Was the AU IRS a bad setup?

jspec_sti · 08-12-2005, 04:25 PM

Recently got into a conversation with some BA owners and they took great time and effort in telling me the superioty of their BA suspension setup - "Control Blade IRS".

From memory, I believe the AU's had a double wishbone IRS setup, which imposed a weight penalty on the car but gives a hell of a lot of grip (based on my experience owning one). Was this such a bad setup compared to the BA Control Blade IRS?

BJMXR · 08-12-2005, 04:37 PM

My friend works for Drive in the Age and has talked of the AU having ALOT of rear grip. Its a great IRS system, however he claimed the BA's IRS is better as its lighter and has less unsprung weight, and still maintains great rear end grip. He also mentioned that the AU and the BA Rear setup s all over what Holden still uses.

When they tested the AU they actually broke a few driveshafts because of the massive rear grip it has... the same with the BA apparently. Moreso the breaks were from attempting a full grip drag start from say 3000 rpm getting an optimum launch as opposed to dropping it at 5000 and spinning the rears.

So perhaps the BA is better, but hey... i got NO concerns with my AUII!

geckoGT · 08-12-2005, 04:46 PM

At least neither chew out tyres like the setup from that other manufacturer. They are both good and the last AU I drove (AUII Fairmont Ghia VCT) was an absolute pleasure. In fact it was smoother than my XR8 but then again the XR corners better (different types of car, haven't driven a AU XR).

BJMXR · 08-12-2005, 04:58 PM

Thats interesting you should mention that as ive heard the new BA on the 18in Factory wheels chews out tyres in as little as 20,000 km. Perhaps a result of rear grip levels from the BA IRS? Anyone had this problem with their 18's.

geckoGT · 08-12-2005, 05:00 PM

the 18's have a very soft compound and yes I only got about that out of mine (they are a performance tyre, not high mileage). The difference is it was even wear and not the inside edge like that other manufacturer.

clontarf_x · 08-12-2005, 05:19 PM

I would say the AU IRS is definately a golden egg in terms of AU design.

Rear grip in my AU3 XR6 ST is excellent, with the 18" rohs on the back

I can give it hell around corners and it doesnt even think about losing traction until I give it a little tap on the go fast pedal

Nothing quite like not slowing down for 90 degree corners

AnthonyQLD · 08-12-2005, 05:32 PM

This Is a little off topic but would a AUI XR6 have LSD? and if im not mistaken the IRS only came out on the II and III series..... Is that correct?

LUXO_8 · 08-12-2005, 05:34 PM

the AU setup is great. its also able to be retrofitted into XE-EL as well...which would make a great conversion...

stiddy · 08-12-2005, 05:50 PM

Quote:

Originally Posted by AnthonyQLD

This Is a little off topic but would a AUI XR6 have LSD? and if im not mistaken the IRS only came out on the II and III series..... Is that correct?

the AU XR6 series 1's have LSD, well mine does.. but no IRS..
i think some of the lateish AU1's came out with IRS
same with the VCT engine, some late series 1's had VCT's

the IRS is awsome, only downfall is that its a little heavy compared to solid beam..

galaxy xr8 · 08-12-2005, 06:02 PM

The AU rear end(IRS) is a fantastic set up, but ofcourse with evoulution, the BA/F would be a better design.

AnthonyQLD · 08-12-2005, 06:03 PM

Quote:

Originally Posted by stiddy

the AU XR6 series 1's have LSD, well mine does.. but no IRS..
i think some of the lateish AU1's came out with IRS
same with the VCT engine, some late series 1's had VCT's

the IRS is awsome, only downfall is that its a little heavy compared to solid beam..

That what i thought, thanks Stiddy.

Tickford Kid · 08-12-2005, 06:06 PM

AU IRS has issues with upper shock mounts braking regulary.

SVR73 · 08-12-2005, 10:04 PM

My aug 98 XR6 vct has tickford tuned IRS & Tickford LSD. Big mother of an LSD and the grip level is unreal. The bi plane spoiler creates good downforce

AU1 XR6 hp did not come from factory with IRS or LSD, was watts link
IRS /LSD was a $1,000 dollar option

buickman · 08-12-2005, 10:39 PM

[QUOTE=TS 50]AU IRS has issues with upper shock mounts braking regulary.[/QUOTE

Its the rubber mount that can cause problems. But is a easy fix.
The AU IRS is a well engineered set up. It looks very simular to the 929 Mazda's of 1982- 87 a excellent handeling car but underpowered by the MA ohc 2ltr mtr.
Nearly every write up gives the AU IRS the thumbs up & a much superior set up than the GMH one

AnthonyQLD · 08-12-2005, 10:43 PM

Quote:

Originally Posted by SVR73

My aug 98 XR6 vct has tickford tuned IRS & Tickford LSD. Big mother of an LSD and the grip level is unreal. The bi plane spoiler creates good downforce

AU1 XR6 hp did not come from factory with IRS or LSD, was watts link
IRS /LSD was a $1,000 dollar option

How can you tell if it has LSD? (not my car)

12 · 08-12-2005, 11:13 PM

Quote:

Originally Posted by BJMXR

BA's IRS is better as its lighter and has less unsprung weight

I thought Control Blade as fitted to BA was actually heavier than AU IRS??

I've driven a few BA's with IRS and AU's with IRS, and my preference was the AU IRS... but not by much. The AU IRS seemed to handle the tight turn in and out of corners better than BA IRS, which seemed a little bit quick to throw the tail out.

**FTE217** · 08-12-2005, 11:16 PM

[QUOTE=buickman]

Quote:

Originally Posted by TS 50

AU IRS has issues with upper shock mounts braking regulary.[/QUOTE

Its the rubber mount that can cause problems. But is a easy fix.
The AU IRS is a well engineered set up. It looks very simular to the 929 Mazda's of 1982- 87 a excellent handeling car but underpowered by the MA ohc 2ltr mtr.
Nearly every write up gives the AU IRS the thumbs up & a much superior set up than the GMH one

AUIRS is great but I'm ****ed for the 3rd time the rubber mounts again are gone !
Whats the easy fix you mention ? That it's easy to do the job which yes it is.
Do you know of a better version than the genuine mount ?

dxr88u · 08-12-2005, 11:41 PM

Quote:

Originally Posted by stiddy

the AU XR6 series 1's have LSD, well mine does.. but no IRS..
i think some of the lateish AU1's came out with IRS
same with the VCT engine, some late series 1's had VCT's

i could be wrong but i am certain all au xr8's,xr6 VCT and fairmont ghia's had IRS and LSD as standard and was optional on all other sedans.

as far as the 6 cylinder VCT engine goes it was available from the early stages of the au release and was also standard fitment to the fairmont ghia's. i hope i have not lead anybody up the garden path with what i have said.

:

geckoGT · 08-12-2005, 11:45 PM

Quote:

Originally Posted by 012

better than BA IRS, which seemed a little bit quick to throw the tail out.

Nah mate, that is just the grunt under the bonnet wanting to do that!

:

08-12-2005, 11:56 PM

Quote:

Originally Posted by dxr88u

i could be wrong but i am certain all au xr8's,xr6 VCT and fairmont ghia's had IRS and LSD as standard and was optional on all other sedans.

Standard fitment never saw IRS and LSD at the same time from all the checking I have done. Could option this combo from series 2 I understand. Ford decided the IRS and traction control substituted well enough and LSD was taken out of the equation.

dxr88u · 09-12-2005, 12:03 AM

Quote:

Originally Posted by AUGhiaV8

Standard fitment never saw IRS and LSD at the same time from all the checking I have done. Could option this combo from series 2 I understand. Ford decided the IRS and traction control substituted well enough and LSD was taken out of the equation.

sorry, like i said if i got my facts mixed up, but my au xr8 series 1 has IRS, LSD and i have no traction control, was not even offered as an option so i am lost.maybe the combo your talking about was offered that way in the ghia, not sure will wait to be corrected by somebody in the know.

:

12 · 09-12-2005, 12:06 AM

Quote:

Originally Posted by geckoxr8

Nah mate, that is just the grunt under the bonnet wanting to do that!

:

LOL...

Comparing AU3 XR6 to BA1 XR6.. and both cars would be pretty much equal in power to weight ratio, AU lighter with slightly less power, BA heavier and slightly more power. I even liked the drive/handling of the AU V8 a little bit more than the BA1 V8 (XR8). Just my preference.

buickman · 09-12-2005, 10:15 AM

Quote:

Originally Posted by Bluedriver

AUIRS is great but I'm ****ed for the 3rd time the rubber mounts again are gone !
Whats the easy fix you mention ? That it's easy to do the job which yes it is.
Do you know of a better version than the genuine mount ?

Third time? I've still the original mounts but have remove them once to check when I lowered the car. I would be ****ed to for the third time

Try Kelray on 1800 245 748 for tech support or kelray@kelray.com.au as they are the manufacturers of nolathane products which might have a product that would last longer in your car.

09-12-2005, 01:29 PM

Quote:

Originally Posted by AUGhiaV8

Standard fitment never saw IRS and LSD at the same time from all the checking I have done. Could option this combo from series 2 I understand. Ford decided the IRS and traction control substituted well enough and LSD was taken out of the equation.

STD fitment on a AU I XR6 VCT is IRS and LSD 100% guaranteed ,I owned one for 2 years or more then got the XR8

Grip levels on the AU1 was fabulous compared to non IRS EF i had I use to hit a corner hard and wait for the slid , but it never moved .

LSD Had a dark red filler plug from memory
STD diff had black

Suspension/rear description Independent, double wishbone, lower transverse links, coil springs and anti-roll bar.

09-12-2005, 08:55 PM

Sorry guys, I was referring to the Ghias only ... left a key word out!

Casper · 09-12-2005, 08:58 PM

ok, lets set the facts straight as far as LSD/IRS on the XR6's
There are 2 XR6s as we all know, the HP and the VCT. Both were avaliable from the very first AU (appox sept 98). In tha AU 1 BOTH came standard with LSD.. it was not an option. It was a standard feature..3.45 LSD. In addition the XR6 VCT (sedan) came STANDARD with IRS AND 3.45 LSD (mine has it and is a Nov 98 car that hade NO options fitted).
The XR6 VCT continued with IRS AND 3.45 LSD for the entire model life (AUI, II, III) whereas the XR6 HP lost the LSD as standard part way through the AUII model and it became an optional extra.

As for the IRS.. it is amazing to say the least. I would say its only shortfall over the BA IRS is weight (so yes, the BA IRS would be "better")... but given the "plumper" bodyweight of all the BA/BF's, any benifit it may have gained was lost by the weight of the car. Now an AU with the BA IRS... that would be DAMN impressive!

Casper · 09-12-2005, 09:02 PM

Also, for the curious, this is a good image of the AU IRS that lets you see how it hangs together:

LUXO_8 · 09-12-2005, 09:03 PM

Quote:

Originally Posted by Casper

. Now an AU with the BA IRS... that would be DAMN impressive!

even still, just what is the weight difference between the 2 IRS setups....

would it really make all that much difference? would it be noticeable by the average owner / enthusiest or would it really be one of those minor differences only really felt on a track??

either way it'd shoite all over a live axle lol...

Casper · 09-12-2005, 09:08 PM

Quote:

Originally Posted by MADNC_8

even still, just what is the weight difference between the 2 IRS setups....

would it really make all that much difference? would it be noticeable by the average owner / enthusiest or would it really be one of those minor differences only really felt on a track??

wouldnt be that much.. Maybe 20kg or so. Certainly nothing you would even notice until on the track as you said.
As for grip.. I've driven both.. you cant tell the difference, both are impressive although the BA is noticably smoother but that could be springs/shocks makeing the difference.

HP Dude · 09-12-2005, 11:09 PM

Quote:

Originally Posted by SVR73

AU1 XR6 hp did not come from factory with IRS or LSD, was watts link
IRS /LSD was a $1,000 dollar option

Incorrect. AU1 XR6HPs came with LSD standard. Series 2 and 3 did not; it was an option.

IRS was never an option on the XR6HP: if you wanted IRS on an XR6, you had to buy the VCT.