Troux

iTrader: (4)

I'm running a swap car with some very tight hood clearance. I am trying to come up with ways of fitting in a good strut bar, and the idea of attaching a bar between the head and the strut tower on each side of the engine bay intrigues me. I plan on running solid motor mounts, so would there be much more NVH transmitted to the chassis in addition to what those bring? Would the engine vibration affect the chassis movement?

Thanks.

Sam Strano

iTrader: (41)

Not a good idea. The engine in this car is not meant to be a stressed member, and even if it was, not in that direction. What the hell kind of engine or intake are you running anyway?

turbowhistle86

iTrader: (7)

yeah....I was gonna say, I'm no chassis engineer, but I don't think that's a good idea.

impaled

bad idea. even with solid mounts you are going to have some lateral [rotational] torque from the engine.

plus the vibration could rattle the bolts (or various other things) loose.

Troux

iTrader: (4)

Thanks for the input, guys. It's an FD RX-7 with an LS2. I'd like the option to upgrade to a taller intake in the future, though.

2002_Z28_Six_Speed

iTrader: (19)

I would think about something more like a motor plate. But its more for a race car.

ae13291

iTrader: (8)

i have seen like 350z's put that kinda stuff on but theres is more like a shock not literally a solid bar, you will break something. sick swap btw

01CaMMMaro

iTrader: (25)

just take your hood off then you can fit it show off that sexy LS2

Troux

iTrader: (4)

Motor plates don't seem like they would add the same stiffness of a solid bar, even a flatter design.

z28bryan

iTrader: (7)

Wouldn't the cylinder head be a poor place to attach it to regardless? That way the heads would be resisting the engine rotation. Not sure if it would make any huge difference or not, but it just seems like a bad idea.

BMR Tech

iTrader: (9)

Motor plates add more front end stiffening than you think. The plate running from the driver side to the passenger side is very strong in this position and adds greatly to front end stability from side loads because this is along the strength of the plate.

BMR Tech

iTrader: (9)

Most all motor plates use one or more of the cylinder head accessory bolts as an attachment point.

2002_Z28_Six_Speed

iTrader: (19)

I see what you are saying but they aren't a paper thin plate. Yes, a sheet that had bends in it would be stronger but most of the forces would be applied in the direction of the plate so you aren't seeing any bending action in the plate.

They make the car harder to work on though....

z28bryan

iTrader: (7)

My bad.. I was talking specifically about the strut tower brace being attached to the cylinder heads. I didn't see the beginning discussion about motor plates.

I also have a stupid question. What are motor plates anyway?

Troux

iTrader: (4)

See here:
http://www.tpmotorsports.com/plumbing.jpg
It's the flat panel that runs on the face of the motor, and is connected on either side of the frame.

I don't see what the difference is going to be between a motor plate and the idea I had, since they are bth connected to the frame/body and heads.

z28bryan

iTrader: (7)

There probably isn't, but in that case you connect the block too. If you only connected the STB to the heads, would that be different? I don't know.. just tossing the question out there

Troux

iTrader: (4)

Well by way of the engine mounts and subframe, the block is connected to the frame. Think of this as the bottom of the frame connected to the bottom of the engine. Connect the top of the engine (heads) to the top of the frame (strut towers), and you're basically boxing the engine in. Even with solid mounts, there is some pivoting allowed about the crank's axis. By connected the heads to the strut towers, you would completely eliminate the engine rotation relative to the car.

Still, I'm not sure why BMR recommended a motor plate over a strut bar going to the heads, especially since motor plates involve some welding or drilling in the body/frame.

leadfoot4

iTrader: (1)

Not necessarily, Lee. The motor plates that I'm familiar with, through a couple of oval track cars I was involved with, either mounted between the water pump and accessory holes on the front of the block, and/or the block/bellhousing in the rear of the engine. These plates then bolted to tabs which attached to the frame. Both cars, I should note, were fabricated steel chassied cars.

z28bryan

iTrader: (7)

Wouldn't you need modification to fit the shock tower bar anyway?

leadfoot4

iTrader: (1)

Yeah, one would think so.