View Full Version : IRS cv/half shafts
My question is two fold. Are the half shafts stock mustang parts or are they modified (I ordered them from factory five with the kit). If they are stock then how strong are they? Has anyone upgraded them?
edwardb
03-11-2016, 04:52 PM
I can only speak for the newer 2015 Mustang based IRS in my currently under construction Roadster. The same setup that's now available for the 33 HotRod. I have no experience with the previous IRS version. The CV axles supplied by Factory Five for the 2015 setup are not stock axles. They are shorter and beefier. They do use the same Ford CV joints, but the axles themselves are custom. They are from The Driveshaft Shop in NC, and are very high quality pieces. Keep in mind this car weighs much less than the Mustang. I see no reason to upgrade them.
That is exactly the response I wanted to hear. I was actually looking at the driveshaft shops just in case I needed to upgrade, so I guess it was meant to be.
Its not the weight of the vehicle that the shafts are rated for , its the HP output you are putting through them. I purchased a set from the driveshaft shop as I have 750 HP, and with a safety factor went with 900 HP CV shafts. I don't know what the shafts that come with 2015 IRS are rated for and what engine output you are running. But those are the considerations. Good Luck.
edwardb
03-12-2016, 08:09 AM
Agreed the CV axles are rated by HP, but the lighter weight of our builds has to come into play somehow compared to a Mustang. With power adders and stickier tires, the Mustang guys are breaking the stock axles with hard launches. Higher horsepower (and quite expensive...) aftermarket axles are available from multiple sources including Ford Racing. The CV axles provided by FF for my 2015 IRS build Roadster are 1.18 inch in diameter, and much beefier than the stock Ford axles. I picked up a complete rear IRS new take-out assembly, so had all the pieces and could compare the axles side by side. I have no idea what HP the FF supplied axles are rated at, but based on the box marking, they are from The Driveshaft Shop, a highly reputable source and one of the suppliers of the high horsepower aftermarket Mustang axles. I'm doing a Coyote build with performance street tires. I'm confident they will more than handle what I'm planning to give them.
EEP, when you purchased from the drive shaft shop did they know your cars specs or did you just order mustang sizes?? I plan on being in the hp range that you are. I am going to hit up FFR tomorrow and see whats good.