I am considering buying an 87 gnx. I need some info on them and i figure you gm guys would be able to help. I need to know hp, 1/4 mile time, production numbers, and what you guys think one would be worth. The one I am considering buying has 4,500 miles on it, has never seen rain or snow. The owner of the car now bought the car two years ago with 2,500 miles on it. It spent the 8 years before that in a museum in california. Nothing on the car makes it look like it was ever driven. It is in absolutely perfect condition. The owner has all paperwork and the jacket and hat saying gnx and 241 (the number of the car) that came with the car. What is something like this car worth? Any help would be appreciated.

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91 rs, convertible, K&N, Edelbrock open element cleaner, 3.73, B&M mega-shifter, goodmark cowl-induction hood,tinted windows

 

Try this site. They're family over there.
www.turbobuick.com
They will be happy to answer all your questions.
547 were built. Typically, the magazines numbers off the showroom floor were 4.7 0-60. 1/4mi 13.40 @ 104. factory hp was 300.
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85 calif. iroc
383/A4
9" rear

[This message has been edited by calroc (edited February 24, 2001).]

 

In addition, www.buickgnx.com has valuable info and informative links.

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85 calif. iroc
383/A4
9" rear

 

I am not sure about the value of the GNX(I know it is alot though.) The power for the GNX was not accuratly reported by Buick though. It was faster than the 87 vette. GM however said that no two door passenger car could be rated higher than their top of the line vette. The Grand national was even faster than the vette that year. I think.

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1989 GTA TRANS AM
Was a TPI 305 & t-5 car.
Is now 383 stroker w/ the same T-5
World products Sportsman II heads. Lunati pistons and custom ground camshaft. Will dyno after the break in but is estimated at 450 hp and 520 ftlbs. The T-5 is on a suicide mission.

 

Yeah, most places say the gnx is the fastest american car to come out of the 80s, and i guess gm likes sying that the vette is the fastest gm car. A guy at slp told me that the firehawk is actually rated low in hp because gm doesn't want to advertise something as better than a vette, that was before the vette hp increased though (two years ago i heard it).

 

I have a friend who has number 251 GNX and it is up for sale for $38,000. It has 192 miles on it.

Pete

 

Only like 500 gnx were ever built ,no matter what buy that car,it sounds like it is the best example of a gnx i have ever seen,such low miliege"i know spelt it wrong"

 

The GNX was rated at 275HP and would run the quarter in the mid 12's. The car was faster than any Vette produced that year. The price new on the car was around 30k. Today, they are still about 30k as an average. Some people are asking upwards of 40, but that's their asking price. I don't expect that they'll see it. If I remember correctly, 0-60 was in the mid to upper 4 range.

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87 IROC 350 TPI with less than 10k original miles
www.users.uswest.net/~smoyer/iroc.htm

 

The GNX is fast,but did not run mid 12's when they were stock.0-60 in high to mid 4's,and quarters in mid low 13's.They had a factory rating of 276hp and 360tq but it was closer to 300.The Turbo T/A was slightly faster.



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1990 Trans Am GTA
Black/Black leather
350 auto 3.23 dual cats
SLP package
SLP torque converter
SLP shift kit
Fastchip PROM
245/50/16 GSC's

G-Tech
0-60 5.1 1/4mile 13.6@104

 

The 87 GNx was the fastest production car GM commissioned in the 80's. It was rated at about 275 hp and 360tq. Sadly it was all underrated for insurance purposes. It has well over 300 hp it smoked everything Gm had off the line and still does. A.S.C not GM build these beasts and only built 547 of them. These are the Grand Nationals to end all Grand Nationals, but these cars in pristine condition with less than 10,000 miles command anywhere from $30,000 to about $48,000. They have a specific rearend setup with a torque arm and a panhard rod. This is GNX specific and only owners of a GNX can get parts for this and the rest of the car with the vin#. The rear end has recently been reproduced but is not the exact replica. A.S.C made some changes with a more efficient turbo some ecm mods, exhaust, wheels and tires. The GNX is faster than the TTA due to these mods, if you want to take it for a spin do it,It'll be a ride of a life time. Don't be scared off if it runs rough at idle they all due before they warm up. With some very MINOR mods or left as is this is one serious vehicle to EVER roll of any assembly line. Good luck to you, I wish I were in your shoes there would be no doubt in my mind whether to buy it or not, a chance like this comes up once in a lifetime.

 

89 Callaway TT 6spd 0-60 4.2 1/4mile 12.4@115
87 Buick GNX auto 0-60 4.7 1/4mile 13.5@102
89 TurboTransAm auto0-60 4.6 1/4mile 13.4@103

What about a 89 Callaway TwinTurbo?It wasnt GM installed but neither was the GNX.That was the fastest GM car of the 80's though,and I Know the GNX's had slightly better off the line traction,but I still have to disagree with you on the GNX's being faster then the TTA,all the TTA's Ive seen stock had better times then the GNX,but its so close who knows exactly what was done to the cars as far as boost and chip etc.The TTA's were however much faster topspeed.I believe their was an old issue of Musclescar that tested 2 bone stock cars and the TTA won.I think this topic was posted not to long ago,but I forget if any the outcome was.Just for curiosity,I think I'll check over at one of the Turbo boards and see what they think.


[This message has been edited by black5.7GTA (edited March 01, 2001).]

 

Go to this site

http://www.buickgnx.com/

then go to pictures and files, then go to GNXvette.mpg

This was done a few years ago but it shows a GNX racing a Calloway twin turbo Vette. The Gnx won all 4 times they raced. You can read the little statement before downloading the movie.

So in response to your comment the GNX was the fastest car commisioned by GM in the 80's, and for the price of the Calloway you could buy 2 GNX's and still have money to insure it

 

Pino91Formula,go to www.turbobuick.com and see my thread on this debate.You will see some unbiased responses.

 

check the end of the thread that you started

 

Just to let everyone know all the buick info i stated here was stated by my friend who is A buick guy , and a Grandnational and GNX info expert. when it comes to GN's I go to him

 

You said this Callaway Vette Vs. GNX was done only a few years ago? Was the wear on the two cars identical (Same mileage and abuse)? There's a guy on this board with a stock LB9 IROC running mid 16's. My lightly modded LG-4 runs mid 15's. Does that mean that after a couple mods the LG-4 is the fastest IROC??
Even brand spanking new no two cars are identical. You can't judge the faster of the two by one race. Also I don't feel the GNX page is a good resource...

Those Callaway Vette's were insanely fast, I'm kind of having trouble believing that the GNX was hands down a faster car.

Just a comment, in that video, those cars sound like friggen jets! Want one want one want one...

 

Oh,thats where you got the unbiased opinion from For those of you that did not read my thread over there the outcome was, I stated the Callaway(89)was faster,quicker,then a GNX with the only rebut being a Popular mechanics article from 1987 in which a quarter of 13.4 is listed for the GNX and none was listed for the Callaway which lost,and was an 87 anyway,and supposeadly had a bad alternator and wasnt giving full boost.(Yeah I know excuses,excuses,the 87 still should be fster,but just barely)but the 89 was considerably faster,(6spd and about 50 more horses)and the times I listed on this thread for them(and the GNX)are the best I had seen or heard totally stock.I had the opportunity to drive in a 90 Callaway before(hopefully someday I'll get another one)and it felt like I was in a windtunnel As for the GNX,being the SECOND fastest GM production car of the 80's is nothing to sneaze at.

[This message has been edited by black5.7GTA (edited March 05, 2001).]

[This message has been edited by black5.7GTA (edited March 05, 2001).]

 

But as was stated by my friend the callaway vette was not a GM option you had to go get it done or purchase it through callaway , where as the GNX WAS A GM option , which was under warranty from GM , unlike the callaway.

 

yeah corvettes suck anyways(in my opinion) no one said which real GM car was faster. the TTA or the GNX, and where does the regular GN fit in the mix??

 

SuperZ,corvettes suck?Whatever.I guess your Z is the much better car As far as your question,through my experience,the GNX is quicker off the line due to its suspension,but by the end of the track the TTA will pass it due to just about equal power,better aerodynamics,and lighter weight.There are a lot of variables but I think its safe to say that the majority of brand new TTA's were faster than most new GNX's.Here is what I have on the GN

87 GN auto 3.42 0-60 4.9 1/4mile 13.9@99

 

i don't necesarily hate corvettes, i'm not fond of them though. i really hate most of the old rich farts that drive them around. if you are gonna have a car as expensive as a corvette, and a car built like a corvette, drive it like a corvette, not a chevette. and i'm only a poor college student who can't afford anything anyhow, so corvettes are way out of reach to me. besides i have always loved camaros, firebirds, and 80's G-bodies. corvettes just don't do it for me, sorry if i offended you. and i did not say my z was better.

 

superz you asked where does the GN fit into all this well i would say right behind the TTA and GNX, but for all production cars built in 87 the GN was the fastest in GMs line up. it beat the 87 vette in every category except handling and braking?(not sure about braking definetly handling though.) even top speed(which is hard to believe looking at the designs of the two cars but it did it). i believe they classified the GNX as something special, even though it was a GM vehicle modified with McLearen parts that could be bought at a GM dealership, since you have to build a certain amount to be classified as production and i dont think 547 cuts it could be wrong but the 87 GN beat the snot out of corvettes this i know. heres a good acronym for BUICK that i am sure every one has heard before
Best Use In Corvette Killing.
TINFY

 

I tend to dispute that the '87 'Vette's top speed was beaten by the GN. The GN's top end was governor limited to 124 mph. Any 305TPI Camaro would top that, let alone the 240hp 'Vette.

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85 calif. iroc
383/A4
9" rear

 

87 Grand National auto 3.42 0-60 4.9 1/4mile 13.9@99 Topspeed 124
87 Corvette L98 auto 3.07 0-60 5.7 1/4mile 14.2@98 Topspeed 154

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1990 Trans Am GTA,Black/Black Leather,350,auto 3.23,Dual Cats,SLP Package,SLP Torque Converter/Shift Kit,Fastchip,GSC's,G-tech 0-60 5.1 1/4mile 13.6@104
Previous Thirdgen
1986 Camaro IROC-Z

 

ok guess i am wrong but i could have sworn i read it somewhere that even the top speed was better. oh well i dont even remember where i read it. so how fast do you think they(GNs) would go if the govenor was removed? and why did they limit them to 124 mph man thats weak.TINFY

 

The basic mid 80's chassis/body design is still for a N/A low hp/tq V6 or V8/auto. Aerodynamically not the best for high speeds, either. Guess GM thought it wouldn't be safe much above 124. Cowl shake and other vibrations/noises will get you thinking. There are lots of GN guys going way faster now. Go to www.turbobuick.com and ask them how it feels.

 

Testing Testing 1 2 3.

 

Yes dont forget the T-types, and turbo-t's in all of this.

 

Agreed, Super6. They are not forgotten. Outside the Buick community we may tend to catagorize them in with the GN's when comparing performance to others, but they have their own personality.
PS. Wonder when this thread will be locked. This is, after all, an F body restoration/history site. Thank you Drew & Willie.

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85 calif. iroc
383/A4
9" rear

 

If the aero was bad at 124 then why did some NASCAR teams use them? At Daytona back in that day, no restrictor plates, everybody was running around 210 MPH.

My TTA had a governor also at 130 MPH at 4000 rpm's.

 

20-psi, You can't compare a production Regal to a Nascar tube chassis with sheet metal resembling a Regal for aerodynamics and ridgidity. And the body templates weren't even close.

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85 calif. iroc
383/A4
9" rear

 

You wanna know why GNs had speed limiters? Real simple. Goodyear Eagle GT tires with an s-rating. Strangely enough, GNs are allowed that far over the 112mph limit on S rated tires.
I never knew TTAs had a speed limiter. That makes no sense, as it should have came with V rated rubber.
...ed

 

They dont have a speed limiter. They would go 160+ off the showroom floor.



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Mike
1989 Turbo Trans-Am
11.25@121.25
Only had the valve covers off once... 106K miles and still going. 300+ Runs.

1998 Trans-Am LS1 6 Speed
13.10@106 Bone Factory Stock

 

I still have Motor Trend magazines from 1987 where there was a speed test of all the domestic muscle cars including the Daytona (hahaha) and the article clearly states that the test engineers couldn't ascertain the top speed of the Grand National because of a limiting chip installed due to the type of rubber GM put on the cars. When max speed was reached the cars had plenty left. BTW you could buy a better chip and z tires if you so chose once it was off the lot. Next time I'm at the parents place I will get the info if you guys want. It has ALL the speed times for the Mustang, Vette, Trans Am, Z28, Grand National, & Daytona circa 1987.

Cheers
Robin

 

How I found out about the limiter was friving south on I-95 towards Dc and saw several imports racing. I had to show them who was the king and took off after them and passed them with the pedal down the whole time. I looked at the speedo once and it said 132 at 4000 rpm. I stayed into it for about 15 seconds and looked down again and I was still at the same speed and rpm. I took the car back to the dealer, it was still new, and complained about it, they said it had a limiter built into the chip and no one should be driving that fast anyway

 

As far as that speed limiting comment goes, it is true. GM wouldn't let a car have a top speed over it's tire limit. That's why the IROC-Z's have the "Z" in the name. They came with Z rated tires and weren't speed limited due to this.

 

Your kidding right?Where the heck did you here that from?The Z in IROC-Z has nothing to do with the tires,it stands for Z-28!85-87 IROCS came with V rated tires anyway.

 

wow, i posted this topic a long time ago and didn't expect this kind of feedback. We passed on the car, we are waiting for a limited edition or final firehawk (not the 1000 produced 10th anniversary which is more than ever before produced). Thanks for all of the info, i really like the car, but a firehawk would be better in my eyes. And as for the z in iroc z, it is from z-28, but if i remember correctly 124 is the limit on a z rated tire (not that that has anything to do with any part of the iroc name.

 

I saw an episode of American Muscle Car on speedvision a few weeks ago and they said the 87 GNX had 276 horsepower after tweaking the intercooler and turbo.

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• Red '91 Z-28 350
• 700-R4 Trans
• T-tops
• no major power
  gaining mods, K&N
  Filter, Flowmaster
  exhaust -series 80-,
  exhaust cut-outs
• Best E.T. 15.0@93mph, Will improve that 1/4 mile time this spring.
• HardlinePerformance