Stiffening the convertible chassis

[redmist]

To avoid the inherent issues mentioned with the homemade "butt-brace" why dont you put inside the car under the rear seat attached to the head of the rear subframe bolt?

[bimmer_E30]

it's easy, if you want to stiffen a vert e30, just sell it lol.

[3bvert]

To avoid the inherent issues mentioned with the homemade "butt-brace" why dont you put inside the car under the rear seat attached to the head of the rear subframe bolt?

I wqas wondering that too

[CorvallisBMW]

To avoid the inherent issues mentioned with the homemade "butt-brace" why dont you put inside the car under the rear seat attached to the head of the rear subframe bolt?

Not possible, the whole rear unibody section of the convertible is very different than the coupes/sedans. There is no access to the subframe from inside the car on a convertible.

[Alpina]

I have a S38B38 and the subframe is lowered by 20mm

i hope it will fit

[SwiftE30]

So here is my car with H&R sport kit, springs and shocks, before i dropped in an s52 (still working on the turbo build though) I am really unhappy with the ride height and stance. The back sags way too low. i rode in my friends 325i coupe with m52 swap tht had GC coilovers with 500 front and 625 rear. My plan is to go with 550 front and 675 rear.



I know that an s52 turbo vert is going to flex like none other, soo My question for all of you is, has anyone thought of eliminating the ragtop and welding in some triangle brackets and connect the rear shock mounts to stiffen up the rear? if it were possible i would prefer to do this and eliminate the ragtop all together.

Also, i was thinking that welding in a half cage without the main loop going above seatbelt harness, or somewhere around there, so you cant see it from a side view, might be a good idea. This would really stiffen up the back for sure.

Any input is greatly appreciated! Thanks.

[Pac1373]

^Why^ if you want coupe stiffness, the easiest and least expensive way to do it is to buy a Coupe. Deleting the ragtop, and filling the back with a half of a cage will negate this being anything other than a tool for a very specific range of weather/driving conditions.


P.S. thread is back from the dead...

[SwiftE30]

I would have like to have gone the coupe route but my father bought the car new back in 89 so it's what we went with. And yeah I know deleting the ragtop will limit it's options but the car is not a daily driver at all. It's strictly being built to drive it, and drive it hard. I also plan on getting a hard top for the days we do want something over our heads. I'm just looking for some options and people's suggestions on how to stiffen up the back.

Thanks for the input.

[devon.818]

gonna buy that xbrace in the first post of this thread. good looking out!
alread have a sparco strut brace, GC kit with 450f 750r and tree house racing bushings all through the front of the car. gonna do some poly bushings in the rear and in the Diff.

i was thinking about doing a rollbar(for saftey, keep thinking if the car flips i die lol). but dont want to loose the "vert" ness of it....

i know a brace could be welded in behind the front seats across the body and attatching to the floor, would do a lot!

anyway as the car sits it out handles my old sedan that was on vogtlands and billy sports, rear strut bar, front sway, and new suspension bushings. that thing had soooo much body roll, the vert...well it stays damn flat in the corners

[SwiftE30]

gonna buy that xbrace in the first post of this thread. good looking out!
alread have a sparco strut brace, GC kit with 450f 750r and tree house racing bushings all through the front of the car. gonna do some poly bushings in the rear and in the Diff.

i was thinking about doing a rollbar(for saftey, keep thinking if the car flips i die lol). but dont want to loose the "vert" ness of it....

i know a brace could be welded in behind the front seats across the body and attatching to the floor, would do a lot!

anyway as the car sits it out handles my old sedan that was on vogtlands and billy sports, rear strut bar, front sway, and new suspension bushings. that thing had soooo much body roll, the vert...well it stays damn flat in the corners

yeah i most likely will too. Definitely need to get a skid plate combo up front also.
How do you like your rate for the front and rear? 450 seems a little soft.

I really dont want to do a full cage because i dont want to loose the look of the vert. i want to do something like this

http://www.r3vlimited.com/board/showthread.php?t=107147&highlight=removable+roll+bar

minus the main loop that goes above the seats and the bars that go into the rear seat. I would do something that runs along the top portion of the rear quarter panel just above the speakers still below the visible level though.

and possibly something like the bar that runs underneath the exhaust thats shown in the beginning of this thread.

[devon.818]

i really dont think the front rates are soft lol. at 100+ on the free rolling over bumps and gaps ect it gets bouncy but keeps the oil pan off the ground!
i will buy KONI shocks eventually.

yeah there has to be somthing. maybe a single hoop behind the driver that ties into some sort of frame into the floor?

[ROLLingKING]

race skids cross brace!

[devon.818]

race skids cross brace!

lol you are biased hahaha

[CorvallisBMW]

I would have like to have gone the coupe route but my father bought the car new back in 89 so it's what we went with. And yeah I know deleting the ragtop will limit it's options but the car is not a daily driver at all. It's strictly being built to drive it, and drive it hard. I also plan on getting a hard top for the days we do want something over our heads. I'm just looking for some options and people's suggestions on how to stiffen up the back.

Thanks for the input.

tying the rear shock towers together in a 'vert is pretty pointless as they are already tie together by all the extra sheet metal in the double rear bulkhead. Take off the black oval shock tower covers in the top stowage area and take a look, you'll see what I mean. The only spots that will make a difference enough to warrant welding in bars would be between the seat belt shoulder mounts (behind the rear seat, aft of the doors) and between the front of the car and the back (spanning the gap where the doors sit)

[SUICIDE109]

The convertibles really get the biggest bang out of the Zen/Mason X brace, they never should have left the factory without one.

All of the E30's should of lol