Whereas early-on many of the TR (Turbo Regal) cars were over-boosted (over 18psi w/ pump gas) causing engine components (usually head gaskets) to fail; Tim's "new" 1987 Buick GN was well-maintained and unmolested, so it lasted many years and miles.
Back in the day we remember these black Buicks bursting on the scene running low to mid 14's right off the showroom floor. Its carbureted V-8 cousin (the Monte Carlo SS) would run mid to high 15's. TR's were known to trounce on TPI Vettes, TAs, IROCs, 5.0 Muskrats and even the baddest of the imports-the Nissan 300ZX Turbo. This well-know fact gave the Turbo Buicks a reputation--don't mess with that badass Buick.
Tim's chilled boost `87 will give us the opportunity to go back to the 80's and upgrade his ride using today's technology and higher quality components. Recent electronics are much faster to enable the precise amount of air/fuel and timing for a safe amount of added boost. There are many affordable (20-30 grand) late-model performance cars that run 13 to 14 second ETs out-of-the-box. The competition is much faster these days. Our goal is to update this early GM high-tech performer to surpass today's performance standards along with rock-steady reliability.
For the baseline, we drove the Buick to our happy testing grounds (Raceway Park, Englishtown, NJ). Tim changed all the fluids (engine, trans, rear) to Torco's line of synthetics. The filters (oil, gas, air and trans), ignition wires and plugs were replaced before the strip-test. We hoped this blast-from-the-past Buick would still run its number. Just like back-in-the-day we launched at roughly a 5-6psi boost (LED gauge hard to read and inaccurate), any more and the brakes won't hold. We let the trans shift for itself and ran a respectable 14.43 at 93.18mph with a 2.16 sixty-foot. That's actually great for a 23-year old, high-mileage, 3.8 Turbo. A half-hour later a back-up run showed us a consistent 14.45 at 93.18mph with another 2.16 sixty-foot.
The aforementioned ignition wires were the best-quality, carbon core (suppression) OEM type wires available from a local parts store. For a good comparison we ordered a set of spiral core "Livewires' from our friends at Performance Distributors. These much lower resistance wires will provide optimum spark to the plugs. We installed the Livewires during the usual 30-minute cool-down period. After a quick 2-second burnout we approached the starting line. After our launch the scoreboard lit up to a quicker 2.13 sixty-foot, and a 14.37 at 93.47 going through the traps. Considering the barometer was falling fast as the humidity increased (along with a 5-degree rise in temperature), amazingly the plug wires still managed to reduce ET.
It's understood that a turbocharged motor needs more air to inhale as it forces additional air through it. K&N has been the air filtration, air-flow leader for over 30-years. Tim brought along a K&N air-inlet system he purchased at the E-town Spring Swap Meet. Again we used cool-down time to remove the restrictive stock air cleaner and replace it with the hi-flow piece. Right away response improved as did the 60-foot (2.10) and the 1320-ft (14.25 at 94.53). Quite satisfied gaining 2-tenths for the bone-stock baseline we called it a day.
Dyno Tune Time
We pondered how much power this throwback to the 80's would produce. At the time GM underrated its turbo V-6 at 245 net horsepower. Would this stock boost (12-13psi) six-cylinder show us 200hp to the tires? To find out, we visited our close-by friends at Tune Time Performance in Toms River, NJ. Tune Time uses a Mustang Dynamometer, which will accurately monitor our test results.
Before our dyno test Tim installed a set of Auto Meter gauges to monitor the boost level and fuel pressure. TT's George Hatzinikitis ("Huzzy") strapped the GN to the rollers. Next it was tune-master Matt Hauffe (Tune Time's owner) putting the hammer down, but he had to lift, the air/fuel was too lean at 12.2 to 12.7 (11.5 to 12.0 is ideal). We raised the fuel pressure from 37 to 43psi (idle/no vacuum) to help the lean condition. In order for us to have a baseline, Matt made a risky pull for us--the A/F was only slightly lower at 12.1 to 12.4. This run on the rollers established a baseline of 208rwhp at 4000rpm and 256 lb-ft torque at 3000rpm. Boost maxed out at 13.1 psi.
Next we replaced the stock chip with a new custom street chip for 93-octane.
This Turbo Tweak chip (courtesy of Cotton's Performance) was designed to raise the boost to 17psi. When Matt attempted to make a full pull, he had to lift when the A/F climbed over 12.5 as the boost increased over 13psi. Next, Matt worked resetting the parameters using his scanner to tune-in 10-percent, then 20-percent more fuel-still the A/F was too lean, forcing early lifting on the gas pedal for incomplete pulls. After a 30-minute cool-down, Matt made a complete pull (with Tim's blessing, if it blows, oh well). The A/F was still dangerously lean (12.2 to 12.7) but with 17psi boost, torque shot up to 320 lb-ft (a gain of 64 lb-ft) with hp at 210 (only 2hp gain). These TB's make torque! At that we called it a day. We heard about the importance of a good fuel pump and the "hotwire" pump harness, which we should have installed before going to the dyno. Turbocharged motors need more fuel than naturally aspirated mills. With such an unsafe and lean A/F, we contacted Racetronix to order a high pressure/volume fuel pump assembly and their Hotwire fuel pump harness.
We spoke with our friends Jose Torres and Dan Smith at Jose Motor Sports (over 20-years of TB experience) explaining our lean A/F condition when we dyno tested. They said the first two things you must-do to a TB is replace the valvesprings and install a "Hotwire" fuel pump harness. Dan explained the stock springs were wimpy (80 lbs new, 60-70 lbs worn), and when you consider forced induction, it's hard for the valves to close under boost conditions. Learning that, we installed their recommended mid-90's LT1 replacement valvesprings (110lbs) and felt a noticeable power improvement. It also idled smoother along with better throttle response.
Next up we needed a sufficient fuel supply and called Racetronix for their super hi-quality fuel pump assembly and "Hotwire" harness. It was a true plug-and-play affair. Again, we felt a noticeable difference. Now we felt confident to revisit the dyno and see if we had a "fuel safe" A/F. We kept our fingers crossed the stock 28-pound injectors would be up to the task.
Once again at Tune Time, Matt plugged in his scanner after George secured the GN and calibrated the dyno's computer. The first pull showed we were up to 350 lb-ft torque and 223rwhp. On that pull the A/F was still lean at 12.1 to 12.3 during the power curve--this only meant we should have installed larger injectors to compliment the new fuel pump & "Hotwire" harness. For the minutes-later backup pull Matt dialed-in 10-percent more fuel. A/F was better down low (11.5 to 11.9) but still too lean (12.4) at the top of the pull. We decided to let it cool down (25-minutes) while Matt programmed 20-percent more fuel into the mix. This raised the torque to 358 lb-ft and horsepower to 239. The A/F was leaner and more unsafe 12.5 above 4000rpm. Looks like larger injectors will be mandatory before our next upgrade--we need Tim's 3.8 Turbo to stay alive!
All-in-all we realized big-time gains in torque (102 lb-ft) and 31rwhp. Not too shabby from just changing the chip, fuel pump, "Hotwire" harness and valvesprings. With such a big-time gain in torque, we mounted slicks to ensure traction for our track test. Unfortunately, we were rained out for our track dates and will report our gains in the next installment. Stay tuned.