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.

 

I wouldn't be too surprised if the GNX ran these numbers very rarely under ideal circumstances only. Today's engine management systems have very precise monitoring of air flow, manifold pressure, air and engine temp, AFR, and the ECU can make adjustments on the fly. In the 80ies there computer management systems were still in their infancy, so the sensors weren't precise enough, ECUs weren't advanced enough, and very few people had the knowledge and equipment to work with them.

 

i love the grand national / GNX and would be very surprised if it ran those numbers... assuming lobuxracer is to be believed, (which i strongly think he is) the GNX is slower than a stock supra turbo which does the 1/4 mile half a second 'slower' than the GNX

and having driven a stock supra turbo, there's no way it makes 'only' 320 hp... my initial reaction was people need this to be even faster!?

anyway lobux already posted the C/D article for the GNX and they got 13.5s in the 1/4 mile which is very impressive but 12.7 (stock at least) will never happen... i'd love to be shown video evidence that proves otherwise though

 

Yeah, I don't see it either, 13.5 to 12.7 is just too far of a stretch.

 

Intake air temp is a major factor.

 

Sadly it wasn't just the encryption that made the Supra ECM uncrackable. G-Force had daughter boards you could have installed in the factory ECM with an EPROM, but they even admitted there was a great deal of the code they could not figure out, even with a native Japanese speaking tuner (a guy they called Tadashi). I have one of their modified ECMs sitting on the shelf. It died for some reason a while ago, which was pretty sad for me because it was difficult to see the difference between it and an OEM unit if you didn't know what you were looking at. G-Force went under and re-emerged as 4 Square, but that was a long time ago.

The NA Supras (2JZ-GE) had a distributor. The turbos (2JZ-GTE) did not. Over time the GE also lost its distributor and gained VVTi. IMHO, the GE head has vastly superior ports and makes a better performance engine, but the GTEs got all the attention. Sort of....

GM always designs for stoplight to stoplight performance on their bread and butter cars. I had a crap GM X car (Citation) I got to keep miles off my Supra, and even that thing was pretty spunky from 0 - 40 because it was geared to get up to speed quickly. It's not a bad choice for the motoring public at all. If you want top end, then, yes, cams, porting, intake, exhaust all need to be looked at to shift the torque delivery to a higher rpm.

The EPA didn't mandate open ECU data. They mandated the OEMs provide the ability to reflash their ECUs to update the operating parameters in the event something happened after public release. The Supra was one of the players in this. The EPA discovered the Supra had a "test mode" that was invisibly invoked under dyno conditions producing very different results (read very compliant) than the program that was used in normal operation. They were pretty pissed off about this, so they mandated the ability to reflash ECUs where Toyota had chosen a zero chance of modification in the late 80's and early 90's to comply with EPA rules saying the code should not be alterable.

 

Now this Mercedes engine might very well be the best 6 cylinder engine ever... at least so far.

 

Crap perfectly describes the build-quality and engineering of early Citations. I had a 1980 myself.......arguably the worst new car I ever owned, even worse than the notoriously sloppily-built Chrysler products of the period.

 

Since we were discussing the Buick GNX with the venerable 3800, check this video out - what a find with only 56 (fifty six) miles!!!


This looks to be Bensonhurst area of Brooklyn, NYC. Only a few miles from where I live, and my driveway isn't much wider than the one in the video.

 

the after result looks amazing! so what would it take to get this car into a state where it could be 'reliably' used on a daily basis?

 

Belts, hoses,change all fluids, tires... I'd have the radiator cleaned and pressure tested also. I wouldn't daily drive this type of car myself. What a find!

 

Oh the 3800 has a special place in my heart. The step off and low end torque in those were great. Stab the gas and you’re off in a hurry.

Lol I was on the freeway last night and was forced to gun it to get into my lane and I had to step on it pretty hard, ended up at 100mph (not intentionally). The car I was passing trying to get ahead of was an old Buick Park Ave with a 3800. Haha.

The interstates here have all turned full nuclear, racetrack.

 

If you remember, the Park Avenue Ultra (and some of its Olds/Chevy/Pontiac sisters) had the 3.8L supercharged.

 

best engine ever? i'd say the lexus v8 is right up there too!