TURBO TAXI
WE’RE NOT READY TO POP THE CHAMPAGNE CORKS YET, BUT THE TURBO TAXI IS GETTING QUICKER BY THE DAY
The taxi drives to Sydney, cooks a gearbox and gets within a bee’s franger of an 11-second pass
WE BOUGHT a taxi and we turboed it. At its core that may sound like a pretty simple concept, but when you consider that the Turbo Taxi still runs on LPG, things get a little more complicated.
The number one question we get asked is: What did it cost?
We can’t answer that yet, because we still haven’t finished, but it’s probably not as cheap as buying an XR6 turbo and boosting the bejeebus out of it – and that’s kind of the point. We’re not trying to replicate something that’s been done 100 times already. By trying to push our 1760kg taxi into the 10-second zone on LPG we’re aiming to break new ground.
Last month we took our taxi on a massive 1800km round trip to Sydney Dragway and back, and ran a new PB of 12.30@114.6mph. We actually ran four 12-second passes that night, but it revealed that traction was becoming an issue.
Knowing that we had plans to do something about the rear end, we kept an eye out for a suitable replacement and we jumped on a complete BF XR8 LSD rear cradle and differential when it popped up for $300. With 3.46 gears and beefier 30-spline axles, the XR8 rear end had a lot going for it, but it was the LSD centre that was the real prize. However, with magazine deadlines being what they are we had to turn the job over to the guys at MPW Performance.
Bolting in the XR8 rear end was slightly more painful than we’d anticipated. Compatibility issues between the BF sensors and FG wiring loom caused us no end of problems. Eventually we solved the issue with a few washers to space the longer FG sensors out of the BF rear
end. Then we headed towards the setting sun and Heathcote Raceway.
Bumper-to-bumper Friday afternoon traffic with the rest of the unwashed hordes meant we didn’t get to Heathcote until after 8pm, and it was almost 9 before we hit the track.
On the first run I decided to forgo the two-step and just stage the car on the footbrake. When I felt the taxi start to move I just let it go and it launched cleanly with a 1.99-second 60-foot time. Not the best we’ve ever done, but at the other end of the track the time boards told a different story – 12.17@119mph.
After hearing the good news I jumped straight back in for another pass. This time I gave it a bit more welly in the burnout and the engine bounced right back, proving that the new valve springs we'd put in were doing their job. I used the two-step in conjunction with plenty of footbrake, and, on hearing the familiar bopbop-bop of the limiter, I released the button for a 1.90-second 60-footer. By half-track I was doing almost 95mph (151km/h) and the Falcon was rocketing down the track.
“It’s pulling like a train,” I yelled, and the taxi crossed the line with a 12.0009@121.33mph – a new PB, and so close to the 11-second pass I so desperately wanted. So I headed back around for another go.
This time the burnout was all business; enough to warm the tyres, but I had no interest in melting them. The tree counted down and when I heard the engine on the limiter I released the button and pulled a 1.91-second 60-foot time. Not the best, but up there, and the taxi took off down the track and crossed the line with another 12.17@119mph. Maybe it held a gear too long; I couldn’t say. But it was strange; a time that had me jumping for joy just 40 minutes earlier now
left me disappointed. That’s drag racing for you.
With the night coming to a close I let Aiden have a crack and see what he felt about the power of the taxi, but wheelspin at the line killed his 60-foot time and the car ran 12.31@119.97mph. We headed to the hotel determined to do better the next day.
Unfortunately, that’s not how it turned out. The problems may have been caused when I filled up that morning with LP gas of another brand to our usual BP, but it could have easily been the fact that it was 10-12 degrees hotter than the night before – or maybe a combination of both. Whatever the problem, the car was at least 3mph down on the previous night, and struggling to 60-foot below the two-second mark. Then the transmission temp alarm went off and the car started to smell of burnt trans fluid, throwing another wrench into the works.
Knowing that we still had to drive the taxi back to Melbourne, we decided to call it a day after eight passes – the quickest of which was a 12.47@116.9mph. The smell of burnt transmission fluid followed me all the way home, but the taxi handled the three-hour trip without a hitch.
Then we started exploring our options. We needed a new transmission; that was a given. So we had a chat to the guys at Preston Automatics. They’ve done plenty of tough BTR four-speed transmissions and it was clear that any kind of conversion (Powerglide, TH400, etc) was going to be ludicrously expensive. So we’re going to get Preston Automatics to do the work and we’ve bought a good second-hand XR6 Turbo trans to build up.
We also talked to the guys at TCE (Torque Converter Engineering) and discussed our needs, and they came back to us with a custom 9.5-inch converter with a stall speed of around 3600-3800rpm.
Back at MPW, we swapped the trans and converter out and slotted in the XR6 Turbo trans and TCE converter. On the road the difference was immediate. My first launch test saw the
converter rev to 3600rpm on the footbrake with street rubber (anything after that just turns into limiter-bashing wheelspin).
Now we can’t wait to get the taxi to the track. With plenty of extra rpm on the line we should be in the 11s without a problem – famous last words! After that we’ll pull the trans out for the team at Preston Automatics to rebuild and send the taxi back to Jason at Tunnel Vision for the second set of injectors. Then it’s just a matter of pumping in more boost until it runs 10s or dies – and we’ve got a couple of spare motors. We’ll let you know how it goes.