Sorry. It isn't intended to be rambling. It's a matter of making sure that incorrect information or procedures aren't being provided here.
HELP major carb issues
- Thread starter 78mali350
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The fact that you rate premium gas as a must have shows your ignorance. Running higher than necessary octane will make less power, not more. Remember that the higher the octane rating, the slower the fuel burns. While you can make more overall power on high octane gas with an engine built for it, you will make less power with it in an engine that does not require it. I run 87 octane gas whenever possible in my vehicles, including my 265k mile daily driver. I run 89 octane in my 355 and it runs just fine because the combination of compression and total timing coupled with the combustion efficiency of the head/piston combo is sufficient not to require it. Both vehicles are quicker with lower octane fuels than with premium. Neither has any detonation issues as they are tuned right. The by gosh or by golly method of setting timing may work in a shitty stock engine with 8.5:1 compression, but is not advisable as it is easy to over advance the timing at higher RPM's and make less power. There's a good reason no one who knows what the heck they are doing runs more than 38 degrees total timing in a Chevy V8, and that is that it has been proven to make less power that way. Some more efficient combustion chamber designs like even less timing to make max power. Remember that the timing allows the combustion to start with the piston down further in the cylinder so that you can achieve peak cylinder pressure at TDC. That produces max power. Only with either a dyno or repeated testing on a drag strip can you determine the ideal setting by measuring the timing and it's effect on the power curve.
Backyard is backyard, stock is stock, and 600+ HP 383 is 600+ HP 383.
What works for one works, and for obvious reasons won't work for the next guy with something totally different.
If you drive a stock G body with stock power, you are one like me who obviously does not give a F what your strip or dyno power is. You tune backyard style most likely, and it works. With a standard exhaust, you can easily hear any detonation. Sometimes putting on a Flowmaster system as the first "performance" upgrade can be the worst enemy to the novice. I have used timing lights and lab tachs to set dynamic timing, but use my ears and senses to get whatever engine I have in my old cars to work the way I want it to work, that being smooth idle, no noticeable heavy throttle detonation, and good MPG. Tuning is an art with carbureted engines, and every car and engine is a different case. Overall driveability for your tastes is what is most important, not that you can beat the other neighborhood donkey off the line once a week.
-UT-
What works for one works, and for obvious reasons won't work for the next guy with something totally different.
If you drive a stock G body with stock power, you are one like me who obviously does not give a F what your strip or dyno power is. You tune backyard style most likely, and it works. With a standard exhaust, you can easily hear any detonation. Sometimes putting on a Flowmaster system as the first "performance" upgrade can be the worst enemy to the novice. I have used timing lights and lab tachs to set dynamic timing, but use my ears and senses to get whatever engine I have in my old cars to work the way I want it to work, that being smooth idle, no noticeable heavy throttle detonation, and good MPG. Tuning is an art with carbureted engines, and every car and engine is a different case. Overall driveability for your tastes is what is most important, not that you can beat the other neighborhood donkey off the line once a week.
-UT-
Yeah, my G body's drivetrain was built with a constricting set of parameters that most people building one would not try to abide by. The car had to be capable of being used for Pizza delivery. It had to have a stock idle quality. It had to have a Quadrajet carb and HEI as well as a stock air filter housing. It had to get better fuel economy than the stock V6, and the car had to run mid 13's in the 1/4. It had to be able to run on 87 octane gas if necessary.It also had to look stock under the hood and be able to use mostly stock tune up parts, hoses, belts, accessories, etc. So far, I have checked the combo using airflow data from Chevy High Performance and plugged it all in to Dyno 2000, and the engine seems to make the right amount of power for the weight of the car to be able to run mid 13's ( not together enough to run it down the strip yet), and when I was forced to drive it for a month, it got better fuel economy by about 2mpg city as compared to the V6. That being said, I have to know how to tune the stock parts properly to get the maximum efficiency from them, and as I have made several cars from carb'd V8's to turbo 4's with EFI run right, I do know what I am talking about.
Yeah, I have a job that requires me to work 50-60 hours a week and am a half time college student right now, so sleep is hard to come by. Tomorrow is my last day at work and I start a new job Wednesday that is 30-35 hrs a week so I can avoid insanity...lol
85 Cutlass Brougham said:
Seeing as we're already a little off topic...
Please break your longer posts into paragraphs? It's brutal on the eyes. 🙂
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