Since getting our Project Jetta TDI in September '08, we've become huge advocates for turbo-diesels, especially after a Revo software upgrade produced 270 lb/ft at the wheels and we still got 45mpg on the freeway at a steady 75-80mph.
So when Dave Anderson from ABD Racingwerks in Riverside, CA suggested, and I quote: "Our car will crush yours," when referring to a TDI they'd built for a customer, we felt obliged to make him eat our soot.
On first inspection, the two cars were very similar - both wore the same Votex body kit available from any VW dealer. Not only is it probably the most attractive kit for the Mk5 Jetta, its OE quality makes it both durable and easy to fit.
This is the same body kit fitted to the TDI Cup racecars and also found on the Jetta TDI Cup Street Edition - a road version of the racers with the option of the same styling as well as 18'' wheels, GLI suspension and brakes, available at your local VW dealer.
So in the styling dept, the scores were even; 1 - 1. When it came to wheels and tires, the ABD car boasted 19x8.5'' Privat Netz wheels with 235/35 R19 Nitto NT05 tires. Our car has 19'' BBS CH with ContiSportContact 3 tires and, although it's a question of personal taste, we felt our wheels won this round - 2 - 1 to et.
As for suspension, we fitted KW V3 coilovers with adjustable bump and compression damping. We'd gone on record for suggesting these motorsport-oriented components were slight overkill on a street car, but they were remarkably comfortable all the same, so we didn't sacrifice much for the handling. However, the white car trumped us with Eibach's Multi-Pro R2 coilovers, complete with remote reservoir dampers as well as Eibach sway bars front and rear.
As it turns out, the car belonged to an Eibach employee, so he was bound to fit the best. In this instance, the R2 kit includes adjustable rebound and compression damping. The remote reservoirs allow for simpler adjustment, better damper fluid cooling, and a superior damper design with shorter bodies and more intricate valving.
Combined with sticky Nitto tires, this Jetta was set for trackdays, although its auto transmission suggested otherwise (more of that later). It's certainly a more extreme approach than our car, but we can't help thinking it's overkill. And the ride quality was slightly harsher than our KWs, without it seeming to control body roll any better. So technically, the ABD car pulled the score back to 2 - 2 but its open to debate...
The brakes on the ABD car were totally stock, giving us the advantage with our drilled and grooved EBC rotors and pads. And while these gave us improved bite for the past 15000 miles or so, we have to report the pads have suddenly got extremely noisy. The wear rate is fine - we have almost 10mm of material left, but the grinding sound is dreadful and needs investigation. We'll still take the win, though; 3 - 2 to us.
The frugal 2.0L TDI motor is tuned for torque and fuel economy. We found to our cost that extracting more from it can cause headaches, with an intake and exhaust failing to improve over stock. However, our Revo software took power from 126hp to 146hp and torque from 226 lb-ft to 274 lb-ft at the wheels. It was a torque monster and we loved it.
ABD had taken a different route to a similar solution. The hardware consisted of its own air intake system and a front-mount intercooler, which looked intimidating behind the deep front grille.
The software was uprated using a module from Bully Dog Technologies. The company specializes in domestic diesel powerplants, but its Jetta device simply plugs into the VW's injection pump wiring harness. It's said to add 25hp and 30 lb-ft, which would take the car to 150hp and 256 lb-ft, if you use our stock numbers for reference (since ABD hadn't visited a dyno).
With its auto tranny, the team had also fitted a Sprint Booster throttle pedal control. It basically plugs into the throttle pedal and removes the delayed throttle response present in modern drive-by-wire cars - we fitted one to a five-speed Audi A4 1.8T (et 7/09) and found it worked well, giving sharper throttle response, especially from a standstill and at low speeds.
On the road, the ABD TDI felt lively. It certainly had plenty of surge off the line but the auto 'box was disappointing. We specified a six-speed manual on our car for this reason - you need to keep a TDI in its sweet spot, and an auto doesn't allow you to do that effectively. If you understand how diesels work and want more than a commuter car, buy the manual...
With more parts fitted (albeit with less power), we reluctantly gave the win to ABD, tying it at 3 - 3.
With a title on the line, it all came down to performance. Who would be faster?
We lined up on a quiet stretch of private road. On the count of three, we dropped the clutch and the race was on.
Or we thought it was, but it appeared the ABD driver wasn't ready, so we backed up and started again. But on the second start, and every subsequent run, the automatic transmission held the car on the line for vital tenths of a second. Despite the Sprint Booster's best efforts, the auto was hopeless (see the video at either eurotuner.com or youtube.com/eurotuner for proof).
While we could hold any revs we wanted and drop the clutch to achieve the perfect, tire-chirping start, the ABD car just sat there for agonizing moments.
Once under way, the two cars seemed fairly evenly matched but we'd hold the gap through to third gear, where the road ran out. We think our advantage would be even greater in the higher gears, where the extra torque would help more, but for having a manual transmission alone, we claim the victory. We won!
The point of this exercise was to prove there are many ways to achieve similar goals, and that TDI performance can still be fun. However, the last word goes to Sam who was watching from the verge, taking photos: "So were you racing? They're so quiet it looked like you were just driving together!"