circusboy

iTrader: (2)

i am going to put a cam in my car and i was wondering how it would effect my gas mileage.

i've been doing some reading about cams and came up with this question.

what effects gas mileage more the duration or the lsa of the cam? or is there more to it than that?

777

iTrader: (21)

It's more of a combination of both. The biggest factor is your right foot so don't forget about that.

circusboy

iTrader: (2)

ok. let's assume my driving habits remain the same, lol.

777

iTrader: (21)

Ok if your driving habits stay the same you are still going to lose gas mileage depending on how big the cam is (duration and lift) and the lsa that it is on.

Basically take this equation:
[(int. duration + exh. duration)/4] - LSA then multiply the answer by 2

This equation is for overlap. It will tell you how much your cam "lopes" at idle. Since lope/overlap bleeds off compression you will use more gas at idle, and since any cam you get that is larger than the one you had previous to it will take in more air/gas mixture you will increase fuel consumption at any given rpm. So there is no way around getting worse gas mileage with a cam. Basically the more overlap your cam has the worse gas mileage you will get. This should be enough information for you to do your own research and plug in the cam specs to the equation.

circusboy

iTrader: (2)

Thank You 777

JoeyAnderson

iTrader: (20)

My cam certainly didn't help my gas mileage, lol.

It did increase power though, and that is what I was after. It's give and take.

Nine Ball

iTrader: (38)

Keep in mind that the addition of a longtube header system without catalytics will typically offset any losses in fuel economy from a cam. If you did a cam and header install, and didn't go too huge with the cam, your mpg will probably remain the same.

777

iTrader: (21)

True. Intake, headers, free-flowing exhaust w/o cats will increase your gas mileage.

Allergik2dyin

That is if you dont romp the **** out of your car because of the new power. It's very tempting.

777

iTrader: (21)

2nd post:

JoeyAnderson

iTrader: (20)

I got my cam and headers/full exhaust installed at the same time. Enjoying the new power, my miles per tank went from ~310 to right at 205.

DEFINITELY keep your foot out of the throttle if gas is an issue.

TTPBilly

13mpg??? ouch.. is that what most people with H/C are seeing?

JoeyAnderson

iTrader: (20)

I'm cam only, and I'm sure my results aren't typical. I bet I was at full throttle more than half of the time, and thats including the dyno tune.

I don't drive the car enough to give a consistent, normal gas mileage estimate! LOL

luv2spd

iTrader: (1)

My avg. seems to be down about 2 mpg or so.

Keenov

iTrader: (5)

Well, normally people don't run their tanks dry. He probably fills up just below 1/4 tank which would be around 12.5 gallons. So, 205 / 12.5 = 16.4 mpg.