question about driving standard autmobiles. - Page 2

DAM · 03-29-2004, 04:27 AM

Quote:

Originally posted by A~G
thatz what i mean though.. if he goes from 1st to 5th, he's going what... like maybe 50km/h... when he puts it into 5th it takes alot of fuel to keep it rotating and bring it up to speed???right?no? maybe? i dunno?

True, extreme engine strain on skipping that many gears

felixthecat · 03-29-2004, 04:44 AM

Quote:

Originally posted by BigD
Mathematically that doesn't make sense because you're achieving the same deltaV. But that's with a 100% efficient engine. Internal combustion engines are extremely inefficient, especially when working in our cars through a drive train - for every HP you produce, you waste almost as much (in a car it's probably MORE). So the less time you ask for your engine to work (force applied over a distance), the less energy you waste. So aside from the wear and tear on your engine and suspension, hauling ass up to a constant speed makes sense.

smart cookie.....ive actually seen a test by volvo proving that the best fuel economy was made by flooring the car up to 70kph and then aplying light throttle to maintain cruise,turned out to be more fuel efficient that steadily accelerating...this was over a 2 km distance....fact

ZiMMie · 03-29-2004, 05:01 AM

LAMO even zimmie knows better than that..

lvan · 03-29-2004, 05:04 AM

Bro we all see the case.....Just tel him not to miss shift ...

**thinair** · 03-29-2004, 06:13 AM

I go from 3rd to 5th all the time in my truck.

I too have read that it is more fuel efficient to get up to your cruising speed quickly, then shifting into your highest gear and cruising. Like if you're going to cruise at 80km/h, then shift through the first 2 gears, and when you get to 80 just skip 3rd and 4th and go straight into 5th. Just don't shift really fast when skipping gears. Let the synchro's catch up a little first, either half double clutch, or wait a second in N. My truck grind when going quickly from 2-5.

Like in my truck I can redline in first at 45, then shift into 5th and cruise from there

I cruise all the time at 50 in 5th, no strain, no noise. I just can't keep it in 5th if I have to go up any grade, or accelerate quickly. Keep in mind I never go from 1st to 5th, except as a joke when people are in my truck.

BigD · 03-29-2004, 03:10 PM

Nah. Your tranny is just a gear box. The total weight of the two gears being turned is the same. Their relative size changes. In 4th, they're the same, lower gear the engine gear is smaller, in 5th, the engine gear is bigger. But the slower you can spin your engine at a given speed, the less energy you're wasting. So "overdriving" your engine at constant speed is a good idea. Just make sure that if you're choking it down really low, you downshift before asking any significant acceleration because flooring an engine that's under maximal load at low rpm is the worst.

1st to 5th is stupid cause you'd just stall. But redlining 1st,2nd and then into 5th is fine. I sometimes do 2nd to 4th or 3rd to 5th.

Quote:

Originally posted by A~G
Ur friends a dumbass. at 5th gear ur turning larger plates in the tranny so naturally u need more fuel to keep it turning . wasting "gas" is more like it.

correct me if i'm wrong. I prefer to be corrected and learn something than to continue thinking i'm right.. (Big D ... aka Mr. Physics )

jeffrie · 02-11-2005, 09:16 PM

Quote:

Originally Posted by felixthecat

smart cookie.....ive actually seen a test by volvo proving that the best fuel economy was made by flooring the car up to 70kph and then aplying light throttle to maintain cruise,turned out to be more fuel efficient that steadily accelerating...this was over a 2 km distance....fact

This is what I do and generaly get better milage then most, thought I was just me not weighing much geuss my driving habit has something to add to this as well, 1st gear - 5th is pretty useless that gear maxes out the econometer no matter what your doing, 2nd to 5th I do alot in traffic, get up to speed quick, pass, cut off ect.. The quicker I get to cruising speed and not have to do the previously mentioned the happier I am, apperantly saving fuel as well.

sirex · 02-12-2005, 11:28 AM

this is a very old thread.

sadda///M · 02-12-2005, 11:51 AM

I always skip a gear in city driving.

From standing: 1->2->4-5
When moving up in light to heavy traffic: 2->4 or 3->5 and vice-versa when slowing down.

Skipping a gear or two is dictated by certain traffic conditions. Skip a gear it's good

sirex · 02-12-2005, 01:31 PM

I dont think the gears would be numerically sequenced if they weren't meant to be used in that order. Ie 1-2-3-4-5 However, say you are driving, on the highway, you suddenyl need to break.. So you clutch in, break, that will reduce your speed, so then you will need to drop at least 2 gears lets say... in a case like that skipping a gear is ok, least I would think so.

I dont think skipping a gear while accelerating really does anything, unless you are lazy, and feel like just poping it into a gear and leaving it their.. Is their any proof, aside from what people think, that there is any benefit at all? if there is, then cool. If there isn't, then it doesn;t matter as long as it doesn;t cause any negative effects to the vehicle.

Bmwstylz · 02-12-2005, 01:40 PM

I never skip gears! they are there for a reason... I personally keep my rpms in the power band all the time... 3500-4000rpm irrespective of speed.

My car was designed to do 4000 rpm all day on the highway, so I'm not gonna lug it around at 2500 in town to save gas.

sirex · 02-12-2005, 02:40 PM

yeah, and also just cuz you are a lower rpm, doesn't exactly mean you save gas either.

windwagen · 02-12-2005, 02:58 PM

Normally, If I'm getting onto a highway, I'll use 3rd for the ramp, then I'm doing 120 when I merge, which is the cruising speed. If I use 4th and 5th, I'd just be switching in and out immediately. WTF for? I go from 3 to 6. If I'm hitting it hard, but don't want to speed, I' regularly go from 2 to 6th. In fact, I don't use 5th much at all.

No one mentioned skipping gears downshifting. I go from 6 to 3 if I'm under 140kph. Under 90kph, I'd go from 6 to 2....but you'd better have your double clutch skills honed.

My gear skipping has got nothing to do with saving gas. University fuelathon cars use top gear (even at low speeds) and full throttle. The theory is that the mixture is lean at WOT and low engine speed. It's a formula for detonation and knock, for which one way to combat is to add more fuel. Make sense?

aziz · 02-12-2005, 04:56 PM

u can do it, but 2-5 might not be good all the time.

**thinair** · 02-12-2005, 06:20 PM

There is nothing wrong with skipping gears, as long as you stay within the RPM range of your motor, also when downshifting and skipping gears it's much better for the synchros if you rev match. Like if you doing 100 and your in 5th, and you slam on the brakes hard, there is no harm going into second if you rev match and engage 2nd below redline.