Gary Peloquin described customers’ reactions to the Stage II Diff Upgrade this way: “The first reaction is that people really notice the difference in the steering response under power. The car steers tighter – on the throttle the car goes toward the apex. The guys who live in the snow and the ice really love the added winter traction”. If those descriptions sound to you like the way people describe the action of the high-priced Torsional differential, you’re on the right track. Make no mistake, this under $100 easy to install product is no substitute for a $1,000-plus Torsional installation. However, it’s a great alternative for the person on a limited budget or the racer in classes that do not allow a full-on limited slip or special differential. The original pre-load differential was introduced with the second year GTI, back in 1983 on the 1984 models. New, it felt like a limited slip on the rack, but one turn by hand and it was clear that the two or three pounds of preload it offered was of little or no value as a limited slip. It was probably added by the factory to reduce vibration, but that didn’t stop the less-scrupulous tuners from touting it as a limited slip, even in stock form ! This upgrade isn’t something new, either. Peloquin’s came out simpler Stage I version with about 25 pounds of breakaway torque some five years ago, after a solid year of development and Peloquin’s-style testing – which is to say severe testing. In February of 1996, Peloquin added the StageII Diff Upgrade with about 85 pounds of breakaway torque, obtained by further modifications to the brass washers and more preload. Which kit should you have? Garys advice is, “The Stage I kit works pretty well for the person with the bolt on 8V, i.e., bolt-on tuning items like a cam and exhaust. ( Stage I No longer available ) Stage II is essential to the 16V owner and to those with more involved 8V motors.” What’s the Diff Upgrade do to differential life? Not much, one way or the other, Peloquin stated. It recommends the shims and brass washers be replaced at the 50,000-mile mark, or after every season for the racers.
THE BOTTOM LINE
Does it work? The engineers in the crowd will tell you that even in second gear, a mid 8V motor has more than 850 ft-lb of torque at the axle, engine torque multiplied by the finial drive ratio (eg., 110 x 2.12 x 3.67). In the face of that, Stage II’s 85 ft-lb seems trivial. That’s one reason I wanted to try the mod-just to see if it works. Flying in the face of all logic, I’d have to say that the Peloquin Diff Upgrade works pretty well. I’ve had Torsional diff’s and the feel isn’t all that different under autocross or hot street conditions. I was impressed not only with the Stage II as installed, but with the completeness of the kit as well, along with the excellent, well-written instruction sheets. This is a neat product with a terrific price-to-performance ratio.