Koni & BMR Fabrication Suspension Upgrade - Shock And Awe - Tech
The Sti Killer Cuts 3 Seconds Off Its Lap Times And 3-Tenths In The Quarter With A Simple Suspension Upgrade, Courtesy Of Koni And BMR Fabrication
From the March, 2011 issue of GM High-Tech Performance
By Justin Cesler
Photography by Justin Cesler, Scott Parker
After a full year of hard work, blood, sweat (not my sweat mind you, but the sweat of quality mechanics, builders, painters, and tuners) and tears (those were mine), the STI Killer is finally ready for us to begin heavily testing suspension, tires, wheels, brakes, and anything else that makes it haul the mail around a road course the quickest. Built specifically from the ground up to allow us to test anything we, and by extension you, want, the STI Killer is not only a fun car to drive but it is a car with a purpose and a mission: to dominate all other cars in its class on any road surface, including the auto-cross, road course, dragstrip, and street.
If you have been following along with our progress, you have already seen our '01 Camaro receive a new GMPP LS6 engine, a D&D Performance T56, a full host of bolt-on parts, a built rear-end and a set of awesome 6-piston CTS-V Brembo brakes. Until now, the Killer has been good at making noise and spinning the dyno rollers, but its stock suspension has made it difficult to get around a road course and do what it's supposed to do. During our first round of testing ("A Killer on the Loose," Jan '11), we found several things wrong with the Camaro, as lap after lap we blew through braking zones, lumbered heavily into corners and generally just fought to make a clean road course lap. As our friends and critics watched on, the Killer did what it could, mustering several 1.10-second lap times and spinning its way to a 12.996-second quarter-mile pass.
However, this month, the STI Killer was on top of its game and we left the track with much, much better results. As you will see on the following pages, this month's project was all about suspension. With help from BMR Fabrication, Koni North America and our trusty pals at AntiVenom, we were able to install several key suspension components, including BMR's all-new 1-inch hollow front sway bar and re-designed lowering springs, and the results were impressive. In just a couple of laps around Gainesville Raceway's 1.6-mile road course, we were able to drop lap times into the 1.07-second range, running a new best of 1.06.707-a gain of 3.289-seconds from our previous endeavors. The Camaro felt smooth, predictable, and fast, especially during post-apex power-on cornering.
With the 1-inch hollow front sway bar and the Koni shocks set 4-turns from soft, the Killer exhibited zero understeer, even when intentionally pushed too hot into heavy corners. This was one of the most surprising aspects of our install, as we initially expected the 295/30/18 Nitto NT05's up front to object to heavy turn-in, but the combination proved to be almost perfect. At no point did we feel the nose fight our inputs and the steering response was excellent, even in the low speed, heavy turn-in corners.
Out back, however, well, that was another story. Once our speed picked up, the rear was quick to rotate, although it remained predictable. We're not talking about hit the brakes, turn in and spin type of rotation, but just a slight drift to the outside of the corner. Once settled and turning, the Killer was a beast, with great mid-corner grip and a stable feel. The BMR sway bars certainly worked well, taming the Camaro's roll center and keeping the car flat and planted through the turns. On-throttle exits were, well, awesome. It seems that our 295/30/18-inch Nitto NT05 rear tires are simply no match for aggressive throttle application and many a corner became a dance of throttle modulation, counter steering and smiles, as the rear tires went up in smoke. We must take a minute to praise the Eaton differential we installed earlier this year ("10-bolt Basics," August '10), as it applied power evenly throughout the entire test session and showed no signs of slipping or one-wheel peeling.
The STI Killer was in for...
The STI Killer was in for a treat, courtesy of BMR Fabrication and Koni North America. From front to back, you can see Koni's highly touted single adjustable shocks, BMR's lower control arms, sway bars, Panhard rod, and re-designed lowering springs.
To gain access to the suspension,...
To gain access to the suspension, we loaded the Killer up on our in-house lift and removed the 18-inch OE Wheels and Nitto tires from all four corners. Then, the AntiVenom crew got to work on the front suspension, removing the spindle from the upper control arm, unbolting the factory sway bar and removing the two shock-to-control arm bolts.
Up in the engine bay Kyle...
Up in the engine bay Kyle Miller removed the master cylinder from the brake booster and slid it towards the center of the bay. This gives just a little bit of extra clearance to access the four strut-top bolts. Two of these are held in with traditional bolts, while the rear most mount holes are fixed with Torx head bolts.
The upper strut mount, A-arm,...
The upper strut mount, A-arm, and factory shock come out as one unit, although the upper A-arm isn't held in place by anything at this point, so be careful while removing it and don't drop it on your toes!
Using a spring compressor...
Using a spring compressor (you can buy one from Summit Racing or rent one at a local parts store) Greg safely compressed the stock spring and removed the top nut, to free the stock strut top. We were reusing these, hence the removal.
Our BMR 1.25-inch, 550-lb/in...
Our BMR 1.25-inch, 550-lb/in front springs slipped right over the new Koni Sport (Yellow) front shock. With the single-adjustable Koni shocks and the improved, stiff front springs, our '01 Camaro will ride great and handle like it is on rails.
Adjusting the Koni shocks...
Adjusting the Koni shocks is a little different, as you have to rotate a small disc within the top of the shock body. On a fourth-generation Camaro, this adjustment is made through the springs, which can be a little tricky out on the road but nothing to worry about.
With the strut top bushing...
With the strut top bushing and A-arm back in place, Greg slid the entire assembly back in place and, since he is skilled, tightened the top nuts with his other hand. If I were attempting this, I would need a friend in the engine bay to do this and I suspect you might too.