Hey, sup. I just spent an entire summers worth of savings on an 1989 IROC w/ a 350. The kid I bought it off of had only had for a little over a year. The guy who had it before him apparently did a few mods to the car. It has sometype of siamese runners on it, no logos on the side or anything. It seems to fly pretty good, I was wondering if there may be other mods on it. How can I tell if a different cam been installed. Could I measure the distance the valve stems move or something? Also, First gear only lasts for a second or so when I floor it. Off the line it really takes off, I was thinking it may have steeper gears in the back. I pull 2000 RPM @ 60 MPH w/ a 700r4 tranny. Is this normal? Thanx guys.

 

Ohh, yeah it also has an adjustable pressure regulator. How do I play with this?

 

How's the idle? If it is lumpy and agressive sounding then maybe a different cam? Don't get a lumpy idle confused with a loud idle which would mean a low restriction exhaust. Take the car into the upper rpm's, does it still pull prety hard? If it does then probably a new cam. If the runners are siamesed then they could be SLP or AS&M. Too find the rear gear ratio, put the selector (gear shift) in drive, "D" NOT "OD", and bring the car up to 70mph. Look at the tach, take that rpm and divide it by 1000 to get the rear gear ratio. Example: I'm going 70mph with the selector in "D" and the tach says 2700rpm, well 2700/1000 is 2.7 which means that I have eighter 2.73:1 for a 10bolt rear or 2.77:1 for a nine bolt rear. Count the bolts on the cover it find which rear you got. To properly "play" with the AFPR you need to hook a fuel pressure guage to the schader valve on the passenger side fuel rail. Pull the vaccuum line off the regulator and plug the line going into the plenum. Start the car and note that pressure. The stock setting is 42psi. For a very mildly modded setup, like yours assuming you don't have a cam, I would think that anything over 45psi is too much. To adjust, turn the screw on to the AFPR and watch the guage. Do not go over 52psi, it will put a strain on your fuel pump that might kill it. Fuel pumps are not fun to change eighter!!
Have Fun!!

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1989 Iroc-Z L98 Original engine-58K miles!!

SLP 1 3/4 SS headers, Hooker Areochamber catback, no cat, BBK AFPR, Hypertech 160* fan switch, ported and gasket matched plenum, TB coolant bypass, relocated MAT sensor, screenless MAF sensor, K&N filters, Accel cap and rotor, Taylor SpiroPro 8mm wires, Bosch Platinum plugs, Mobil 1 Synthetic 15W50 motor oil, and more to come...
Best ET- 14.24@96.76MPH / 2.17 60ft on street tires with the crappy B/W 2.77 gears.

Homepage currently under construction: http://www.iit.edu/~wicktho/len

[This message has been edited by My Slow Iroc-Z (edited October 25, 2000).]

 

Get a chip!!!

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TPI 305,
Gutted airboxes,
gutted MAF,
K&N filters,
Corvette Servo.
14.9@93mph

"Speed kills, wanna live forever, drive a Ford."

 

I have an 89 IROC-Z with a 350 as well. Based on the fact that you say it takes off real hard off the line and first gear only lasts a second, and that you pull 2000 rpm @60mph..... you have a 3.23 rear. 2000rpm @ 60 with a 700R4 is the proper rpm for a 3.23 rear. I have the 3.23 rear in my car and the 700R4 and it comes off the line REAL HARD as well. This is because of all the torque, and because of the 3.08 first gear of the 700R4 mating with the 3.23 rear.

That combo equals deadly first gear. That is basically where I win my races, in first gear. It dies out in second because of the really large gap between 1-2 (3.08-1.90) so I take people off the line and beat them at the begginning.

Just throwin in my 2 pieces of copper.

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1989 IROC-Z
350c.i. TPI
rebuilt 700R4 with shift kit
3'' Monza Pacesetter cat back exhaust (minus the muffler)[SOUNDS OF THIS ON MY WEBPAGE]
new dual cats
3.23 Posi rear
hypertech chip
under drive pulleys
adjustable fuel pressure regulator
K&N Air Filters
Excalibur alarm, keyless entry and remote start
new:
struts, shocks, bearings, distributor, cap, rotor, alternator, battery, regulator
245 ZR16 50 Tires, Rotors and brake pads all the way around

Go to my webpage to find out more about it.
You can also see pictures, and hear sounds as well.
http://go.to/iroc-z

AOL IMer: JRShotliff

 

ya, I have 3:23 and am usually out of first by the time I get through the intersection, and like 89IROCZ i cruise @ about 2 grand at 60

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90 IROC 5.7l (L98)
ram air, K&N's, air foil,Flows