1987 Buick GN Turbo V-6 - 10-Second TR

The radiator support bracket was removed previously by the owner while he was cleaning and painting the engine compartment, and the stock unit was replaced by a polished Champion billet aluminum unit. The two middle 10mm bolts that connect the bumper to its support are removed, and so are the clips that the bolts go into.

With the car raised and Jack Cotton standing on a ladder, Brian installs the intercooler from the bottom...

And it mounts with two bolts and 1/2-inch nuts on top, which Jack puts through the bumper support while Brian holds the cooler.

Brian drills out a 7/16-inch hole in the lower intercooler bracket, lines it up with the hole in the lower radiator support, deburrs the back side of the bracket, then slides in the bolt, washers and 1/2-inch nut.

He then test-fits the cooler's pipes before reattaching the plastic air dam's screws.

Check out how the Cotton intercooler looks behind Frank's grille--this is one of the biggest intercoolers for Turbo Regals out there!

One of the most powerful aspects of this 10-second V-6 build is the brand-new XFI EFI system by FAST. The fuel/air/spark crew, known for creating excellent ECUs in the past, has really pulled out all the stops with this one. Highlights include a faster microprocessor and Windows-based software, MAP sensor adaptability from 1 to 5 bar, a built-in wideband O2 system, boost control, built-in diagnostics, individual cylinder correction, fan, torque converter, and A/C control. And the Quik-Tune feature allows four levels of tuning to be summoned with the flick of a switch! With a simple adapter harness this powerful ECU is the perfect complement to the Buick Turbo mill.

Here, ATR headers are bolted up using SCE copper gaskets and a light coating of RTV. Note that the center bottom bolt hole hasn't been converted to a stud; the header clearance prevents it here, so an Allen bolt is used. Cotton's likes to convert over to ARP header studs for a build, as you never have to worry about stripping threads again. Once the header's washers and nuts are on, the headers are torqued "tight". One technique Cotton's likes to use is tightening these nuts multiple times, as the copper gaskets will settle in and loosen the nut a bit. Once it's been tightened four times, these gaskets won't leak.

Cotton's will be using a Turbonetics 70mm turbocharger with a P-Trim .82 A/R housing. As an ATR downpipe with an external wastegate will be used, Brian uses a template to correctly port the wastegate hole. Leave it as-is and you risk massive boost creep; and in internal wastegate applications, port it too much and the puck won't seal correctly. When it's the correct size, Cotton polishes the hole with a stone.