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EuroTuner Got Boost? ink & pics: Drew Hardin |
Tech Facts: PES T-28 1.8T turbo
system, including Garrett T-28 turbocharger, cast exhaust manifold,
fuel injectors, custom ECU tuning, new mass-air sensor, intake
plumbing. Last month, as part of our 1.8T engine guide, we showed you the installation of a T-28 turbo system from Performance Engineered Systems (PES) on a 2000 Passat sedan (see Part One) We chose the PES system to illustrate a 1.8T upgrade for several reasons. the Garrett T-28 turbo PES uses is massive, far bigger than the Passat's stock K03, and bigger than the K04 units some other companies use in their 1.8T kits. Now, a big turbocharger can be a good news/bad news deal: Good from the standpoint of air flow capacity and potential power gains; bad because a big turbo can also mean big turbo lag, which can hurt everyday drivability. We saw this installation as a chance to see how the hair dryer would perform on the street, not just the track. Speaking of performance, we were also impressed by the fact that PES was unafraid to use real chassis dynamometer numbers to prove its kit's worth. their tests of a 2000 Passat saw flywheel horsepower jump from the stock 150 to 270, and peak torque climb from 155 to 275. We figured we'd subject our test car to the same level of scrutiny. But our expectations were even higher. If you read last month's installment, you know that our 2000 Passat was equipped with a number of mods before we got to it, including a custom air intake system, a large Spearco intercooler, Ignition Solutions plasma coil packs, and a Neuspeed 2-inch after-cat exhaust system. With these pieces in place, the Passat put out 153 horses at the front wheels while strapped to the Dynojet chassis dyno at Morgan Motorsports in Reseda, California. PES typically figures a 15 percent power loss between the front wheels, so we reported the Passat was making at least 176 horses at the flywheel. With that as a starting point, PES guessed that its T-28 kit could push the flywheel power to the 300hp mark. As if to seal the deal, Femi Adegoke, the Passat's owner, didn't stop with the new turbo. He also replaced his exhaust system with a fully custom, 3-inch, stainless steel pipe setup and high-flow catalytic converter. Here's what's happened since then. It turned out that Adegoke's car was the first 2000 Passat with a Tiptronic transmission to receive one of the PES T-28 kits. So right off the bat, the wheel-to-flywheel power translation changed. Based on tuning other Tiptronic cars (notably Porsches), PES knew the slushbox would soak up another 6 percent of the power between the flywheel and the road wheels. So our baseline number of 153 wheel horsepower would calculate more realistically to almost 187 hp at the engine. Being the first Tip-Passat with he kit also called for some specialized electronic tuning. For one thing, PES strongly recommended Adegoke install once of the company's Tiptronic chips. The Tip chip reprograms the transmission to reduce the time between lever movement and the transmission's actual shift, so that the quickly spooling engine doesn't outrun the tranny when the throttle is mashed open. The stock Passat Tiptronic tends to take its sweet time from when you bump the shifter to when the next gear is engaged. Initial dyno runs were in order with the new turbo setup and showed the car to be much stronger, but not where it should be. Power at the wheels was in t he 235-245 range, which translated to 287 to 299 flywheel horsepower. Not bad, but shy of the 300hp goal. We could tell that something wasn't right with the car. Black smoke belched form the exhaust pipe, and the air/fuel ratio was so rich that its readings on the dyno's computer fell off the chart—literally. To its credit, PES was right there to help troubleshoot the situation. A couple of factors were at play. Adegoke had neglected to remount the engines smog pump when he reassembled the engine, and that was wreaking havoc with the engine's computer. In addition, the engine chip was sending too much fuel through the kits big fuel injectors. That's something of a safety feature tuned into the chip. According to Garrett Lim of Garrett Integrated Automotive Corporation (GIAC), which is PES's tuning partner. Extra fuel keeps the engine from going lean and grenading at high-boost levels. All well and good for casual driving with occasional wide-open-throttle bursts, but not necessarily optimal for the kinds of instrumented tests we were doing. So Lim re-worked the chip's fuel mapping and adjusted the calibration of the mass-air meter as it related to fuel delivery. None of which was easy, admitted Lim, since Andegoke's 2000 model was drive-by-wire, and and automatic to boot. "It's trick to ge those big injectors to work with drive-by-wire, and the newer models are even worse, because there's even more data in the ECU. " By comparison, the chip in Lim's Passat, a '99 with a stick shift and a mechanical throttle linkage, was relatively simple to program. When it left
GIAC after an aftyernoon's work, Adegoke's Passat had just the
right aur/fuel mix at start-up, idle, part and wide-open
throttle, said Lim. "And we got to a solid 20 lbs of boost
with no detonation," he added. Now what about the big turbo's drivability? After some tiem behind the wheel, we came away impressed. At low engine speeds, and especially when the tiptronic was not engaged, the car was docile enough for grogery getting. Flip to Tip mode, though, and you unleash a beast. From about 3,000 rpm to when we hit the rev limiter at 6,000, the rpms climbed fast, as did our speed. Almost too fast. Even with the PES Tip chip installed we had to hit the lever at about four grand for the shift to take effect before the fuel shut off at 5,900 or so. After a few minutes practice, though, it wasn't tough to do. Yes, we did say after 3,000 rpm. We purposely upshifted too soon on one test leg and buried the throttle at about 1,800 rpm. then we waited. Waited soem more. Watched the tach inch upwards, but felt no surge of power until the needle hit 3,000. After that, it was hyperspace time. If you're looking for truch-like bottom-end torque, this system is not for you. But unlike some cars (can you say VTEC?) that don't have any guts until five or six grand, the PES-equipped 1.8T gives you a real rush much sooner. It'll last longer, too, especially when Andegoke lets GIAC back under the Passat's hood to push the rev limit up a bit. That and tune the car for more boost and 1000-octane race gas. But that's another story. Stay tuned. In case you missed the installation in last month's issue, this shot will graphically demonstrate the difference in size between the Garrett T-28 turbocharger in the PES kit (left) and the stock K03 turbo. Turbo size directly affects the volume of air flowing in and out of the engine, ehich directly affect drivability, especially in real-world, city street conditions when you're constantly in and out of the throttle. However, our test drives found that not to be the case. One
of the details we didn't show you last month was the Spearco
intercooler Andgoke mounted below the bumper. It's big enough
to effectivly cool
the intake charge, but its not so huge as to cause a big pressure drop
between
the turbo
and the intake manifold. ThePES t-28 turbocharger installation in the 2000 Passat was clean, with the turbo tucked away in the stock location just below the exhaust manifold. The only tip-off to the mod is the open-element air filter and heat shield that separates the filter from the hot turbo.
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