Solid to Independent Rear axle

I hear ya. :thumbup:

and I do too much hopping around corners for my liking...

wheel hop in IRS, if you have lots of power.

but LESS wheel hop than a live axle setup

acbarnett said:

but LESS wheel hop than a live axle setup

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are you joking? why are all drag cars live axles???? dude you must be kidding

*axle hop I meant, and drag cars don't do twisties, which I love

Quote:
V8 supercars don't use IRS

MACH FYV said:

Neither do Porsches for the most part and they seem to do OK.

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You should realy THINK before you blab your mouth. If we all go around sounding like you do talking before thinking we will all say that Porsches are rear engine, front wheel drive cars that use solid axles transfer cases. Come on dingo. No Porsche has EVER had a solid rear axle. They can't! They have transaxles (rear mounted transmissions with integrated differentials).

Now if you want to talk about supercars, or Porsches, or any other noteworthy performance icon, then maybe we should consider installing a torque tube and transaxle. Weight distribution, independent suspension, same idea that Corvettes, Saleens, Porsches, some Alfas, etc use.

i have both and the irs(in good shape) is smoother but the older wore out non irs handles better

I don't want to build a drag car. A IRS seems appropriate for what I plan on doing.
Buying a 960 would be the easiest alternative but then you have to a 960 and not a 940 turbo.

The 960 has alot more options that I don't want.
Thanks for the input.

edit: Just learned the 940SE had IRS. Was it a turbo??

yes the 940se WAS a turbo, although it was 1991 only, and it had the earlier non-squirter engine and it has the 960-style hood and interior. The sedan is also the only one that came with an IRS system though. I would look to getting a cheap 940se and switching your newer (and much nicer) engine into it. Also a thing to keep in mind is that I'm talking about the US-model 940SE, if you want a 940SE (i.e., a 960 with a 940 turbo engine) but live in europe, look for what was called the 960 turbo and get a sedan.

I got my IRS from a US-model 940se, and although it's highly impractical to convert the car, my ideas for doing it have a whole lot more to do with an attachment to the car (and the 940-specific interior and hood) and a desire to do something new and unusual than they do with any sort of practicality. That said, it doesen't look like it would be too difficult of a swap, especially if you have access to a lift.

any thoughts on the difficulty of swapping a 240z rearend into a volvo?

it is a macpherson strut design.....so I don't think it would be that hard.

Fab the bracing and the coilover mounts into the rear wheelwell and run a rear brace connecting the two?

Any thoughts?

acbarnett said:

and I do too much hopping around corners for my liking...

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I gently suggest that perhaps this is more a result of the linkage geometry, rather than it is a result of any inherent quirks in the basic configuration.

I mean dude, come on.

There is no end to examples of live-axle cars that take corners all day long without the axle-hoppin problems that you're complaining about.

Perhaps you've heard of NASCAR?
Or maybe the slightly less-well-known sport of rally racing?

I think your problem is that there's a loose nut behind the wheel.

If an independent axle is no better than a solid axle why was it offered it the first place.

There is a reason, the arguments against have no relevance.

In addition the question posted was not which is better a solid axle or an independent. Anyone with an ounce of common sense knows the answer.

VOLVORacr said:

If an independent axle is no better than a solid axle why was it offered it the first place.

There is a reason, the arguments against have no relevance.

In addition the question posted was not which is better a solid axle or an independent. Anyone with an ounce of common sense knows the answer.

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Stop being a newbie, Kevie and John know what they're talking about. Plus I'll always back up a local In your case, an IRS won't necessarily net you faster times (if you track it) or better handling, that's all.

Look, just because it's newer doesn't mean it's better.
Engineering suffers from fads, too.
Not to mention marketing forces, which sometimes demand features for no reason other than sex-appeal.
Not that I'm saying that IRS is a fad, I'm just making a generalization.

Facts:
Live axle is pretty f'in good when it's done right.
IRS is pretty f'in bad when it's done wrong.

As it comes from the factory, Volvo live axle is adequate for a stock vehicle.
As it comes from the factory, Volvo IRS is adequate for a stock vehicle.

For racing, the upgrade path for live axle is clear, with several suppliers.
For racing, the upgrade path for IRS is relatively unexplored. Diff is small. Half-shafts are small. Sub-frame is big and heavy. Lots of big rubber bushings mean that geometry is only vaguely predictable.

So, in a roundabout way, I AM answering your question as to why there is no information on this site about swapping from live-axle to IRS. In our specific case (Volvos), the IRS does not compare favorably to live-axle based on a performance to cost comparison.

Maybe money means less to you than most people, or maybe you have a lot of spare time to track down parts and do fabrication work.

When I look at crazy Swedish and Finnish rally cars, I don't see IRS setups. I see live-axle. I also know that there are a LOT of guys up there, and the competition is pretty intense, so if there was one thing like IRS that was an advantage, they would be using it.

I'm not trying to be an a**hole. It just comes naturally.

Kevin Hawkinson said:

Not that I'm saying that IRS is a fad, I'm just making a generalization.

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Yet IRS is hardly new technology. It's been around for ages.

Then again, some of those nifty cars that one might consider capable road cars (like the Alfa Spyder) used live axles.

Me, I'd like the car to handle well, and not manage to work every freaking piece of cheap ass plastic apart in the process. The prospect of a smoother ride is quite seductive.

To say that there's no upgrade path for the IRS is perhaps quite pragmatic. However, the more buzz generated around it, the more likely we are to find reasonably priced upgrade bits for it. I seem to remember people poo poohing the 16V head for being too complex and expensive. ::looks at Kenny::

right now, all it looks like the IRS needs is to have the strongest live-axle diff I can get swapped in, along with a new stronger set of rear lower control arms. Home-made poly bushings will go in as many places as I can fit them, and I am trying to figure out how hard it would be to get beefier halfshafts for the setup.

VOLVORacr said:

If an independent axle is no better than a solid axle why was it offered it the first place.

There is a reason, the arguments against have no relevance.

In addition the question posted was not which is better a solid axle or an independent. Anyone with an ounce of common sense knows the answer.

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Dooooood,
if anyone with an ounce of common sense know "the answer", and as we know there are plenty of European sedan cars well back into 1960s (old enough to remember the 60s?) with independant rear,
Then why do even long term stauch supporters of IRS change the designs in their product lines CONSTANTLY?

BMW changes everything repeatedly.
The Mitsuburu and Sububitchy WREX and Evos , especially the EVO have also changed the design drastically several times.

To this one person with a full ounce of brains, it seems clear that getting it right is awfully difficult, even for experienced suspension Engineers, and at least a few might have at least an ounce of brains. I knew one, once.

To answer your first question why it was offered, the answer is RIDE.
And packaging.
IRS cars can and do get by with much less tunnel.


Now somebody said maybe a Z car rear end.
On that tack, I'd say no because alternate ring and pinions cost over $800.

Now ABC Barnett could scoot over to Holland Auto wrecking on Treble Cove Road in fawkin Billerica and have a look at the big stout looking third Gen Toiletta Stupra complete set up as it is pretty goo looking, and deffo the biggest easily available stuff that you can get alternate ring and pinions for reasonable money (about $180) (aside from parent company Ford's 8.8 stuff). Big enough and beefy enough that I am making adaptors to us them in my fave car the Xratty.
Just pulled another one yesterday, 4.3 ratio and BIG fawkin LSD with 4 planets and 6 discs per side. Yum.
Toitta Stupra stuff is far easier for adapting.

By the way, what sort of racing do you do?

so are you suggesting I gank the entire rear suspension setup? or just the diff and halfshafts and try to adapr those to the volvo subframe and rear setup?

acbarnett said:

so are you suggesting I gank the entire rear suspension setup? or just the diff and halfshafts and try to adapr those to the volvo subframe and rear setup?

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Get everything if you can including a rear sway bar from a 940se or early 960 sedan since 760s don't have them. But keep in mind that IRS is heavier than the solid axle on volvos.

One modification I want to make is to replace the panhard rod with a watts link. Does anybody make a suitable diff cover for our cars?

Or how about a REAL rear sway bar that is attached to the body like the front bar with separate end links attached to the axle.
This one is even better.