Modified IRS K-frame for Lowered Cars

[sands vsParticipant vs commodore View build HERE Member since: March 1, 2015 Posts: 619]

vnssnv wrote:

If your handy with the tig. Have you thought about removing the irs completely and fitting a solid vn diff? All problems solved then.

Youd have to change the whole rear floor pan which is a structural part of the car.

[BradParticipant 2002 VU SS View build HERE Member since: November 9, 2015 Posts: 14]

I have modified the camber mounting point, made boxed section and cut the roof out of the standard mount.

Made boxed section with extra hole 20mm higher, I get basically zero camber at a height of 625mm (measuring floor to lip).

Also it’s a good idea to have subframe bushes that are either solid or hard urethane as the top of the box will sit very close to the body.

I also modified the control arm with 4130 chromoly tube arm on the toe section and used a heim joint. Also made coilover bracket for double adjustable Viking/qa1/strange coilovers.

 

[benkParticipant Sydney View build HERE Member since: August 23, 2015 Posts: 85]

Brad wrote:

I have modified the camber mounting point, made boxed section and cut the roof out of the standard mount. Made boxed section with extra hole 20mm higher, I get basically zero camber at a height of 625mm (measuring floor to lip). Also it’s a good idea to have subframe bushes that are either solid or hard urethane as the top of the box will sit very close to the body. I also modified the control arm with 4130 chromoly tube arm on the toe section and used a heim joint. Also made coilover bracket for double adjustable Viking/qa1/strange coilovers.

 

Very interesting setup! do you have any pics?

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

^+1 for pics…

[dazedv3Participant VIC92 VP Calais View build HERE Member since: March 8, 2015 Posts: 31]

+2 for pics

[ImmortalityParticipant 97 HSV Senator 185i 02 VX L67 Calais View build HERE Member since: August 31, 2015 Posts: 535]

Definitely require pics

How do you intend to reinforce the original shock mount to take the full weight with the coil-overs fitted?

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

I guess you could do some JDM reinforcing cross bracey thing between the towers?

 

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Thinking about it i guess like IJs Lexcen?

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

VRSenator065 wrote:

Thinking about it i guess like IJs Lexcen?

Think it’s more the lower mounts that are in question Gary, I’d given it some thought when I did the IRS conversion in the Tonner but the factory mount is single sided and not really designed to take a spring load..

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

I must admit I havent really understood the benefit of going to coil overs on the rear given the work involved.  Its the fundamental geometry of the set up thats up the shit really to be brutally honest.

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

VRSenator065 wrote:

I must admit I havent really understood the benefit of going to coil overs on the rear given the work involved. Its the fundamental geometry of the set up thats up the shit really to be brutally honest.

Yep Swing Axles are NOT the way to go….

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Especially “semi” trailing ones.  I mean rule number 1 of suspension design surely has to be to minimise caster and camber change through travel. And the geniuses at Holden managed to design in both!

[[TUFFVQ]Participant Melbourne1991 VQ 304 View build HERE Member since: March 2, 2015 Posts: 171]

Sorry for the delayed response, but yes Gary that link you posted from Geforce is exactly what I meant.

I’m glad others have done it and as such it gives me the confidence to hack into it and give it a whirl. Thanks very much for following it up.

I have nolathane cradle bushes already so that’s no problem. Think I’ll finally fit a nolathane diff bush as well.

[dazedv3Participant VIC92 VP Calais View build HERE Member since: March 8, 2015 Posts: 31]

Would you be so kind as to update us on your progress as I myself am quite interested in this type of thing also with my VP Calais.

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

[TUFFVQ] wrote:

Think I’ll finally fit a nolathane diff bush as well.

Maybe consider the Harrop diff cover, little more diff oil volume and better mount?

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

This just popped up on the G Force FB page

 

[cava454Moderator 93 VR BT1 View build HERE Member since: February 20, 2015 Posts: 2 390]

Link?

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

https://www.facebook.com/photo.php?fbid=919146178166021&set=a.106014002812580.13767.100002119414202&type=3&theater

[dazedv3Participant VIC92 VP Calais View build HERE Member since: March 8, 2015 Posts: 31]

So do those control arms actually change the suspension or camber or simply allow more room for a wider tyre?

[JabaParticipant Perth, WAVZ Senator View build HERE Member since: February 18, 2015 Posts: 103]

The Gforce items are designed for more tyre clearance, the suspension geometry remains the same, and the camber would also remain the same. If you were to fit those, you’d also need to weld in the brackets that change the mounting position of the arms to the subframe that Gary has linked above.

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