[(Flexion)]

I just had a few random questions about engine/gas consumption issues.

OK, let's say that I'm travelling along doing 35 MPH in 3rd gear. When I shift down to second gear, the engine speed pops up to around 3500 RPM. My question is, if I now push on the gas pedal, it will sustain that 3500 RPM engine speed but will the gas consumption be consumed more or less considering that it is the forward momentum of the vehicle to keep the engine speed that high?
:xcrazy:
And one more somewhat related question... If two identical trucks go side by side down the same hill, one in neutral, and one in first gear the whole time, would one use up more gas than the other besides the the time difference it would take before they got to the bottom?

 

[TQM3 (Last IFS in AZ)]

More rpm= more friction. You will consume more fuel this is why there are overdrives on modern vechicles!

 

[BigBadBob0]

Interesting thing about this is that my VW has a little digital gas mileage display (who knows how accurate). At ~70mph on flat ground in 5th gear the gas mileage is displayed as better (by as much as 5mph) than it is in 6th gear.

Luckily theory differs from practice all of the time and hence we shouldn't concern ourselves with such theories

 

[eep]

...mmmm six speeds...
do you know the gear ratios for the tranny? maybe they set it up so 4th gear is still 1:1, 5th is a slightly shorty overdrive and 6th is extra tall OD. So you really SHOULD be doing 90mph when in 6th for the best MPGs

Interesting thing about this is that my VW has a little digital gas mileage display (who knows how accurate). At ~70mph on flat ground in 5th gear the gas mileage is displayed as better (by as much as 5mph) than it is in 6th gear.

Luckily theory differs from practice all of the time and hence we shouldn't concern ourselves with such theories

 

[wslytoy]

well as far as the 2 trucks going down hill, the truck in neutral won't burn any gas at all b/c it can be done w/o the truck cranked, LOL!!

 

[JLtaco]

Your sig is friggin' funny, thankx for the giggle :rofl: :rofl:

 

[96tacolx]

And one more somewhat related question... If two identical trucks go side by side down the same hill, one in neutral, and one in first gear the whole time, would one use up more gas than the other besides the the time difference it would take before they got to the bottom?

Even if the truck in neutral is running it will use less gas than the one in 1st gear. It will also beat the one in 1st gear down the hill because the trannsmission won`t be holding it back.

 

[Nanotruck]

I wonder....

What would happen if I had a computer, narcotics, and some free time?

 

[BigBadBob0]

4th is 1.1
5th is .86
6 is .72

 

[mudferret]

I wonder....

What would happen if I had a computer, narcotics, and some free time?

You'd either be designing video games, or webmastering a fetish porn site.

 

[BLT2RCKTRD]

You'd either be designing video games, or webmastering a fetish porn site.

lol, if that isn't the truth

 

[not2XS]

Even if the truck in neutral is running it will use less gas than the one in 1st gear. It will also beat the one in 1st gear down the hill because the trannsmission won`t be holding it back.

Somewhere I got the impression that these trucks actually cut off fuel to the engine when it is being over-run (part of reducing emissions). Probably just my imagination. But if it is true, then zero fuel is less than it takes to idle an engine!

 

[not2XS]

well as far as the 2 trucks going down hill, the truck in neutral won't burn any gas at all b/c it can be done w/o the truck cranked, LOL!!

No engine braking & no vacuum for the brake booster. Fun ride

 

[rojodiablo]

Can tell you one thing about fuel consumption. Went to no.Cal to dive abalone, and cruised I-5 for some great mileage;19-20 mpg at 70 on cruise control. Decided to bump the go pedal after a pit stop, and that mileage PLUMMETED at 80-85 mph. Down to around 15 mpg for the extra 15 mph. Oh well. All in the name of science!!