lt1camaroman93

Have any of you guys just run a front motor plate and no mid plate? I know to use the side bar to keep the motor from walking front to back, but is just the trans mount and the front motor plate enough? The only reason I don't want to run a mid plate is because it seems like a real pita to get to on a 4th gen. Thanks for the help guys.

96speed

I ran a motorplate without a midlplate (with no engine limiter - though I'd recommend one) for about 200 miles. A little much for a street car, so I pulled it out. I looked at Steve Quinn's car and he didn't use either as well.

Ryan

Mousebuilder

You can use just the front motor plate with no problems. Make SURE you run a solid trans mount though, or you could crack your bellhousing. I run just a motor plat/solid trans mount on my S/G Nova (600+ HP) and have no problems.

96speed

For the record, I was runing a solid trans mount. Like Mouse mentioned, I sure wouldn't run anything else without an engine limiter or midplate. Heck, If you're running a motorplate, why wouldn't you run a solid transmission mount? (Rhetorical)

Ryan

Stephen 87 IROC

Front motor plate only with a limiter and a poly trans mount here. I don't recommend a solid tranny mount for anything. Too much chassis flex unless you have a total tube chassis car.

I'd like to put a mid plate in soon mainly just for safety. If the tranny tailshaft ever breaks, and it could, the tranny would fall onto the ground. In my car, the header collectors would get damaged before the tranny would hit.

Technically if you run a front and mid plate, you wouldn't even need a tranny mount. Many highway trucks with 18 speed roadranger trannys are only held up by the bellhousing bolts. A few trucks have a support spring above the tranny but it's only on the high torque models. The spring doesn't hold a lot of the tranny weight. An automotive tranny isn't very heavy and the six 3/8" bolts can easily hold the tranny up.

camaro_dave

with my new engine/trans i'm running motor and mid plate with no trans mount. the tranny i got doesn't even have a place to put a mount on it ha ha
B&Jtransmissions.com

1racerdude

I have run a front,mid,and polly mount with lateral bars.
I was told by several that do chassis work, the first time I did plates, NOt to run a solid mount under the tranny as it WOULD bust the tailshaft housing. I did not make it solid and never broke a housing. Never got brave/or saw the need to go the solid route after that.
With an aluminum bell housing(J&W shield) I was affraid of 800FWHP breaking my glide without a mid plate.

Brady

I ran a motor plate with no mid plate and a poly trans mount without problems.. IMHO, running a motor plate or solid motor mounts and a solid trans mount in a stock uni-body car could easily break the tranny (weakest link)..

lt1camaroman93

Thank you very much guys..

edholio

My current setup is custom solid motor mounts, mid plate and solid tranny mount (custom crossmember). Class I was running in wouldn't allow a motor plate. When I first put the car together I used a poly mount and broke the tailshaft on the first pass.

Part of the philosophy behind a plate is to make the motor a part of the chassis adding rigidity to the chassis.

IMHO, if the car has a cage that is integral with SFC or rocker bars and you're running one drivetrain mount as solid they should all be solid. But your chassis must be rigid.

lt1camaroman93

The car will have a 10pt in it and sfc's. I just don't know if i have room for a 5" downpipe with motor mounts.

edholio

If you're going to run a motor-plate, I would run a mid-plate and a cross-member for the transmission mount. Think of the motor-plate and mid-plate as cross-members adding rigidity to the chassis. You get the added benefit of mounting the motor and tranny off of those "cross-members". Some may argue that a flat piece of 1/16" steel isn't very rigid, but you bolt a motor on one side and tranny on the other and it becomes extremely rigid. My mid-plate is SFI approved and has a integral flexplate shield.

The main hoop and a-pillar bars on my cage are not tied to the floor but are tied to the SFCs. We pushed the bars thru the floor, welded the cage to the SFC, then welded in the cross-members, then pushed the cage back up and squared everything up and then connected the sub-frames. The only place we used plates was to connect the Ness bar to the rear suspension mount points.

As my combination evolves I will be adding a motoplate and probably leave the motormounts, using the motor as an additional crossmember for the k-member. The more chassis points you can triangulate the more rigid the chassis.

Brady

Just curious, how did the poly trans mount break the tailshaft? Or as Mousebuilder said, "crack the bellhousing"

edholio

My bad....I misstated using tailshaft when I meant tailshaft housing.

Arrived at this conclusion because the trans mount was the only place for flex in the drivetrain, for items that should not have been moving. For my combination the poly mount didn't work. Inserted a solid mount and no problems in over 75 passes.

Brady

I kinda figured you mean tailshaft housing, doesn't really matter though. My thought is that if the car flexes with a poly mount, the mount will deflect. If the car flexes with a solid mount, the next weakest part will deflect (tranny).. I don't think the smart move would be to solid mount the transmission in hopes of making the car sturdier... Your route works and is proven so my thinking must be flawed. thanks.