IRS vs live axle

bryson · Post by **bryson** » Mon Nov 13, 2006 12:31 pm

What are the benefits and drawbacks of each? I just picked up an older Corolla and it has a live rear axle. I'm considering changing some things around on the rear end anyway, and I'm trying to decide if it would be worth my time to put together an independent rear. What do you guys think? Would a properly tuned 4-link solid rear be at a significant disadvantage to an independent rear?

The Dark Side of Will · Mon Nov 13, 2006 12:46 pm

What I've read says there aren't many handling advantages of IRS over a GOOD live axle setup on smooth pavement. The live axle's primary drawback is unsprung weight, which gives IRS a noticeable advantage on rough or bumpy surfaces.

donk_316 · Post by **donk_316** » Mon Nov 13, 2006 1:37 pm

dude... AE86?

Pyrthian · Post by **Pyrthian** » Mon Nov 13, 2006 1:49 pm

a solid axle is better for flat pavement - like a dragstrip
if theres any unevenness, then the IRS is better

when the pavement gets uneven, the solid axle will not be "flat" against the pavement, which mean the tires wont be as "flat", which means less traction.

Tha Driver · Post by **Tha Driver** » Mon Nov 13, 2006 1:55 pm

:salute:
sayonara

The Dark Side of Will · Mon Nov 13, 2006 2:03 pm

Pyrthian wrote:a solid axle is better for flat pavement - like a dragstrip
if theres any unevenness, then the IRS is better

when the pavement gets uneven, the solid axle will not be "flat" against the pavement, which mean the tires wont be as "flat", which means less traction.

What makes the live axle "better"?

stimpy · Post by **stimpy** » Mon Nov 13, 2006 3:32 pm

Tha Driver wrote:Unsprung weight - especially on bumpy roads like Will said.
On "an old corolla" why bother? Why even ask? :scratch:

A question that can be asked of most vehicle modifications. We all should be driving identical Chevy Impala sedans.

product1620 · Post by **product1620** » Mon Nov 13, 2006 3:50 pm

AE86 FTW? going drifting?

Pyrthian · Post by **Pyrthian** » Mon Nov 13, 2006 4:35 pm

The Dark Side of Will wrote:
Pyrthian wrote:a solid axle is better for flat pavement - like a dragstrip
if theres any unevenness, then the IRS is better

when the pavement gets uneven, the solid axle will not be "flat" against the pavement, which mean the tires wont be as "flat", which means less traction.

What makes the live axle "better"?

less chance of the wheels chattering
and handles the "lean" of the car better when you have a majorly torqy motor
and, usually much stronger

beleive me - all weak arguements - I'm for IRS

The Dark Side of Will · Mon Nov 13, 2006 4:42 pm

Pyrthian wrote:
The Dark Side of Will wrote:
Pyrthian wrote:a solid axle is better for flat pavement - like a dragstrip
if theres any unevenness, then the IRS is better

when the pavement gets uneven, the solid axle will not be "flat" against the pavement, which mean the tires wont be as "flat", which means less traction.

What makes the live axle "better"?
less chance of the wheels chattering
and handles the "lean" of the car better when you have a majorly torqy motor
and, usually much stronger

beleive me - all weak arguements - I'm for IRS

I'll help you get rid of those weak arguments, then.

Wheel hop isn't determined by chance... it's determined by suspension settings. Wheel hop is a sign of a very specific tuning problem. Live axles are somewhat less susceptible to it because they're SOOO DAM HEAVY.

Live axle CAUSES the car to torque over with a powerful engine. IRS does not.

Corvettes and Mustang Cobras can put down a hell of a lot of power. There's a company that makes IRS parts for C2/C3 Vettes that's NHRA legal to 7.50's.

product1620 · Post by **product1620** » Mon Nov 13, 2006 4:45 pm

Didin't the "terminators" have really bad wheel hop issues???

bryson · Post by **bryson** » Mon Nov 13, 2006 5:44 pm

Yeah, it's an AE86 -- I don't plan on ever dragging the car, nor do I plan to do any drifting. I'm excited because it has all the things that I like about my older VW's, but it has all the cool stuff that Toyota was doing in the 80's. I am going to build the car up to really enjoy the mountain roads up here and to track as often as I can afford. I don't know if the advantages of an IRS will be worth the fabrication and money required to make it work. I may look into it much later, but I won't make it a priority.

teamlseep13 · Post by **teamlseep13** » Mon Nov 13, 2006 10:36 pm

Not worth it to convert an old live axle car like a Corolla to IRS in my opinion.

I love IRS's, but this is what I would do if I was making one.
Take a Ford 9in rear end and fill it with the best internals you need for the power level you are at.
Cut the axle tubes off.
Make a box for it and attach the box to the chassis so the rear end if seperate from the suspension.
Run halfshafts to the hubs, and make a good old double a arm suspension.

Mach10 · Post by **Mach10** » Mon Nov 13, 2006 10:43 pm

bryson wrote:all the cool stuff that Toyota was doing in the 80's.

You mean, like, Rusting? :thumbleft:

befarrer · Post by **befarrer** » Mon Nov 13, 2006 11:27 pm

Mach10 wrote:
bryson wrote:all the cool stuff that Toyota was doing in the 80's.
You mean, like, Rusting? :thumbleft:

lol, thats what they like to do here in Canada, cant take the cold or something.

Tha Driver · Post by **Tha Driver** » Mon Nov 13, 2006 11:37 pm

:salute:
sayonara

Tha Driver · Post by **Tha Driver** » Mon Nov 13, 2006 11:42 pm

:salute:
sayonara

teamlseep13 · Post by **teamlseep13** » Tue Nov 14, 2006 12:33 am

The machining would cost me nothing.
It would allow me to have a bulletproof rear end, have the suspension geometry as I want it and know it is stiff.
When was the last time you saw a stock Jag or Z rear-end take over 800 ft-lbs with slicks?
Now I wouldnt do unless I had an insane motor but its just fantasy.

bryson · Post by **bryson** » Tue Nov 14, 2006 10:34 am

Haha yeah yeah the rust -- don't get me started. Finding a clean chassis is damn near impossible. I just liked Toyota's lineup, and after being under a few clean ones (mainly the MR2 and MKII Supra), I really like how a lot of things were done. It's all kind of quirky and cool. Not to mention, I love the 4AGE series of engines.

Mainly, I like the 2200lb curb weight and the potential for relatively little money. I've got a 1.6L 20v engine that is the same code as the stock engine, just a newer iteration that I'm going to build and put in the car. I won't be making insane amounts of power, so I'm going to try to use the lightest rear end that will still hold the power. Hopefully the stock rear will hold up. I should only be making 300hp or so, and I'm not going to do any hard launces or anything, so hopefully it will hold. If not, I've looked at everything from a Volvo solid rear (uses a Dana 330) to a RX7 TurboII, a C4 Vette, and 1g DSM rear. It would be slick to be able to use more aluminum suspension components, but the stock stuff seems pretty decent.

My goal is to have a car that is comparable to the Elise or Miata, but for significantly less money. I initially wanted a mkI mr2, but I like the room I have with a hatchback. I love the idea of being able to throw four tires in the trunk and head to an autocross or track day. Also, it's got a lot of what I really like about the Celica Supra, only much lighter.

The Dark Side of Will · Tue Nov 14, 2006 2:36 pm

Graft in MkII Supra rear suspension. It drops out on a rubber-isolated subframe.