TA Performance and Duttweiler Engineering perfect turbo-V6 construction

How two speed shops perfected the balance between real street and “pro-street”

What it really boils-down to in the world of small motor building is that the bottom-end of the motor in-question, no matter how many cylinders, must be built to stand the utter beating that the applications of hi-po building exert. Without a strong bottom-end, the small-displacement motor that is setup for a high-performance application becomes no more than a potential “pipebomb,” except with pistons and a cam.

In a June 2009 issue of Hot Rod, writer Marian Davis laments GM’s--specifically Buick’s--habit of offering hi-po packages, only to revert backwards. The two specific examples that Davis cites are the ’70 Buick GS Stage I 455 and the mid-to-late ‘80s, Grand National. In referring specifically to Buick’s turbo V6, Davis comments further that there is still hope, as long as aftermarket builders/suppliers like TA Performance and Duttweiler Engineering continue to provide intercooled-turbo perf setups for Buick’s 3.8 liter mill, originally a cast-iron motor.

TA Performance in particular offers a custom setup for the turbocharged 3.8 motor, Buick’s now-famous “Turbo 6,” that actually improves some of the factory flaws found on the original, cast-iron motor. For example, the original Buick V6 block featured a relatively restrictive oiling system, with oiling jackets that were designed in a way that forced the motor oil to go through several, 90-degree turns before reaching the main reservoir in the oil pump and circulating throughout the rest of the engine. Both TA and Duttweiler have their own mechanisms for achieving maximum motor lube; TA Performance has re-machined the oil-feed holes in the block so that the B1 hole is slightly higher and better-aligned with B2, eliminating the 90-degree bypasses and allowing direct access to the main oil sump, where Duttweiler Engineering has developed an external oiling system, eliminating the use of the internal passageways completely. Another key feature of both the TA and Duttweiler V6 blocks is that they are aluminum, where stock Buick V6 blocks were cast-iron. The difference is that the aluminum motor weighs just shy of 300 pounds, while maintaining Buick’s factory dimensions; compact and built with a long-stroke, billet crank, the aluminum, 3.8 V6 makes a great platform for sand rails, touring cars and other performance vehicles that are built for off-road and/or handling.

Another key point where TA and Duttweiler have found the right formula for V6 performance is in the use of a 3.625” crank for durability, making durability a priority, by far, over weight. TA Performance, for example, is capable of producing 700 horsepower on a 3.8 V6 with twin turbos, producing a total of 18 pounds of boost with 112-octane race fuel. With that much boost, the engine builders’ emphasis is on bottom-end strength; since the motor itself uses boost instead of RPM to build horsepower, the crankshaft doesn’t have to wind sky-high to make the motor do what it’s supposed to do. The result is that the motor puts out substantial torque and power bands at relatively low RPMs. For example, Duttweiler’s V6 produces 707-horse at 5700 Rs, while peak torque is 668 foot-pounds at 4100 Rs. The V6 has a quick response time, which is uncommon for a small-displacement motor; Duttweiler’s V6 starts producing torque between 2500 and 2800 RPM. Torque output from 2900 to 3200 Rs exceeds 500 foot-pounds, and max torque, over 600 foot-pounds, is produced between 3300 and 5900 Rs, meaning that the turbo-6 produces power and torque that is actually manageable, something that can rarely be said for either V6 or V8 platforms.

The other design of importance is in the cam; TA Performance uses an even-fire cam grind with a 1977-and-earlier, odd-fire nose design with a removal distributor drive gear, a feature that prevents the cam’s thrust plate from crashing-into the front oil galleys, a common problem with stock, even-fire cams.

Like the block, these aftermarket turbo-6s use aluminum heads, featuring 1.6:1 rocker arms, small block valves with bronze-walled guides, 14-bolt patterns as opposed to the stock V6’s 8-bolt pattern, and metal-body/rubber-top valve seals to prevent oil consumption, a great cause of detonation in turbo motors.

Overall, both TA Performance and Duttweiler Engineering have mastered the art of small-displacement performance; they have built turbocharged V6s that are capable of being de-tuned for the street, while still being very-much capable of acting as pro-street setups; this balance is and always will-be the hallmark of great performance-tuning.

- Sal Alaimo Jr., B. A. (5/25/11)

S. J. A.