89305rs

Ok last year we took our camaros out. Mine had a worked 305 TBI and his has a 350 TPI. My 305 TBI was faster than his TPI 350. My car went a 15.5 and his was just a shade slower like a 15.55 or something. Now what could be the problem with his car??? It also has a hard start quite a bit. Could it just need a good tune up or maybe a fuel filter? And if that dosent work what could be wrong? Its also running quite a bit warmer than it should (220*) Could it be a filter starving it of gas and running it lean causing warm running temp and poor performance?? It is an 88 350 iroc. thanks for any advice-joe

89305rs

also what is stock Fuel pressure on these cars. Line on or off. Thanks-joe

87z-28man

theres alot of factors that go into it. were you both running the same tires? how "worked" is your 305? is his 350 stock? both automatics? rear gers may be the same. it could just be a good tune up needed, but you gotta sit down and look at EVERYTHING. let us know some more details and we can probably help with finding an answer

89305rs

Well Same time runs, His tires were 245s mine were 225s, I had 3.23 gears he has the 2.77 9 bolt, Mine had tbi mods, TPI heads, LT1 cam and headers. His is a stock TPI 350. My question is why is his car so slow. I know the TPI 350s were faster than 15.5 @ 89-90 mph.

87z-28man

they were heavy cars, the 350 TPI's didnt come stock with that much horsepower, only 220-245. it could be just the tune up like you said, or the engine could be getting tired. how many miles are on it? whens the last time it DID have a tune up?

RedIrocZ-28

Mine ran 14.989 @ 92 mph with 3.73 gears and a flowmaster muffler. 89 350TPI.

His car needs a 180* thermostat, new plugs, wires, distributor cap & rotor, and a gear swap to somthing like 3.73's. 3.42's would be more preferable if he were not going to go as heavily modded as I will be. After that, if he adds a new 2400 Convertor he may do just fine and be mid 14's.

89305rs

I just got off the phone with him. Im not sure when it had a tune up last. I know he hasnt done one on it. He has only owned it for about a year and it isnt driven much. We will be doing a tune up on it this week. He has a 180* thermostat and it still runs 220*. Im not sure on the milage. We arent looking to spend much on mods because were building a 370 stroker for it. But i was just making sure that there wasnt anything wrong with it for when he sells it later. He needs some of the money for the swap.

codyss

A 180 degree t-stat is useless. Nor does it have anything to do with his car running 15.5's

Two of my friends have 350 TPI IROC's one is a 1988 and the other a 1990. The 88 stock ran a 14.89 and the 1990 with very minor mods ran a best of 14.2.

89305rs

1) My car previously ran a 14.6 it was just one of the muggiest hottest days around here. It also ran a 12.7 @ 107 with a 125 shot. It had no tuning on the computer either.

2) We will be doing a FULL tune up on his car this week. I tested the fuel pressure last night and with the line off it was 42-43psi and 37-38 with it on.


codyss i never said that was the problem. I was just stating that with the 180* thermostat it still ran 220*. I also never stated that it had anything to do with his car running 15.5. I was however stating that a lean condition would make the motor run hot and the 180* thermostat didnt help.

Drkhrse89

First off his car running 220* is right inline with where it is supposed to. From the factory GM set the computer to turn on the primary fan at 228* and the secondary fan at 242*. Just putting in a t-stat is not going to get him running in the 180* range. You will either need to reprogram the prom to have the primary fan turn on earlier, put in one of those hypercrap fan switches, or hard wire the fan so you can turn it on as you please.

On the gear swap if you can find some gears for the 9 bolt cheap please let me know because I would like to buy them ALL. Those gears are really hard to come by, you would be better off swapping out the rear end with a fourth gen rear. If I remember rightly the 3.70 gears for the 9 bolt run about $250ish and the install kit is pretty high as well.

I agree with the rest on the tune up, make sure you are running a good plug, wire, cap/rotor combo along with the other maintenance like oil change, tranny fluid change, rear fluid change, fuel filter, and make sure the other sensors are in good working order like the O2 sensor, pcv valve, etc. Stock fuel pressure should be set at 37psi +-3psi. I personally am running at 34-36 right now because my car was running extremely rich for some reason. So the myth of just turning up fuel pressure to get more power is not a good one. A free/cheap thing he could do to help out would be the porting of the plenum, runners and lower intake to help it breathe a little more. I would start with the once over and then if he has the moeny to start swapping parts there are a ton of things he could do to make his car faster.

BOZS89IROC

Check the O2 sensors also. If they are bad it will send his fuel system into the "limp home mode". Although I think his performance would be much worse than 15.55.

Marc 85Z28

First of all, have you verified the engine displacement by VIN and engine castings?

Second, the early 87-88 350 cars weren't as potent as the later cars, especially when equipped with the single exhaust and ****ty 2.77s Remember, they were only good for 210-230HP depending upon year and model.

Third, is it that much of a surprise that a 305 with heads, cam, exhaust, and who knows what else kept pace with a stock 350?

92'RS-DFI

Engine temp has alot to do with how good your car run the 1/4 mile! I've tested this many times. Try running around 170-200. I used Redline Water Wetter and that worked great and so did taking the t-stat out and or running the fans with a switch in the staging lanes and getting the temp down. SO yes temp matters. With my TBI car I run 14.89 at 91 mph and the temp is 180 and the outside temp is 70f or so. If you keep the engine cool the car runs faster its fact!

BOZS89IROC

That is true. But I think it has more to do with keeping the intake air temp down. Which like you said keeping the engine cooler will prevent high intake temps and also reduce the risk of detonation. But the cooler the air entering the intake, the more dense it is and the more fuel can be added to it. That's why you have intercoolers for forced induction units and also why you see some people icing their intakes before a race.

Just my 2 cents.

92'RS-DFI

Very true!