does cam size really affect mpg?
#1
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does cam size really affect mpg?
Hi guys,
i know this sounds like a really stupid question, but how much of a difference does cam size play in mpg?
right now, i have a custom grind 228/232 .571/.588 113LSA in my car with a 3500/2.5 Stall, 3.73 gears and various other mods. I currently get about 12mpg in this car and its my DD. With gas price being above $3.00 i am debating going back to a stock form to gain a bit more fuel efficiency.
I know most people, including myself, dont buy these cars because they are fuel efficient but this is getting to be ridiculous.
Will I gain any increase in mpg by just changing my cam back to stock or even going with a smaller one (GT2-3 or so)?
i know this sounds like a really stupid question, but how much of a difference does cam size play in mpg?
right now, i have a custom grind 228/232 .571/.588 113LSA in my car with a 3500/2.5 Stall, 3.73 gears and various other mods. I currently get about 12mpg in this car and its my DD. With gas price being above $3.00 i am debating going back to a stock form to gain a bit more fuel efficiency.
I know most people, including myself, dont buy these cars because they are fuel efficient but this is getting to be ridiculous.
Will I gain any increase in mpg by just changing my cam back to stock or even going with a smaller one (GT2-3 or so)?
#2
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Yeh - it also depends on your tune. I have a mild street cam, ported heads and bolt-ons.... Mileage is OK at the moment.
I recently leaned out the car with LS1Edit. It gets much better mileage and is more powerful after the tune...
I don;t think you want to tear into your motor and rip out the old cam for the stock stick but it is your car....
I recently leaned out the car with LS1Edit. It gets much better mileage and is more powerful after the tune...
I don;t think you want to tear into your motor and rip out the old cam for the stock stick but it is your car....
Last edited by ACW; 09-09-2005 at 11:48 PM. Reason: no political discussion here
#3
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The smaller the duration/lift the less air/fuel you'll be putting into the combustion chamber = saved gas = better mileage. Of course it also depends on the tune, that can help or hurt your mileage quite a bit. I'd do it if you're familiar with cam swaps and are that worried about gas prices, but don't expect TOO much of a mpg gain.
#5
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It can be argued that a larger cam with lots of overlap to bleed off compression will require less fuel at lower rpms. If you can keep the RPMs low and drive gently, you should be okay...
I recently took a 300 mile trip home from upstate NY and averaged just about 28 MPG with my f-13 cam and 4.10s. Although my tires were at 36 Lbs for the trip, and there was about 1500 feet vertical drop to help me.
I recently took a 300 mile trip home from upstate NY and averaged just about 28 MPG with my f-13 cam and 4.10s. Although my tires were at 36 Lbs for the trip, and there was about 1500 feet vertical drop to help me.
#6
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I get just over 15MPG in town and ~24MPG on the highway with mods in sig.
Brian
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01 NBM Z28- A4 w/3.23s, TSP Black Lid, Hooker Catback, Pacesetter Headers w/ORY, ASP Pulley, Ported Throttle Body, TSP Torq. v3(231/234) Camshaft, TCI 4400, PRC Stg 1 Heads
Texas Speed & Performance
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01 NBM Z28- A4 w/3.23s, TSP Black Lid, Hooker Catback, Pacesetter Headers w/ORY, ASP Pulley, Ported Throttle Body, TSP Torq. v3(231/234) Camshaft, TCI 4400, PRC Stg 1 Heads
Texas Speed & Performance
www.texas-speed.com
(806) 866-0734
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I get about 19-20 mpg city and more like 25-28 mpg highway driving with a TR 224 112lsa and full bolt-ons. Just run your tires at optimum psi and keep your right foot off the gas to get better mpg. I don't think it would be worth the time to swap out your cam with a stocker to get slightly better gas milage.
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#8
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I'd look at the tune first too. 12 mpg seems low, I'll bet there is 2 mpg right there. To add to Robert's list, can the idle speed be reduced a bit and are you real rich at start up? Do you lock-up at a low speed in 3rd gear? Raising your 1-2 and 2-3 part throttle shift points by 2-3 mph may help as you'll ride the converter less.
I think it is safe to say that a smaller cam will be more efficent at low rpm, but the payback may not be there.
I think it is safe to say that a smaller cam will be more efficent at low rpm, but the payback may not be there.