Independent rear suspension

[Keithmania]

I have access to a Lincoln LS 8.8 IRS. I have never wanted to take my Jeep crawling, but I came across Child9's toyo dual turbo I6 swap here http://www.naxja.org/forum/showthread.php?t=1033211 and thought how well would it work out with an IRS setup for street use. The thing I guess I am most interested in is feasibility. I have read other threads how its not all that feasible cause of cost in making it work for crawling but thats not my intent. Anyways, as mechanically inclined as I am, I am new to the world of fabrication and I know that making that rear end work with my jeep would be tons-o-fab work. Any input is appreciated...

 

[GrimmJeeper]

if you don't have the means to build it yourself, the cost alone would be the prohibitave factor. anything will work with an unlimited budget, it's all about how much of that you can couter-balance by doing yourself.

 

[IXNAYXJ]

I have thought about making an IRS set up for the race Cherokee, but I just don't see the return on the effort. I have a Monster Miata (345 rwhp) in which I use a Thunderbird SuperCoupe IRS 8.8 so I'm familiar with what you're proposing.

There are about 134,179 things I would do to a Cherokee before doing an IRS set-up. Unless you're just hard set on doing it for the fun of the project, in which case it won't matter what we say anyway.

EDIT: After reading your post more closely and noting your (self proclaimed) lack of advanced fabrication ability, DO NOT ATTEMPT THIS. This would be a challenging undertaking for even the most advanced fab shops.

-Matt

 

[FlexdXJ]

DO NOT ATTEMPT THIS

^This^


This would be a cool thing to see but I agree with Matt, that is a big undertaking even for a very good performance shop.

 

[Keithmania]

Note to self:

DO NOT ATTEMPT THIS.

!!!

N'uff said then.

 

[CherBear]

I have thought about making an IRS set up for the race Cherokee, but I just don't see the return on the effort. I have a Monster Miata (345 rwhp) in which I use a Thunderbird SuperCoupe IRS 8.8 so I'm familiar with what you're proposing.

There are about 134,179 things I would do to a Cherokee before doing an IRS set-up. Unless you're just hard set on doing it for the fun of the project, in which case it won't matter what we say anyway.

EDIT: After reading your post more closely and noting your (self proclaimed) lack of advanced fabrication ability, DO NOT ATTEMPT THIS. This would be a challenging undertaking for even the most advanced fab shops.

-Matt

Pics of the MM!

 

[IXNAYXJ]

Pics of the MM!

-M

 

[CherBear]

What did you stuff into it? 5.0? Lsx?

 

[IXNAYXJ]

What did you stuff into it? 5.0? Lsx?

Ford Racing crate motor, GT40 heads, Grant Race Demon carb, Tremec T-5 WC, blah, blah, blah. 348 RWHP...it scoots.

-M

 

[xcm]

i would love to mess around with an airbagged irs setup in a minitruck, something using a jag irs would be cool. it would be scary if you wanted it to do tight fast corners though, you'd have to do math and all that. swaybars, spring rates. sounds expensive.

 

[rockclimber]

you could look into a TTB setup for the rear... not sure if it has been done in an XJ before, but anything is possible right?

and TTB is enough like solid axle to make it not that much more difficult than a linked rear.

one day I will have a front TTB xj with ~36" travel trailing arm rear, then I will get into the go-fast stuff... until then its solid axle crawling for me.

 

[Boostwerks.com]

Disclaimer: fab at your own risk.

If I we're to do this, I'd use a rear outback or STI diff with subi knuckles/axles. The rear subframe assembly might fit, but would more than likely need a lot of fab.

Ford Racing crate motor, GT40 heads, Grant Race Demon carb, Tremec T-5 WC, blah, blah, blah. 348 RWHP...it scoots.

-M

:thumbup:

 

[dasbulliwagen]

Disclaimer: fab at your own risk.

If I we're to do this, I'd use a rear outback or STI diff with subi knuckles/axles. The rear subframe assembly might fit, but would more than likely need a lot of fab.



:thumbup:

I agree on the rear subframe bit. It would make it tons easier if your donor had a rear subframe with all the suspension parts already lined up and where they need to be, that way you would just need to fab in the subframe, and maybe the upper shock/strut mounts and adapt the driveshaft. It would take MUCH less fab that way. Just my 2 cents.

 

[Keithmania]

The Lincoln IRS I have access to is complete. Its the whole rear assembly, including the brake calipers, the sub frame, shocks, differential, half shafts... everything. I think I could probably get the tranny and drive shaft too, but thats all ECU controlled if memory serves me correct. My problem is as stated earlier. I am new to the fab world, and not sure if I could handle a fab project of such EPIC BIBLICAL proportions!

I am trying to find a different application for that rear end. I have driven a Lincoln LS before and lemme tell you the rear end on that thing hooks up like crazy, so I'd like to see some use out of it other than it being a donor to the next metal compost pile.

 

[IXNAYXJ]

I'm all about combining random vehicles to make a better, cooler end product...which is why I don't understand the goal here. What would you gain going IRS? Seems like complexity for the sake of complexity that will likely result in a worse performing end product.

 

[Keithmania]

Read up a few posts. I decided to not do the project cause of its fab complexity. And not sure why the added complexity would make a worse end product. If all the geometry was figured out, I would expect cornering, and street sport driving would be greatly enhanced over a solid axle setup.

Though, like I said it won't be going in my xj... I have had my eye on a 3rd gen Camaro, but really I will just see if I can part it out, might start saving for my own 2JZGTE swap.

 

[bjoehandley]

I'm still not sure on IRS systems. Some years back Shelby was supposed to be putting a Jag style IRS on his '65 Mustangs and found in the development testing that the IRS wasn't worth the added expense on those cars.

 

[IXNAYXJ]

And not sure why the added complexity would make a worse end product. If all the geometry was figured out, I would expect cornering, and street sport driving would be greatly enhanced over a solid axle setup.

My concerns would be more along the lines of "what would an IRS/solid front axle vehicle handle like?" Yes, all the geometry would be figured out, but for a Lincoln LS...a very different car from an XJ. Also, as bjoehandley points out, a good solid rear end can work just fine...look at the current Mustang. Back when you could get a Mustang with IRS or a solid axle ('03 Cobras had independent rear, GT had a solid axle), Saleen chose to use the solid axle as the foundation for their cars.

-Matt

 

[bjoehandley]

My concerns would be more along the lines of "what would an IRS/solid front axle vehicle handle like?"

I'd have to wonder about that too, especially with something tall like an SUV. I've seen it on street rods (some kind of beam/tube axle up front with a Vette or Jag rear), but those were likely more show and really go in a straight line than go around corners at speed. If I were going to put an IRS on an XJ or MJ, I'd just look at some of the street rod stuff out there and go indy all around on a 2wd model, but at that point, you might as well buy an old RWD Volvo wagon to hot rod.

Yes, all the geometry would be figured out, but for a Lincoln LS...a very different car from an XJ. Also, as bjoehandley points out, a good solid rear end can work just fine...look at the current Mustang. Back when you could get a Mustang with IRS or a solid axle ('03 Cobras had independent rear, GT had a solid axle), Saleen chose to use the solid axle as the foundation for their cars.

-Matt

Good point on the Cobra IRS, I guess Ford used a bunch of fairly soft rubber bushings in those which is some of what caused all of the issues instead of a solid mount or using urethane, delrin, or even a much firmer rubber. The guy who told me that has told me that he's put one of those IRS system in his Fox Body convertible (haven't seen it in person yet though) and replaced all the rubber with delrin and aluminum bushings, which he has said got rid of many of the issues related to that IRS.

Personally, I do think that making an XJ that can corner even better while keeping the two solid axles would be more impressive and different than stuffing somebody else's IRS off a car under one.

 

[John(XJ)Jeep]

@bjoehandley

You do understand how hard that is to explain that to somebody. Especially to people that think dropping a "350 in it" as the answer to every car question.