5 speed question about MPG

[pyro]

Hey I recently got my first manual car and was wondering when not driving it fast and trying to save gas or what ever what rpm should you shift? Like which is the best one for fuel economy?

[Jay 535i]

Hey I recently got my first manual car and was wondering when not driving it fast and trying to save gas or what ever what rpm should you shift? Like which is the best one for fuel economy?

Shift as early as is possible without lugging the engine. All things being equal, higher gears are better -- but don't lug the engine!

When coming to a stop, don't shift into neutral until the very last moment. With a manual transmission, when you are coasting in gear you are buring NO FUEL AT ALL.

[pyro]

Shift as early as is possible without lugging the engine. All things being equal, higher gears are better -- but don't lug the engine!

When coming to a stop, don't shift into neutral until the very last moment. With a manual transmission, when you are coasting in gear you are buring NO FUEL AT ALL.

Really so when engine brakeing the engine stops injecting fuel? i always shift into nutural.

[Jay 535i]

Really so when engine brakeing the engine stops injecting fuel? i always shift into nutural.

Yup. No need for fuel as the road wheels are turning the engine round. Watch your fuel-o-meter. It goes towards infinity during engine braking, but not during idling.

As soon as you shift into neutral, the engine needs fuel again to keep idling.

Stay in gear right up until the last moment. As the tach approaches 1, shift into neutral then.

This is good for your brakes, too, BTW. Use this technique consistently and you'll be amazed at how much less you're using your brakes. Just make sure you're blipping the throttle on downshifts so that you're not transferring all that wear to your clutch.

In fact, this technique will probably save you more on brakes than it will on fuel. In any case, it's good form.

[Kobe Diesel]

Yup. No need for fuel as the road wheels are turning the engine round. Watch your fuel-o-meter. It goes towards infinity during engine braking, but not during idling.

As soon as you shift into neutral, the engine needs fuel again to keep idling.

Stay in gear right up until the last moment. As the tach approaches 1, shift into neutral then.

This is good for your brakes, too, BTW. Use this technique consistently and you'll be amazed at how much less you're using your brakes. Just make sure you're blipping the throttle on downshifts so that you're not transferring all that wear to your clutch.

In fact, this technique will probably save you more on brakes than it will on fuel. In any case, it's good form.

Although this technique allows for reduced fuel consumption and elongates brake component life, it puts strain on the transmission internals.
In the long run, it would be more expensive to repair a transmission than to replace brake pads and rotors.

[kick7ca]

From what I've read, yes using 90% throttle and shifting early is most effecient. I believe the motor runs most effeciently at 100% throttle so the 90% thing makes sense. Get up to 4th asap and shift really early and don't lug the motor.

Whatever you do, the mileage still sucks in these cars. However I did SMOKE a brand new Acura RL! Very satisfying.

[Torque]

Does the 90 percent throttle then shift at low rpm work the same on the autotragic tranny too?

[Jay 535i]

Although this technique allows for reduced fuel consumption and elongates brake component life, it puts strain on the transmission internals.
In the long run, it would be more expensive to repair a transmission than to replace brake pads and rotors.

I don't see how this could put more strain on the tranny that normal driving. It's certainly less strain than full throttle acceleration. With proper rev matching, the strain should be minimal.

If it's anything to go by, I drive my 1986 Celica (200,000km) like I stole it. I've put 100,000km on it since I bought it. It still has the original clutch, which works perfectly. The transmission shows no signs of wear. And in that 100,000km I've changed the pads and rotors only twice.

[Anthony (M5 in Calgary)]

I don't see how this could put more strain on the tranny that normal driving. It's certainly less strain than full throttle acceleration. With proper rev matching, the strain should be minimal.

If it's anything to go by, I drive my 1986 Celica (200,000km) like I stole it. I've put 100,000km on it since I bought it. It still has the original clutch, which works perfectly. The transmission shows no signs of wear. And in that 100,000km I've changed the pads and rotors only twice.

Personally, I only downshift if I expect to need the lower gear. Otherwise I approach a red light in whatever gear I happen to be in and de-clutch as the RPMs near idle. Extra downshifts do add wear to the trans and clutch (albeit minor). Brakes are cheaper than clutch/trans.

From past attempts at mileage conscious driving, I can say I found little difference in consumption regardless of whether I drove easy or hard so I always choose hard. By hard, I mean heavy throttle and 5-6k shifts for most acceleration. Of course YMMV

FWIW, I get 14-15L/100km in city driving. 6 throttles, heavy car... My commute is not a gridlock crawl either.

[Jay 535i]

Personally, I only downshift if I expect to need the lower gear. Otherwise I approach a red light in whatever gear I happen to be in and de-clutch as the RPMs near idle. Extra downshifts do add wear to the trans and clutch (albeit minor). Brakes are cheaper than clutch/trans.

I never said he should downshift through the gears as he approached a stop light. Only that he should leave it in gear, as you say you do.