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wfritts911

The "Ultimate" IRS Swap for S30s

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wfritts911    4

Sorry guys, fell off the map for a bit while I finished up with school. Got everything almost finished up yesterday. Will be mailing out parts Tuesday unless something happens. Front diff mount is tacked up just needs a jig built for it and finished welded. Uprights are fully welded. Strut tubes are tacked up, just need finish welded. Mustache bar is good to go except I have to shave a bit off the mounts to move the differential further towards the front by a hair. Stub axle adapters are fully welded. But enough talk, here are some real photos of what is going on.

 

Mustache Bar

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Front Diff Mount

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Strut Tube

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Strut Tube Loaded

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Complete Upright

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Don't have any pictures of this exact setups axles, but mine are pretty much the same thing, but please excuse the crude other parts, I didn't have the fancy tools I have at my disposal back then. The second picture shows the F150 outer CV joint with the stock F150 axle bar still in it(Which is quite short). The first picture shows it on the car with the chromoly porsche 930 axle and the duct tape clips holding it in place hehe.

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Hopefully this clears stuff up and shows that this really is happening. This setup uses the Koni 8610-1437race strut insert. Off the shelf coil over pieces, stock top hat. Camber can be adjusted in the upright. Front diff mount similar to the RT mount. The lower piece captures it on the top and bottom(The lower brace is missing a piece of metal to go on the other side of the circle piece). 3/16 plate, waterjet and broke. Mustache bar is 6061 that is waterjet. The mount pieces use poly bushings and are CNC machined. Now that I'm done with school, I will have a lot more time to do work. Will be ordering metal sometime this week hopefully for 10 sets. Pricing to come this weekend hopefully.

 

Questions/Comments/Criticism is welcome.

 

-Will

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SUNNY Z    12

I hope you have better luck than I did with the front diff mount. I couldn't ever get the mount I built to stop moving.  It was making my car have bad wheel hop on street tires, and it actually broke the welded nuts off the body.  I'm making a different front mount that will be welded to the tunnel.... Take that, torque!

 

You might have better success, and it would probably work for a lot of people, but If I was going to do a bolt-in again, I'd make some sort of pinion snubber that goes straight up to the body.

Edited by SUNNY Z

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RebekahsZ    106

Texas300, you gonna be showing your car or beating the hell out of it? Before johnc mass produced his subi conversion stubs he asked me to install them, challenge them, tear down and inspect them for defects. THEN, he put them into production. I took them to the track and dropped clutch and did four full throttle gear changes on them 90 times before I inspected them by his protocol (granted that was with an L6, but that's what that system was designed for). You game for that? I foresee same problem as SunnyZ. We need a forward crossmember to bolt to, and according to old posts, we need both the mustache bar and the front mount to be either rubber/poly or solid, but not one of each. If you could design one, I think most guys serious enough to invest in this much of a mod would be willing to weld or pay a welder. And when I say "invest", I don't mean just money-this is gonna take time to assemble, and every time I fix something AGAIN, it takes a little bit of my Z-love and steps on it. I dont know how many re-dos i have left in me. If ANYBODY can do this, it is Will.

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texis30O    26

I plan on beating on the car.  It is not a cream puff, it is not being built to be a cream puff...... I plan on eventually using this car for Time Attack. FIRST I have to get used to the car.  With a COMPLETE new drivetrain it could take some time as I have other things in my life that take priority ( family, business).  With that said I don't know too many people that can abuse vehicles like me.....

I once severed the cab of my truck from 6 of 8 body mounts, destroyed 3 transmissions, and blew up a rear diff....all within a 3 year period......

I have a tendency to push things.  Hell yesterday I was roll racing on the highway with my LIFTED crew max Tundra.......lol

I have a feeling that I will be tearing this apart due to usage fatigue....

I am going to have over 600whp on tap I am expecting to break things......

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SUNNY Z    12

I plan on beating on the car.  It is not a cream puff, it is not being built to be a cream puff...... I plan on eventually using this car for Time Attack. FIRST I have to get used to the car.  With a COMPLETE new drivetrain it could take some time as I have other things in my life that take priority ( family, business).  With that said I don't know too many people that can abuse vehicles like me.....

I once severed the cab of my truck from 6 of 8 body mounts, destroyed 3 transmissions, and blew up a rear diff....all within a 3 year period......

I have a tendency to push things.  Hell yesterday I was roll racing on the highway with my LIFTED crew max Tundra.......lol

I have a feeling that I will be tearing this apart due to usage fatigue....

I am going to have over 600whp on tap I am expecting to break things......

 

 

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wfritts911    4

I debated the front mount a LOT. I mean a LOT. There really isn't another good way to make it bolt on and be simple. Sean will be putting this setup through the works, and if there is a problem with it, I will correct it. If it was me, I would run a couple of weld beads along the tunnel and the mount, on the front side of the mount. It sits in the same location as the RT mount does, and should never need to come out. The diff can come in and out without removing the mount. Running a couple welds and the front part of the mount makes them "easy" to get to if it did ever need to come out. You could put a couple on the rear part as well, but its a little harder to get to I think. The mount I have been running only bolted to one side of the tunnel, and I welded it in. Granted I'm not making 600rwp nor did I ever get a chance to put some slicks on, but never had an issue with it.

 

I will be coming up with pricing in the next couple days hopefully. And I would like to have some sets done before the end of the month(So I can take them to Z Fest up in Branson, MO), but that might not happen. Also will be working on a 5 lug front setup with some big brakes for Texis300 in the very near future, looking at either 6 piston or 4 piston calipers, 13ish inch rotor, z31 hubs probably. Planning on the only custom part being a caliper bracket and maybe a small spacer, so it should be reasonably priced

 

-Will

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NewZed    56

 

Front Diff Mount

 

attachicon.gif2014-05-11-0320.jpg

 

 

Looks like a short lever arm, with the small bolts in to the tunnel as the fulcrum, and a hinge at the nose of the diff.  Seems like a strut (the basic solid engineering kind) straight up from the nose of the diff (the hinge point) to something solid above would remove those problems.

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260DET    25

This is not a "Ultimate IRS Swap for S30's" as I know it, irrespective of it's benefits it's not an ultimate IRS, for a circuit car anyway. Try replacing the entire rear end with a double wishbone setup and go from there if 'ultimate' is the goal. I got over car hype talk a long time ago :)

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RebekahsZ    106

Potato-potaato. Don't call the whole thing off! Have any of you guys blown up an outer CV on the Z31T axles? I'm thinking ahead of maybe buying Will's kit to hang an 8.8 center section, but using a "hybrid" of his axles and the Z31T outer CV (by the hub). I'm in no rush.

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socorob    4

That's what I was wondering. If you could use the 8.8 with custom shafts so I could use the outer CVs and hubs (early Q45 larger CVs and shaft) and mate that to the Ford stuff in the center so I could keep all the TTT stuff at the wheel end.

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wfritts911    4

When I said ultimate IRS setup, I was refering to strength of the drivetrain components. My bad for any confusion, but when you start to blow drivetrain components up, this setup is the best. But yes, doing away with the struts I suppose would lead to the actual "ultimate" IRS setup. When you start selling those I will retract my "ultimate" title and you can have it

 

The glory of this setup is the axle bars and both CV joints are off the shelf components. No custom axle bars that run 500 dollars plus. You could probably buy my whole upright setup and sell what you have and be cheaper than trying to find someone to make a custom axle bar to mate the nissan stuff to the porsche stuff. And then when you break that custom axle bar you are out a lot of money. My axle bars cost 220 a PAIR for chromoly axles. You can pick these up from any number of buggy/VW stores online. And if the chromoly stuff isn't good enough, 300M bars are under 500 bucks a PAIR I believe. My outer CV you can get brand new, from any parts store(They carry them in stock), for ~50 bucks. Inner CV is a very common porsche 930 unit. Parts stores stock the hub incase the bearings ever go bad. Coil over parts are off the shelf from A1 racing. I am also willing to bet the F150 outer CV is bigger and stronger than the Q45 stuff, and MUCH easier to find.

 

-Will

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texis30O    26

My problems are not the limitations of the Ford 8.8 diff.  I was told by the shop building my diff that there is a good possibility that I will grenade the rear diff housing with the whp that is expected from my motor set up..... so we will see.

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SUNNY Z    12

My problems are not the limitations of the Ford 8.8 diff.  I was told by the shop building my diff that there is a good possibility that I will grenade the rear diff housing with the whp that is expected from my motor set up..... so we will see.

 

I've seen dozens of 4000# cobra tanks at over 1200whp beating on these.  I wouldn't be too worried.

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Six_Shooter    13

That's an interesting front diff mount. 

 

Try it out, but I agree that I think you'll find that at least on some cars the captured nuts will break loose. If need be, I would look at making a mount that is based off the crossmember, where the stock diff mounts at the front, then create a snubber or limiter strap to reduce the pinion angle change during accel. I know the problem with this is that the 8.8 diff is much shorter than the long nose R200, and so you get some leverage happening using stock mounting points. This is something I am trying to work out in my own set-up.

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