TrakRat Posted April 11, 2012 Report Share Posted April 11, 2012 (edited) From REAL PERFORMANCE MUSTANGS BOSS WHO? ZL-WHAT? RPM Member "TrakRat" James Dounis' 2011 GT500 GR40 Mustang Written by James Dounis Photography by Full Throttle Images A year and a half ago I wrote about finally purchasing my dream car, a 2011 Shelby GT500 SVT Performance Pack. I mentioned that the car is a rocket in a straight line and quite competent at the track, though not nearly the surgically precise track weapon that my Griggs GR40 1996 Cobra had been. Several months ago I sold my Cobra (as was the agreement I made with my fiancée if I was to buy the GT500) to Jimmy Shaberg, owner of The Fox Shoppe in Portland Oregon. I dearly missed the car though, the Griggs suspension truly made the driver feel fearless of any curve, dip, slide, or tire spin. The car would simply read your mind and spit you out the other side of a turn with no drama, and then begged you to do it again even faster the next time. This is a sensation that is missing in the Shelby. The SVT Performance Package from the factory is very competent on track while being tame enough to commute in. Understandably, Ford had to make some concessions because it is hard to please everyone. You can read on many internet forums where one person thinks the car rides too hard, while another thinks it’s too spongy. My chief complaint is that the chassis has all the pitfalls of an IRS car with relatively few benefits of the solid axle. There is not enough traction, and tire spin is often met with wheel hop or the rear end sliding wildly from side to side. Mashing the throttle makes the rear bumper drop several inches and if the tires aren’t spinning, the driver is constantly correcting the right/left/right wander caused presumably by the squishing rubber control arm bushings. So this winter when the mod bug bit me, I decided rather than making more power and further amplifying the few pitfalls of the chassis, I decided it was time to tame the beast. Scott Jensen, head of Real Performance Group, let me know that RPM (Real Performance Mustangs) is now a dealer for Griggs Racing suspensions and the 2011 GT500 GR40 systems were complete and ready to take orders. This really got my attention. It seemed logical to install a complete system designed for your car rather than mixing and matching re-boxed ’05-‘09 items from manufacturers A, B, and C. When you add it all up, the price of admission is steep, but not much more than other top shelf offerings from the competition, especially when you consider how much better it will function as a cohesive package. After working unheard of amounts of overtime, I finally called Scott, discussed different options, and placed an order that consisted of a GR40SS kit with quiet bushings and splurged with a Watt’s link. I added a few options such as the complete front urethane bushing kit and 315 width tire kit. The SS kit includes custom valved Koni adjustable shocks with coilovers, caster/camber plates, lower control arms, and the famous Griggs Torque Arm system. While the majority of The Fox Shoppe clientele are Fox Body Mustang owners, Jimmy without hesitation will restore, upfit, or race prep any ‘79 and newer Mustang. After buying the Cobra, he was very impressed with its capabilities and was excited to get an opportunity sink his teeth into installing a Griggs system in an S197. And after seeing his attention to detail and attention to quality in his work, I was excited to give it to him. Judging by the weight of the boxes that arrived full of equipment to be installed on the car, you would think we would be adding a lot of weight to an already heavy vehicle, but this was not the case. With all the factory parts that come out of the vehicle, net weight only increased around 20 pounds. After the kit was installed, Jimmy fine-tuned ride height, alignment settings, and shock firmness. The stagger of 19/20 inch wheels that were part of the SVT Performance Package have always annoyed me and limited tire choices, so I obtained and additional pair of 20 inch rear wheels to install up front. Yes, the rear 20 inch SVTPP wheels with 285/35-20 Goodyear G:2’s fit, thanks to a ¼ inch spacer to avoid contact with the Brembo calipers. Now with the equipment installed and the stance dialed in, it’s time to hit the road! First impressions: Man, this thing is firm. While the ride is quite smooth on the highway and smooth surface streets, potholes and rough Tacoma roads were a bit punishing. The car feels very solid, response from the chassis is immediate, and body roll is nearly nonexistent. Put your boot in the throttle and the rear bumper no longer drops to the ground like a dog with worms dragging his rear across the driveway. It grips much better and stays arrow straight. If you light the tires, again the rear follows faithfully until you tell it to do otherwise. Your braking is also dramatically improved. There is no nose dive or ponderous tail wagging to speak of. When you jerk the wheel the nose immediately changes direction and the rear instantly follows. Remembering that the torque arm is direct link to your bottom and the rear shocks are directly mounted to vehicle without the factory upper bushings you can hear the whirr of the differential gears. It’s not obtrusive and the fiancé actually said “It sounds kinda cool.” As I accumulate some miles, I can’t tell if the initial firmness has softened a bit or my backside has gotten used to it, but for the most part the ride is not bad at all. Expansion joints and bad roads, however remind you that you do in fact have a racing suspension installed. Appearance: Low and aggressive. This is where form follows function. The look is all business, no “stretch”, “poke”, “waffle”, or “hella flush” nonsense, just business. At full lock and maximum suspension articulation (front tire shoved up as high as possible before lifting the rear wheel), the front tires ever so slightly graze the inside of the front fender lip. When these tires are gone, I may look into Pilot Super Sports with slightly shorter sidewall. The dramatic forward rake the car had stock is gone and from every angle, the car has a hunkered down appearance with the bottom of the Watt’s link and the rear sway bar peeking out from under the fuel tank. There also seems to be a lot more people coming up alongside and giving thumbs up. Performance: We just had a string of warm days up here in the Pacific Northwest and I have been able to attack ramps and cloverleaves much more aggressively. Below 50 degrees these tires harden into plastic barrels, but now that there is some heat in the Goodyears, cornering grip is mind bending. When accelerating in 1st, modulating the throttle at the edge of adhesion is far easier and with enough heat, second gear can go straight to full throttle. I had expected the car to tramline horribly with the wide front tires but truthfully it is no worse than it was stock, and it may in fact be better. The car certainly has more nerve than I do at this point, so I’m creeping up on its limits as to not find surprises when I do finally reach them. There is a track day in the near future with The Fox Shoppe at Oregon Raceway Park to allow us to experiment with different settings and final tuning to suit my driving style. I thank Scott with RPM and Jimmy at The Fox Shoppe for all their help throughout this build and to Full Throttle Images for the outstanding photography. Look for more information soon as we document this car’s track prowess. Edited April 18, 2012 by TrakRat Quote Link to comment Share on other sites More sharing options...
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