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I supported Toymods
Banned User
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Brisbane
Registered:
May 2002
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IRS Conversions
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Sun, 26 June 2005 09:17
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Theres been a lot of talk lately about IRS conversions. So I want to know peoples thoughts on why these are an advantage in the three main forms of motorsport spoken about on these forums. Drift, drag and circuit.
I also want to know which IRS setup is preferred in the above forms of motorsport. The conventional IRS or the newer control-blade type setup as found in Jags and the new Coons.
Has anyone got the link to the Jap IRS kit that was available a while ago?
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: IRS Conversions
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Sun, 26 June 2005 09:25
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IRS is superior when you have bumps, as one side doesn't affect the other side so much, and has less unsprung weight.
also you can set up camber/castor on the rear wheels better than a live axle.
then again, a de-dion(sp?) rear can also be set up with angles, and has in-between unsprung mass.
for drag, maybe live axle is better as there is less suspension angle change with the forces involved.. for circuit.... maybe IRS is better IF you can set up the camber-curve to suit the car..
for drift... who cares, they are not gripping with the rear anyway  it's all about making the rear slip....
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I supported Toymods
Banned User
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Re: IRS Conversions
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Sun, 26 June 2005 09:32
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| oldcorollas wrote on Sun, 26 June 2005 19:25 |
for drag, maybe live axle is better as there is less suspension angle change with the forces involved..
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What do you mean less angle change? Do you mean the camber of the wheels not changing with the live angle?
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for drift... who cares, they are not gripping with the rear anyway it's all about making the rear slip....
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One of the main reasons I started this thread 
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Location:
New Zealand
Registered:
May 2002
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Re: IRS Conversions
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Sun, 26 June 2005 10:44
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For drift you NEED grip or no smoke, simple as that.
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I supported Toymods
Banned User
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Location:
Adelaide
Registered:
September 2003
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Re: IRS Conversions
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Sun, 26 June 2005 23:28
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It looks nice, but don't like some of the construction in the arms. The joints aren't the best design.
I also wonder why a well setup 'proper IRS' (as opposed to the MA61/Crumpledore type) is not better for drags when compared to a live axle ?
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I supported Toymods
Banned User
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May 2002
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Re: IRS Conversions
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Mon, 27 June 2005 00:11
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| bbaacchhyy wrote on Mon, 27 June 2005 09:28 |
I also wonder why a well setup 'proper IRS' (as opposed to the MA61/Crumpledore type) is not better for drags when compared to a live axle ?
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Exactly. I would think that good IRS setup would achieve the same as a live axle in the drag situations. I can understand other IRS setups under performing due to the camber of the wheels changing.
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Location:
New Zealand
Registered:
May 2002
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Re: IRS Conversions
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Mon, 27 June 2005 00:23
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It is very hard to eliminate all camber change in an IRS setup, and even minor changes gets magnified when you are running serious sized wheels. Basically live axle has a lot more consistency, more practical knowledge on getting it to work is around is easier to setup.
Callum
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I supported Toymods
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Re: IRS Conversions
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Mon, 27 June 2005 00:28
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| Purple_Beasty wrote on Mon, 27 June 2005 10:23 |
It is very hard to eliminate all camber change in an IRS setup, and even minor changes gets magnified when you are running serious sized wheels.
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Agreed, the exact reason I have been talking about the two different IRS setups. The Jag setup that is being used in the newer Fords is spot on.
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I supported Toymods
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I renounced punctuation
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Re: IRS Conversions
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Mon, 27 June 2005 02:35
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It's all about the camber change as the wheel goes thru its travel. Setting up a double wishbone IRS takes time - there are quite a few 8-9 second IRS JZA80s in the USA. That said, there are plenty of very quick Datsun 1600s/240Z out there - I suppose after 30 years of development, it's possible to set up even a trailing arm IRS to be great.
I suspect that the theoretical/academic limitations of each setup only come into play in the upper echelons of motorsport. I remember reading that F1 cars have a total of 12-13mm suspension travel - hard to belive that such limited suspension travel could have a profound effect on a car's corner speed (given that there are so many other factors at play)!
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I supported Toymods
Banned User
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May 2002
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Re: IRS Conversions
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Mon, 27 June 2005 02:41
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Some good points. Do the JZA80s have a double wishbone setup?
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I supported Toymods
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Perth
Registered:
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Re: IRS Conversions
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Mon, 27 June 2005 02:53
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| Cool1 wrote on Mon, 27 June 2005 10:41 |
Some good points. Do the JZA80s have a double wishbone setup?
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Yep.
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Location:
Brisbane
Registered:
February 2003
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Re: IRS Conversions
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Mon, 27 June 2005 03:04
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are there any decent pics/drawings of the control blade? i find write-ups but cannot visualise the thing.
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Location:
Adelaide
Registered:
September 2003
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Re: IRS Conversions
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Mon, 27 June 2005 03:09
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| thechuckster wrote on Mon, 27 June 2005 12:34 |
are there any decent pics/drawings of the control blade? i find write-ups but cannot visualise the thing.
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It is a messy thing to look at. Not pretty at all. Most of the componentry is pressed steel to reduce the cost.
The new Holden one is pretty schmick as well, but looks equally as ugly. It will be an absolute bastard to chnage a centre !!!
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I supported Toymods
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Perth
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Re: IRS Conversions
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Mon, 27 June 2005 03:15
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Easy, just make sure it's strong enough and works well enough to not warrant replacing As for looking pretty, so long as it works 
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I supported Toymods
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Re: IRS Conversions
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Mon, 27 June 2005 03:22
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So does the double wishbone setup in the JZA80s and the like achieve the same as the control blade setup, or is there still the camber issues?
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Location:
Adelaide
Registered:
September 2003
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Re: IRS Conversions
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Mon, 27 June 2005 03:34
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Don't forget, the setups like Control Blade and the VE Crumpledore setup are tuned for road car use, and as a result still have a fair bit of compliance in them so they are "nice riding".
They are still on the conservative side, but have pretty good control.
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Location:
Brisbane
Registered:
February 2003
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Location:
Adelaide
Registered:
May 2002
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Re: IRS Conversions
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Tue, 28 June 2005 00:00
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looks like a front end to me, but cool idea none the less- looks like a double wish bone with the top wishbone inboard mount half way up the shock tower. (bit hard to see though)
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Location:
Adelaide
Registered:
September 2003
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Re: IRS Conversions
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Tue, 28 June 2005 00:12
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| RobertoX wrote on Tue, 28 June 2005 09:30 |
looks like a front end to me, but cool idea none the less- looks like a double wish bone with the top wishbone inboard mount half way up the shock tower. (bit hard to see though)
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Nothing new there. It is a SALA type setup that Honda have used a lot, and is a modification of the McPherson strut, but combines some of the great advantages of double wishbone setup.
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Location:
Adelaide
Registered:
May 2002
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Re: IRS Conversions
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Tue, 28 June 2005 21:54
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yeah, looks pretty cool 
Any idea how effective it is in practice? Any advantages over double wishbone setup? or is it more of a compromise?
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I supported Toymods
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Re: IRS Conversions
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Tue, 28 June 2005 22:05
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I have a Jag rear end comming very shortly so stay tuned for pictures 
The Jag rear end is looking very promising! Its very simple which requires little space under the car, but its very effective.
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I supported Toymods
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Location:
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I supported Toymods
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