IRS vs. live axle weight diff.

[Uncle Meat]

U.M., I don't think you are comparing apples to apples in this photo. The 8.8 in the pic shown doesn't have brakes, shocks or upper and lower control arms, all of which are on the IRS piece. That's not to say that the solid axle isn't lighter, it is, I just don't think this picture gives an accurate representation of the differences.

In that specific picture you are absolutely correct. However this is the only photo I have that shows the two setups side-by-side so someone can really get a feel for all the parts that make up a complete IRS. Please feel free to rip the IRS out of your '01 and then get a similarly equipped 8.8 and set them side by side for a better set of comparison pics.

U.M.

 

[bditty50]

Here is a good site for mustang suspension and it talks about the IRS and it has a 75lb weight increase to a solid axle. So with the right parts you can even out the weight.


http://www.miracerros.com/mustang/t_suspension.htm

 

[Uncle Meat]

I still think the IRS in the 03/04 Terminators weighs more than the IRS versions in previous years. The torque brace and half shafts were beefed up for the Terminators so I'm sure the weight difference is a little greater than what many think.

U.M.

 

[Dan_Soprano]

I still think the IRS in the 03/04 Terminators weighs more than the IRS versions in previous years. The torque brace and half shafts were beefed up for the Terminators so I'm sure the weight difference is a little greater than what many think.

U.M.

yes, the 03/04 IRS assembly is considerably heavier do to the reason you listed. not actually sure on how much though.....

 

[01BLKSNK]

According to 5.0 mustang & superfords the live axle is 66 lbs lighter.

 

[98 Saleen Cobra]

Ok, well after reading all of this, now i'm curious about the terminators capabilities on a roadcourse with IRS.. If you get the whole MM setup, the ultimate grip in a box package, will it out perform a terminator with 8.8 and all MM stuff on it?? I'm just curious because I haven't seen or heard of a 04 cobra on a roadcourse with IRS that is all done up.. I know that you are a drag racer but, U.M any info that you may have would be greatly appreicated on this question..

 

[Uncle Meat]

Well a properly modified IRS with all the aftermarket goodies compared to a properly modified 8.8 with all of the handling related upgrades is still going to weigh more. Plus there is driveline loss. Takes more power to turn the wheels on an IRS setup than on a straight axle. I would surmise that all other things being equal the straight axle would still have the edge. Keep in mind that the IRS is made up of more components and parts so there's a higher chance of failure compared to the straight axle. There's a reason why you don't see professional road racing Mustangs using the IRS for competition.

U.M.

 

[98 Saleen Cobra]

Well that definatly makes sense. Thank you for your knowledge on this. I really appriecate it.

 

[tomustang]

From what I have archived, was in a mustang mag is:

The IRS reduces rear lift under braking, making driving the Cobra hard a much more forgiving task. It improves the vehicle's attitude and control, with a full 0.75 ins. (1.9 cm) more suspension travel available. And it reduces the unsprung weight of the Cobra by 125 lbs. (57 kg). As expected, the IRS carries with it a fairly stiff weight penalty. To help compensate for the system's extra 70-lb. (32-kg) heft, SVT engineers extracted close to 50 lbs. (23 kg) from the car. The result: a weight distribution that moves from a 57%/43% front-to-rear split in the 1998 model to 55%/45% with the 1999, a significant enough amount to equal the effect of moving 80 lbs. (36kg) off the front wheels. Ford didn't limit its tweaks to the rear wheels, however. Besides the addition of the IRS, Ford also addressed other aspects of the chassis to improve the car's handling characteristics, like widening the rear track by 1.2 ins. (3 cm) to match the space between the front wheels and lowering it overall by 0.25 ins. (0.6 cm).