Modded Mustang Forums banner
Cancel

strenthing my IRS

1348 Views 27 Replies 11 Participants Last post by  M.P. Cobra Fan, 
C
Strengthening my IRS

so i have a 99 cobra and its got pretty much every bolt on possible except pullies for now. im about to put a 4.10 in it to liven it up a bit but i dont want to blow my irs setup. i was thinking bullitflow irs brace and front and rear bushings but i thought id take a few opinions from the pros. my questions are 1. are pulleys even worth getting? and 2. how much of a difference should i be seeing going from a 3.27 rear end to a 4.10. thanks guys!! btw heres a vid of it with the slp loudmouth 1's before i switched them out with magnaflows for the people who are wondering what loudmouths sound like. my hair is also alot shorter now hahaha;)

Reply
Save
Like
21 - 28 of 28 Posts
T
Lefty said:
You'll see a HUGE difference w/ the 4:10's in there.
Click to expand...
yeah great mod!
Reply
Save
Like
M
CobraVert69 said:
i did some research on the cost of having bushings installed and its about 800 dollars so i was wondering if its a bad idea to put the 4.10 gears in w/o a bushing kit and maybe just with an irs brace. atleast for a little while. i dont really launch the car so im not sure what i can do. i really want to get some AFS wheels for it but i dont think ill be able too with the bushing kit. whats your input on it guys?

thanks!
Click to expand...
yes you can just do the 4:10 swap, however the torque multiplication will amplify the wheel hop (in theory)
Reply
Save
Like
M.P. Cobra Fan
I get less hop now with the 4.10's. More spin though.
Reply
Save
Like
C
i guess what im trying to ask is do i really need bushings to put my 4.10 in and if i dont would i have to worry more about breaking IRS?
Reply
Save
Like
M.P. Cobra Fan
No, you really don't need bushings, but it is a very smart move. You might as well replace atleast the IRS Differential bushings while you have the diff out of the car though. This will only add a couple of minutes to the total install time, and the ones from MM are not a bad price either. I would HIGHLY recommend atleast doing that. FTB or MM your choice, but do atleast on of them. I would also highly recommend getting one of the braces installed at the same time. Putting it in later is just going to cost more money in the long run.

As far as breakage, you will only have to worry about it if you are dirving the car hard.
Reply
Save
Like
CammedMysticCobra
Best Cobras to buy 90 percent of time are old guy Cobra owners lol. Than theres the 10 percent which are just like the young people who buy it from the old guy.
Reply
Save
Like
M
CobraVert69 said:
i guess what im trying to ask is do i really need bushings to put my 4.10 in and if i dont would i have to worry more about breaking IRS?
Click to expand...
If you read the article on Full Tilt Boogie Racing Homepage they attribute most if not all the breakage to wheel hop. if you're careful to not stay in the throttle while it's hopping you shouldn't have to much to worry about.
Reply
Save
Like
M.P. Cobra Fan
It's not just wheel hop. You can control wheel hop with the right set of springs and throttle control. However, if you have sloppy diff bushings, your diff will still shake like Oprahs thighs. Your diff shaking is bad bad bad.
Reply
Save
Like
21 - 28 of 28 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Modded Mustang Forums
A forum community dedicated to all Ford Mustang owners and enthusiasts. Come join the discussion about performance, racing, builds, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
96 - 04 Modular Mustangs V6 Mustangs New Members Introductions 2005 - 2010
Top