Anyone Have Rigid Engine Mounts?

M

Mac Attack

Legendary Member
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Hello,

Does anyone have rigid engine mounts? If so, were they part of a "drastic" track build, or was this modification done separately so you could tell what effect it had on noise/vibration/harshness?

I'm curious as to exactly how much extra noise and vibration this would cause being transmitted into the cabin. I already have a lexan rear divider pane and a bare engine firewall so my car is somewhat noisy. That doesn't really bother me, and I was thinking going to solid mounts wouldn't make it THAT much worse.

The reason I'm asking is because I'm thinking about going to a solid front engine mount that I could re-engineer and get more space for proposed exhaust piping into the drivers side of the engine bay for turbocharging. Going to a solid front mount would necessitate all other mounts being solid so I don't overly stress my new solid front mount.

Thanks in advance,

Dave
 
FXMD ran them for awhile.

What was learned by them and Nick at Applied Motorsports who builds our gearboxes is they contribute to breaking gearboxes very quickly from being too rigid and not allowing any flex.
Less is good, none is not.

The one like SOS sells is what we are using now without problems.

http://scienceofspeed.com/products/engine_performance_products/NSX/ScienceofSpeed/engine_mounts/

Mac Attack said:
Hello,

Does anyone have rigid engine mounts? If so, were they part of a "drastic" track build, or was this modification done separately so you could tell what effect it had on noise/vibration/harshness?

I'm curious as to exactly how much extra noise and vibration this would cause being transmitted into the cabin. I already have a lexan rear divider pane and a bare engine firewall so my car is somewhat noisy. That doesn't really bother me, and I was thinking going to solid mounts wouldn't make it THAT much worse.

The reason I'm asking is because I'm thinking about going to a solid front engine mount that I could re-engineer and get more space for proposed exhaust piping into the drivers side of the engine bay for turbocharging. Going to a solid front mount would necessitate all other mounts being solid so I don't overly stress my new solid front mount.

Thanks in advance,

Dave
Click to expand...
 
Last edited:
Hi Mac,

I have the SOS engine mounts too. Front and rear. They do transmit more vibration into the car but nothing drastic.
 
Have you seen the STMPO mounts?

attachment.php


http://nsxprime.com/forum/showthread.php?t=151391&highlight=stmpo
 
Thanks for the feedback on the STMPO and SOS mounts.

The mounts I was proposing would be completely rigid - no flex. I hadn't thought gearbox problems would become an issue but since they do, I won't be going to completely rigid mounts!

Dave
 
STMPO's aren't totally rigid from the looks of them.
They are nice looking well made mounts for sure.

Mac Attack said:
Thanks for the feedback on the STMPO and SOS mounts.

The mounts I was proposing would be completely rigid - no flex. I hadn't thought gearbox problems would become an issue but since they do, I won't be going to completely rigid mounts!

Dave
Click to expand...
 
Mac Attack said:
Thanks for the feedback on the STMPO and SOS mounts.

The mounts I was proposing would be completely rigid - no flex. I hadn't thought gearbox problems would become an issue but since they do, I won't be going to completely rigid mounts!

Dave
Click to expand...

Did you read this part of his first post?

"Stiffer bushings are available for higher horsepower applications."
 
Moses said:
Did you read this part of his first post?

"Stiffer bushings are available for higher horsepower applications."
Click to expand...

Admittedly, no. Thanks for pointing that out. If I were to buy new mounts, I would go with STMPO's. They are definitely well-engineered, constructed, and cost-effective too.

Dave
 
Bumping this with a bit of a technical question.

What durometer (shore A or D scales) is about the "safe" limit for engine mounts?

Assuming it's a solid center.

I've seen other aftermarket mounts quoting something like A45 to A65. A local fellow that races BMWs recommended something more along the lines of D45 (which is equivalent to A95 or there-abouts if my memory of materials science class is still intact)

Just looking for some input so I don't end up compromising transmission/engine wear and/or losing fillings by using a too-rigid material.
 
Are you filling these old OEM mounts yourself, or are you buying a whole new aftermarket mount?

If you're filling these, may I ask what material you're planning on using? I'm still trying to decide what to do with mine. My 20YO OEM mounts are in great shape actually. I may just etch them and completely fill them with the flexane.

Thanks,

Dave
 
Mac Attack said:
Are you filling these old OEM mounts yourself, or are you buying a whole new aftermarket mount?

If you're filling these, may I ask what material you're planning on using? I'm still trying to decide what to do with mine. My 20YO OEM mounts are in great shape actually. I may just etch them and completely fill them with the flexane.

Thanks,

Dave
Click to expand...

That Flexane stuff sounds pretty simple. The OEM rubber isn't sleeved/press-fit into the mount. It's actually molded in, and the inside of the ring that holds it is actually wavy, so you'd have to do some machining to go back and press-fit something in.

I'll see what my guy here comes up with and if it's easily reproducible I'll update this.

My front and rear mounts were VERY worn, one of them hadn't totally failed yet, but was only about a centimeter from being split through on both sides of the rubber isolator. I could tell it was rocking around the last time I was at the track.
 
I did my front and back ones with flexane. I got the primer, roughed up the oem rubber with a dremel, mixed and poured. Easy as pie. I was going to go with the SOS ones but had to put my car back together for an event and decided to do this in the meantime. Before I did I read TONS about it on the DSM and evo forums, all good reviews. After running maybe 5 events with them, I'm happy and don't think I'll swap them.

Everything I read, apparently the primer use is key for longevity

<a href="http://smg.photobucket.com/albums/v680/xburnitallx/?action=view&current=1331191453.jpg" target="_blank"><img src="http://img.photobucket.com/albums/v680/xburnitallx/1331191453.jpg" border="0" alt="Photobucket"></a>
 
Last edited:
I did my front and rear mounts with 3M Windoweld three years ago.

From my research, it was equivalent to a shore A 100 durometer.

Now, three years later, I must not have done a good job etching (I didn't prime either), because I need to redo them.

Here's urethane's I'm considering. This time I'll etch them better with a die grinder and use a urethane primer.
http://www.mcmaster.com/#catalog/118/3629/=gknfnq
 
illwillem said:
I did my front and back ones with flexane. I got the primer, roughed up the oem rubber with a dremel, mixed and poured. Easy as pie. I was going to go with the SOS ones but had to put my car back together for an event and decided to do this in the meantime. Before I did I read TONS about it on the DSM and evo forums, all good reviews. After running maybe 5 events with them, I'm happy and don't think I'll swap them.

Everything I read, apparently the primer use is key for longevity

Click to expand...

Nice, where can i get this flexane & how long does it take to cure b4 putting back on the car?
 
I cant remember, I followed a link off of a forum. It wasnt all too cheap, like $110+ for the primer and the actual rubber. It will have enough for two mounts. i let mine sit for 7 hours to cure then re installed it and didn't drive the car for another day.
 
So my guy came up with basically two D45 material cones with a sleeve connecting them to accomodate the stock mount without having to machine the mount itself. They are press-fit, but removable if I want/need to change them later.

D45mounts.jpg


Maybe not as robust as the STMPO, and I suspect slightly harsher than the SOS offerings, but they got the job done at the track over the weekend.

The car has lost a little of the "relaxed" nature when cruising on the highway and there are some resonant frequencies that you feel more. It was still completely tolerable for 4 hours and didn't drown out the radio, but might not pass the "girlfriend" test quite as well. Time will tell I suppose if I regret the change or not, but if I do, as I mentioned above the inserts are replaceable so It'll just be an issue of providing my friend with enough beer to make some softer inserts.
 
Last edited:
Was hoping for a quick update from the DIY folks who poured flexane or 3m? How has the longevity been? Seems like if one does not do a good job etching/priming the OEM rubber it will break away in due time.

I was hoping for something just stiff enough to withstand the tq of a low boost FI setup. I have a feeling i'll be tearing thru my OEM mounts fairly soon but I do still do long drives so something not stiff but just stiff enough would be ideal. What durometer rating would you recommend for this level of density?
 
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I was under the car this last weekend and check everything, I actually took the back mount off the car and inspected it under the work light for any cracks, it was dirty but look like it did the day I put it in. So far ive got about 12 track days on them so far. I took my time and dremeled every single mm of the oem rubber than took my time getting a good though cleaning and coating with the primer. I have read on the EVO forums (and on the package) that that is the no. 1 key to the flexane lasting. So far so good.

I looked but I could find the receipt for the rating of the one I used. Im almost 100% sure that i have half a can of primer still left at home. If you end up doing flexane lemme know and you can borrow mine and save some cash.
 
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illwillem said:
I was under the car this last weekend and check everything, I actually took the back mount off the car and inspected it under the work light for any cracks, it was dirty but look like it did the day I put it in. So far ive got about 12 track days on them so far. I took my time and dremeled every single mm of the oem rubber than took my time getting a good though cleaning and coating with the primer. I have read on the EVO forums (and on the package) that that is the no. 1 key to the flexane lasting. So far so good.

I looked but I could find the receipt for the rating of the one I used. Im almost 100% sure that i have half a can of primer still left at home. If you end up doing flexane lemme know and you can borrow mine and save some cash.
Click to expand...
Thanks! I'll take you up on your offer kind sir! We're all local in LA. If I don't see you at the next track day I can swing by. Will try to figure out the rating of flexane to buy in the meantime.
 
illwillem, or someone, needs to make these. They will sell. The STMPO's were beautiful but fairly cost prohibitive.

I bough the transmission 75A (street/strip) mount from SwapShowParcing for $135 (http://www.swapshopracing.com/contents/en-us/d831.html#p5061).

I'd be happy to pay upto that for a as good or better quality. If you can make 20 of these and you can make $2,000, easily. You just would take the customer's motor mount, strip it, put the material and boom, you just made $100.00...
 

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