Buick GN vs. Supercoupe specs....

I researched the compression ratio of each engine.Thunderbird SC: 8.2:1
1987 Buick GN: 7.8:1

Does anyone know which would have the advantage with the same power adder under equal boost? :confused:
 
More boost on pump gas with less compression..

Downside is loss of low end power...GN's have major turbo lag and not due to the turbo being to large
 
Iam insane!! I have 9.89-1 compression with 10% overdrive on the blower. It was bad news till I got the double intercooler and ic. fan. Now its awesome! I run 100 octane racing gas almost all the time and the car is not a daily driver. I plan oon doing as many more mods as money ditcates. I have heard poeple say tis is too much but now that the car is sorted out I love it. My boost is at 13 lbs.
 
Interesting!

I am basicly trying to guage the performance of my turboed Ford SC engine, and the closest comparison is Buick's turbocharged engine. Since we have more compression in our block does it mean that we can't make more boost off the line? :confused: It should be fair to say that we have an advantage of more torque off the line if we made the comparison of the two engines without any boost. My car is capable of 12psi (stock), but I am really curious as to what the turbo will produce. Any guesses? :confused:
 
tim said:
Iam insane!! I have 9.89-1 compression with 10% overdrive on the blower. It was bad news till I got the double intercooler and ic. fan. Now its awesome! I run 100 octane racing gas almost all the time and the car is not a daily driver. I plan oon doing as many more mods as money ditcates. I have heard poeple say tis is too much but now that the car is sorted out I love it. My boost is at 13 lbs.

HEHE! Tim I will have to ponder over this one for a few minutes. :)
 
is the comp ratio from the GN's the same as the GNX's you should try to find the specs of the GNX's engine i think they made somewhere around 275-300hp and upwards of 360 ftlbs i think there ratio was higher than the GN's something similar to the SC's
 
92silverlx said:
is the comp ratio from the GN's the same as the GNX's you should try to find the specs of the GNX's engine i think they made somewhere around 275-300hp and upwards of 360 ftlbs i think there ratio was higher than the GN's something similar to the SC's

Thanks man! I will look up that data if I can. :cool:
 
OK,OK, heres the scoop on the 1987 GNX

Manufacturer GM
Type V-6
in 90° vee
OHV
12 valves total
2 valves per cylinder
Main bearings 4
Construction cast iron block & head
Bore × stroke 96.50mm × 86.40mm
3.8 in × 3.4 in
Bore/Stroke ratio 1.12
Displacement 3791 cc
(231.341 cu in)
Unitary capacity 631.83 cc/cylinder
Compression ratio 8.00:1
Fuel system SMPFi
Aspiration Turbo
Compressor type
Intercooler Y
Catalytic Converter Y
Max. output
(SAEnet) 279.8 PS (276.0 bhp) (205.8 kW)
@4400 rpm
Max. torque
(SAEnet) 488.0 Nm (360 lbft) (49.8 kgm)
@3000 rpm
Maximum rpm
Coolant Water
Specific output 72.8 bhp/litre
1.19 bhp/cu in
Specific torque 128.73 Nm/litre
 
frank are going to run a different cam? i noticed the GNX made its peak HP higher in the RPM range and its torque peaked around 3K it might be a good idea to run a cam that allows you to make the most of your turbo setup
 
92silverlx said:
frank are going to run a different cam? i noticed the GNX made its peak HP higher in the RPM range and its torque peaked around 3K it might be a good idea to run a cam that allows you to make the most of your turbo setup

Naaaa! I have been assured that the stock cam should work out fine. Also our beasts are already set up for boost, so not many things will need to be altered except:
Exhaust,
Intake
Bigger intercooler
Fuel system upgrade
chip/or standalone computer
Turbo
FMIC
:D :D :D
 
V6Sprout said:
I thought the GNX was the turbo 8's and the GN were the turbo 6's :confused:


Both V6. One of the things that made the GNX special was a ceramic impeller. I can't off the top of my head remember what else they changed.
 
Frank,

You won't need a stand alone system, just a dyno tune and custom chip.

BTW, I finished doing all the turbo system prep work on my 347 today. Other than a slight coolant leak at the t-stat housing everything seems to be okay. I'm planning to take it for a drive tomorrow and make sure everything is working like it's supposed to. It sure was easier to start up with the MSD ignition wired up.

David
 
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David Neibert said:
Frank,

You won't need a stand alone system, just a dyno tune and custom chip.

David

Yeah! That sounds good, but I am also thinking of our new V8 turbo project that will begin soon after yours is done. :cool: My brother, Fred, and I have been talking about how his car will be done and a standalone system may be required. I am all over the place in my mind David, but my intentions are exactly like you mentioned. I have also been curious about XR7 Dave's talent in the chip arena. I will be talking to Dave after HP Performance shows us what they have to offer. Maybe Dalke can improve on it. :cool:
 
dirtybird91 said:
Yeah! That sounds good, but I am also thinking of our new V8 turbo project that will begin soon after yours is done. :cool: My brother, Fred, and I have been talking about how his car will be done and a standalone system may be required. I am all over the place in my mind David, but my intentions are exactly like you mentioned. I have also been curious about XR7 Dave's talent in the chip arena. I will be talking to Dave after HP Performance shows us what they have to offer. Maybe Dalke can improve on it. :cool:

Frank,

Just don't let HP talk you into buying a stand alone ($1500-$2000 extra) without giving the stock EEC and chip a try first. Like you said, your computer is intended for forced induction, so it shouldn't be a big deal.

The one I'm using isn't nearly as good and came out of a 91 LX, so if Dave can make it work, yours should be easy.

David
 
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