running very lean, what is the down side
running very lean, what is the down side
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Lean cylinders are hot cylinders. It can burn rings up and make you detonate. Why do you want to run it lean? Optimum power and efficiency is a tad better when you are on the lean side a little but the counter effects aren't worth it. If you get too lean you just damage the engine and get less power and efficiency.
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Elder User
Joined: Nov 2002
Posts: 526
Likes: 0
From: Spokane WA
With my 4barrel MC carb at Idle with a warm engine I alternatly turn in the fuel screws until I reach a ruff idle then turn out to a ruff idle then about half way between.
I have a comp cam extreme cam installed and the idle is a tad ruff.
I have a comp cam extreme cam installed and the idle is a tad ruff.
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
You are just adjusting the idle circuit. This really won't effect wide open throttle mixtures so you should be okay. You still don't want to run lean at idle. Adjust your idle mixture with a vacuum guage and find the spot where vacuum is the best.
Elder User
Joined: Jun 2003
Posts: 886
Likes: 1
From: Houston/Hope BC
Optimum power is made rich, around 12.5:1 fuel/air. Lean is good, just not too lean. Rich mixtures accelerate cylinder wall wear. This is one of the reasons modern fuel injected engines routinely exceed 150K or more miles. Better cylinder lubrication. Get an O2 sensor and display and tune right.
