What needs to be done to properly reinforce a subframe?

[e30polak]

I'm looking into reinforcing the chassis by next summer because I'm going turbo. I want everything to be taken care of, so I don't have to worry about it later.

Aside from an obvious roll cage, how can you reinforce the subframe?

[Van Westervelt]

Front or rear? Front you pretty much just need to box in the underside of the motor mount flange and weld another plate on the mounting surface (bottom side) before boxing it in.

[BeirBrennerE30]

Front or rear? Front you pretty much just need to box in the underside of the motor mount flange and weld another plate on the mounting surface (bottom side) before boxing it in.

and the swaybar mounts on it... reinforce those too. Actaully anywhere that a swaybar touches in an e30 needs to be reinforced.

[shiboujin]

I did nothing.. my car's fine. You CAN box in the front subframe but that makes taking in/out motor mounts a pain. I'd get stiffer bushings for the diff/rear subframe cuz thats how I shattered the diff shield on my rear subframe.

[Van Westervelt]

Ah yes, the sway bar tabs, forgot about them. Good mounts and bushing are probably the cause of 75% or more of structural failures.

[E30_fiend]

I think Chris is also worried about traction and twisting of the rear subframe. I have heard of "A-ing" in the rear trailing arms. I.E. from this "/ \" to this "/-\".

I honestly think the weakness of the rear subframe is the diff cradle. As well as where the carrier bushing mounting point. Maybe plate the cradle and the carrier point.





Taylor

[robmespeedy]

Whats up Buddy! here how i did my front.

http://r3vlimited.com/board/showthread.php?t=60069

[evil_twin]

I like this thread.

[Mike]

I did nothing.. my car's fine. You CAN box in the front subframe but that makes taking in/out motor mounts a pain. I'd get stiffer bushings for the diff/rear subframe cuz thats how I shattered the diff shield on my rear subframe.

Damn, do work son!

[shiboujin]

Go hard or go home?

[weaksauce]

Go hard or go home?

i'll vote hard

[Iain]

The front end is pretty simple. AKG sell weld-in and bolt-in reinforcements for both subframes if you don't want the hassle of cutting the metal out yourself.

With an angry 6.0L going in mine I'm going to be doing a fair bit of work in the rear-end to stop it twisting up. This will include "A"-ing the trailing arms and plating & bracing areas where the diff cradle and out-rigger mount to the chassis. I'll also be adding in a kind of roll cage to the boot, which will go from the diff-mounting points on the floor and triangulate to various points in the boot.

I'll put up pics when I'm doing it, even though I'm going to not bother with a BMW diff and will just use a Nissan R200 (as I know I won't break that) so that might make it a bit different to you blokes.

[Mike]

[QUOTE=Iain;1833337]
With an angry 6.0L going in mine I'm going to be doing a fair bit of work in the rear-end to stop it twisting up. [QUOTE]

More info!

[Iain]

I'm doing an LSx swap, using an L76/L98. Its a weekend-only car, so it'll have a big (240-ish) cam, valve springs, custom 1 7/8 headers, straight-pipe intake, no PS, no aircon, pulleys, tougher pushrods, lightweight flywheel and some CNC heads and ITBs if i can get the coin together.

I have a build thread on here which I haven't updated in a while, but will be getting into soon.