Favorite stock IRS setups...| Grassroots Motorsports forum |

4cylndrfury UltimaDork
2/13/13 12:18 p.m.

What are your favorite IRS setups?

go!

mistanfo SuperDork
2/13/13 12:24 p.m.

Miata. Easily obtained, the ehole subframe unbolts with no more than 6 bolts (might even be 4).

GameboyRMH GRM+ Memberand UltimaDork
2/13/13 12:25 p.m.

Beaten...if I were to transplant something, it would be from a Miata.

Ranger50 UberDork
2/13/13 12:28 p.m.

None.

<--old stick (axle) in the mud.

93EXCivic MegaDork
2/13/13 12:33 p.m.

Jag for a swap.

RossD UberDork
2/13/13 12:38 p.m.

8.8" Ford, for the amount produce in multiple platforms => cheap.

wvumtnbkr GRM+ Memberand HalfDork
2/13/13 1:14 p.m.

2nd gen RX7.

Not really, I just thought I would throw it out there. They are not that cheap, not easy to work on, not that strong, and have horrible geometry issues that need to be corrected (with solid bushings in some places).

Just No.

Gasoline Dork
2/13/13 1:17 p.m.

Second the 8.8" Ford.

yamaha SuperDork
2/13/13 1:23 p.m.

8.8" from the t-bird/cougar/svt cobra, and the e30 325is setup

stan_d Dork
2/13/13 1:42 p.m.

Nissan 240sx

fidelity101 HalfDork
2/13/13 1:46 p.m.

In reply to wvumtnbkr:

the geometry is great for offroad, when you remove the sway bar... and correct that rear toe steer in the knuckles with a solid bushing, the rear toe is the only adjustable thing back there but then again its not stock anymore...

edit: TL:dr Even I cannot defend it in stock form!

mad_machine GRM+ Memberand MegaDork
2/13/13 2:04 p.m.

I must be the only person who likes the old "semi trailing arm" sets up Porsche and BMW were fond of using. Simple, robust, and likely to kill you if you lifted or touched the brakes mid-corner

yamaha SuperDork
2/13/13 2:22 p.m.

In reply to mad_machine:

I personally somewhat like them

ReverendDexter UberDork
2/13/13 2:44 p.m.

yamaha wrote: 8.8" from the t-bird/cougar/svt cobra, and the e30 325is setup

I thought the Thundercougarfalconbird IRS was only a 7.5". (The Mustang unit is definitely an 8.8").

Gasoline Dork
2/13/13 3:01 p.m.

In reply to ReverendDexter:

http://grassrootsmotorsports.com/forum/grm/88-irs-donors/40447/page1/

Knurled GRM+ Memberand UltraDork
2/13/13 6:58 p.m.

4cylndrfury wrote: What are your favorite IRS setups? go!

Anything not on my car!

Knurled GRM+ Memberand UltraDork
2/13/13 7:01 p.m.

ReverendDexter wrote:
yamaha wrote: 8.8" from the t-bird/cougar/svt cobra, and the e30 325is setup
I thought the Thundercougarfalconbird IRS was only a 7.5". (The Mustang unit is definitely an 8.8").

Some V8s and most/all Mark VIIIs were the 8.8. The Cobra's version of the IRS sucked (well, so did the T-bird, but it wasn't a performance car) but it does yield an aluminum housing diff chunk.

Note that GM opted to use an iron rear in the ATS because the aluminum ones would deflect too much, necessitating compromises that made fuel economy worse, not better, despite the reduced weight.

amg_rx7 Dork
2/13/13 10:59 p.m.

Miata FD RX7 RX8

Gasoline Dork
2/14/13 8:56 a.m.

I found a picture of (my useless collection) Explorer IRS chunks for comparison. Still aluminum as the Cobra/Mark VIII, but more strengthening ribs and heavier. Also have a sturdier mounting diff cover.

fidelity101 HalfDork
2/14/13 9:04 a.m.

I don't think I like any stock IRS system come to think of it...

DaveEstey SuperDork
2/14/13 9:44 a.m.

Miata. Hard to go wrong with double wishbones.

ReverendDexter UberDork
2/14/13 9:51 a.m.

Knurled wrote: The Cobra's version of the IRS sucked

What makes you say that? My understanding is that the only part that sucks is that SVT spec'd solid or poly bushings to mount the IRS subframe, and Ford brass insisted on rubber for NVH or financial reasons. The rubber mount lets it squirm, which does bad things.

Or is it because it was compromised to use the existing mounting points for the 4-link?

Cuda Reader
2/14/13 11:37 a.m.

ReverendDexter wrote:
Knurled wrote: The Cobra's version of the IRS sucked
What makes you say that? My understanding is that the only part that sucks is that SVT spec'd solid or poly bushings to mount the IRS subframe, and Ford brass insisted on rubber for NVH or financial reasons. The rubber mount lets it squirm, which does bad things. Or is it because it was compromised to use the existing mounting points for the 4-link?

The cobra IRS was not perfect by a wide margin, but it was pretty good and with a few upgrades could be spectacular. The IRS cobras are still one of the most fun Mustangs to drive.

mad_machine GRM+ Memberand MegaDork
2/14/13 12:17 p.m.

ReverendDexter wrote:
Knurled wrote: The Cobra's version of the IRS sucked
What makes you say that? My understanding is that the only part that sucks is that SVT spec'd solid or poly bushings to mount the IRS subframe, and Ford brass insisted on rubber for NVH or financial reasons. The rubber mount lets it squirm, which does bad things. Or is it because it was compromised to use the existing mounting points for the 4-link?

From what I have been led to believe.. it only sucked for burnouts and drag style launches