Installed the Midwest Chassis 9" with Motive 3.70's today
07-25-2009, 08:27 PM
#1
Installed the Midwest Chassis 9" with Motive 3.70's today Things had the possibility to go real smoothe but we ran into a couple of snags. One being the assembly of the reluctor, bearing and seal on the axle. Spent a decent amount on the first one making sure we got it right. Second snag was they shipped us one bolt for the torque arm/crossmember mount that was way big so we had to use one from the shop. Another thing was we were shorted four washers that go under the nuts to hold the third member in place. We also had to grind a little on the inner portion of the housing so the third member would slide in place and bore the thirds holes to an oversize since they wouldn't clear the studs easily. It bolted in nicely to say the least! If we would have had it fully assembled to start I think this would have been a 3-4 hour job just swapping.
07-25-2009, 08:31 PM
#2
It took some time for the clutch packs to act right. First couple turns it was like a spool including backing out of the garage. Now you can feel them on turns but it is decent. We set the pinion angle at -3 degrees so don't know how that compares to others. When we pulled it back in the garage for inspection it was pretty hot. Do they normally get fairly hot? I get a slight whistle at all speeds but when I say slight you crack a window and you can't hear it. I don't know if I want to screw with it or not and it might just be the way it is with this kind of setup.
Gotta call Monday about the hardware!
Gotta call Monday about the hardware!
07-25-2009, 08:53 PM
#5
One other issue I forget to mention we found when we pulled it in the garage was the top of the housing hitting on the exhaust where it goes up and over. We heated it with a torch and hammered in just a little to clear.
The 10 bolt weighed 145 lbs dry. The 9" weighed 205 lbs. dry. We found the torque arm/crossmember from MWC 15 lbs lighter than the UMI pieces I used with the 10 bolt. So the weight gain was 45 lbs going to the 9". I also feel I lost about 15 HP going to it... something I feel when I mash it.
The 10 bolt weighed 145 lbs dry. The 9" weighed 205 lbs. dry. We found the torque arm/crossmember from MWC 15 lbs lighter than the UMI pieces I used with the 10 bolt. So the weight gain was 45 lbs going to the 9". I also feel I lost about 15 HP going to it... something I feel when I mash it.
07-26-2009, 01:40 PM
#6
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Congrats on the install! I remember how good it felt getting the POS 10-bolt out of there. No issues with the Strange 12-bolt install, but having a 9" under there is even better. Have fun!
07-26-2009, 07:21 PM
#7
Been driving it all day and had two people in so far that said the noise can't be heard. I think I am listening for it! It sounds real good today and I don't know if it is the pinion angle from -2 to -3, more weight on the tire or what but it transfers better than when I went 1.59 60'. I think it will go 11's now! Should really shine and make me not worry when I put the heads/cam/intake/tb on. Bitch is going to move out!
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07-27-2009, 05:16 AM
#9
The rear with center was about $2500. I went with the full length arm and he ships a relocation crossmember to get it off the trans tail.
Couple of nice pluses for the 9"
- Good gear selection
- Lots of parts out there for it
- No shims to set the ring up
- You can set the gears up on the bench by pulling the third
- If you have 2 or 3 centers you can run different gears in all
Couple of nice pluses for the 9"
- Good gear selection
- Lots of parts out there for it
- No shims to set the ring up
- You can set the gears up on the bench by pulling the third
- If you have 2 or 3 centers you can run different gears in all
07-28-2009, 07:13 PM
#10
I just got all the corrections done today. With 3.23's I was 67 MPH at 2k RPM's. With the 3.70's I am at 58-59 MPH at 2k RPM's. Now when I am going down the highway I have to hold about 2300 RPM to get 65 MPH. IMO after doing the 9" and these gears it is nuts in an auto A4 to go anything more if you do any highway driving really.
07-29-2009, 05:17 AM
#15
They were extremely minor as far as what I expect when doing aftermarket swaps. That extra weight right on the tires is helping traction and transfer. My butt-o-meter says I can get that 11 now on the stock motor and improve on the 1.59 60'. I think I am going next Wed. How about you?
07-29-2009, 05:41 AM
#16
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They were extremely minor as far as what I expect when doing aftermarket swaps. That extra weight right on the tires is helping traction and transfer. My butt-o-meter says I can get that 11 now on the stock motor and improve on the 1.59 60'. I think I am going next Wed. How about you?
Usually don't go down Wed., sometimes Fri, but my next trip down will be a Saturday for sure. Let me know what you do.
08-19-2009, 07:03 AM
#20
Several hundred miles now and trips 140 MPH + and smoothe as butter. Track times for sure by next Wed.
I am loving this posi unit. First thing in the morning it acts a little like a spool until the oil gets moved around then it is great. Glad I didn't get a locker or spool!
I am loving this posi unit. First thing in the morning it acts a little like a spool until the oil gets moved around then it is great. Glad I didn't get a locker or spool!