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SVT Cobra 8.8 IRS in a '78 280z

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Hey Guys,

 

I've been tossing around the idea of modifying and installing an entire Cobra 8.8 IRS subframe in my 280z. I've taken a few rudimentry measurments for the project, and it appears that the overall track width only increases by about six inches. whille the overall depth of the assembly is about an inch "taller" than the stock 280z rear setup. Im thinking that with some large flares and a fair amount of offset that the tires would fit with out any issues. As far as the subframe bolt up, I was thinking to shorten the mounting "ears," for lack of a better term, and fabricate corosponding hard points on the car for the bushings. Sure it weighs more, but with a good set of halfshafts its damn near bulletproof and, I think, fully capable of handling anything my limited budget and an LS2 can throw at it. I don't have any pictures right now as I was using a friends IRS assy and we're now in two different states. I've searched for this and the best thing I've found was modifying the stock rear to accept the 8.8 center section. Thoughts? Questions? Comments? Concerns? Anything would be appreciated.

 

R/

Murph

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Seriously?

 

I would have expected some interest in this subject. At the very least, some flaming responses as to the functionality/brokea**ness of the Ford 8.8 rear.

 

I'm going to slog ahead with this, and see if I can pick one of these up in my area(Great Lakes, Il) for a reasonable amount of money. I will then attempt to install it without reducing it to so many metal shavings on the garage floor.

 

-Murph

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"but with a good set of halfshafts its damn near bulletproof and, I think, fully capable of handling anything my limited budget and an LS2 can throw at it"-Same goes for the R200 that is in there.

 

It's a lot easier to find new carriers and change ratios with the 8.8 though IMO. I also got the car as a shell, and therefor, lack an existing rear to work with. Hence my decision to go a different route.

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Go for it. Too much work for me to take on, but I'm glad you are game for it. If the project gets out of hand, you can always just put a straight axle in it. Are you planning on narrowing the rearend or just letting the tires hang out? If my R200s fail to hold up, after using up my spare parts, I'll be going to a narrowed straight axle like a 9-inch or 8.8. Less moving (articulating) parts equals greater durability.

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Hey Murph,

I'm one who always enjoys seeing what others come up with for parts swapping and sharing, and would not discourage your plans, however. As stated above the difference of weight advantage of the r200 and near bullet proof cv axles are available from the Driveshaft shop. I bought the so far only set of 280zxt dimensions, coppied by the driveshaft shop and according to them 900hp proof. Another member here with a turboed chevy v8 and drag built 240z went through the process of having these made by the Driveshaft shop, (available for others to purchase) and was using Modern motorsports billet stub axles, which I also scooped up from him. I'm not sure how much the route you are planning on going will be or if that is even an issue for you, with just wanting to do something different. Either way if you do proceed, keep us all posted.

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Absolutely, this is going to be a slow project, but I will try to document and report as I go along. There's a lot of those little " while I'm at it's" though. However, I've pretty much decided that the 8.8 subframe will be unique and a great weekend killer to take on. As far as narrowing the rear end, I may do that at a later date but for now I'd like to try and fit the whole original unit in there. If it turns out to be impossible then I'll look into tackling the fabrication of entirely new upper and lower control arms, the plethora of odds and ends that will need and getting custom half shafts made.

 

-Murph

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I plan to install a Ford 8.8 IRS in my 240, I have one sitting in my garage in parts right now, and another (that will be going under my GF's '65 Mustang), sitting at a friend's storage barn right now.

 

I'll deal with the extra fabrication, to spend less than $300 on an LSD, wider selection of gears, which are easy to come by, and less parts overall between the diff and the wheel, making for possibly stronger assembly.

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i believe someone on Stancewerks is doing this swap

 

I'm guessing that would be me...

I picked up my Cobra rear end this spring, and will be incorporating it into the new frame.

 

6768902105_3374508798.jpg

IMAG0089 by SENZA PARI #1, on Flickr

 

6768968957_ae44bb048e.jpg

IMAG0077 by SENZA PARI #1, on Flickr

 

7469602600_fe6627793a.jpg

IMAG0094 by SENZA PARI #1, on Flickr

 

7469596942_f1d0c73222.jpg

IMAG0097 by SENZA PARI #1, on Flickr

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Holy Balogna Batman!

 

I agree, more tire is needed. I'm a little envious of how nice that rear end looks... I just tossed the one I had, it was trash('99 model that was rusted almost completely out and when I opened the chunk up, there was so much metal flake I couldnt find the gears). I'm saving up to get a better specimen. I'm not planning to go with the full frame rebuild like that. If I had the time, and the Navy actually payed decent, I would do exactly that though. As it is I think im going to graft some "rails" under the car and tie them into the subframe and the tube front I'm currently attempting not to ruin.

 

-Murph

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I see a lot of upside on this... Gear selection, better LSD available support from the aftermarket, if converting the whole axle setup, you won't need to buy the 5 lug swap parts.

 

Those of you touting the R200 are missing all of the above. Sure it's strong. Sure it can handle power. It's NOT very versatile and to make it strong and convert it to 5 lug for better brake size/options, you'll spend a small fortune. I think I've got over $4K in my Q45 conversion/brake setup.

 

I'll be following this thread as well as Senza Pari's build.

 

Mike

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I used to be a tech for ford dealers so I know the parts well.I was thinking of another way to attack this problem.the 2000- ford explorers had irs rear axle with 8.8 diff.Build new macpherson strut housing/bearing carrier that attaches to the lower control arms. Use the new modular wheel bearings-like the mustang irs rear ,explorer.the modular wheel bearings will bolt to a flat steel plate.A company like mosier can build the correct length axle shafts to use the ford cv joints.Building new mac strut housings would allow you to use penske or king shocks that could be custom valved.The explorer 8.8 diff will bolt to a z moustache bar.

post-57-005584500 1342803853_thumb.jpg

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I hate to be the guy that rains on the parade, but the geometry on these setups are not that great. The subframes were designed to mount in place of the four link setup on the V6 and GT chassis. If you can find a Kenny Brown modified subframe, it may help, but you have to run his aftermarket arms which are expensive and not made all that well. The 8.8 is pretty indestructible and has a great selection of diffs available, but the axles can sometimes leave something to be desired. I believe it has a lot to do with play in the CV joints from the factory. Some are better than others, and the aftermarket selection seems to have the same or worse issues. Make sure to get a later 03/04 IRS setup with the 31 spline differential inputs as opposed to the earlier 28 spline. They are much stronger. The later setups also have a much stronger cross member. My other big issue with the Ford setup is the single shear damper (shock) mounts. It's fine if you leave the factory coil spring setup, but its a problem if you switch to a coil over. That bolt is not designed to transfer the loads that are originally handled by the spring on the A-arm.

 

Additionally, if you're dead set on doing this, replace the bushings and other parts with something worth the time. Check this guy out:

Full Tilt Boogie Racing

 

or

 

Maximum Motorsports IRS

 

There are also a lot of damper options with my favorite being the KW Variant 3's that retain the factory spring location and add an oval track style spring perch adjustment in the spring bucket.

 

Here's a decent article written by the guy who owns Full Tilt Boogie Racing:

IRS Tech Article

Edited by Moridin

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Has there been any forward progress on this? It wouldnt be that hard to have a custom axle shaft made, there are companies out there who do this stuff all the time (the driveshaft shop).

 

The more issues I have with my axle shafts, the more I want to get rid of everything nissan back there altogether.

 

I mean, if the S2000 guys can do it, SURELY we can.

 

They DO drive hondas :rolleyes:

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Neat project. The cost of upgrading a stock S30 rearend to disc brakes, LSD, coilovers, adjustable arms and axle stubs that won't break is outrageous in my opinion. These kind of swaps can be FAR cheaper and work just as well if you like fabricating stuff.

 

Sure it weighs more...

 

How much does the ford stuff weigh?

 

Here is my stock 240z rear suspension/diff/brakes on the scales for reference. 215.2lbs

post-11686-088257200 1345301040_thumb.jpg

post-11686-009797000 1345301049_thumb.jpg

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Any more progress on this? I'd be curious to know what sort of strut setup you'd use.

 

Someone should buy just the fabricated lower pieces of Techno Toy Tuning's rear end setup. I believe that allows you to use the Z32 stub axles, and then have a custom half shaft made from that companion flange to the ford stuff. <_<

 

Someone should do this.

 

Better yet, someone should make a KIT for this to be done. I can't believe how much time / resources have been spent on adapting nissan stuff to work for the S30, when the ford parts are just plain and simple stronger, more readily available, and MUCH more affordable. Oh, and If someone does do this, PLEASE center the damn wheel in the wheel well. That bugs me every time I look at an S30

 

But who would want to put non-nissan parts on an S30? Gross.

Edited by SUNNY Z

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Wow..

I was just searching to double check on the z32tt spline count. I was thinking the same thing. Use an 8.8 diff with hybrid z32/Ford shafts and use the ttt plates! Better and less expensive gear and LSD options. I'm just gathering parts and notes as I get this body work done.

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Hey guys,

 

Quick update. I've been working my ass off. The Navy isn't great for downtime... Anyway, I scrapped the SVT rear idea. I bought a C4 Vette rear subframe for the car... It's a Dana 36 which, I know, isn't the greatest... However, I only payed $200 for it and it's in great shape, I plan to mess with it for now and if I eventually break it- Oh well I'll drop the money I would have spent initially on an 8.8 and upgrade to the far beefier Dana 44. the definite upside to the Vette assembly, is that it is a very similar design to the stock system and IMO will be an easier retrofit, as well as being way, way lighter(ie: I can pick the whole thing up by myself. I'll post actual weight once I get my scale back from the neighbor). I promise to post pictures as soon as I get a chance.

 

R/

Murph

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