Altitude adjusted pulley question
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Altitude adjusted pulley question
The lowest elevation, where I live, is about 5,000ft. My car typically runs between 5,000 and 10,000ft. I know that I can run an extra 3psi or so to get it up to stock levels at sea level. I am going to buy the modular kit so that I can change them out easily especially if I go on a trip to a lower elevation. I am thinking that I will get the stock 3.8 pulley for my daily commute as well as the 3.4 for fun on the weekends. Now, the question. I will probably purchase two additional pulleys for when I do the heads and cam. What should I get? I would like one for the heads and cam setup that I will probably do in the next couple of years, and then one when I do a full buid-up later on.
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Mark, your mileage will likely go UP as you mod. The engine will run more efficiently. I'm one of the most heavily modded Series 1 L67'* here, and get the best mileage of all of them.
#4
Originally Posted by willwren
Mark, your mileage will likely go UP as you mod. The engine will run more efficiently. I'm one of the most heavily modded Series 1 L67'* here, and get the best mileage of all of them.
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Originally Posted by GonneVille
Originally Posted by willwren
Mark, your mileage will likely go UP as you mod. The engine will run more efficiently. I'm one of the most heavily modded Series 1 L67'* here, and get the best mileage of all of them.
Realistically a smaller pulley will lower your mpg though. Suppose you were flowing 300cfm at 2600rpm and that was enough to keep you at 70mph. Well after the pulley maybe you're getting that 300cfm at 2200rpm. You're not as deep into the pedal but 300cfm needs a certain amount of fuel no matter what rpm it happens at.
Mods that increase MPG are things like roller lifters, roller rockers (stock ratio), advancing your timing, upgraded ignitions, or any other thing you can do to make the engine run easier. Just so happens Will has most of that list
JMO though :P
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Originally Posted by willwren
Mark, your mileage will likely go UP as you mod. The engine will run more efficiently. I'm one of the most heavily modded Series 1 L67'* here, and get the best mileage of all of them.
I am going to do the intake, maybe headers, and leave it. I may get the modular pulley set, and leave it stock for commuting.
#7
Before my pulley swap, with an intake and downpipe, I was getting around 30 MPG on the highway. After I got my pulley swap (3.4") last November, I was getting around 25 to 26 MPG on the highway. It was also very windy out that day, so it may have affected the milage. After that, I got a set of ported manifolds as well as a PCM upgrade, and now I am around 30 MPG on a cold day on the highway.
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10-14-2005 08:00 AM