I have a 3.4 DOHC power plant that has been through allot of upgrades. I have helped a few people over the internet for mods for their Grand Prix's. Unfortunately these mods that I have done are not inexspensive. The following areas of mods include, engine, transmission, computer, suspension, exhaust, brakes, tires and wheels and fuel system.
ENGINE
internally balanced to within 1 gram
block shaved 5 thousandth ( where heads mount to block )
heads shaved 10 thousandth
3 way angle seating on each valve (24 total valves)
heads ported to match gaskets ( not polished, this would smooth air flow to much )
(note : GM did not miss that much )
intake and plenum also ( as above )
I have an additional motor for parts. In which the heads I am going to have additional work done. The only info I will let go on this set is that they will have slightly larger valves. Approx. $750 per head not counting valves and lifters, lifters alone are $26 each. I will probably only gain 10 hp per head. But keep in mind, it takes 12 hp to go 1 mph faster. Not cheap huh ??
TRANSMISSION
My car was special order in Feb. 1992 with a Getrag 5 speed. So far the trans has held up. The only mod was a Centerforce clutch set. This past Feb, I removed the Centerforce set and replaced with a GM stock set. I do not recommend a Centerforce clutch in any front wheel drive car. The Chevy/Pontiac 3.4 DOHC V6 has weak spot, and that is the internal thrust bearing, which I have been through 3 and am on the 4th. The Centerforce pressure plate has a little too much strength and the clutch plate a little too much bite.
COMPUTER
I originally started with a HYPERTECH chip, but was not happy with it. I now have a SUPERCHIP INC. from Florida. So far I am very happy with it for Superchip custom built my chip for what has been done to the car. The rev limiter now hits at 8000 rpm, not at 7000 rpm. (sometimes I shift at 7000 grand- due to the chip, but very hard on the thrust bearing. the stock clutch is a little more forgiving on the thrust bearing. the Centerforce clutch is also harsh. the stock clutch set seems to be holding a little better. i have also learned that if your clutch slips a little at engagement, the torque curve comes up higher once the car starts to move.)
SUSPENSION
KYB Struts (front and rear) Front camber , top at 2 degrees in. Rear camber, top at 1 depree in.
Soon to come, rear adjustable camber kit. (available from Moog Chassis ) new upper struts mounts, front and rear ( hopefully from Energy Suspension )
EXHAUST
2 - 2 chamber Flowmaster Mufflers. 2 1/2 in and 2 1/2 out
Replaced converter with one from Random Technologies
BRAKES
Raybestos pad on all for corners
New powder coated caliphers from a local source
GT Rotors (all 4 corners)
GT Rotors were turned once and re-dimpled to 1/4 inch deep each side on the front
rotors and drilled all the through on the rears.
TIRES AND WHEELS
255 50 R16 BF Goodrich Comp T/A VR4 (front and rear)
TSW BLADES 16 x 7.5 (25 mm offset to compensate for original rims of 16 x 8
with 35 mm offset
FUEL SYSTEM
1987 Buick Grand National, stock GM fuel pump of 65 psi
1992 - 1996 stock fuel regulator of 40 psi
6 injectors from MSD Fuel management (which are GM Motorsport race injectors)
Each are 19lb per hour (4 jet)
Have 6 of 24lb per hour (6 jet)
Will install these when I have Superchip "re-burn" my computer chip. I initially
had these in early Jan 98 for 2 days for a test run. Car had a slightly stronger
pull through hard accelleration, but had a detonation between 4500 and 5500 rpm.
I drove a total of 33 miles and used 1/4 tank of fuel.
Here are a few more engine notes that I did not get to include on the first e-mail
Custom Ram Air via a hose from a Hypertech kit for a 93 and older Mustang and
using a cone air filter from K&N
Camshafts will remain stock--to exspensive to custom grind and won't really give
any gains due to still using a computer.
Compression Ratio -- 10:25 to 1 (11:25 to 1 once other heads are done, once this
is done, my engine will become an interference motor--laymans terms, slip
timing and jam a valve through piston)
185lbs psi in each cylinder due to compression ratio.
Spark plugs-- AC DELCO Rapid Fire no 8
so far I have not burned the tips of these. Previous Bosch and NGK V-POWER
were not so lucky.
Engine is producing currently 297 hp at 5600 and 305 hp at 7000, torque is 291 at
5500 and 280 at 7000.
After I do the additional injectors and head mods, it will should top out at
335 to 340 hp with out the help of NOS or any type of super charger. Boring the
current engine would gain and additional 12 hp but would give up a lot of strength
in the block. So I have let it alone -- so far !
Please email me back with either a reponse or suggestions or even a question.
Total invested is above $8500 -- this is including rims and tires. Horsepower is not
cheap to come by.
Thanks and Later, Jay