seattlejester Posted February 29, 2016 Share Posted February 29, 2016 When I had my STI R180 and I was quizzing my subaru friend, he did say he had a couple guys go RWD pass through the shop he worked at, but given that they did that for drifting and such, they usually ended up going with a welded setup. And given the AWD and the 50-50 torque split, although some subaru's have torque split controllers, the torque at the engine is not quite what the rear diff sees. An example given to me was a 500hp car, with 20% drivetrain loss with the AWD system brings about 200hp to the rear diff, I know that is hp, but you can imagine torque can be similar. The roadkill datsun is pushing more then your power levels through the rear, but not many miles, so you are indeed more or less one of the many guinea pigs on longevity. Ah very interesting. I didn't realize those stubs stuck out that far, I thought they would sit pretty close to the differential. Well kudos for you for taking a peak before taking everything apart, my friends favorite method for checking diffs are the figure 8 and then a quick off the ground check as chicken man suggested, granted those can be misleading with the droop involved. Looking forward to the video. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted March 1, 2016 Share Posted March 1, 2016 That top edge is a weld, not sure grinding that down is a good idea either. Looks like some RLCA's might be in your future. Either that or stiffer springs. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 1, 2016 Share Posted March 1, 2016 (edited) I'm just not sure I like the idea of grinding down the outter edge of my bolts... or if I should grind down the top ledge of the A-Arm so that it won't impact... Have you checked the diff angle? It might need adjustment anyway. Raise it and align it. A little bushing shaving and some washers would probably solve the problem and improve the angle. Even if the angle is right, a shave and some washers would probably get you where you want to be. Edited March 1, 2016 by NewZed Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 1, 2016 Author Share Posted March 1, 2016 True, might have to invest in some aftermarket a-arms or stiffer springs... I did grind a little bit of it off and that has drastically reduced the noise however it is still present under hard loads. But this is clearly the issue and diff is working fine. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 1, 2016 Author Share Posted March 1, 2016 NewZed when you say shave it... are you talking about the mustache bushing? or the front mount? Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 1, 2016 Share Posted March 1, 2016 I was thinking of the mustache bar bushings. It sits on the urethane if you have those, so you could shave the top bushing and put a big washer under the bottom to raise the back of the diff. If you have stock rubber, you'd have to grind the metal center sleeve and add washers underneath to raise it a bit since the rubber is bonded to the sleeve. Then shim up the front to match, or not since the V8's tend to need the nose down, at least when RT designed his front mount. Just thinking about moving the diff since it's attached to your problem. You obviously won't have to move it much. A set of urethane control arm bushings might also move the A-arm slightly if you still have stock rubber, or stop some of the squat. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 1, 2016 Author Share Posted March 1, 2016 I do have stock rubber there... so that might be a good suggestion to swap to urethane and cut the top off some. Hmm might do that this weekend then. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 1, 2016 Share Posted March 1, 2016 The stock rubber mustache bar bushings let the diff move quite a bit. Grab a bar end and move it up and down, you'll see. 1 Quote Link to comment Share on other sites More sharing options...
seattlejester Posted March 1, 2016 Share Posted March 1, 2016 If you go to ES poly bushings it comes with two washers, to install one on top and on bottom. You could just fit both to the bottom or just leave the top one out. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 1, 2016 Share Posted March 1, 2016 Those washers are what clamp against the sleeve. And one has a bigger hole than the other. The small hole goes on the bottom. The urethane is held in between, sandwiched, but not compressed. You can get similar washers at the hardware store though. If he has stock rubber now though, he might find that the back of the diff is hanging low anyway, if they're old. Time sag. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 1, 2016 Author Share Posted March 1, 2016 True and already just ordered a set a urethane bushings for it. We'll see if that fixes my issues, if not then I'll have to figure something else out. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted March 1, 2016 Share Posted March 1, 2016 I'll have to go back and see, but I thought the stud was pretty small so that the metal sleeve would sit against the frame rail if needed. If not, then you could get thinner washers as new zed says that would do the same task. I thought there were two thick washer/rubber grommet things stock that held the mustache bar up i addition to the bushings. I know slop side to side happens as the interior bushing deteriorates, didn't know it could be top and bottom. It has been a while since I have seen a car without an upgraded mustache so I may be thinking incorrectly. Quote Link to comment Share on other sites More sharing options...
johnc Posted March 1, 2016 Share Posted March 1, 2016 I've seen that problem before on R200 and R230 installs. A class 10.9 button head caps crew might solve the problem. Don't cut on the a-arm. You might also check your diff mounts to how much they move. The diff might twist enough for the bolt heads to hit the a-arm. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 1, 2016 Author Share Posted March 1, 2016 Hmm didn't think they made button head caps that big? Might have to look into that as well! First need to pull one out and find out it's size and see if I can order 6 of them for that side. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 9, 2016 Author Share Posted March 9, 2016 Urethane mustache mounts shortened on one side fixed the issue. No more noise and plenty of space for the new axles. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 9, 2016 Share Posted March 9, 2016 I assume it's been too wet to go do some real burnouts? It's an interesting setup, people will probably be interested in how it holds up. Did you say what you're using for the front mount? Not stock rubber and the belt? Quote Link to comment Share on other sites More sharing options...
CableSrv Posted March 9, 2016 Author Share Posted March 9, 2016 I was able to get a nice burn out before the rain really hit, but ya so far no issues. I am using ron tylers mount with a urethane bushing. In the next month or so I plan to take the diff down and do an inspection and see how it's holding up. I also have a new bottle of Motul 300 gear oil for it. Quote Link to comment Share on other sites More sharing options...
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