Precision Turbo Upgrade On A 1987 Buick Grand National - Turbo Buick Basics, Part 3

Replacing A Tired Turbo And Adding A Handful Of Bolt-Ons For An Easy And Safe 49 HP

Dan Foley Mar 1, 2010 0 Comment(s)

Next up on our test quest was to exchange our throttle body for a ported stock unit from Jose Motor Sports. While working on the induction we would remove the plenum "hat'' (aka doghouse) and install an RJC Racing Airflow Distribution Power Plate. The RJC ADPP has proven, after extensive research and testing, to evenly distribute and maximize airflow to all the cylinders through the lower intake manifold. This enables the Power Plate to eliminate low airflow to the front cylinders, which notably cause lean knock timing retard conditions. It's a well-proven performer used by many of the fastest Turbo Buicks. Jose Torres (Jose Motor Sports) has high regards for the RJC Racing ADPP-he uses one on his 9-second ride (March '08) and mentioned we'll love the results. And we did. On our test loop, after installing the ADPP and ported throttle body, we felt better throttle response and a noticeable power increase.

1003gmhtp_11_o Precision_turbo_upgrade_on_a_1987_buick_grand_national Bell_tappers 1/28

Unfortunately, the next day on our ride to Tune Time we felt slippage in First and Second gear. Good thing dyno testing is done in the gear with a 1:1 ratio (Third gear in a 200-4R). The RJC ADPP lived up to its reputation, and we were impressed to learn that we picked up 15 hp (without any knock retard issues). This enabled us to add more timing (4 degrees) and fuel (10 percent) to gain another 7 rwhp. Now the A/F was at a safe 11.8 to 11.9:1 This was great considering our previously lean A/F conditions. At that point we left the new tune alone, thanked the Tune Time guys for all the dyno testing, and drove home.

In a perfect world we could have strip-tested the results from the new turbo, boost controller, bigger downpipe, and power plate, but in this real world the transmission went south, slipping away. We missed our track test day, but felt the Buick could have dipped into the 12s. Once the transmission is rebuilt and teamed-up with the right stall speed converter, we'll get to see what a gain of 117 rwhp and 190 lb-ft of torque is worth from the bone stock baseline (14.25 at 94.53 mph). Hopefully, the over-100,000-mile Buick V-6 motor continues to survive the added boost and the host of bolt-ons. Stay tuned.

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