Who is BS'ing who?

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cuda67 said:
805moparkid said:
and you badger people who get better milage than you LOL...

I am not badgering anybody kid, I haven't a need too. I am, was, trying to find out what the folks who claim better mpg are doing to achieve these averages. I would like to stretch my driving range that's all. Sixteen gallons of gas won't get me to Daytona at 8 mpg. I plan on changing to 3:55 gears but I don't think that will help my mileage just might help my hole shot. Changing to a lower gear will probably reduce gas mileage, imo. But thanks for your tech. advise.
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ok then i mis took the original post and im sorry...

well let me give you my thoughts in the gear thing....

if you drive around and most of your local speed limits are say 60-65... you obviously want to cruize at that speed...(unless your like me, a numbers chaser!)

now if the engine with that 230* duration cam is most efficent at lets say 2800rpm, then thats where the engine needs to be...

so now figure out what gear will allow you to go 60-65 at 2800-3K and i guaranty you your mileage will go up...

now i understand your thinking but revving the motor takes more gas... well that would be true if it was running less efficent than when the overlap and scavenging was sucking in extra fuel at the lower rpm than needed...

so what im saying is that good mileage doesn't equal low rpm's...
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805moparkid said:
now i understand your thinking but revving the motor takes more gas... well that would be true if it was running less efficent than when the overlap and scavenging was sucking in extra fuel at the lower rpm than needed...

so what im saying is that good mileage doesn't equal low rpm's...
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Yep, not always.
 
inkjunkie said:
My statement about my bike was not based on emotions, just 100,000 miles of facts, or should I say riding it. Not trying to argue with any Einstein that is present. No point in saying anything more for me, the only way to prove my statement would be for the doubters to ride the bike and verify what I have said....and the bike is long gone...
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I agree with you. I wouldnt doubt your bike got better mpg at 75 in 6th as apposed to 6th at 55 because as you said it was working at optimal rpm of the engine to make power. It probably uses a tiny bit more gas, but you are also covering more ground faster, Giving you better mpg so the little extra gas you use doesnt out weigh the ground you covered. Of course it probably would have even gotten better mpg working in the same rpm range say in 5th going 45, but this isnt the case because that is too slow for the highway. He and I did not claim faster in general = better mpg. Just at certain speeds at a certain rpm. I am no expert, but this is just my thinking on it.
 
805moparkid said:
cuda67 said:
ok then i mis took the original post and im sorry...

well let me give you my thoughts in the gear thing....

if you drive around and most of your local speed limits are say 60-65... you obviously want to cruize at that speed...(unless your like me, a numbers chaser!)

now if the engine with that 230* duration cam is most efficent at lets say 2800rpm, then thats where the engine needs to be...

so now figure out what gear will allow you to go 60-65 at 2800-3K and i guaranty you your mileage will go up...

now i understand your thinking but revving the motor takes more gas... well that would be true if it was running less efficent than when the overlap and scavenging was sucking in extra fuel at the lower rpm than needed...

so what im saying is that good mileage doesn't equal low rpm's...
Click to expand...

I used to think lower rpms meant better mpg as well. I noticed it for my first time driving 35mph in 3rd gear in my dart putting 1,300rpms down a long stretch of road along the coastline...It gobbled up gas way faster than at highway speeds...
Click to expand...
 
72DartCustom said:
I agree with you. I wouldnt doubt your bike got better mpg at 75 in 6th as apposed to 6th at 55 because as you said it was working at optimal rpm of the engine to make power. It probably uses a tiny bit more gas, but you are also covering more ground faster, Giving you better mpg so the little extra gas you use doesnt out weigh the ground you covered. Of course it probably would have even gotten better mpg working in the same rpm range say in 5th going 45, but this isnt the case because that is too slow for the highway. He and I did not claim faster in general = better mpg. Just at certain speeds at a certain rpm. I am no expert, but this is just my thinking on it.
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yea it sounds like it should work like that, except it always takes more power to go faster and more power requires more fuel, the increase in speed can never overcome the increase in fuel consumption,
they are called the "laws of thermodynamics" and they are the most basic fundamental principals upon which all mechanical things operate,
 
caferacerx said:
yea it sounds like it should work like that, except it always takes more power to go faster and more power requires more fuel, the increase in speed can never overcome the increase in fuel consumption,
they are called the "laws of thermodynamics" and they are the most basic fundamental principals upon which all mechanical things operate,
Click to expand...

"now i understand your thinking but revving the motor takes more gas... well that would be true if it was running less efficent than when the overlap and scavenging was sucking in extra fuel at the lower rpm than needed..."

I believe what 805moparkid is saying right there, is what is happening with my particular set-up. at lower rpms its drawing in more fuel than needed. It would make sense based off of my results. But I totally understand what you are saying. It would work that way all the time in a perfect world, but it doesnt because of factors that were just listed. if a gas engine worked most efficient at all rpms, then it would, but gas engines dont.
 
I think it's pretty clear at this point that people who know how to tune (or at least care enough to learn) are the ones who get the better gas mileage. Of course when you have the attitude of "I just wanna go FAST no matter what it takes" you won't care if your car/engine combo is set up for less than optimal efficiency. Want to just throw on a new carb and go? Think about it for a minute, how much fuel do you think is wasted having a 12.5:1 A/F ratio at cruise? And where is that fuel going, OUT THE TAILPIPE and collecting on the cylinder walls to wash away the critical tiny bit of oil that makes it all the way up there from the bottom of the bore. Not only are you wasting gas and polluting you are making your engine wear out faster, all for NO good reason IMO. OK rant over lol...
 
And just because I dont want to reply to this thread anymore. For anyone else who refuses to believe my experience driving my car, or refuses what anyone else has explained to what the cause may be..Then this is expecially for you..Well, I have a secret...My dart defies the laws of physics, they dont apply to it. My car rolls up every single hill. The closer I get to the equator, magnetic fields from the South and North Pole equalize. With 0 electromagnetic waves acting on my car, it only needs to exceed 80mph to break the sound barrier..Im only left to believe one thing. Someone has possessed my Dart.. Please help restrict the evil demons from my car... Dont let them contaminate me!

~Thanks
 
When I was in college during the "fuel crisis" of the early 1970s, I drove from Daytona Beach, FL back to home on LI. I-95 was not yet complete and the gas stations on the new parts of the interstate were few and far between in the Carolinas at that time. There was a concern that not many of the existing stations would be open all night and I did the drive without shutting off the engine for 22+ hours.

The car: 1968 GTX, 440, auto, 323 gears. All stock. Fresh tune. I had a set of Goodyear G70-15s on the rear for the trip. I bumped the secondaries to not open until about 65 mph. I had put Hedman Hedders on the car between semesters, but did not have enough cash for mufflers, so the only exhaust system on the car was the headers.

Because I wanted to get as much mileage as possible, I drove the car like there was an egg between my foot and the gas pedal. I kept the car at no more than 60 mph so that I could gage my progress by mile markers (1 mile per minute) to get an idea when I would reach the next town. I kept a miles/fuel log religiously.

The bottom line is that I was making about 400 miles per tank on the flats through Florida, Georgia, South Carolina, and North Carolina (I would start looking to gas up when the gas gage needle read 1/4 tank, however many gallons that indicated). Mileage decreased a little in the hilly areas of Virginia and again when more traffic appeared on the road in the northeast section of the trip from about Richmond, VA to LI. My computed mileage was around 20-22 mpg average for the trip through the flat lands on the over night part. I still might have the trip log somewhere.
 
FISHBREATH said:
When I was in college during the "fuel crisis" of the early 1970s, I drove from Daytona Beach, FL back to home on LI. I-95 was not yet complete and the gas stations on the new parts of the interstate were few and far between in the Carolinas at that time. There was a concern that not many of the existing stations would be open all night and I did the drive without shutting off the engine for 22+ hours.

The car: 1968 GTX, 440, auto, 323 gears. All stock. Fresh tune. I had a set of Goodyear G70-15s on the rear for the trip. I bumped the secondaries to not open until about 65 mph. I had put Hedman Hedders on the car between semesters, but did not have enough cash for mufflers, so the only exhaust system on the car was the headers.

Because I wanted to get as much mileage as possible, I drove the car like there was an egg between my foot and the gas pedal. I kept the car at no more than 60 mph so that I could gage my progress by mile markers (1 mile per minute) to get an idea when I would reach the next town. I kept a miles/fuel log religiously.

The bottom line is that I was making about 400 miles per tank on the flats through Florida, Georgia, South Carolina, and North Carolina (I would start looking to gas up when the gas gage needle read 1/4 tank, however many gallons that indicated). Mileage decreased a little in the hilly areas of Virginia and again when more traffic appeared on the road in the northeast section of the trip from about Richmond, VA to LI. My computed mileage was around 20-22 mpg average for the trip through the flat lands on the over night part. I still might have the trip log somewhere.
Click to expand...

the "egg between your foot and the gas pedal" is a perfect example of how to get optimum efficiency and maximum fuel mileage
 
OK lets talk about operating efficiency at different RPM ranges (for the sake of this discussion we must assume an engine in good working order and properly tuned)
efficiency being defined as the amount of fuel needed to cause the engine to turn one revolution
yes it is true that an engine can run more efficiently at a higher RPM, meaning that it takes less fuel to turn one revolution than at another or lower RPM range, and that does have some effect on fuel mileage
that doesn't mean it takes less fuel to turn a higher RPM, it just effects how much more fuel is needed, as it always takes more fuel to turn more RPM, because turning a higher RPM equals more work,
each revolution requires energy to move the pistons and rings up and down, to open the valves against the force of the valve springs, the faster you spin the oil pump the more effort is required, same goes for the water pump, alternator, P/S/ pump, fan, rod and main bearings, front and rear main seals, and every other moving part that makes up an engine,
so you must multiply the amount of fuel needed to turn one revolution by the number of revolutions, the difference in the amount of fuel used to turn one revolution will never offset the amount of fuel needed to turn more revolutions, no mater how much more efficient it is at one RPM vs another RPM

now if you would like to test this, just go out to your car and start the engine, let it warm up if you like, then gently depress the gas pedal and allow the engine RPM to increase, hold it there for a few seconds, now release the gas pedal and watch the corresponding decrease in RPM
the only conclusion that can be derived from this is
more fuel = more RPM
less fuel = less RPM
so therefore it must be true that the opposite is also true
more RPM = more fuel used
less RPM = less fuel used
and that is why increasing the gear ratio in the rear axle will always be accompanied by a corresponding increase in fuel consumption at any given speed, or lower MPG
 
caferacerx said:
OK lets try this again
it doesn't matter if the bike is long gone or out front with a full tank I don't NEED to ride it (although it would be fun) to disprove something that is a factual impossibility
to increase speed you open up the throttle
when you open the throttle, you "give it more gas"
when you give it more gas you USE more gas simple as that,
if it could go faster using LESS fuel you would have to close the throttle to speed up
so you are telling me when you give it less gas it goes faster?
now do you see how utterly ridiculous that sounds?
in order to increase speed you need to increase power
in order to increase power you need to increase the amount of fuel you give it,
and when you increase the amount of fuel you give something it uses more fuel not less
what is actually happening is your bike was geared at a much higher range than the average car, I am guessing around 20 MPH more combined with the much lower wind drag of a motorcycle, the amount of fuel it used to go 75 MPH was only slightly more than the amount of fuel it used to go 55 MPH giving the illusion of better MPG, in fact the difference in fuel economy was minimal, but in order to maintain 75 you need to crack the throttle open a bit more than you need to maintain 55 correct? :coffee2:
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Simple thing, at 55, with the way it was geared, the bike was lopeing along at an engine speed where it simply was not efficient where at 75 it was not. Theory does not always = real world. That being said it is somewhat apparent that you are far to hung up on theory to listen to anything except what you read in a book somewhere so I am not going to continue in a discussion where we "agree to disagree"........if I wanted to do that I would still be employed at the USPS........hmmmm.....by any chance you are not a supervisor for them are you???
 
caferacerx said:
yea it sounds like it should work like that, except it always takes more power to go faster and more power requires more fuel, the increase in speed can never overcome the increase in fuel consumption,
they are called the "laws of thermodynamics" and they are the most basic fundamental principals upon which all mechanical things operate,
Click to expand...

Your mistakes are:

1. "except it always takes more power to go faster and more power requires more fuel"

2. "the increase in speed can never overcome the increase in fuel consumption"

It all depends where your power band is and how aerodynamic your car is.

You have a mistaken, simplistic idea of the drag on a vehicle due to aerodynamics. You are generally correct but you have to specifically calculate it for a specific vehicle.

My 64 Barracuda also got better fuel economy at 70 than at 55.

Always believe what you have seen and experienced before theoretical BS. Don't be so fast to put down others, learn from their experience, yet keep a watch on the BS meter.
 
there is reality and there is fiction
and the reality is
IT IS IMPOSABLE
im·pos·si·ble
   [im-pos-uh-buhl] Show IPA
adjective
1.
not possible; unable to be, exist, happen, etc.
2.
unable to be done, performed, effected, etc.: an impossible assignment.
3.
incapable of being true, as a rumor.
4.
not to be done, endured, etc., with any degree of reason or propriety: an impossible situation.
5.
utterly impracticable: an impossible plan.

this is not theory this is COLD HARD FACT

two different vehicles can get different fuel economy's at different speeds, one getting better mileage at a 70MPH than another one at 50MPH, they can even be the same make model year engine gear ratio, the only difference being one is vastly more efficient than the other

and I am not talking about going at one speed, stopping tuning the engine, then continuing at another speed and comparing the results, that is not apples to apples, said car would get better MPG across the board with a proper state of tune, and worse mileage at any speed when way out of tune
I am talking about ONE car in a PROPER state of tune with all things being equal,
MPG will ALWAYS decrease with speed and RPM, there is just NO way around it
there are certain absolute truth's in physics and this is one of them
I mean come on people this is 6th grade science not advanced physics
common sense tells you in order to go faster you need to STEP ON THE GAS?
what do you think happens when you step on the gas? the throttle CLOSES?!?!?!?!?!
if that is what you believe then you have a lot of learning left to do,
I know common sense aint what it used to be but COME ON! this is ridicules
 
Well gentleman I'm surprised it lasted 5 pages but this threads time has come. Once an argument reverts from the everyday experience to discussion on aerodynamic theory what's next drag coefficients. I guess you'll all have to agree to disagree and move on, CYa.:hello2:
 
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