Self-contained IRS?

The Daytona Prototype/LeMans thread got me to wondering about candidate IRS units.  I asked the question in my last post but maybe we need a separate thread.  What's the opinion of The Hive on IRS candidates for a scratch-built prototype?

....Miata?

If you're talking a rear-mid engined prototype I would be looking at FWD drive trains and suspension. That won't result in a lot of choices with manual transmissions, especially if you wanted a FWD V8 combo. Cars like a FWD LS  equipped Impala or the V8 Taurus come to mind.

In reply to stroker :

The Jaguar IRS is one of the easiest to adapt in addition to dozens of different Jaguars.  It’s used in hot rods, kit cars and many race cars. From narrow 50 inch wide tracks to big sedan widths.  You can find gears for it in many ratios and both Spicer and Dana make even more sets 

It withstands horsepower/ tire widths  of a massive variety. 

If you're thinking front engine, rear drive.. 240sx, Miata, E34 BMW wagon.  The Mn12 tbird looks interesting too. Should be pretty stout.

C4 Vette has a unique rear suspension if you want something different.

For most of these options, you'd need to fabricate up some upper coilover mounts, but that's probably not absurd if you're already considering a homebuilt special.

Mn12 t bird is a good width for a typical midsize car build, i used one in a grand prix.  The only non self contained part is upper spring perch

I knew that XJ-S was the answer!  Inboard rear brakes!  What fun to change out fast when racing!

Jag    -   C4     -       Maybe ford 8.8.   

Later (but earlier than the fwd/awd versions) Ford Explorer 8.8? Maybe - never looked closely at them and they might be porky.

The manual trans C4s were IRS Dana 44 If my googling is accurate.

The Miata has superior geometry to the C4. Upgrade the diff if the stock Miata unit won’t handle the torque, but I can’t think of a reason to choose a C4 setup over it unless a.) it’s going in a cruiser, not a racecar. And b.) it fits the recipient’s track width/chassis better. 

What about the Cobra rearend from late 90's Mustangs that bolts in to Foxbodies, or is that what you were saying?

BMW 5 series wagon is pretty nicely self contained.

wheelsmithy said:

What about the Cobra rearend from late 90's Mustangs that bolts in to Foxbodies, or is that what you were saying?

 

It's a design rather compromised by the need to bolt in place of a solid rear axle. An irs adapted to fit what was still essentially a 78 ford fairmont.

Or, if you want a miata rear subframe, pm me. I have one with an open diff I want to sell. I also have front corners (no cross member for front) the rear is missing a halfshaft and an upright 

pres589 (djronnebaum) said:

I knew that XJ-S was the answer!  Inboard rear brakes!  What fun to change out fast when racing!

Group 44 managed to win a whole bunch of Trans Am races with inboard  disk brakes.  Reduced unsprung weight is the prime advantage. 

However later Jaguars went out board if inboard is a deal breaker. 

Doesn't the Jag setup use the half shafts as the upper suspension member like a C3 Vette? This has a bunch of force channel through the diff / spider gears. 

In reply to Apexcarver :

No doubt, you speak the truth. Just spitballing on the self contained idea.

Explorer? I keed, I keed.

I have a Cobra 03 terminator 8.8 31 spline 3.55 geared limited slip center section I need to sell.  I have two and only want to keep one.

How wide is the track?

How heavy is the car?

What engine is going to drive it?

What is the budget?

What gear ratios do you need?

Pete

I think the E30's rear suspension is pretty self contained except for the upper spring perches. The rest is all bolted to a crossmember

If you’re looking at trailing arms, then the 924/944 rear suspension is a completely contained unit as it is meant to be removable for service.

I wouldn’t use it for this purpose, I’d go with a C4/C5 setup, but at last the Porsche stuff is ready to go with a decent transaxle and halfshafts that fit, etc.

pres589 (djronnebaum) said:

Doesn't the Jag setup use the half shafts as the upper suspension member like a C3 Vette? This has a bunch of force channel through the diff / spider gears. 

Yes!?! Your point?  Geometry wise it can be adjusted to whatever your requirements are. If you are worried about strength, it is capable of dealing with massive forces and I’ve seen it under more than a few pickups. The big Jaguar sedan weighs over 4600 pounds. Add 4 fat old duffers and golf clubs and it still holds up.  ( by the way the parts are basically the same in the big sedan or light XKE, including the needle bearings to ensure accurate alignment that most rubber bushings don’t.  

In reply to Patrick :

Is there a decent aftermarket for the MN12 suspension?

In reply to AnthonyGS :

Out of curiosity, what would you want for it?

Nissan/Infiniti 350/G35 unit is a pretty little package. Factory Limited is readily available.

Maschinenbau used one on Dasaniti.