TURBO TAXI

WE’RE NOT READY TO POP THE CHAM­PAGNE CORKS YET, BUT THE TURBO TAXI IS GET­TING QUICKER BY THE DAY

Street Machine - - Contents -

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.

While rac­ing at Heath­cote saw us hold­ing a new PB – 12.000@121mph – the next day’s rac­ing at the Aus­tralian Ford Fo­rum Drag Na­tion­als saw the taxi run­ning off the pace with a toasted trans­mis­sion

Ex­ter­nally the two trans­mis­sions look the same, but the BTR95LE (bot­tom) is the stronger XR6 Turbo trans­mis­sion while the BTR93LE is the fac­tory unit from the taxi. It’s held up well con­sid­er­ing the abuse, but the time has come for a fully built trans from Pre­ston Automatics We’ve ditched the old con­verter and re­placed it with this brand-new cus­tom item from TCE. The old unit was lim­ited to about 3100rpm, but the TCE con­verter will let us hit 3800rpm on the start­line and should knock a cou­ple of tenths from our ET

It may not look like much of a dif­fer­ence, but the 30-spline axle from the XR8 rear end (left) should han­dle a bit more power than the stock 28-spline item (right). But the real rea­son we changed the rear end was for the LSD set-up Our new PB: 12.0009@121.33mph. Oh so close to the 11sec zone. Not bad when you con­sider we’re only mak­ing around 13psi boost and still run­ning on one set of in­jec­tors

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