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#46
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Re: Suspension Talks: Understeer & Oversteer
Kia ora Nevin,
I agree with what you are saying, but I am confident that a rear bar is in no way going to satisfy the requirements raised within this thread. I have not stated that a rear bar is useless, only that it will not prove effective for the application involved here. The opening paragraph reads. --- Hey guys, I guess it is time to refresh the issue of the SVX's suspension, especially after all the recent mods that are now available. In hopes that this thread will evolve to become a how-to-guide for racers, autoxers and engine modders. The subject definitely needs discussion.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#47
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Re: Suspension Talks: Understeer & Oversteer
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I agree that within the confines of this topic, the rear bar has now been discussed at length, and that there are still many other areas to consider as well.
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Jesus is the remedy 2015 Expedition EL Ecoboost Ebony Pearl '95 Subaru SVX LSi Home of the Bontrager Works 22mm rear sway bar!! |
#48
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Re: Suspension Talks: Understeer & Oversteer
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The rear-end hanging out style described above may be appropriate for rear-wheel drive cars, but it doesn't work for SVX's. We can't use the rear drive wheels to push the car through the turn. Applying extra power in a turn causes oversteer in a rear drive car, it usually causes understeer in our car. To get oversteer and thus rotation in an SVX you need to decelerate, to shift weight off the rear wheels, either with a throttle lift or with braking. The tail out strategy is really only achievable and useful in an SVX in very tight turns, where you turn in under heavier braking and the rear end comes around. By compacting the turning in a tight corner, you can stop turning sooner and accelerate sooner, with the wheels straighter which is much more effective at putting the power to the ground. For higher speed corners, the strategy is similar, but not as dramatic. The basic strategy is to get the turning mostly done before you slam the accelerator, often using light braking to make those front tires stick and taking weight off the rear so it will rotate. If you don't follow this strategy, one of two things will happen. either you will understeer and have to turn more and possibly lift in order not to plow off the road, or you may, like I have done, spin, as both ends of the car reach the limits of adhesion at the same time and the rear slides quicker than the front. As for the rear sway bar, I'll see this weekend how it does. A stiffer front sway bar would certainly be a welcome addition. Bill is the only person I know of with one of those.
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____________________________________________ 95 LS-i Red, 31,xxx; bone stock for now; Daily Driver 94 LS-i Emerald Pearl, 106,xxx,; 246 whp; Tomyx snorkus and HKS Cold air intake; PWR aluminum radiator, silicone hoses; Inline thermostat; enhanced coolant routing; external power steering and oil coolers; Phenolic intake manifold spacers; 2004 WRX 5 speed transmission; ACT Clutch Kit, Heavy Duty Pressure Plate, Lightweight flywheel, performance disc; Group N motor mounts; ‘07 WRX 4-pot front calipers, cryo-treated slotted Tribeca rotors; Hawk HPS ferro-carbon pads; Frozenrotor rear slotted rotors; SS brake lines, Axxis Ultimate pads; Rota Torque 17x8 wheels; 245/40-17 Bridgestone RE01-R's; Koni inserts with Ground Control coilovers, Eibach springs; K-Mac camber/caster adjustable strut mounts; Urethane swaybar bushings; Bontrager rear sway bar; Urethane differential bushing; Custom Whiteline adjustable rear lateral links; Outlaw Engineering forged underdrive pulley; custom grind Web intake and exhaust cams (11 mm lift, 250° duration); solid lifters; CP custom aluminum forged 11 to 1 pistons, Brian Crower coated SS intake & exhaust valves; Brian Crower upgraded springs w/ titanium retainers; NGK sparkplugs; RallyBob (Bob Legere) ported and polished cylinder heads; Eagle H-beam rods; ACL Bearings; Cometic Head gaskets; ARP head studs & fasteners; Hydra Nemesis EMS; Wideband O2 sensor; 740cc Injectors; Walbro 255lph fuel pump; Upgraded WRX starter; Equal length SS headers (3 into 1); dual Magnaflow cat converters; 2 into 1 into 2 SS exhaust with Bullet muffler; OT Fiberglass hood; Oil pressure gauge; Programmable shift light, 2017 Subaru Forester XT, metallic dark gray, 29,xxx 2005 Porsche 911 Turbo S Cabrio, 24,xxx 2006 Subaru Outback LL Bean, 166,xxx sold 92 LSL Dark Teal, Smallcar Shift Kit - sold Last edited by shotgunslade; 04-29-2010 at 02:53 PM. |
#49
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Re: Suspension Talks: Understeer & Oversteer
Okkkk now... since everybody agrees that we need a front swaybar, I think the right debate here would be related to its thickness and shape.
For the thickness... I leave it to the experts. For the shape, it is currently an "L" + "I". I guess fabbing the same style would be costly as hell, I guess we need someone to fab it (Nev?) the same as the rear, a continuous "U". Yeah I know, it will be a PITA to install, but on the other hand it is a "one-time PITA" installation if memory serves right... Plus it would be cheaper to fab. Who cares to start hammerin' me
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Danny 1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon) 1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration 2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection. |
#50
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Re: Suspension Talks: Understeer & Oversteer
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There is only two situations which apply during racing. The car is under maximum acceleration or maximum braking, i.e. the exception being very fast sweeping corners a situation not covered within your description. Otherwise the driver is simply pissing about. “Front wheel, rear wheel and all wheel drive cars need different strategies to go fast.” There is no strategy as such, there is but instinct and judgement. A driver has it, or he does not. It can be detected a mile off. The guy who sits up on the steering wheel and points the car, as against he who sits back and feels the car with his body and directs it accordingly, with hands and feet. “To get oversteer and thus rotation in an SVX you need to decelerate, to shift weight off the rear wheels, either with a throttle lift or with braking. The tail out strategy is really only achievable and useful in an SVX in very tight turns, where you turn in under heavier braking and the rear end comes around.” Exactly as I have decreed. But damn it in a motor race, who would lift the throttle if not braking or negotiating a very fast sweeping corner? There is confusion here as to what is a tight corner. A corner/turn is any section of the road which can not be negotiated, without substantial slow down using the brakes. Otherwise the term, "sweeper or sweeping turn" is more applicable. “For higher speed corners, the strategy is similar, but not as dramatic. The basic strategy is to get the turning mostly done before you slam the accelerator, often using light braking to make those front tires stick and taking weight off the rear so it will rotate.” Slam the accelerator? It is very clear that you have never negotiated a fast sweeper, nor have you driven in a real motor race and been any where near the limit. You are probably talking about a medium radius corner, but on entry why would you be wasting time under light braking? Furthermore slamming the accelerator on any sort of real racing car, will cause wheel spin and loss of control. If you are seriously racing, braking before the corner will be at absolute maximum stopping power, maximum possible forward weight will have then occurred. If braking can be continued through the corner, the car is not on the limit and is not going as fast as it could be. I have raced front and rear wheel cars and when I first ran a front drive car I read all the theory, but could make no sense of it. I simply got aboard and drove the thing with an open mind, relying on the seat of my pants for instruction, rather than some form of theory. I quickly found that it was easier to set the rear out under braking on entering a corner, than with rear drive. Traction from the front, was automatically catered for without special thought. If the car spins out on a sweeping corner at high speed, after the car has rotated and as is going backwards, the brakes should be applied hard. The weight then transfers to the rear and the front slides with the car then moving inwards, back onto the circuit. With the brakes held on the spin continues to the outside and off at ever reducing momentum. It works believe me. I am describing a situation where you have lost it, and any thought of opposite lock correction is worthless. This advice transcends, --- “brakes are the last resort.”
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#51
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Re: Suspension Talks: Understeer & Oversteer
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Where racing set ups are involved, it is usual to provide adjustment via a means of shifting the point at which leverage is applied. However this can be difficult within a confined space. As I previously suggested, it is an advantage if an existing OEM bar, from some popular vehicle can be used at least as a basis.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#52
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Re: Suspension Talks: Understeer & Oversteer
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'94 Laguna Blue LSi ~159k.......JDM ultra short-geared 3.900 STi Version 7 6-speed w/ Cobb shortshifter, ECUtune 244,8.1mm/256,9.1mm i/e cams, group N motor mounts, '97 grille, JDM clear corners, Momo JDM Legacy GT steering wheel, apkarian's LED tails, silver STi BBS wheels, PWR radiator, redstuff pads f/r, drilled/slotted rotors, bontragerworks rsb #18, Koni/GC 450f/375r coilovers, Megan Racing adjustable lateral links, KMac c/c plates, Stebro exhaust, ECUtune 1v5, Optima battery in the trunk where it belongs. Turbo project '97 Ebony LSi ~137k #036.......Power mode mod, JDM clear corners, BBS wheels. AUX/pocket mod Now a mod "over there" ............Photo album |
#53
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Re: Suspension Talks: Understeer & Oversteer
It is so difficult arguing with such a world famous racing driver. I guess my instructor at the Panoz School, Joe Foster (Google him), doesn't know what he is talking about. Thank God we all have Trevor to keep us on the right path.
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____________________________________________ 95 LS-i Red, 31,xxx; bone stock for now; Daily Driver 94 LS-i Emerald Pearl, 106,xxx,; 246 whp; Tomyx snorkus and HKS Cold air intake; PWR aluminum radiator, silicone hoses; Inline thermostat; enhanced coolant routing; external power steering and oil coolers; Phenolic intake manifold spacers; 2004 WRX 5 speed transmission; ACT Clutch Kit, Heavy Duty Pressure Plate, Lightweight flywheel, performance disc; Group N motor mounts; ‘07 WRX 4-pot front calipers, cryo-treated slotted Tribeca rotors; Hawk HPS ferro-carbon pads; Frozenrotor rear slotted rotors; SS brake lines, Axxis Ultimate pads; Rota Torque 17x8 wheels; 245/40-17 Bridgestone RE01-R's; Koni inserts with Ground Control coilovers, Eibach springs; K-Mac camber/caster adjustable strut mounts; Urethane swaybar bushings; Bontrager rear sway bar; Urethane differential bushing; Custom Whiteline adjustable rear lateral links; Outlaw Engineering forged underdrive pulley; custom grind Web intake and exhaust cams (11 mm lift, 250° duration); solid lifters; CP custom aluminum forged 11 to 1 pistons, Brian Crower coated SS intake & exhaust valves; Brian Crower upgraded springs w/ titanium retainers; NGK sparkplugs; RallyBob (Bob Legere) ported and polished cylinder heads; Eagle H-beam rods; ACL Bearings; Cometic Head gaskets; ARP head studs & fasteners; Hydra Nemesis EMS; Wideband O2 sensor; 740cc Injectors; Walbro 255lph fuel pump; Upgraded WRX starter; Equal length SS headers (3 into 1); dual Magnaflow cat converters; 2 into 1 into 2 SS exhaust with Bullet muffler; OT Fiberglass hood; Oil pressure gauge; Programmable shift light, 2017 Subaru Forester XT, metallic dark gray, 29,xxx 2005 Porsche 911 Turbo S Cabrio, 24,xxx 2006 Subaru Outback LL Bean, 166,xxx sold 92 LSL Dark Teal, Smallcar Shift Kit - sold |
#54
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Re: Suspension Talks: Understeer & Oversteer
Harvey as always your crappy posts are based on nothing but sarcasm. I have been their and done it. There is no shame in saying so when posting relative information. You by contrast claim engineering status without the required credentials.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#55
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Re: Suspension Talks: Understeer & Oversteer
I would just take the sarcasm with a grain of salt.. We know that you are very knowledgeable when it comes to engineering and especially when it comes to unique cars like the SVX, as is Harvey and many others here but not everyone is happy or going to agree.. That's the internet..
Constant battles.. Fun isn't it?
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1992 Pearl White LS-L "Ruslana" #4946 - 180k on body, 95k on engine. Mods: ECU bead crush, 15 min mod, 20 min mod, drilled/slotted rotors & Axxis ceramic brakes, SS lines, 17" Evoke F1 wheels, XS-HF137 Sony Xplod speakers, 6000k HID's (lows & fogs), resistor mod, 1˝" Sleek Spoiler mod, custom exhaust by svxfiles, '02 WRX aluminum racing radiator by svxfiles, Summit Racing 400# x 300# springs w/ Koni's by svxfiles, ClassGlass fiberglass hood /w scoop, Nevin's rear sway bar, '97 grille, phenolic spacers, custom LED interior lighting, custom paint. †"War doesn't determine who is right, only who is left"† Work to be done: Tinted windows, clear/LED tail lights, tailbar mod, "Power Mode" mod, Supertone horns, clear corners & headlight lenses, 2 pc splitters or custom bumper, Alcyone side skirts, TruSpeed Stage III SVX Intake, Hydra, 4.44 tranny swap, JDM auto folding side mirrors, engine rebuild, super charger, STi seats, bone leather interior /w SVX emblem, dash overhaul, SVX decals, paint (stock color). Total cost?: 22k At least it's going down..
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#56
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Re: Suspension Talks: Understeer & Oversteer
Again sarcasm rather than fact. My guess is that you have not properly interpreted what you have been told, and your instructor thank god, has not been game to sit along side you when you drive close to the limit. I commiserate with him.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
#57
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Re: Suspension Talks: Understeer & Oversteer
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AND GUYS CAN WE PLEASE KEEP IT CIVILIZED IN THIS THREAD?
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Danny 1994 Silver SVX in hybernation, awaiting for the monsterous awakening (Lebanon) 1967 Mercedes-Benz 250SL Euro Specs, Hard/Softtop, White/Red. Under Complete Restoration 2013 Mercedes-Benz SL350 Euro Specs, White/Red. Mint... Another step into SL Collection. |
#58
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Re: Suspension Talks: Understeer & Oversteer
Gosh, I never knew I was a playboy with a big check book.
Gene
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Gene and Ben 1992 SVX LS AWD 110K - Liquid Silver 1994 SVX LSi AWD 128K - White Pearl (daily driver) 1994 SVX LSi AWD 95K - Emerald Pearl (sold) 1992 SVX LS-L AWD 115K - Dark Teal 4.44 swap (sold) |
#59
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Re: Suspension Talks: Understeer & Oversteer
I know I should keep it civilized, but some of the opinions expressed here are wrong and misleading. The hairy chested, devil take the hindmost attitude toward driving expressed here is obsolete, expensive and ultimately dangerous. I certainly wouldn't want to share the track with any harboring those ideas.
Racing drivers don't die behind the wheel very much anymore; certainly not like they used to. Many of the heroes of my youth, Wolfgang Von Trips, Jimmy Clark, Peter Revson, Bruce McLaren, Mark Donohue, and later, Ayrton Senna died in track accidents, but attitudes have changed, and things are much safer. You don't have to make off-track excursions to learn how to drive your car and to learn where the limits are. Trevor is right that you feel what the car is doing and adjust to it. You explore the limits gingerly, feeling what's happening, then when you detect the limit, back off or correct. Having said all that, driving strategies are appropriate. The range of responses to any given situation is vast. Knowledge of your car, how it responds, and likely successful approaches to different types of corners, and different conditions narrow that range so that you can explore what works best. As for always driving full throttle or full braking, that is hogwash. I have ridden with some very good drivers, and they are very smooth. They do utilize throttle lifts to loosen the rear end, and a touch of throttle to settle the car during transitions. They rarely coast, but they are often modulating, either throttle or brake. While braking before a turn may be full on braking, really good drivers, on the appropriate turns, will leave a little extra speed to shed during turn-in, so they can get some extra front end grip to tighten the turn-in. That braking is not full on, it is merely to get some additional front end weighting. So, I really don't know what this argument is about. We have recognized that while the new rear sway bar may help street driving to feel more controlled, it could be detrimental driving at the limit, depending upon the balance between front and rear roll stiffness. Excessive rear roll stiffness in a front heavy, all wheel drive car results in increased understeer, sometimes unexpectedly acute. I related some strategies that I have found to be successful, trying to utilize braking or throttle lifting to increase front tire bite, and avoiding, to the extent possible, full throttle at high turning angles. These observations were greeted by a roar of senescent testosterone, spewing truths, half-truths, and errors indiscriminately. At least, that is my opinion. So, ban me. I'd rather be banned than have some member of this forum go out to the track and explore the limits of his car by cutting grass, only to discover that the SVX is not also good at cutting down trees.
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____________________________________________ 95 LS-i Red, 31,xxx; bone stock for now; Daily Driver 94 LS-i Emerald Pearl, 106,xxx,; 246 whp; Tomyx snorkus and HKS Cold air intake; PWR aluminum radiator, silicone hoses; Inline thermostat; enhanced coolant routing; external power steering and oil coolers; Phenolic intake manifold spacers; 2004 WRX 5 speed transmission; ACT Clutch Kit, Heavy Duty Pressure Plate, Lightweight flywheel, performance disc; Group N motor mounts; ‘07 WRX 4-pot front calipers, cryo-treated slotted Tribeca rotors; Hawk HPS ferro-carbon pads; Frozenrotor rear slotted rotors; SS brake lines, Axxis Ultimate pads; Rota Torque 17x8 wheels; 245/40-17 Bridgestone RE01-R's; Koni inserts with Ground Control coilovers, Eibach springs; K-Mac camber/caster adjustable strut mounts; Urethane swaybar bushings; Bontrager rear sway bar; Urethane differential bushing; Custom Whiteline adjustable rear lateral links; Outlaw Engineering forged underdrive pulley; custom grind Web intake and exhaust cams (11 mm lift, 250° duration); solid lifters; CP custom aluminum forged 11 to 1 pistons, Brian Crower coated SS intake & exhaust valves; Brian Crower upgraded springs w/ titanium retainers; NGK sparkplugs; RallyBob (Bob Legere) ported and polished cylinder heads; Eagle H-beam rods; ACL Bearings; Cometic Head gaskets; ARP head studs & fasteners; Hydra Nemesis EMS; Wideband O2 sensor; 740cc Injectors; Walbro 255lph fuel pump; Upgraded WRX starter; Equal length SS headers (3 into 1); dual Magnaflow cat converters; 2 into 1 into 2 SS exhaust with Bullet muffler; OT Fiberglass hood; Oil pressure gauge; Programmable shift light, 2017 Subaru Forester XT, metallic dark gray, 29,xxx 2005 Porsche 911 Turbo S Cabrio, 24,xxx 2006 Subaru Outback LL Bean, 166,xxx sold 92 LSL Dark Teal, Smallcar Shift Kit - sold Last edited by shotgunslade; 04-30-2010 at 08:55 AM. |
#60
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Re: Suspension Talks: Understeer & Oversteer
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There has been a lack of understanding, because my description covering relatively tight cornering, as is most affected by a front roll bar, has been taken to apply to sweeping bends, where that described in the above paragraph applies. Reference to my posts will make this clear. As for the hairy chested rough untidy driver, they do not go very fast. A factor of risk has always been part of many sports. Without it such sports lose their appeal. I am no longer interested in motor racing, but have great appreciation of rally drivers and their navigators. It has been stated that I do not know what I am about. I anticipate being accused of showing off, but bugger it, I am going to defend myself. --- The photo at the head of this post, appeared in the largest of N.Z. newspapers, heading an article covering a national series of motor races. The caption was, "A Wet Day at Pukekohe" and was/is considered quite spectacular, to the point of being again published in the current issue of the magazine, Classic Driver, captioned "That's Car Control." The photographer had no problem in catching the action, as I had been setting up the same drift lap after lap. The car has just topped a notorious rising sweeper and is progressing at around 90 MPH, after having bounced over a much feared undulation at the top of the rise. The surface is very slippery because it is raining, and the car is fitted with standard cross ply road tyres. Knowledge of the circuit is required in order to fully appreciate the circumstances involved. Using the technique described here, I have just overtaken an MG midget on the inside. Believe it or not, the MG, due to money spent, had the legs on my SP250 Daimler on the main straight, and it was necessary for me to get the better of him on the more demanding parts of the circuit. Setting up the same attitude when the circuit was dry, did not require opposite lock. Having drawn attention to the photo, I point out that careful scrutiny will disclose immediately inside the front right wheel, the bottom of a link connecting a specially fitted roll bar. The bar was taken from a wrecked GM Holden. At this point the sarcastic can let fly, I do not give a damn.
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Trevor, New Zealand. As a child, on cold mornings I gladly stood in cowpats to warm my bare feet, but I detest bull$hit! |
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