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SVT Shelby GT500
The rear suspension that could have been
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<blockquote data-quote="68fastback" data-source="post: 9243014" data-attributes="member: 44957"><p>Just some comments on some of the IRS pieces I've seen in this thread:</p><p></p><p>The Carling re-developed IRS for S197 is based on the Klaus Arning T5 IRS that was developed by Klaus when he was an engineer working for Ford in the 1960s. It was intended as the IRS for 1964.5 Mustang. It was shelved due to cost and the fact that it didn't materially improve lap times of what would become the GT350 on the tracks they planned to clean Corvette's clock on, so was shelved. On real-life roads, no doubt it would kick a live-axle's butt, but let's not get on IRS vs live axles. Klaus Arning's son, Ralph Arning, is the Ford ombundsman at the Flat Rock plant -- great guy, as many of you probably know. Duane Carling knew Klaus way back when and decided to resurrect the T5 design (MustangIRS.com) It's more sophisticated than it looks -- the retro fit version is quite light, given it's a retrofit and therefore not a hard-point-optimized native design. Additionally, it holds a pantent on it's rear-steer self-correcting geometry which was licensed by Mercedes for many years until computers got sophisticated enough for Daimler to figure out how to do their own self-correcting design without infringing the Arning patent, at which time they stopped licensing it from Klaus (who, as I understand it, retained the patent rights after retiring from Ford).</p><p></p><p>Dunno what the more modern unit Jes_csx posted pics of is from but it's very cool, imho. I do recall that Ford did a full mock-up of an IRS for the S197 based on the Explorer IRS because that was the only one at hand that could take the torque of the GT500, so that just might be it (dunno). That could be the IRS that caused Ford to say things like 'it would add $5-10K to the S197' -- comments that, no doubt, were made because they helped justify not doing an IRS because that decision was already made when they talked to the magazines. No way a native-designed IRS done in volume needs to cost more than a good audio head-unit, let alone a couple of Tata Nanos (lol).</p><p></p><p>The control blade IRS referred to was developed by Dana Australia for the Aussie Falcon. It's actually fairly slick and light for a production IRS that is a non-native design (the car wasn't designed for IRS, like the IRS Cobra mustangs, so it was adapted). Control blade IRSs are a good compromise in that they are relative cost-effective (still considerably more than a live axle tho), relatively light for a stamped unit (tho not as light as a native design or, better still, a native design using lightweight materials).</p><p></p><p>Yes an IRS weighs more (in general, exotic materials aside) than a live axle and costs more (universally). As far as weight goes, realize that an IRS ads very little unsprung weight (and greatly reduces unsprung weight vs a live axle), so almost all the weight it adds (which for a native/dedicated design is not all that much) and 100% of the sprung portion of that weight (most of it) improves the weight distribution of the car. Better still, move the gearbox back there too! On a GT500 that combination might add 130lbs for a good native design (nothing exotic)but most of that will be sprung weight that improves handling and compliance. Including the gearbox move and an alloy block (ala 2011 GT500) and W/D could approach 50/50. By contrast, virtually all the weight of a live axle is unsprung. This is why, I'm sure you all know, live axles just can't handle as well on imperfect real-world roads (in most of the US, but not all) but can kick butt on the relative smoothness of a road course (set up right, etc) ...and, along with cost, is why it was shelved in both 1964 and 2005. </p><p></p><p>As far as cost goes an IRS will always cost more, but that difference can come down rapidly with volume. Could the 2013 Mustang be an all-IRS build for that reason? Will the Mustang models 'split' for 2013 with a native-designed IRS determining the chassis hard-points such that a live axle can be easily swapped in via an FRPP kit? That could be a best-of-both worlds strategy that would drive the volumes needed to drive IRS cost down and still give the drag racer the preferred live axle. Better still, push IRS across the all new global RWD platform Ford has been developing and the volumes will really drive cost down and possibly permit lightened pieces to boot. Does anyone think Ford would be developing a Global RWD chassis with at least a 12 year life (thru 2025 or so) and not have it be a native IRS? I personally doubt it can be anything but IRS, but we shall see both what it is and what models share it in due time. I'd expect the 2013 Mustang to be one of them along with a RWD sport-wagon of some sort -- a segment Ford has no presence in but DCX, GM and others do, tho at various price points.</p><p></p><p>I kinda like the best-of-both-worlds scenario best as long as the hard-points are determined by the IRS, not as the later Cobras were done. The Cobra IRS worked well enough (handling-wise) but added more weight and was weaker than a native design could have been. Still it was an early attempt of one chassis sharing both suspension types, but the hard points were, unfortunately, driven by the existing live axle design. No way Ford wil make that mistake again, imho, in a world-class global RWD platform to underpin several derivative models, etc.</p><p></p><p>Peace, brethren.</p><p></p><p>Dana Aussie Falcon contro-blade IRS...</p><p></p><p><img src="http://www.trueblueford.com/images/BA_IRS2_lrg45.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="68fastback, post: 9243014, member: 44957"] Just some comments on some of the IRS pieces I've seen in this thread: The Carling re-developed IRS for S197 is based on the Klaus Arning T5 IRS that was developed by Klaus when he was an engineer working for Ford in the 1960s. It was intended as the IRS for 1964.5 Mustang. It was shelved due to cost and the fact that it didn't materially improve lap times of what would become the GT350 on the tracks they planned to clean Corvette's clock on, so was shelved. On real-life roads, no doubt it would kick a live-axle's butt, but let's not get on IRS vs live axles. Klaus Arning's son, Ralph Arning, is the Ford ombundsman at the Flat Rock plant -- great guy, as many of you probably know. Duane Carling knew Klaus way back when and decided to resurrect the T5 design (MustangIRS.com) It's more sophisticated than it looks -- the retro fit version is quite light, given it's a retrofit and therefore not a hard-point-optimized native design. Additionally, it holds a pantent on it's rear-steer self-correcting geometry which was licensed by Mercedes for many years until computers got sophisticated enough for Daimler to figure out how to do their own self-correcting design without infringing the Arning patent, at which time they stopped licensing it from Klaus (who, as I understand it, retained the patent rights after retiring from Ford). Dunno what the more modern unit Jes_csx posted pics of is from but it's very cool, imho. I do recall that Ford did a full mock-up of an IRS for the S197 based on the Explorer IRS because that was the only one at hand that could take the torque of the GT500, so that just might be it (dunno). That could be the IRS that caused Ford to say things like 'it would add $5-10K to the S197' -- comments that, no doubt, were made because they helped justify not doing an IRS because that decision was already made when they talked to the magazines. No way a native-designed IRS done in volume needs to cost more than a good audio head-unit, let alone a couple of Tata Nanos (lol). The control blade IRS referred to was developed by Dana Australia for the Aussie Falcon. It's actually fairly slick and light for a production IRS that is a non-native design (the car wasn't designed for IRS, like the IRS Cobra mustangs, so it was adapted). Control blade IRSs are a good compromise in that they are relative cost-effective (still considerably more than a live axle tho), relatively light for a stamped unit (tho not as light as a native design or, better still, a native design using lightweight materials). Yes an IRS weighs more (in general, exotic materials aside) than a live axle and costs more (universally). As far as weight goes, realize that an IRS ads very little unsprung weight (and greatly reduces unsprung weight vs a live axle), so almost all the weight it adds (which for a native/dedicated design is not all that much) and 100% of the sprung portion of that weight (most of it) improves the weight distribution of the car. Better still, move the gearbox back there too! On a GT500 that combination might add 130lbs for a good native design (nothing exotic)but most of that will be sprung weight that improves handling and compliance. Including the gearbox move and an alloy block (ala 2011 GT500) and W/D could approach 50/50. By contrast, virtually all the weight of a live axle is unsprung. This is why, I'm sure you all know, live axles just can't handle as well on imperfect real-world roads (in most of the US, but not all) but can kick butt on the relative smoothness of a road course (set up right, etc) ...and, along with cost, is why it was shelved in both 1964 and 2005. As far as cost goes an IRS will always cost more, but that difference can come down rapidly with volume. Could the 2013 Mustang be an all-IRS build for that reason? Will the Mustang models 'split' for 2013 with a native-designed IRS determining the chassis hard-points such that a live axle can be easily swapped in via an FRPP kit? That could be a best-of-both worlds strategy that would drive the volumes needed to drive IRS cost down and still give the drag racer the preferred live axle. Better still, push IRS across the all new global RWD platform Ford has been developing and the volumes will really drive cost down and possibly permit lightened pieces to boot. Does anyone think Ford would be developing a Global RWD chassis with at least a 12 year life (thru 2025 or so) and not have it be a native IRS? I personally doubt it can be anything but IRS, but we shall see both what it is and what models share it in due time. I'd expect the 2013 Mustang to be one of them along with a RWD sport-wagon of some sort -- a segment Ford has no presence in but DCX, GM and others do, tho at various price points. I kinda like the best-of-both-worlds scenario best as long as the hard-points are determined by the IRS, not as the later Cobras were done. The Cobra IRS worked well enough (handling-wise) but added more weight and was weaker than a native design could have been. Still it was an early attempt of one chassis sharing both suspension types, but the hard points were, unfortunately, driven by the existing live axle design. No way Ford wil make that mistake again, imho, in a world-class global RWD platform to underpin several derivative models, etc. Peace, brethren. Dana Aussie Falcon contro-blade IRS... [IMG]http://www.trueblueford.com/images/BA_IRS2_lrg45.jpg[/IMG] [/QUOTE]
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The rear suspension that could have been
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