i think it was in the doug review of the grand national, but he said the owner of that grand national bought the car back in 1987 after one pulled up next to his at the time brand new corvette and totally smoked him lmao

 

Ironically my Optometrist was the president of the local Corvette club for many years. But he gave his last Corvette to his oldest son when he went to college, and still has the Grand National.

 

well of course! the grand national is far more special with more performance potential

 

I smoked a GNX in my bone stock Supra in 1995 two different times. Easy pickins'.

 

Didnt know there was a series III

 

lol nice... was it actually a GNX or just a 'regular' grand national? i'd believe it either way i couldn't believe how fast a stock 1994 supra turbo felt, and that was after a year of already having the E55

believe me the supra is higher on my list of cars i want than an old buick regal with a turbo and some black paint

 

For sure GNX unless they were posers with GNX badges. The owners were very surprised. I suspect they were stock too. Lots of options to get more out of those things much like the Supra, and had either of them been modified, the Supra would have lost badly.

 

Just learned that the turbo charged version in the Grand National in 1978 already used distributorless computer controlled ignition. Impressive, especially that many engines used distributors well into the 90ies, LS400 using it until 1998.

 

For the final year, 1987, Buick introduced the limited production GNX, for "Grand National Experimental", at $29,900. Made in partnership with McLaren Performance Technologies/ASC, Buick produced only 547 GNs with the interior trim package, that were then sent off to McLaren and upgraded into the Buick GNX. Buick underrated the GNX at 276 hp (280 PS; 206 kW) at 4400 rpm and a very substantial 360 lb⋅ft (488 N⋅m) at 3000 rpm of torque,[10] although actual output is 300 bhp (304 PS; 224 kW) and 420 lb⋅ft (569 N⋅m).[11] This was created to be the "Grand National to end all Grand Nationals." Changes made included a special Garrett AiResearch T-3 turbocharger with a ceramic-impeller blowing through a more efficient and significantly larger capacity intercooler with a "Cermatel (ceramic-aluminum) coated" pipe connecting the intercooler to the engine. A GNX specific E-EPROM, low-restriction exhaust with dual mufflers, reprogrammed turbo Hydramatic 200-4R transmission with a custom torque converter and transmission cooler, and unique differential cover/Panhard bar included more of the performance modifications. Exterior styling changes include vents located on each front fender, 16 inch black mesh style wheels with VR-speed rated tires, and deletion of the hood and fender emblems. The interior changes of the GNX included a serial number on the dash plaque and a revised instrument cluster providing Stewart-Warneranalog gauges,[12] including an analog turbo boost gauge. Performance was measured faster than the Ferrari F40 and the Porsche 930 with a 1⁄4 mile (402 m) time of 12.7 seconds at 113.1 mph (182 km/h) (0.3 and 0.8 seconds quicker, 2.9 and 13.3 mph (21 km/h) faster) and a 0-60 mph (97 km/h) time of 4.6 seconds (0.4 and 0.3 seconds quicker, respectively).[13] GNX #001 is the 1986 prototype currently owned by Buick and sometimes makes appearances at car shows around the US. The GNX used a unique torque arm that was mounted to a special, GNX only, rear differential cover, for increased traction. The torque arm rear suspension alters the suspension geometry, making the body lift while planting the rear tires down, resulting in increased traction.

 

Electronic ignition is a bit older than that. Chrysler first started offering it in 1972 as an option, although admittedly a much simpler version than what is available today. GM and Ford waited a few more years.....till around 1975 or so, with the then-new catalytic converters.

 

Those performance numbers are entirely unsubstantiated, and likely someone's pipe dream. The real numbers in the articles below make it clear why a bone stock '94 Supra smoked a GNX not once, but twice in two different venues with two different GNXs and their drivers. Not enough power for the weight compared to the Supra (BTW, mine with a single modification puts well over 300 hp to the wheels despite being rated at 320 crank by the factory, and it weighs 3415 on a certified scale).

https://www.roadandtrack.com/new-car...987-buick-gnx/
https://www.caranddriver.com/feature...l-gnx-history/

 

Old FI cars were also notoriously hard to have running properly. They didn't have modern engine management systems. Even modified Supra's often didn't run quite right with aftermarket ECU, ignition systems, and fuel delivery systems.

It's nothing like today when you can easily get over 100hp with a simple piggyback or ECU tune on FI BMW engines without any adverse effects

 

But that's really where the GN-T and GNX shined. They were WAY advanced for their time in terms of engine management with distributorless ignition and knock sensing, and like the Supra, they responded extremely well to modifications and UNLIKE the Supra, you had people who could give you a different EPROM and make significant improvements. I really disliked how Toyota locked down engine management with their cars for AGES. Custom Denso processors, custom microcode ROM/instruction sets, using internal PROMs for critical functions, etc.. Strangely enough it was the EPA who forced Toyota to allow external software updates when all the domestics had been doing it for years. Don't get me wrong, I have a lot of respect for the Grand National turbo cars. It's not an easy win, and you might be horribly embarrassed even in a pretty fast car if you encounter a modified one.

 

yea i've always been very skeptical of those acceleration times for the GNX... 12.7 seconds in the 1/4 mile and 4.6 to 60? i mean my car stock will consistently run in the mid to low 12s (high 11s with slightly more slick tires but who's counting) and do 0-60 in the mid to low 4s so there's no way a stock buick that's two decades older with a 200 hp deficit and fewer more slowly shifting gears will put down those figures

i mean claiming it's quicker than a ferrari F40? lol good luck with that... also i don't think the McLaren that made the GNX is the McLaren that I've heard people claim it is

 

Supra ECU data was fully encrypted, so you could only do very minor adjustment tricks with piggy tails, but if you wanted to get serious with bigger turbo, injectors and fuel pump you had get an aftermarket ECU. They weren't even that expensive compared to the rest of the parts. I believe that at least earlier MKIVs had distributor ignition, and many people also swapped these with after market computer controlled ignition systems.

I know pretty much nothing about GNX, but I doubt its 80ies fuel injection system and ECU were advanced enough where you could gain much by reprogramming. GM did not have many FI applications, GNX was one of the very few, and I'm pretty sure for that motor it was already pretty much at the maximum from the factory. In the 90ies many guys reprogrammed their modified GMs, but these were mostly NA V8 guys. A friend of mine for shts and giggles reprogrammed a rental Chevy to have something like 40mph speed limit.

Still, if you wanted these big old GM engine to produce respectable power at the top, you had to get more aggressive cams, and because of their nature they idled like crap and ran like crap in the low RPM range. Good for drag strip, but utterly useless for daily driving. Japanese motors with variable valve timing could do both.

That being said, I didn't know EPA mandated open ECU data? I've heard quite the opposite, at least from the Ford diesel guys - some of the data is now encrypted in order to prevent people from getting rid of cats, EGR and DPF systems.