Irs?

[Teal94]

Was just wondering why so many are swapping to the irs rears. Wasnt the irs the weak link in the Cobra and reason for swapping back to a regular axle? Im not knocking anyone for doing it just want to know everybodies thoughts. Im sure handling has got to be way better and other than that it looks pretty cool too.

 

[Rice_slayer]

Handling and smoother ride. They are a lot nicer to use on a road course than a SRA. They can be made strong for the strip to. Different strokes for different folks!

 

[justinschmidt1]

Ive been entertaining the idea of an IRS in my car...but dk if its worth it.

I mean, from what I hear it will add 150 lbs to the rear end which is kind of a big deal to me. Although it would even out my car...im kinda worried about launching on slicks with it.

But since my car is mostly driven on the street, it may actually help traction on the street.

Im torn.

 

[Teal94]

Thats kinda what I was thinkin also. Pretty sure Ive talked myself out of it completely.

 

[justinschmidt1]

Thats kinda what I was thinkin also. Pretty sure Ive talked myself out of it completely.

Yea...ive heard without a good bit of $$$ it will break.

Ill add 150 lbs to the car and most likely break a half shaft the first time I try to launch it haha

 

[twovalveterror]

Ive been entertaining the idea of an IRS in my car...but dk if its worth it.

I mean, from what I hear it will add 150 lbs to the rear end which is kind of a big deal to me. Although it would even out my car...im kinda worried about launching on slicks with it.

But since my car is mostly driven on the street, it may actually help traction on the street.

Im torn.

I haven't installed my IRS yet, so this is mostly speculation, but I'm willing to bet that it is not even close to the best set up for the strip. I plan on doing my first run on street tires, and if it doesnt hop around too much, get some slicks and see if it handles those too.

as for the added weight to the back, if you're going to add weight anywhere on a mustang, it might as well be there. its all pretty low to the ground too. not to mention the unsprung weight is actually decreased, which may play a larger role depending on your goals.

 

[justinschmidt1]

I haven't installed my IRS yet, so this is mostly speculation, but I'm willing to bet that it is not even close to the best set up for the strip. I plan on doing my first run on street tires, and if it doesnt hop around too much, get some slicks and see if it handles those too.

as for the added weight to the back, if you're going to add weight anywhere on a mustang, it might as well be there. its all pretty low to the ground too. not to mention the unsprung weight is actually decreased, which may play a larger role depending on your goals.

Hmm, how is the unsprung weight decreased, ive heard that too but wasnt sure what it was actually referring to. Just the fact that with a SRA the whole axle assembly is moving and with IRS its just the A arms and w/e?

I dont mind the weight as much as the fact that I feel like it will break on me. lol

Ive had enough problems with shit breaking, really dont want to add another weak link

 

[Teal94]

Thats what Im afraid of too but Im running an automatic this go around so it wont be seeing 5spd abuse. I didnt know there was that kind of weight difference either.

 

[justinschmidt1]

Thats what Im afraid of too but Im running an automatic this go around so it wont be seeing 5spd abuse. I didnt know there was that kind of weight difference either.

Well im running an auto too...but a kinda of fast one with a 3800 stall. lol

The unsprung weight will help with ride quality probably...

From what ive read traction will suck with drag racing so im not gonna do it.

 

[Gallows]

If it is for a dedicated track car then stick with the SRA and build it up. I presently have a SRA with MM adjustable lower control arms and panhard bar. I don't go to the track and I like the twisty winding roads but I do no like the way the car handles and will be going with an IRS out of a 99 Cobra that was upgraded with 31 spline components, front and rear braces. It will be getting the Full Tilt Boggie treatment before it gets installed and I am looking forward to the increased handling it will give the car.

 

[Teal94]

Had a full built sra in my 95 with double adjustable uppers and lowers,tubes welded,c clip eliminators etc.... Trying to stay away from a full out racecar this time. This car is going to be my daily and I will gradually start upgrading as we all do. Just looking at different options and getting some input from others.

 

[dutch]

They both have their advantages, but I love the IRS. That said, I'll never dragrace because there are no tracks in this country.

The unsprung weight is decreased because the IRS is solid with the frame, only the arms move, instead of the entire stick.

Pro's:

- ride quality, it's a lot less nervous, jumpy, smooth as silk on higher speeds and in corners and on bad roads.
- traction, a lot more and predictable traction on streets/bumps/coming out of corners.
- gives the car a more solid, relaxed feel overall.
- Looks, obviously.

Con's:
- Weight, though unsprung weight is reduced. I didn't really notice the difference of the increased weight but went from 3.27's to 3.55's in the process which may have set that off.
- Price, don't think just the IRS is enough. You'll HAVE to do the bushings (delrin), brakelines, exhaust, etc. Do it right the first time trust me.
- Breakage, which I think is bullshit if you have a streetcar. The terminators break them because they have 600+ hp, don't upgrade the bushings and don't strengthen the diff cover which will result in wheelhop sometimes. 9 out of 10 IRS breakages happen on the strip with slicks and a stock(ish) IRS and people who don't let off when it starts hopping.

There PLENTY of very high horsepower guys running a well prepped IRS (read: bushings, diff brace, etc) who never have problems and wouldn't change the IRS for anything.

The reason some go with the SRA is because they so the strip VERY often, have ridiculous horsepower numbers, and mostly don't care for the pro's of the IRS. (because racecar). In that case, I can completely understand, if you don't care for the ride quality and just want the strongest option back there to prevent braking things and being able to launch as hard as you can.

Most importantly: if you plan on running the IRS, mod that s.o.b. while it's still out of the car. Get all the correct bushings, a diff brace, good springs/shocks, and swap it in! A good prepared IRS will not wheelhop most of the time (except for cold conditions/bad tired) and wheelhop is what kill the IRS. That said, mine hops sometimes when it's wet and cold and I haven't broken anything in over a year of daily driving. Just let off and be warned.

 

[justinschmidt1]

So of my cars about to run 10s, would that classify it as a race car? Lol

Sent from my DROID RAZR using Tapatalk

 

[dutch]

Well yes and no, you also say you like using it as a streetcar. If you enjoy using it as a cruiser/streetcar instead of just going to the track on weekend and get every last second out of it, I'd say you're a good candidate for a well prepped IRS. However, you have a pretty high stalled auto and I've got no idea what that would do in terms of wheelhop.

 

[justinschmidt1]

Well yes and no, you also say you like using it as a streetcar. If you enjoy using it as a cruiser/streetcar instead of just going to the track on weekend and get every last second out of it, I'd say you're a good candidate for a well prepped IRS. However, you have a pretty high stalled auto and I've got no idea what that would do in terms of wheelhop.

Yea, I dont know how it would handle it...you would think it would be easier on it than a manual car but who knows.

I do use it as a street car but I definitely don't want to blow up my rear every time I drive it. lol

Its in the back of my mind...I would probably do it after I run my car in a few months just to see if I can break 10s. I dont really take it to the track that much...at this point I am only doing it to see if I can get a 10.99.

I would prefer better traction on the street which I feel like an IRS might help with....if not the actual IRS, the fact that Im putting 150 lbs of weight on the back end of the car.

 

[dutch]

The IRS will help with real-world (street) traction too. And you're not going to blow the rear everytime you go to the track, just make sure it doesn't hop and ease it out of the hole. plenty cobra's running 10's.

http://www.youtube.com/watch?v=RhUI-ALCJbk&feature=related

 

[CompOrangeSN95]

IRS=road course SRA=drag strip although a watts link will make an SRA handle like an IRS, but you won't have the same ride on the street, SRA will always be more "harsh"

 

[LilRoush]

The IRS is only an upgrade to the STOCK SRA if you are building a road course car. A well sorted SRA will out corner the IRS every day of the week. Ford's IRS isn't up to snuff solely because they forced the design to fit the mounting points of the SRA already in the Mustang. If you really want to corner hard, MM, Griggs and Steeda all offer rear end set ups that due a much better job under the back end.

I'd rock the IRS in a street car or a weekend track car.... but never a dedicated road racer.

 

[bonestock3.8DTH]

Ive got IRS for my car just waiting to install it but thankfully I dont have to really worry about breaking anything on it cause my car doesn't make shit for horsepower. The exhaust will look cool the LSD and 3.55s will be an upgrade from 2.73s and an open diff the bigger brakes the thicker sway bar and the fact its independent sold me on it because I autox my car so it will most definitely help me out.

 

[DropTopPony]

I would do it, but I don't 1/4 mile my car.