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 Turbo Shopping Tips, Mar. 02).
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 Passats 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 capability and potential power gains; bad because a big turbo can also mean big turbo lag, which can hurt real-world driveability. We saw this installation as a chance to see how the hair dryer would perform on the street, not just at the track.
Speaking of perform, we were also impressed by the fact that PES was unafraid to use real chassis dynamo-meter numbers to prove its kits 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 wed subject our test car to the same level of scrutiny.
But our expectations were even higher. If you read last months 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 engine and 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 Passats owner, didnt 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. Heres whats happened since then.
It turned out that Adegokes 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 the kit also called for some specialized electronic tuning. For one thing, PES strongly recommended Adegoke install one of the companys Tiptronic chips. The Tip chip reprograms the trans- mission to reduce the time between lever movement and the transmissions actual shift, so that the quickly spooling engine doesnt 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 the 235-245 range, which translated to 287 to 299 flywheel horsepower. Not bad, but shy of the 300hp goal. We could tell that something wasnt right with the car. Black smoke belched from the exhaust pipe, and the air/fuel ratio was so rich that its readings on the dynos computer fell off the chartliterally.
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 re-assembled the engine, and that was wreaking havoc with the engines computer.
In addition, the engine chip was sending too much fuel through the kits big fuel injectors. Thats something of a safety feature tuned into the chip, according to Garrett Lim of Garrett Integrated Auto- motive Corporation (GIAC), which is PESs 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 chips 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 Adegokes 2000 model was drive-by-wire, and an automatic to boot. Its tricky to get those big injectors to work with drive- by-wire, and the newer models are even worse, because theres even more data in the ECU. By comparison, the chip in Lims Passat, a 99 with a stick shift and mechanical throttle linkage, was relatively simple to program.
When it left GIAC after an afternoons work, Adegokes Passat had just the right air/fuel mix at start-up, idle, part- and wide-open throttle, said Lim. And we got to a solid 20 pounds of boost with no detonation, he added.
The final dyno runs were done on a Dynojet at Z-Engineering in Anaheim, close to GIACs shop, in case any further problems arose. There were none. The car ran solid and strong, turning an at-the-wheels horsepower peak of 258 one day and 254 a few days later, which translates to 314 and 310 hp, respectively.
Now, what about the big turbos driveability? After some time 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 grocery getting. Flip to Tip mode, though, and you unleash a beast. From about 3,000 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 wasnt 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 some more. Watched the tach inch upwards, but felt no surge of power until the needle neared 3,000. After that it was hyperspace time.
If youre looking for truck-like bottom-end torque, this system is not for you. But unlike some cars (can you say VTEC?) that dont have any guts until five or six grand, the PES-equipped 1.8T gives you a real rush much sooner. Itll last longer, too, especially when Adegoke lets GIAC back under the Passats hood to push the rev limit up a bit. That and tune the car for more boost and 100- octane race gas. But thats another story. Stay tuned.