2003-2005 IRS swap - Suspension and Brake Forum

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2003-2005 IRS swap
Tuesday, March 18, 2014 5:21 PM
I have already looked into this heavily and even gone and found some useful donors but, i just recently realized these are all 2002 or older that do the IRS swap. Ok so i might not have done enough research first. so my question is, can you do the 2000-2001 alero irs swap into an ecotec cavalier? As I've found, there is a black canister in the way of where the alero subframe would mount. I know i would have to dent in the spare tire storage a bit but is there any way around deleting the emissions(?) black box. Maybe a relocation. Has anyone heard or done the swap on a 2003-05?

Re: 2003-2005 IRS swap
Tuesday, March 18, 2014 8:46 PM
I have not done the swap but the chassis is the same from 95 to 2005. You will just have to relocate the box.




Re: 2003-2005 IRS swap
Tuesday, March 18, 2014 9:04 PM
The canister is at the same spot for all 2000-05 jbodies. As far as I know the IRS doesn't come close to the canister as it's right behind the gas tank.




On the inside my car looks like a fighter jet.
Re: 2003-2005 IRS swap
Tuesday, March 18, 2014 9:38 PM
I did some more research on it and found a pic of the underside of the alero and it had the same black canister, although i think there is a different angle. I need to go to a yard and measure the correct placement for it. Also is there any issues with me being a sedan? I haven't thought of any but if anyone knows of something let me know please! And one last thing, I need to find a proper place for my inline fuel pump because its mounted in the way on the passenger side rail. the location is where Hahn Racecraft calls for it.
Re: 2003-2005 IRS swap
Tuesday, March 18, 2014 9:59 PM
You can simply move both of those to wherever they fit. No need to measure where the canister is on an Alero or worry about what Hahn says.



Re: 2003-2005 IRS swap
Tuesday, March 18, 2014 10:28 PM
Ok tha'ts good to hear. I'm also wondering if people use this swap mainly for performance? I realize the benefits but wonder if the four bolts to mount the subframe are enough support for track driving.
Re: 2003-2005 IRS swap
Wednesday, March 19, 2014 8:50 PM
IRS beats out a trailing beam for handling pretty much any day of the week.

I've never compared the two unibodies side by side but I would assume the Alero is molded differently in order to deal with the stresses of an IRS whereas the J is molded to use a trailing beam. That said, I don't think there is a huge issue using an IRS on a car designed for a trailing beam. I'm sure the unibody can handle it.



Re: 2003-2005 IRS swap
Wednesday, March 19, 2014 10:39 PM
Few people on here used them as strictly track cars. The only reason I did not do this swap and I had everything available to do it was because I didn't want to buy another set struts and they do not make eibach sport lines for the alero or grand am.




On the inside my car looks like a fighter jet.
Re: 2003-2005 IRS swap
Wednesday, March 19, 2014 11:56 PM
So in all it still seems the right choice for the next suspension upgrade as well as the front spindles to match bolt pattern. And Rob I have been having trouble finding any kind of Coilover setup for the Alero IRS. Although I see that KW might custom make it but I haven't looked into that enough to know. Hopefully. I did see an air over strut set-up but I don't think air is a good choice for this project. I've read that in the past people used ground dynamic coilovers for the rear.
Re: 2003-2005 IRS swap
Thursday, March 20, 2014 5:10 PM
Jason Thompson (forget his screen name on here) irs swapped his sedan. We had been discussing coilover options and he tried a set of Subaru coilovers and found they bolt to the rear knuckles for the nbody irs. He had custom top hats made for his setup and they worked.

You may also be able to use jbody front Koni yellow inserts on the grand am struts and run ground controls or other sleeve coilover option. Youd have to take measurements though as I'm not sure that's been done...



Re: 2003-2005 IRS swap
Thursday, March 20, 2014 6:32 PM
So the subaru's strut worked perfectly with the knuckle? Impreza? Did Jason use a camber option with his top hats?

Re: 2003-2005 IRS swap
Thursday, March 20, 2014 7:44 PM
strat81 wrote:

Jason Thompson (forget his screen name on here) irs swapped his sedan. We had been discussing coilover options and he tried a set of Subaru coilovers and found they bolt to the rear knuckles for the nbody irs. He had custom top hats made for his setup and they worked.

You may also be able to use jbody front Koni yellow inserts on the grand am struts and run ground controls or other sleeve coilover option. Youd have to take measurements though as I'm not sure that's been done...


His user name was MRThompson. Here is the link to the page where he was working on coilovers. That's as far as he got on them, I have them now but haven't made much progress.

They are godspeed coilovers for the Impreza, they are really close to fitting, but they need new top hats and the sleeves need to be modified.



Re: 2003-2005 IRS swap
Thursday, March 20, 2014 9:48 PM
What about air? Could you make a performance oriented air strut?
Re: 2003-2005 IRS swap
Friday, March 21, 2014 10:35 AM
Not really. And not recommended for performance.



Re: 2003-2005 IRS swap
Friday, March 21, 2014 11:55 AM
Your best bet would be to check in at one of the N-body forums and see wha those guys are doing for air and coilovers. You may not be able to find as many kits out there as the J-body, but I'm sure they've found stuff that works well for them. It's already been found out that there are strut inserts that Koni makes which will work on the N-body rear.





Re: 2003-2005 IRS swap
Friday, March 21, 2014 4:10 PM
Nic Crosby wrote:

strat81 wrote:

Jason Thompson (forget his screen name on here) irs swapped his sedan. We had been discussing coilover options and he tried a set of Subaru coilovers and found they bolt to the rear knuckles for the nbody irs. He had custom top hats made for his setup and they worked.

You may also be able to use jbody front Koni yellow inserts on the grand am struts and run ground controls or other sleeve coilover option. Youd have to take measurements though as I'm not sure that's been done...


His user name was MRThompson. Here is the link to the page where he was working on coilovers. That's as far as he got on them, I have them now but haven't made much progress.

They are godspeed coilovers for the Impreza, they are really close to fitting, but they need new top hats and the sleeves need to be modified.


I thought he had new top hats for them and had them mounted on the car. Realistically you could probably redrill the strut tower to accept the Subaru mounts (assuming they fit dimensionally)

I'm planning on a Subaru retrofit when I go irs as they have a ton of options ranging from junk to full out race setups... Just depends on how deep your pockets are.



Re: 2003-2005 IRS swap
Friday, March 21, 2014 6:32 PM
strat81 wrote:



I thought he had new top hats for them and had them mounted on the car. Realistically you could probably redrill the strut tower to accept the Subaru mounts (assuming they fit dimensionally)

I'm planning on a Subaru retrofit when I go irs as they have a ton of options ranging from junk to full out race setups... Just depends on how deep your pockets are.


He did make new top hats for them, but top hats aren't really an issue, OEM's could probably even be adapted to work. The issue is more that the Suby knuckles don't have as wide of a mounting point as the N-body knuckles (front and rear), but once you remake the sleeves to work, you're options really open up as far as coilovers.

I bought Jason's stuff to fit it into my Sunfire, but if I can make it work reasonably enough, I will be doing it to the cavalier as well. The IRS and aluminum front suspension parts are worth it even without coilovers though, even on stock N-body suspension, my Sunfire rides, handles and stops better than the Cavalier with Sportlines and D-specs.



Re: 2003-2005 IRS swap
Friday, March 21, 2014 8:39 PM
i didn't realize the rear knuckles were too wide as well. I remember he had posted about the fronts being wider and also the bolt holes being off slightly.



Re: 2003-2005 IRS swap
Friday, March 21, 2014 9:07 PM
What if you grind down the knuckle an 1/8in or so to clear?
Re: 2003-2005 IRS swap
Friday, March 21, 2014 10:06 PM
It's possible, but I myself would rather make up new sleeves to fit the knuckles, but I'm not bad at fabricating myself and know an awesome welder that would weld them up for me for very little.

Jason only got the one rear made up, he didn't get very far on the fronts.



Re: 2003-2005 IRS swap
Friday, March 21, 2014 11:00 PM
So this might sound dumb but, when you refer to sleeve, your meaning the bottom of the coilover can screw on and off? I've been looking into it a little more and want to find something before I jump into it.

Re: 2003-2005 IRS swap
Saturday, March 22, 2014 9:47 AM
Connor Sobotka wrote:

What if you grind down the knuckle an 1/8in or so to clear?


You'd be better off having it machined down.

quote=Connor Sobotka]So this might sound dumb but, when you refer to sleeve, your meaning the bottom of the coilover can screw on and off? I've been looking into it a little more and want to find something before I jump into it.

The sleeve is the threaded tube that goes over the strut body. The part that moves up and down on the sleeve is the perch.

If I was to do this, I would get the strut to fit, then find an upper perch that works, then call Ground Control, tell them my strut body diameter and a rough spring length. With all the data they have, they can recommend a good rate for that length and piece together a kit for you that will bolt right on. And they'll do it for the same price as an off the shelf kit. They'll probably even put together a full kit (front and rear) for the price of an off the shelf kit.



Re: 2003-2005 IRS swap
Sunday, March 23, 2014 12:49 AM
So in that case would it not be possible to use a strut already designed for the IRS and use the sleeve coilover design. Or would I have to use a specific strut design? Also, I haven't looked into solid mounts in possibly being produced for a spring strut design.
Re: 2003-2005 IRS swap
Monday, March 24, 2014 7:18 AM
You could do it that way but you need to find a strut that will handle higher spring rates. GC would need to know the location of the lower spring perch on the strut and the strut length of travel in order to work out a good spring length. You can get in touch with Koni tech support and tell them the car, they will get you a strut that fits.



Re: 2003-2005 IRS swap
Tuesday, March 25, 2014 5:17 AM
The Koni unit that fits the N-body rear is a cartridge for a Taurus SHO. IIRC, it's an 8641-1287. It will fit into the N-body case just like the fronts do for our cars, Then, as said, contact someone like Ground Control and give them the info. They'll likely want measurements on the car if possible, to give you the best recomendation.





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