Independent Rear Suspension

[GT]

Has anyone installed an irs in their B-body's?  I'm thinking about adapting a Vette Dana-44 and was just curious if anyone has done this and can give some tips/pics/etc. 

[Mike DC]

 
It's pretty uncommon because the kits haven't existed until recently, and they still cost as much as a solid project car.

I think you'd probably get most of the benefit from just a well-done set of mods to the factory solid axle setup. 
(Switch to an aluminum center chunk casting, better spring/shock/sway/bushing rates everywhere, add a panhard/watts, etc.)

 

[willhaven]

I'd go with an XV Motorsports Level II kit if I were doing any heavy suspension mods. It's only a 3 link with a panhard bar, but they've got it tested on a 4 post rig and the performance benefits seem to be real and very significant.

Very expensive though.

[daytonalo]

Go buy  new Vette ??

[suntech]

I would also go to XV, og do like me, making my own 4 link/ wattslink system. Will use the XV level 2 front suspention though. Really nice! Why do you want the vette rearend? is it for the looks? If so, i could understand it, but if it is for handling/drivability, i think you will be much happier with a solid axle, with a 3 or 4 link setup, and panhard/ watts link, and coilovers.

[Upholstery guy]

This company makes a 4 bar kit for mopars http://www.martzchassis.net/chryslera&b.html

[Rolling_Thunder]

This company makes a 4 bar kit for mopars http://www.martzchassis.net/chryslera&b.html

   did anyone else notice you literally have to cut out your frame rails to install that company's front kits ?          

[Mike DC]

 
I think you might as well cut away the factory framerails when building any type of independent-suspension rear axle setup. 

I know it can be done while keeping the factory rails, but the whole job is so big that I'd rather not bother to compromise the end results over it.  There's too many other rusty-framed Mopar bodies out there to use if you're that serious.  And if you're serious enough to wanna attempt the independent rear in the first place, then you're probably wanting to do all kinds of other stiffening & geometry improvements everywhere else on the car as well.  It all seems most suited to a "fabricate-the-whole-chassis" kind of deal.

 

[is_it_EVER_done?]

Keep in mind that only at the highest levels of racing (above even NASCAR) does an independent rear suspension handle better than a solid axle.

A Panhard bar is used on race applications to eliminate the side to side sway of a solid, but even that is of no value on less than a race car. Often, an independent rear suspension will not handle/track as well as a solid axle, even in production cars designed with them.

You can spend the money on many better places to improve handling and performance.

[Mike DC]

 
I think the IRS only really shows the benefits when you're talking about going too-leadfooted-fast over bumpy/uneven roads. 
It would probably help a really fast road racer (100+ mph) because ALL pavement starts to feel rougher in proportion at those kinds of speeds.


An IRS definitely rides more smoothly than a solid axle though, and that's what really gets it onto most modern cars.

[protocolski]

From my  expierience with road vehicle dynamics (college baja racing / classes), my opinion would be that anyone putting IRS system in there charger is wasting a lot of money and time.  If you are doing it for the sake of doing it- go ahead.  BUt if you are doing it to improve handling, as many others have said its not worth it.  In Baja SAE racing this item comes up with regards to what system is best.  solif rear axel saves weight in that type of (when you dont have a huge Dana in teh rear, but a lone atv axle) compared to 3,4,5 link or trailing arm designs.  For a charger its stupid. The dynamics you need to deal with form the shear unsprung mass alone makes it ridiculous to cut it apart and put an IRS in there.

[suntech]

My advice is that if you want to improve handling, and looks, go with the XV rearend, or look at http://www.dodgecharger.com/forum/index.php/topic,10062.0.html, and see what Norwaycharger has done. Talked to him yesterday, and it was superior over the leaf springs, but he needs a little stiffer springrate, as the oner he had was a little to soft. It was also easy to install, and looks neat.

[is_it_EVER_done?]

My advice is that if you want to improve handling, and looks, go with the XV rearend, or look at http://www.dodgecharger.com/forum/index.php/topic,10062.0.html, and see what Norwaycharger has done. Talked to him yesterday, and it was superior over the leaf springs, but he needs a little stiffer springrate, as the oner he had was a little to soft. It was also easy to install, and looks neat.

That setup looks cool, but there is no way it could outperform an adjusted stock system with ballanced spring rates, shocks, anti roll bar. Think about it, you are now supporting the weight at a single point that was never designed (or reinforced) for it, plus you are transferring the lateral and rotational stresses to an un-reinforced area of the floor, while expecting an "all in one" shock, suspension, spring unit to perform 3 functions.

Like I said, it looks cool, so if thats what you are going for, and you have deep pockets, go for it. just don't expect it to improve anything other than looks.

[Mike DC]

 
When it comes to changing the geometry/hard parts of a suspension, "bolt-on retrofit" and "legitimate handling improvement" rarely go together. 

 

[suntech]

Could not disagree more!!!
If that theory should hold water, the automotive aftermarket is just buildt on a lie, and suspention design engineers would be unemployed. Would be no idea having them at work, since the car manufacors could just build the suspention like they did back in 68!!! I agree ofcause in that the coilovers can not be fitted up in the shock/ damper brackets, without reinforsments, but there are room for big improvements. Leaf springs and oil shocks is not exactly last weeks invention!

[Mike DC]

   
Nobody's saying that 40-year-old suspensions can't be improved.  We're just saying that there probably isn't a lot of real-world benefits when you're limited to a stock old unibody structure's attaching points and strengthened areas.  The factory setups can be improved with "soft-part" tuning changes to a pretty significant degree, so it's usually the most cost/effort-effective way to do things.


If you wanna torch away half of the stock unibody and custom-build a new rear subframe area out of square tubing, then be my guest.  I agree that there's definitely some real-world gains to be had if you wanna go that far.