Boy from Oz Posted September 13, 2008 Share Posted September 13, 2008 Many of the bigger diffs discussed on Hydrid Z are hard to find in Oz and the CVs etc even harder. When I bought my donor LS1/t56 wreck (see album) I thought it would make sense to use the LSD diff as well, providing it would fit. There are many practical advantages to using the GM diff down here and they have a great array of ratios as well. I made up two very straightforward pieces, a moustache bar and a diff housing bracket, and today I fitted them for the first time. I couldn't believe how well they fitted - but wait there's more. Without any prior consideration I also refitted the two vertical link mounting braces - perfect clearence. The rear cross piece just needed a smidgin taken off the edge of the horizontal surface where it touched the the diff cover. Then on went the original diff front mounting member - perfect clearence on the universal joint (rubber donut). I now have to design a front mounting bracket and I'm there - hopefully. I plan on using the GM CVs and will need to make an adaptor for the companion flange to the outer CV. I am running an extra-wide rear track so I'm uncertain at this stage whether I will need shorter axle shafts. I first mentioned using the diff on this thread but progress has been very slow. http://forums.hybridz.org/showthread.php?t=124522&highlight=%27gm+diff%27 Sorry for the grotty looking suspension bits - I want to make sure it all fits before powdercoating. Quote Link to comment Share on other sites More sharing options...
aziza z Posted September 13, 2008 Share Posted September 13, 2008 Wow good job. Fits like factory. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted September 13, 2008 Share Posted September 13, 2008 Thats from a commodore isn't it? VX VZ? Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted September 13, 2008 Author Share Posted September 13, 2008 Thats from a commodore isn't it? VX VZ? A VZ Ute actually (see album). I picked up a cheap 1996 diff (3.07 ratio and pre LS1) just to play around with and then got the donor car diff (3.46 ratio). There appears to be very little difference in the casings but the input yokes are quite different. These diffs have been around for a long time. Quote Link to comment Share on other sites More sharing options...
woldson Posted September 13, 2008 Share Posted September 13, 2008 HOLY SNIKEYS! Keep up posted on fit! Great job:) Quote Link to comment Share on other sites More sharing options...
sweetride2go Posted September 13, 2008 Share Posted September 13, 2008 haha, gosh, it shure is an ugly diff isn't it! Great progress though!! I suppose though that GM engineers didn't bother thinking about asthetics when designing it... I've never seen those rubber doughnuts before, but they must be strong though, eh? I wonder about the availability of those in the states, though the only thing I can think of with GM IRS is the Pontiac GTO(ie: Holden Manero). Cheers Ryan PS: Any idea what size the the ring gear is, or equivelent to third member size? Like a Dana 44, 9 inch, etc. ? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted September 13, 2008 Administrators Share Posted September 13, 2008 Regarding the US market, in a quick search, I found the new Pontiac G-8 is the US variant of the rear drive Holden VE Commodore, 2008 model year, (2009 for Canada). I get the impression those Holden diffs were not offered in any other US vehicles prior to ‘08. http://en.wikipedia.org/wiki/Pontiac_G8 http://en.wikipedia.org/wiki/Holden_Commodore Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted September 14, 2008 Author Share Posted September 14, 2008 I get the impression those Holden diffs were not offered in any other US vehicles prior to ‘08. That's disappointing. I thought these might have been made by Borg Warner or Dana/Spicer for a global market. sweetride2go - I believe the rubber universals were introduced around 2005 to help smooth out the power transfer. The donor Ute has 250 kW (335 hp) and weight of about 1600 kg (3520 lbs) so there should be no trouble with an 1100 kg S30. Oh, nearly forgot, the latest G8 aluminium casing diffs have an 8.3" crownwheel - I assume the earlier ones are the same. http://www.users.on.net/~nweber/commodore/ve/ve-specs.html Quote Link to comment Share on other sites More sharing options...
getZ Posted September 14, 2008 Share Posted September 14, 2008 You have me curious if the GTO diff is the same. Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted September 14, 2008 Author Share Posted September 14, 2008 You have me curious if the GTO diff is the same. I'd be surprised if it isn't. I've had a bit of a surf around and the only issue of any certainty is that the latest diffs for Commodores, G8s and the yet to be released are made by ZF in a new $30m plant in our 'rust belt'. http://www.ls1.com.au/forum/archive/index.php/t-34318.html The extra good news is they are stated as being aluminium casing. There are confusing comments about earlier diffs being made by Borg Warner and Dana. However, my diff is tagged ZFC, whether that means ZF casing I do not know. It might be a situation where GM own the design and just have different suppliers from time to time. I'm guessing mind you, but if they are not all beam axles then you might find the diff in any larger IRS GM vehicle sold in the last 10 years. As stated, I'm just guessing. Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted February 23, 2009 Author Share Posted February 23, 2009 Well the glove is not such a perfect fit after all. Having all sorts of trouble configuring the front mount. Thought I could just adapt the Ron Tyler mount but the rubber universal is simply too close to the original mounting twin bolt heads on one side to allow this. Further, those twin points are some distance from the mounting points on the front of the diff making for awkward loads. There really doesn't seem to be any existing points that I can attach a front mount to. The only idea I have come up with is to weld strengthening plates to the curved portion of the body shell and install a cross piece to pick up the two mounting points on the diff - including some kind of energy absorbing fitting. I would appreciate any suggestions people have as to an alternative. Thanks Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted February 23, 2009 Share Posted February 23, 2009 What about coming down from above with those two bolts on the nose of the diff. Can you get to that area to drill two holes strait above, then use some kind of tube sleeve cut to the correct lengths, with longer thru bolts. That way the diff will be pulled up tight against the uni body... just a wild thought... Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted February 23, 2009 Author Share Posted February 23, 2009 What about coming down from above with those two bolts on the nose of the diff. Can you get to that area to drill two holes strait above, then use some kind of tube sleeve cut to the correct lengths, with longer thru bolts. That way the diff will be pulled up tight against the uni body... just a wild thought... Thanks for the comment. I considered that but there are two issues associated with a vertical attachment. Firstly, clearance for the parking brake cables and secondly, as you guessed, the area inside the car above the tunnel at that point (between the two storage areas) is difficult to access, particularly to mount a spreader plate. Registration requirements down here basically allow you to replace or add to the structure, but not remove any of the original. Thinking now of moving the diff 10mm off-centre with a RT style mount, and using different length axles. Any thoughts on that? Quote Link to comment Share on other sites More sharing options...
Mack Posted February 23, 2009 Share Posted February 23, 2009 excuse my crappy MS paint skills, or lack there of, but could you do something like this and use these 4 bolt holes at the front of the tunnel? Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted February 24, 2009 Author Share Posted February 24, 2009 excuse my crappy MS paint skills, or lack there of, but could you do something like this and use these 4 bolt holes at the front of the tunnel? The rubber universal is too close to the bolt head on one of those four points (see photo). I could only go 2-3 mm before the uni would rub on the bolt. Material that thin would need gussets and that would create more interference. Quote Link to comment Share on other sites More sharing options...
MONGO510 Posted February 24, 2009 Share Posted February 24, 2009 Why not use a conventional phlange and u-joint? it will give you more room and be stronger. Quote Link to comment Share on other sites More sharing options...
beso Posted June 22, 2009 Share Posted June 22, 2009 any more progress on this? Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted June 22, 2009 Author Share Posted June 22, 2009 any more progress on this? Yes and no. I have been installing the engine and gearbox to see if there were any alignment issues with the diff. Again it is all technically good news. Using the laser pointers and targets the gearbox output shaft and the diff input can be perfectly aligned. Just haven't hit on a front mount design that I'm happy with. I'm sick of crawling under to car to work on this so I'm putting it back on the rotisserie on Wednesday. Sometimes life can be more enjoyable standing up! Send me a PM with you mobile if you are interested in having a look. Quote Link to comment Share on other sites More sharing options...
beso Posted June 23, 2009 Share Posted June 23, 2009 I may have to take you up on that offer! I've got a 260 sitting under a cover that I'll be starting in december. This diff never cross my mind and I see the things everyday! I'm an apprentice at holden and they get thrown with minor issues so there very available. What motor and box are you using? At the moment I'm keeping my options open, its really going to come down to overall price. Although.. there are a few ls1 warrenty motors stashed away! If you need any info about the diff or other parts let me know and I'll try my best to find out. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 23, 2009 Share Posted June 23, 2009 Yes and no.I have been installing the engine and gearbox to see if there were any alignment issues with the diff. Again it is all technically good news. Using the laser pointers and targets the gearbox output shaft and the diff input can be perfectly aligned. Just haven't hit on a front mount design that I'm happy with. I'm sick of crawling under to car to work on this so I'm putting it back on the rotisserie on Wednesday. Sometimes life can be more enjoyable standing up! Send me a PM with you mobile if you are interested in having a look. Just to be sure, you are aware that you don't want the diff and trans directly in line, right? When you say "perfectly aligned" I'm thinking just that, directly straight in line. U joints need to rotate in order to stay functioning, so you want the front and back offset from each other but at an equal number of degrees. If I were doing this I'd start over (sorry to say) and design a cradle that holds the diff in and make it attach to the chassis maybe at the mustache bar and the front diff crossmember points. Then I'd integrate the lower control arm mounts into the cradle. Quote Link to comment Share on other sites More sharing options...
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