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Suspension Upgrades - Hooked Up And GoneBudget suspension upgrades take the slip and slide out of the Dirty Bird’s first 60 feet. From the December, 2011 issue of GM High-Tech Performance By Justin Cesler Photography by The Author
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It’s amazing how much you can see in just 1⁄60th of a second. On track, watching the Dirty Bird make test hits at Bradenton Motorsports Park, the initial launch looked great, although we could tell something was going on with the stock, worn rear suspension. Our 60-foot times looked decent (1.684-seconds) for a car with this little horsepower and torque, but Greg thought we might be having a moment of wheel spin followed by the car stepping out of the groove to the right. Try as I might, it was hard to see it go down in real time. Luckily, like any serious racer looking to improve elapsed time, we remembered to bring the video camera and tripod along on our last trip (http://bit.ly/oJDawA) and watching each run frame by frame really helped clue us in to exactly what was happening on the launch. As Greg lit the second beam, he would activate the trans-brake, set the car, and wait for green; .031-seconds later, the Dirty Bird began moving, squatting hard over the passenger-side rear tire, which spun in place exactly one time before the Firebird had a chance to move forward. During this initial movement, the driver-side rear tire actually spun and hopped once, although it eventually dug in and settled down. Up front, nothing. We’re talking no weight transfer, no movement, practically dead still as the aftermarket lowering springs and stock shocks did nothing to help move weight towards the rear tires. One second into the run, the Dirty Bird’s suspension was planted, although the twist of the car combined with the slight tire spin had begun to move it out of the groove. By the 60-foot beam, Greg was a full tire width out of the groove (to the right), but luckily the Firebird didn’t start to spin. A little over 12-seconds later the run was over and we were back to the drawing board. What the Dirty Bird exhibited is typical of many F-bodies running improperly setup suspensions. Luckily, fixing these issues on a mild engine setup is simple, affordable, and easy to do, assuming you know which parts to order. For this round, we teamed up with Summit Racing and ordered everything we needed to hopefully drop our sixty-foot times and get the car hooked up and gone for less than 600 bucks and we had everything in our hands just a couple of days later. Eibach Drag-Launch springs with a right rear air bag (PN EIB-9307-140) to help us transfer weight and level out the rear suspension on the hit, Edelbrock weld-on subframe connectors (PN EDL-5290) to keep the chassis stiff, Edelbrock lower control arm relocation brackets (PN EDL-5275) to improve forward bite and eliminate unnecessary squat, and a set of Energy Suspension lower control arm bushings (PN ENS-3-3136G) to minimize deflection and transfer power to the ground. As usual, we employed car owner and master mechanic Greg Lovell of AntiVenom in Seffner, Florida, to do the work and hit up the track to see how much our track times improved. Follow along to see how it all goes together!  1 Last time out, the Dirty...  1 Last time out, the Dirty Bird ran a 12.300 at 109.44 mph on a 1.684-second sixty-foot. AntiVenom was happy with the results, but everyone agreed the sixty could use some adjustment. Between body flex, a lack of weight transfer and a passenger-side twist, old Dirty was struggling to get moving.  2 These aftermarket lowering...  2 These aftermarket lowering springs gave the Dirty Bird a killer stance and a nice ride on the street, but for track duty, they left a lot to be desired. In order to help with weight transfer, we called up Summit Racing and ordered a set of Eibach Drag-Launch springs (PN EIB-9307-140) for the front and rear of our Firebird project.  3 The Eibach Drag-Launch...  3 The Eibach Drag-Launch spring package is not only gorgeous (one of the nicest spring colors we have ever seen), but it is fully functional—with a front spring wound for maximum weight transfer, rears built specifically for the strip, and a right-rear airbag to help balance the chassis and control axle torque under acceleration.  4 Here you can see the major...  4 Here you can see the major visual difference between the two springs. On the right is the lowering spring that AntiVenom removed, with the new Eibach unit on the left. Compressed on the shock, the Eibach will store a massive amount of energy, which will help pop the front end up and keep it there during the run.  5a If you’re going to tackle...  5a If you’re going to tackle this install at home, be aware that a typical spring compressor just doesn’t have the ability to get these massive Eibach springs compressed onto the stock front shocks...  5b ... Luckily, AntiVenom...  5b ... Luckily, AntiVenom has a standalone spring compressor (2-ton), which was more than capable of getting the job done.  6 Sliding the shock assembly...  6 Sliding the shock assembly back in place is a simple job and one that we have covered several times in the past. As a quick tip, make sure you line the upper mount with the lower shock mount before you tighten everything down or you will have to fight with the unit to get everything in place, once in the car.  7 Heading back to the rear,...  7 Heading back to the rear, Greg pulled the stock springs out from between the rear end and the body and set the new Eibach unit next to it on the floor. Before sliding the right-rear spring in place, Greg installed the supplied air line and fitting onto the airbag and placed the bag inside the new spring.  8 Installed, you can get...  8 Installed, you can get a better idea of how the airbag and spring work together. Luckily for F-body fans, the lower spring perch on the 10-bolt has an open center, which is the perfect place to run the airline. Coming through this hole, it can’t get pinched and hung up on anything, which makes routing it a breeze.  9 Greg ran the supplied line...  9 Greg ran the supplied line from the rear spring perch through the frame and up into the Dirty Bird’s rear bumper. Eibach supplies all of the fittings and line to make everything work flawlessly, and a quick run of the drill gave us the perfect mounting point for the Schrader valve.  10 With both springs installed...  10 With both springs installed and the airline ran (eagle eyes will notice we hadn’t ran the line yet in this photo!) AntiVenom was all done with the rear Eibach portion of our install. At this point, we could have loaded the car up and made some track hits, but we knew the Dirty Bird needed a little more work if we wanted to see killer results.  11 We would have loved to...  11 We would have loved to install a pair of adjustable tubular lower control arms on the Firebird, but once again our budget ran significantly shorter than our dreams. Instead, we picked up a set of quality Energy Suspension control arm bushings from Summit for 40 bucks and set out to press them into our existing factory arms.  12a With a press (or a big...  12a With a press (or a big hammer if you’re at home), the stock lower control arm bushings can be removed from the stock arms quite easily...  12b ...First up, Greg put...  12b ...First up, Greg put a little pressure on them with the press and then hit them with an air chisel to push them out of the arm. These stock bushings allow for way too much movement, which is okay for ride quality but terrible for quick e.t.’s.  13 It’s easy to see the difference...  13 It’s easy to see the difference between the Energy Suspension bushings (bottom) and the weak factory units. For even more strength in the lower control arm, you could easily “box” them in with a plate and some welding, but we think these will do the job for now, so we’re done messing with them.  14 One thing that can always...  14 One thing that can always help F-bodies get out of the hole is a quality set of lower control arm relocation brackets, like this pair we purchased from Summit Racing made by Edelbrock. By adjusting the LCA mounting point, we can lower the instant center of the Firebird and increase forward bite while eliminating the nasty rear squat we saw with the old suspension.  15 Last but certainly not...  15 Last but certainly not least, AntiVenom prepped the bottom of the Dirty Bird to receive a pair of Edelbrock weld-on subframe connectors. Designed specifically to reduce chassis flex and improve response, the Edelbrock subframe connectors are built from 1.625-inch, .120-wall steel tubing and tie the front and rear subframes together using weld-on boxed ends.  16 The Edelbrock units fit...  16 The Edelbrock units fit the Dirty Bird perfectly and lined up with both the front and rear floor structure as if they were a factory piece. Edelbrock even includes four separate plates, which box the subframe connectors to the chassis. While somewhat heavy, the reduction in chassis flex is well worth the weight and effort involved with the install.  17 Almost finished, we left...  17 Almost finished, we left Greg Lovell and the AntiVenom crew to weld the Edelbrock subframe connectors and lower control arm relocation brackets in place. With a base 15-psi in the right rear airbag and the lower control arms in the lowest relocation hole, we headed over to the track to see what our budget upgrades could do...  18 All that work and we lost...  18 All that work and we lost 2-tenths?! Instead of spinning slightly, getting up into the powerband and heading down track, the Dirty Bird’s budget suspension helped it dead hook right off of the transbrake, plant both rear tires evenly, and almost pull both front tires, which actually bogged the LT1 and pulled it out of the optimum powerband (increased heat and humidity of the Florida summer didn’t help either). Seems we need to make some more power to get the Dirty Bird back on track, but we’ll tackle that next time, now that we know our wheelspin issue is under control.
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