I have noticed that many LO3's even though they are modified in the same ways run way different times. I know that things like elevation and temp. are main factors but that shouldn't make that much of a difference, should it. Did GM make some of these engines better or what.

1991 Firebird Formula WS6
305 TBI 5-Speed 3.08 Gears
5.0 H.O. Dual Snorkel Air Cleaner w/K&N
5.0 H.O. Y-Pipe
Catco Cat
2 1/2 Intermidiate
Flowmaster Muffler
JET Stage II Chip Without Speed Limiter
180 T-Stat, Low Temp Fan Switch
Hypertech Pullies
MSD Coil, Cap, Rotor & Wires
Holley Ignition Module
Bosch +4 Plugs
1LE Transmission Mount
Zexel-Torsen Limited Slip Differential
Best time 14.573 @ 92mph



[This message has been edited by CODY BEHNKE (edited August 11, 2001).]

 

I think 90 till the end were the best.

 

They were the same technically. Like every other mass-produced item though, you'll get good ones and bad ones. Every once in a while you'll get a lucky combination of just the right parts to make for an accidentally perfectly balanced engine. Also the times differ depending on the options the car has weighing it down. Then there's the usual suspects: How well tuned is it, how good of a driver is behind the wheel, how well has it been maintained through the years, etc...

 

I was under the impression that they are all the same. My guess would be overally tune and condition of the engine is what makes all the difference.

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88 Camaro (The mighty LO3 SC!)
305TBI/700R4/2.73/122,XXX miles
14" Open Element and Flowmaster 80 seires

Next up: headers and gears

 

It's a package deal. Either you do the right mods or you waste money. Gears and posi are universal while a muffler can be a waste of money if you're using the stock pipes and y-pipe. Tim is running 14.2's with basic mods but he has edelbrock heads and 1.6 rocker arms (stock cam and bottom end). His car is also loosing weight all over (100lbs = .1 in the 1/4).

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, Jon (350 TBI!)
91 Red My website

 

chips are different in some too, and keep in mind there were 3 suspension options that many might not even know which they have which will effect times and feel. the chip differences may also effect feel of the car.

 

I agree with everyone else but I know what u mean by all these different times. I have seen stock LO3's run mid to low 16's all the way up to low 17's! Almost a whole second difference. I am sure the ones that ran low 17's need a good tune up but still. The right combo is the biggest thing. Right now, I am having that problem. It just isn't the engine, its also ur suspension/tires. Have to have a nice set of tires to hook or ur gonna get higher times than u should. I am running a 15.3 @93mph and I know I could get a better time if I boosted my fuel pressure and bought some better tires. Futra GLS from Pep Boys just ain't gonna cut it anymore and a full 3" exaust with stock fuel pressure settings is having my car run lean and the engine is pushing air out faster than the injectors can push enough fuel down the intake. Its little things like those that make the big difference. Like everyone else said, everything has to be in tune.

 

The compression ratio changed sometime around 90 I think. My '89 has 9.5 to 1 and toward the end they had 9.3 to one. I think the later ones are the better ones too.

 

Mine is basically stock. Only thing changed would be the air filter. My best run is 16.2 Is that about right, or should I be able to do better? I know I need a tune up bad. I mean nothing has been changed since it was new... unless it broke. I pulled the front two plugs, and they are the stock originals. They are so plugged and worn down it's ugly. I am getting everything I need to do the work, then I'll try to run again. I wanna break into the 15's. Any tips that I should try to improve my time? Besides changing engines?

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'91 RS 305 5.0L V8
Bowtie Grill & Lamps, K&N Air Filter, Centerforce Clutch, and of coarse kickass stereo

 

Well, yes 16.2 would be good on an engine that isn't tuned up right. When I got my car (and it was in PERFECT condition), I ran a 15.7 with accessories bypassed, and as much weight taken off as possible. I would have ran a very low 16 like you if my car hadn't been tuned up. But 16.2 isn't bad considering some of our TBI brethren are running 17s! I'd say 15.8-16.2 is a TBIs average run.

-ws6formula-

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1989 Pontiac Formula WS6
69,000 miles.
------------------------
305 TBI, 4.10 gears, SLP Zexel/Torsen Limited Slip Differential, 700r4 Corvette Servo, LT4 Hot Cam/Valvesprings, GM Aluminum Driveshaft, 2700 RPM Stall, Edelbrock Performer RPM intake manifold, Turbocity TB. Ran on 6-19-2001 again: UPDATED: 14.1 @ 97.68 mph. Dyno'd Bone Stock @ 172.6 rwhp, 266 ft-lbs. of rw-torque.