Potential Of The GN Engine w/Minor Mods

[Scottie-GNZ]

If anyone is comtemplating an engine and wondered about the potential of the GN engine, here is a link to some recipes for tuning this engine in stages. As you read it, keep the following in mind:

- The HP numbers are calculated from the car's performance so it is RWHP, not flywheel as most ads show

- A Z-car will be about 700-1000lbs lighter than a Turbo Regal

- When you look at the performance numbers and play "what if", figure on .1 sec quicker for every 100lbs less or plug the HP and weight in the formula Ron posted at http://www.race-cars.net/calculator/et calculator.html

- The hot SBC advertised at 460hp is probably 370RWHP. Notice what it takes to extract 350 from the GN engine and the next stage with a turbo upgrade made 430.

 

I played "what if" and plugged in a 2700lb Z with 350RWHP and got 11.5 @ 118.4 and with 430RWHP I got 10.7 @ 136. Derek Grubb is probably at the 430 stage with his 71Z and he ran 10.5 @ 129.

http://www.gnttype.org/techarea/recipes/Staged1.html

 

Scottie

[Scottie-GNZ]

Andy, thanks.

 

Pity your buddy with the Malibu did not exploit the GN drivtrain. For a modest investment of about $200, he could have bought a scantool to data log and tune and extract another 100hp without spending a dime on the engine.

 

I made mention mention of Derek Grubb's car in an earlier post and sure he would not mind if I continue to wax gloriously about it. The info in this link is a little dated and I posted the latest I know earlier. As you look at this car, ask yourself this: If you were driving a real hot street car and pulled up next to him at a light, would you give this car a 2nd look?

http://www.eng.fsu.edu/~jthagard/otherzs/Derek/derekGN.html

 

Scottie

[Andrew Bayley]

Scottie,

Visited your web site yesterday and I must say that I was very impressed. It’s nice to see a private web site that is well written and documented. Bravo.

 

Anyway, when I first heard of your GN conversion many old memories and ideas came up from the cellar of my brain. Back in the spring of ’97 my friend and I were going to swap in an 85 T-type drivetrain. Why an 85? Well, some guy out in New Jersey wanted $500 for a car that “ran perfect†with a smashed up rear. 568 miles later we discover the smashed up Buick and watched it run on a maximum of three of it’s six cylinders (poorly I might also add). We went back to Michigan and built up a turbo L28 out of junk yard parts. We were college kids at the time, so money was a big issue. Looking back on it, we are both glad we didn’t get the T-type. Most of the aftermarket parts for a Turbo Buick are for the intercooled version (late 86 – 87 GN’s). The non-intercooled EFI out of the 85 didn’t look like it was the trick ticket.

 

Also, another friend of mine put an 87 GN drivetrain into a 78 Malibu. Running 15 pounds of boost, the car ran mid 13’s. Not great, but respectable for a street car. Eventually he sold the GN motor and dropped in a 383 small block. Currently he is running mid 12’s on the motor. Yeah, the V8 is faster… but the turbo6 was a much better street motor (quiet, nice idle, etc…)

 

One more turbo6 experience (remember, Flint is in Michigan… these cars are everywhere around here). Last Summer I got my butt handed to me by an 84, plain Jane looking, 4 door, Cadillac Sedan De Ville. I thought I was going to waste this totally stock looking Grandpa car, but he ran off a 13.7 vs. my wimpy 14.9 (I was in my Impala, the announcer called it ‘Battle of the Barges’) As I pulled back into the pits, a shiny heat shield caught my eye. Yup, GN powered.

 

I agree that the intercooled turbo6 is a fantastic motor. I think the hardest part about doing something like this is actually finding a good drivetrain. However, I have to wonder how comparable the price would be to a small block of some sort. But the “awe†factor of an intercooled turbo6 would win over a small chevy any day. Well, in my world at least.

 

Happy motoring.

-Andy

[Andrew Bayley]

...nope, probably wouldn't give him a second look.

 

That's the beauty of these cars. A ten second ride can be masked to look bone stock. However, many of my friends make comments that my idle (350 V8) is a dead give a way. I guess this is where the Tubro 6 would help things out a bit.

 

-Andy