Motor mount cups? Do I need them?

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04-24-2012, 10:52 PM

#21

TorqueZombie

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I have a crazy question. If you left the cups out, would it lower the motor by the thickness of the cup....1/8in or so? In theory wouldn't it lower the center of gravity of the drive train a hair? Engine and trans are one piece once bolted together. It probably wouldn't make a big difference to most, but I remember something about old rally cars lowering engines to lower the CG of the car. Sometimes tilting engines back on AWD cars. It works on bikes, but I know the weight of the engine on a street bike it a large percentage of the total mass. Their basically engines with wheels.

04-24-2012, 11:03 PM

#22

Stein

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If you are good enough to notice a CG drop from lowering the motor 1/8" you won't be driving a Miata you would be in a paid ride.

04-24-2012, 11:25 PM

#23

vehicular

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Quote:

Originally Posted by bbundy

Imagine the motor twisting about the crankshaft axis. The C shaped steel part of the engine side of the motor mount will bottom out on the cup if one of two scenarios happen.

1) The rubber part of the motor mount which connects the engine to the chassis fails completely
2) The rubber mount is over loaded and deforms too much.

With the cup in place the design of the system behaves both as a failsafe and an overload bump stop limiting motion.

Bob

IMG]https://www.miataturbo.net/attachment.php?attachmentid=41666&d=1335306516[/IMG]

You are 100% right. I don't know what exactly I was thinking.

04-25-2012, 09:03 AM

#24

turotufas

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I'm having turbo clearance issues with mmr mounts and no cups lol. I need that 1/8 inch back!

04-25-2012, 12:39 PM

#25

bbundy

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Quote:

Originally Posted by turotufas

I'm having turbo clearance issues with mmr mounts and no cups lol. I need that 1/8 inch back!

I slotted the holes in the brackets where they attach to the block. Lowered my engine by ~ 1/4" in so doing. Pan to sub frame clearance is minimal but I haven’t found evidence of the pan hitting the sub frame and I got better clearance between the valve cover and the vented hood I’m using.

Bob