GNX In Current Issue of GM High Tech Performance


New Member
Feb 24, 2008
Current issue of GM High Tech Performance.

1987 Buick GNX - To Hell And Back - GM High-Tech Performance Magazine






The site or even the thought of a GNX as modified as Rob Schneider's would drive many (seemingly) rational people mad. But before you pass judgment, please take a second to hear the whole story. As a lover and former owner of several Grand Nationals, as well as several other fast cars, purchasing a GNX well over 10 years ago when the opportunity presented itself was a no-brainer. It was the king of Grand Nationals, iconic and legendary in status. What no one could have predicted, though, was that a few simple modifications would turn into a decade-long nightmare, or that it would actually have a happy ending.

Instead of a simple valve seal replacement, shop number one left Schneider's beloved GNX stripped of most of its essential components and left to rot before he rescued it. Though a bit gun-shy, he then took the car back home to Las Vegas, Nevada where a local shop was to start the rebuild process, but soon got in over its head with more than just this build. Several years later Schneider showed up with a flatbed and title in hand as the police helped him remove it after the shop had gone under. When the crew at Insane Speed got their hands on Schneider's GNX #442, they were pretty much given carte blanche to make a streetcar to live up to the shop's name and reputation. With a history of building twin-turbo Gallardos, Supras, and just about anything else you can hang a big hairdryer on--Insane Speed knew exactly what to do.

Since very little besides the factory block was left with the car, the shop really did have to start from scratch, which was just fine by them. Starting with the motor, the factory block was bored and honed .030 over before being treated to a GN1 Performance 3.625-inch stroker crank, Scat H-beam rods and JE pistons. Champion GN1 aluminum heads were also worked over thoroughly and CNC ported by builder Brett Bergeron before topping the motor with a Champion intake and Accufab 75mm throttle body. Brett spec'd out a custom hydraulic roller cam, drawing on his many years building Winston Cup and other high-end motors, and added T&D shaft-mount rockers. When put back into the GNX, the new bullet would also be treated to TA Performance tubular manifolds to feed a Precision 67mm turbo. The 4-bolt turbo would be relying on an external Turbosmart wastegate and GReddy PRofec B electronic boost controller to go from 20 to 32 psi once fabrication was complete.

Fabrication at Insane Speed started with a 3.5-inch downpipe, which followed its way all the way to the rear bumper with a 2.5-inch true dual exhaust. Magnaflow mufflers and an electric cutout were used to achieve the best of both worlds in sound. Meanwhile, back up in the engine bay, a cold air intake with a K&N filter and a front-mount, air-to-air intercooler (good for 1,000hp) was fabricated. Of course, providing the V-6 with plenty of cool, dense air is only half the equation. Matching that artificial atmosphere with fuel is where the crew at Insane Speed really shines. Since E85 is plentiful in Nevada, Schneider's GNX was treated to a custom fuel system to take advantage of its high-octane utilizing special Teflon coated braided lines and -10AN stainless hard lines. For the ultimate in reliability and safety, Insane Speed uses a Bosch 044 in-tank pump and a custom surge tank (under the car) with two more Bosch pumps. Owner Todd Allen says their CNC billet surge tank ensures that the GNX will never have to worry about fuel starvation, meanwhile the pumps are good for 500hp a piece on E85--so it will also never have any shortage of volume or pressure either. A Turbosmart FPR-2000 caps off the system, keeping fuel pressure at 45psi at idle and 100psi at wide-open throttle, which works well with the highly-responsive Injector Dynamics 1000cc injectors. However, most of the tuning is done through the FAST XFI system, which has Intelligent Traction Control to keep this 718-rwhp streetcar in check.

As wild as this build became, Schneider never wished to deviate too far from the factory in terms of the GNX's looks or trick suspension. As such, the stock wheels were deemed an essential part of the rebuild, however, the rears were widened to fit a 315mm Mickey Thompson drag radial. Similarly, rather than ditch the GNX's Panhard bar and torque arm, Insane Speed modified the factory parts to improve the geometry and increase bite. First the control arm angle was changed, and in turn the bracket on the factory torque arm had to be remade to bring the pinion angle back where they wanted it. The difference in ride height also required modifying the Panhard bar, so it was cut and the ends were modified--inserting aluminum bushings. Throw in some Spohn sway bars, QA1 shocks and springs, a Baer Extreme front brake kit (a tight fit with 16-inch wheels), and a set of Toyo RA1 front tires, and this GNX is good for more than just straight-line acceleration. In fact, it's more in-line with the supercar concept that the General had intended.

While definitely pushing the limit at times, Rob Schneider's GNX is by most accounts a tasteful updating of a modern classic. Though such a rare collector car is often best left untouched, this high-end build definitely does right by the legendary Buick and its creators at ASC/McLaren--a group that embraced technology such as the Precision turbo's new billet wheel or the slick traction control setup on the XFI engine management. The use of E85 as a fuel source brings the GNX even closer to the forefront, just as it was when the 1987 model was released. And for its lucky owner all of this technology means something else, the nightmare is over--at least for him. The competition isn't so lucky.
Great article, very nicely done.

When will all the commentary start? Like when my GNX appeared in Hemmings Muscle Machines several years ago. "how dare you modify a gnu", "you don't deserver to own it", "can't be a real GNX".

Nicely Done.

Will you be at the Nationals this summer, we park the two next to each other!!


GNX Or not, I think it's a bit tacky - especially the washer fluid bottle.

But of course - it's not my car, and as long as the owner has fun with it.....
VegasSE, nice to see you back on the board !! Cool Post !

Thanks man. Been awhile since I've driven one of the old dogs but MAN this car rips, and just as importantly...STOPS. Rob pretty much let us do whatever we wanted to the car to make it a street killer. :cool:
GNX Or not, I think it's a bit tacky - especially the washer fluid bottle.

But of course - it's not my car, and as long as the owner has fun with it.....

That was the owner's personal taste. He wanted color under the hood from the turbo 6 logo, so that's what he got.
That was the owner's personal taste. He wanted color under the hood from the turbo 6 logo, so that's what he got.

No worries. more power to him. It doesn't do anything for me, that's all. I will never have a car that a magazine would be interested in, so my opinion doesn't mean a lot. :)
I'm really wanting to redo my engine bay and I'm adding stainless washer/rad overflow containers to the list.