing of the bushings, and there's a LOT of em, and they're not cheap, or easy to remove and reinstall
4 - Increased transmission and driveline shock (transmission rebuilds are not cheap either - i KNOW)
6 - Making your date think you don't know how to drive your "rice rocket" as the back end of the RX-7 hops all over the place
"excessive engine noise" confusing the knock sensor ?? are you for real ?
It's obvious you have no experience with polyurethane mounts. Or perhaps you're imagining the effects of solid engine mounts on *piston* engines.
Wait...
"They ALL make excessive engine "noise" and cause false knock readings. "
So... all of us ^^^ with poly engine mounts have mis-tuned engines in your opinion.
And ALL racing RX-7's with poly mounts and other braces are not tuned according your insight...
A lot of us have a lot of experience and work on our own cars here.
Not to a dick but
i can only imagine people reading the threads on this forum wondering what's the right and what's nonsense with people posting stuff like this.
-J
-J
Joined: Mar 2001
Posts: 30,804
Likes: 646
From: FL-->NJ/NYC again!
Well Rich....there is alot more to tuning than that. Most importantly: Knock, IAT, EGT and AFR. You can have a great AFR reading and blow an engine with no problem if other things are not in check. The comments about the engine mounts can be taken anyway these forum goErs wish, I don't care. It's my $.02 take it or leave it.....But Rich, I think you know me better than for me to just be speaking out my ***.
-J
-J
That wasnt directed at you really big J, but I stand by what I said.....of course you have to keep an eye on IATs, and yes, you can pop a motor with 'safe' AFRs if your timing is too aggressive, but again.....I've been around some (not all) of the best rotary tuners out there, and none of them (nada, zip) paid any attention to knock whatsoever, be it on the pfc commander, old school J&S knock retard etc.
From what I've gathered, it's not a reliable parameter to tune for, at least not on a quantifiable numerical scale..... there are guys out there who tune in part 'by ear' or by the sound of the engine.
i'm not running solid motor mounts, but i have solid trans mount (metal) and solid poly differential mounts. I don't notice any bad vibrations, and the drive line feels much stiffer which is extremely nice.
I think the poly mounts would be better then aluminum ones, The poly mounts are very solid yet still filter out alot of noise. Aluminum would transfer more noise through.
I think the poly mounts would be better then aluminum ones, The poly mounts are very solid yet still filter out alot of noise. Aluminum would transfer more noise through.
I would think mounting some components solid and some with stock or urethane mounts would be a poor idea, especiall with the PPF. You would be transmitting a lot of force through the PPF and putting most of the load generated by the drive train wanting to twist on the solid mounts.
my PPF is reinforced, and also braced by the transmission brace so nothing from the transmission back moves. Even with the stock motor mounts my engine doesnt move either. So if its a poor idea my car doesnt seem to mind, and definitely prefers the extra rigidness. My PPF broke when i was running everything stock, which is why it's now reinforced. I may add an engine torque brace but it doesnt seem needed.
airplane apex seals
Joined: Mar 2004
Posts: 552
Likes: 0
From: either sunnyvale or san jose
