5 speed question about MPG

[632 Regal]

wheres the link?

no i'm serious. 90% throtle. they did the test through a hole tank of gas and that combo got the best mileage. also the second best was 90% through 5000 rpm. look for the article!!!

[rob101]

the 528i E28 manual has info on when best to shift i think it was about 2k -2500 rpm. Seems to be about right with my e34 525i m50 as well. I don't pay much attention to the guilt meter (aka fuel economy gauge). i get decent mileage seems to be about the same as my e28 combined cycle to work mostly freeway 80km i use 10L which works out to be
12.5/100 km!! man thats ****

[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.

[SRR2]

Although this technique allows for reduced fuel consumption and elongates brake component life, it puts strain on the transmission internals.

Bah. There's absolutely no evidence of this, nor does any manufacturer I've ever seen issue precautions against the practice. The gears and bearings don't care a fig which way the torque is flowing. I've driven manual trans cars my entire driving life, I've always used extensive engine braking, I *rarely* have to replace brake wear components, and I've *NEVER* had the least bit of trouble with the 22 transmissions I've driven this way. Yes, they get good routine maintenance. No, I don't baby them.

[Jay 535i]

Bah. There's absolutely no evidence of this, nor does any manufacturer I've ever seen issue precautions against the practice. The gears and bearings don't care a fig which way the torque is flowing.

That's exactly what I thought. A 10 second coast from 50-0 doesn't cause any more wear than a 10 second accelleration from 0-50, which you do 20 times a day.