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HybridZ

solid motor mounts?


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I have a 77 280z of which i plan on putting in a blown small block. i haven't seen or heard to much on what style of motor mount or trans. mount people are running with V8 conversions. Do you all still run a rubber mount, urethane, or do you go solid. If solid is the way to go any recommendations on re-enforcing the frame rails in order to take the torque or twist of the engine under hard acceleration? I have a brand new 1992 LT1 Corvette engine of which i plan on rebuilding and modifying heavily in order to withstand 10 - 15 Psi of boost. With this much power i was just unsure of what style of mount is recommended. The ride quality does not concern me at all, for almost all of the suspension i am installing came off a SCCA GT2 280Z racecar that was full tubeframe chassis. Any ideas would be greatly appreciated.

 

-Dave

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Dave, guys are doing all of the above on the Z. You'll find that (if you use the search function) there are stock biscuit users, poly users, and solid mount users---all have their benefits.

 

It sounds like you should take a look at the JTR manual and read it, even if you are good fabricator, since that (JTR kit) is what the majority of the Chevy guys use.

 

Just do a lot of reading in thw site, because it has all the information you are asking about and it has most likely been rehashed several times over.

 

Check out some of the guy's own websites and their racing Z cars---the drag cars in particular---see what they have done to reinforce the chassis.

 

Good luck!

 

Davy

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Im using a poly mount on the drivers side and a rubber mount on the passenger side. You can really feel the vibration from the engine, in fact it rattles everything in the car when I'm under load below 3000 rpm. But the exhaust doesn't bang on the floor and the engine stays really stable in the bay. Personally I would like to reduce the vibration a bit.

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Im using a poly mount on the drivers side and a rubber mount on the passenger side. You can really feel the vibration from the engine, in fact it rattles everything in the car when I'm under load below 3000 rpm. But the exhaust doesn't bang on the floor and the engine stays really stable in the bay. Personally I would like to reduce the vibration a bit.

 

Terry O (BlueOvalZ) is using solid mounts for his car and he doesn't mind them. I guess it comes down to personal preference.

 

Davy

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that sounds pretty good. I just figured if your going to be putting down power that the frame might rip out or solid would twist the car. not so sure of which one would be better. i guess you are right though that it would be seat of the pants feel. well i guess i am off to mocking some up so i can get my motor in there one of these next weeks. right now though i think i am just going to put the L98 from the vette in their with the Martin turbo, until i can do the blown LT1. well thank you guys very much for the input and i'll go do some more research on it.

 

-Dave

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Im using a poly mount on the drivers side and a rubber mount on the passenger side. You can really feel the vibration from the engine, in fact it rattles everything in the car when I'm under load below 3000 rpm. But the exhaust doesn't bang on the floor and the engine stays really stable in the bay. Personally I would like to reduce the vibration a bit.

 

I do notice a bit of vibration from the poly mounts. But I figured it was a free massage, in fact my feet feel great even in long trips, and don't fall asleep. Maybe I had a different attitude about it It never bothered me one bit.

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I'm dubious of any frame rail damage from rubber verse solid mounting configurations. Once the tires hook up, the same torque will be placed upon the mounting area regardless of the type of mount. The only benefit (from the frame rails perspective) is the ramped application of the torque with the rubber mounts verses the immediate application of this same torque with a solid mounting system. In my application, I used front and rear plates, attached with no less than two spaced bolts per corner, and with the rear plate located immediately adjacent to the firewall. This then uses the block to prevent relative twisting of the frame rails to each other, and the firewall/unibody resist the twisting from the rear plate backward. This way, the entire block would have to twist before the frame rails would, and in effect, makes the block a part of the chassis. Important in this though is that the transmission must be solidly mounted as well, making it a 6 point "spinal column" for front half of the unibody in which the engine and tranny act as a solid unit reiforcing the unibody. Add some extra bracing, and you'll end up with a very rigid platform.

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A 3/16" channel iron was welded to the front subframes from the radiator support to the firewall of my Z. A motor plate supports the engine by solid mounts attached to the re-enforced frame. The trans uses a urethane bushed mount. Since my engine is not that radical ( turbo Cam) I don't notice much vibration. But the 4 link rear suspension can be bouncy on rough roads. Front suspension is all stock , so it's ok. Most of the time I don't notice the quality of the ride because I'm hanging onto the steering wheel for "dear life".:-D

 

Hanns

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