1992 Pontiac Firebird - 10.7s for $6,500

Tim Juran's DIY Turbo, Daily Driver 1992 Formula

John Ryan Dec 18, 2007 0 Comment(s)
0707gm_01_z 1992_pontiac_firebird_formula_350 1/10

Tim Juran's journey began a couple of years ago when he spied a mint '92 Formula sitting on a small dealer lot. His ride at the time was a trusty but rusty '91 Formula that had started out black but now was turning an oxidized brown, courtesy of the road salt used over the last 15 Chicago winters. Only $2,200 traded hands, since the '92 Formula had already hit 180,000 miles. Tim almost made it all the way home under his own power, but the engine started knocking just as he pulled into his driveway. As already planned to swap in a forged 8.5:1 engine from his other Formula anyway, this was just a sign that he was destined to turbocharge the new one. Previously, Tim and his brother built a non-intercooled setup for the now departed '91 Formula, and it was a great learning experience-despite the fact that they did things like using PVC pipe as the ducting from the turbo to the throttle body. "Some of that first car was rigged, but heck, I was 18," he recounts.

Currently, Tim's Formula features a stock L98 block bored .030 over, stuffed with forged Speed-Pro pistons and GM 5.7 rods. The block is O-ringed and uses SCE copper head gaskets, a stock crank, stock L98 heads (with a little port work), and a TPIS ZZ9 camshaft round out the long-block. His intake features TPIS long runners and is fully port-matched. In addition to building the engine himself, Tim also rebuilt the factory 700R4 using Art Carr internals. As for the stock 10 bolt, he just added a TA girdle.

The Formula's fuel system uses stock fuel rails, 36-pound injectors out of a late model supercharged GTP, a Walbro 255 intank fuel pump, and a Kenne Bell Boost-A-Pump (with base fuel pressure set at 60 psi). Tim is also using a 749 ECM out of a GMC Typhoon. He re-pinned all of the connections, and used a supercharger tune he found on Thirdgen.org to get the car started. All told, Tim has burned about seven chips for the car over the last two years.

This turbo setup features a Turbonetics 62-1, 1.0 exhaust, along with a Greddy 4-Row intercooler. The intercooler, which was originally specified for a late-model Supra, fits perfectly in the nose of the Formula. He typically sees 14 psi during track passes.

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