1irocz2nv

Hey guys, I have my hands in the air as I can't decide how to mount my torque arm for the LS7/T56 swap I'm in the middle of. There is always "drews crossmember" and fabbing up a mount. I've also seen some people mount it to their sub frame connecters. It's set that I'm getting a crossmember like drews or Skulte that will tuck up my exhaust. What do you guys think? Chime in.

Thanks

HPE

I think you know obviously its a gimme that you'll have to mount it to the chassis rather than the factory tailshaft position.the problem lays with the weak factory 4 crossmember bolts in the unibody. It is really your best option to have something fabbed that welds to the unibody rails with its own bolting hardware to unbolt apart for trans removal- Of course creativity is in order to gain proper ground and exhaust clearance.That LS7 torque is going to strain and pivot those chassis bolt provisions right to hell real quick with anything like a Spohn X-member and torque arm- Spohns stuff is made great- its the chassis that is flawed and weak. I have actually welded on 1 more bolt bracket provision on each side of my Spohn unit to reduce up and down thrust pivot of the mount on the current 4 bolts- I now have 6 bolts- AND MY CAR IS LUCKY TO PUT OUT 165HP TO THE REAR WHEELS but brakes extremely exotic for tons of downward thrust on the x-member bracket mount. This car is slow, but does an amazing 102ft 60-0 on street tires. so I even have problems without a massive LS7

PS - I'd like to see pics of the install

ws6transam

You could go the really, really expensive route and fab in a decoupled torque arm like I did, or you could go the drag-race only route and put in a BMR track kit that welds to the subframe connectors. Or, you could mount it on the tailshaft like the factory did.

HPE is right, there is a significant amount of flex of your subframe when using the Spohn retrofit crossmember. However, the torque arm is pulling on a point that is eight, maybe ten inches farther back than the crossmember mounting bolts: It has a good chance to lever on those bolts with that large amount of moment arm. Skulte's longtube crossmember (which I have as a replacement for my Spohn system) uses the rear rearmost bolt holes in the subframe, and significantly shorten up that moment arm. I dont expect much problems from flex. If I were you, I'd seriously think about using that tailshaft mount alonge with Andris's crossmember: It keeps the torque arm mount closer to the bolts, and will therefore induce less twisting on those crossmember bolts.

Here's a teaser pic that shows how his crossmember fits under the car. You can also see the welded in brackets for my decoupled torque arm, which you can see more photos of if you visit http://ws6transam.org/Gallery/random1?page=3 and then browse the next few pages.

V8Rumble

iTrader: (2)

That's interesting Dan, I've been giving serious thought to selling my Trak-Pak & getting one of those decoupled torque arms myself...

As far as the original question, I would think that it would make sense to either mount it to the SFCs, or perhaps weld in plates to the floorpan (similar to the mounting pieces for a roll bar/cage) that would be able to take the energy from the launch & distribute it over a wider area - but that's just me "thinking off the top of my head", others may well have better suggestions.

Good luck, let us know what you decide to do!

HPE

ws6transam, Thats a beautiful job you did fabbing the exhaust routing and the 4th gen sdtyle bracing for the torque arm. Unfortunately for my situation, I could never run such a setup because the height level of your duals before they Y are low enough they would be crushed almost flat on my car. I had to even shave and reweld the Spohn X-member setup for more clearance and the car will still occtionally rub on it still going over speedbumps- its about +2 inches higher than the bottom of you exhaust at that point mine makes contact. I'll have to shoot a pic of mine where I braced it rearward more with more chassis bolts to reduce the levaraged TQ mount point, but I have alot more ground clearance issues than your car with my ride height.

krisb410

iTrader: (9)

UMI just came out with a tunnel mount TQ arm, it's not on the websight yet, but mine should be here soon.

1irocz2nv

Hey Kris, looks like a nice piece. It's too bad it's not on UMI's site yet as it would be nice to see some install pics. Tell me how the install works out.

HPE

That UMI TQarm x-member is basically exactly like the Spohn one I decribe as to having the leverage problem- UMI's stuff is basically copycat of Spohn stuff.