GN turbo
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Heel & Toe
Joined: Jun 2008
Posts: 17
Likes: 0
Not even close. 550rwhp is easily attainable on the factory stock bottom end and many have pushed in excess of 600rwhp and 650lbs. The rods are fine. When the power limit is exceeded, the crank gets pushed out of the block. I run a girdle to hopefully keep it together a little longer with the stock block, rods, and crank. 602hp and 620lbs for a few years now without a problem. Idles and drives like a stocker. Methanol injection enables this power on 91 octane.
Heel & Toe
Joined: Jun 2008
Posts: 17
Likes: 0
From experience of currently owning both an 86 GN and an 88 C4, I wouldn't do the swap. The turbo lag would drive a C4 owner nuts, and yes it would get worse mileage. I can't pull down 20 mpg with mine, and it's mostly stock. Not to say that I don't enjoy the car, it just kind of belongs in a Buick.
The GN motor isn't as kind to the driver as a TPI motor, you have to kind of time the throttle just right, too much at the wrong time and it'll respond slower, it's finicky like that.
The GN motor isn't as kind to the driver as a TPI motor, you have to kind of time the throttle just right, too much at the wrong time and it'll respond slower, it's finicky like that.
I totally understand the advantages of the NA motors, just trying to set a few things straight.
