New Gear

Before & after pics of my Super 8.8 rear-end with new 3.31 ring & pinion, painted red to match all my other BMR goodness. Coming soon to a racetrack near you ;)

BMR

BMR Lower control arm porn

Nice!

Any advise on Changing out the complete unit? I purchased a complete loaded assembly that I'll be installing (along with axles and spring at the same time) just wondering if you ran into any issues

BMR FTW

Fast64ranchero said:

Any advise on Changing out the complete unit? I purchased a complete loaded assembly that I'll be installing (along with axles and spring at the same time) just wondering if you ran into any issues

Click to expand...

No real issues, a couple of tips that can help you:

1) Loosen axle bolts ahead of time (impact works great)
2) Watch the IRS removal video on fulltiltboggieracing
3) Their video is really good, but it leaves out one step - when working on jack stands, it makes it easier to also remove the lower shock bolts and remove the shocks completely. Otherwise you have the shocks standing up and potentially hitting the underside of the car when you're trying to wheel the sub frame out.
4) I have a low profile trans jack that I use, if you'll be using a floor jack to lower and remove the IRS - I suggest you get a second set of hands when you go to lower the IRS. Jack right underneath the pumpkin. Have one person handle lowering the floor jack slowly and the second person behind the IRS (not underneath it ;)) holding onto the sway bar. The guy holding on the sway bar can easily control and balance the IRS to keep it from tilting / swaying left-to-right and front-to-back.
4) One you get the subframe out, jack it up or lift it up and put it on another set of jack stands. This will allow you to use a floor jack underneath the diff again and lower it out after you unbolt it (the super 8.8 is pretty heavy).
5) Use high torque impact and disassemble everything and take pics of what bolts go where.
6) If your doing aftermarket springs, it might make it easier to completely remove lower control arms, and then install springs and lower control arms after the subframe is back in the car.
7) INSTALL ALL BMR Bushings or lockout kits
8) Note on Diff housing - when you install the new diff, make sure to CAREFULLY install the rear bolts first into the aluminum cover / ears first. It's aluminum, so you can strip these bolts if your not careful.
9) raise the subframe with new diff installed (lower control arms, axles, spindles not installed yet) and remember to reconnect vent tube.
10) use breaker bar in the IRS alignment holes in the rear of the subframe to pry / move the subframe around to line it up so the subframe bolts go in easily (don't force / strip them).
11) install the rest of your BMR bits and OEM parts.
12) go to local track and run new personal best :cheers:

Forgot to add: To remove spindle / knuckle, unbolt the caliper mounts, remove axle nuts and disc (don't reuse axle nuts if staying with stock half shafts). To remove half shafts, I use pry bar near diff and pry a little and then rotate axle to pry a little in three / four different spots. Half shafts will then pop right out. Good luck and let me know if you have any questions.

If he was just changing the pumpkin and axles he should have to drop the complete subframe right?

gsxr1300 said:

If he was just changing the pumpkin and axles he should have to drop the complete subframe right?

Click to expand...

You can remove the diff by just lowering the subframe enough to get to the bolts, but IMHO you might as well just drop it completely so you don't have to work on your back while balancing the pumpkin and subframe (both are fairly heavy). RBS mentioned to me once at the track that if you have DSS half shafts, you can even remove the allen bolts on the inside of the shafts so you don't need to remove the knuckles and half shafts when partially lowering the subframe to service the Diff versus dropping the whole thing out. After you do it once or twice, removing and reinstalling the whole subframe is not that bad. I think its easier then removing the trans :frusty:. Anybody have the remove & install trans easier pro tips

Thanks for the detailed reply, I already have BMR cradle lockouts and Vertical links on the car, Those two items cured my wheel hop at the track. I'm going to tackle this job next weekend. been waiting for over two months to get my DSS axles and they finally got here, springs and new pumpkin been sitting waiting for the axles so I could do everything at once. I'll find and watch the video... Thanks again.

rainmaker said:

No real issues, a couple of tips that can help you:

1) Loosen axle bolts ahead of time (impact works great)
2) Watch the IRS removal video on fulltiltboggieracing
3) Their video is really good, but it leaves out one step - when working on jack stands, it makes it easier to also remove the lower shock bolts and remove the shocks completely. Otherwise you have the shocks standing up and potentially hitting the underside of the car when you're trying to wheel the sub frame out.
4) I have a low profile trans jack that I use, if you'll be using a floor jack to lower and remove the IRS - I suggest you get a second set of hands when you go to lower the IRS. Jack right underneath the pumpkin. Have one person handle lowering the floor jack slowly and the second person behind the IRS (not underneath it ;)) holding onto the sway bar. The guy holding on the sway bar can easily control and balance the IRS to keep it from tilting / swaying left-to-right and front-to-back.
4) One you get the subframe out, jack it up or lift it up and put it on another set of jack stands. This will allow you to use a floor jack underneath the diff again and lower it out after you unbolt it (the super 8.8 is pretty heavy).
5) Use high torque impact and disassemble everything and take pics of what bolts go where.
6) If your doing aftermarket springs, it might make it easier to completely remove lower control arms, and then install springs and lower control arms after the subframe is back in the car.
7) INSTALL ALL BMR Bushings or lockout kits
8) Note on Diff housing - when you install the new diff, make sure to CAREFULLY install the rear bolts first into the aluminum cover / ears first. It's aluminum, so you can strip these bolts if your not careful.
9) raise the subframe with new diff installed (lower control arms, axles, spindles not installed yet) and remember to reconnect vent tube.
10) use breaker bar in the IRS alignment holes in the rear of the subframe to pry / move the subframe around to line it up so the subframe bolts go in easily (don't force / strip them).
11) install the rest of your BMR bits and OEM parts.
12) go to local track and run new personal best :cheers:

Forgot to add: To remove spindle / knuckle, unbolt the caliper mounts, remove axle nuts and disc (don't reuse axle nuts if staying with stock half shafts). To remove half shafts, I use pry bar near diff and pry a little and then rotate axle to pry a little in three / four different spots. Half shafts will then pop right out. Good luck and let me know if you have any questions.

Click to expand...

Thank you for taking the time:cheers:. I want to do the exact same thing but 3.55s

Great choice of gear especially with a SC. 3.73 are way too much.