down shifting and not coasting - Toyota Yaris Forums

wushumasterku · 03-23-2006, 10:43 AM

Hi folks,
I have a question about driving manual. do you downshift all the time? or do you let you car coast to stop and use brakes when necessary?

i heard that the "modern" engines don't actually use any gas when you leave the car in gear. now is this same as downshifting (when they say leave it in gear?) but when you let your car coast in neutral, the engine actually uses some gas.

I'd like to hear your thoughts on this.

thanks

DJ_SpaRky · 03-23-2006, 11:13 AM

good question, I am interested to know too as this will be my first manual car.

celica girl · 03-23-2006, 02:59 PM

Personally I don't downshift unless I'm taking a corner. The way I see it brakes are cheaper to replace than a clutch. Unless you know how to rev-match properly when you downshift I say just pop it into newtral.

echo_hrs · 03-23-2006, 04:52 PM

Downshift all the way...If you downshift properly you're not going to wear out your clutch...

Sp33dY · 03-23-2006, 05:05 PM

I downshift 90% of the time ... Depends on what speed im slowing down from :) Sometimes go from 5th to 3rd to N, or 4th to 2nd to N, really dpeends on the road and conditions!

Idjiit · 03-23-2006, 05:11 PM

Heel-toe'ing is half the fun of owning a manual, so you bet I downshift/rev-match.

As for the technical question, I would be very surprised if downshifting consumed less fuel, but I suppose it's possible.

celica girl · 03-23-2006, 05:52 PM

Quote:

Originally Posted by echo_hrs

Downshift all the way...If you downshift properly you're not going to wear out your clutch...

Exactly... that involves rev-matching. I'm not too good at that.

SmellyTofu · 03-23-2006, 05:56 PM

Yes all modern engines from the 90's to now run on no fuel when it's at a certain engine speed so yes, downshifting runs over (general rule of thumb is around 1500-1700rpm for petrol.. lower on diesel) will use less fuel than coasting down but you wouldn't use all that much at idle anyway. It also helps emissions in case anyone really cares.

Idjiit · 03-23-2006, 06:04 PM

Quote:

Originally Posted by SmellyTofu

Yes all modern engines from the 90's to now run on no fuel when it's at a certain engine speed so yes, downshifting runs over (general rule of thumb is around 1500-1700rpm for petrol.. lower on diesel) will use less fuel than coasting down but you wouldn't use all that much at idle anyway. It also helps emissions in case anyone really cares.

Err... But downshifting would mean higher revs if you're maintaining the same speed.

why? · 03-23-2006, 07:01 PM

I use my brakes as little as possible, but I don't make the engine brake any more either, as that uses fuel. I just disengage the clutch and coast to a stop.

SmellyTofu · 03-23-2006, 08:28 PM

Quote:

Originally Posted by Idjiit

Err... But downshifting would mean higher revs if you're maintaining the same speed.

Your wheels run the engine when you're going down a hill in a lower gear (rather the other way around when you're accelerating). Engine speed doesn't mean you're using more fuel.

Out of interest, drive a car with a instantaneous fuel consumption gauge. You'll find idling at say 80km/h down a hill, you'll be using <0.5L/100km but when you're using engine braking, you'll be using 0.0L/100km.

TRD_Yaris · 06-10-2006, 05:40 AM

This is an EXTREMELY interesting topic..i've been wondering about this for many years. I love rev-matching on both up and down shifts, and I pretty much coast to slow down for stop lights. but, it would be really cool to use a measuring device to check actual fuel consumption (like in many 90's BMWs)..

boxerboy · 06-10-2006, 08:59 AM

When the engine is running it is burning gas. I have yet to wear out a clutch in any car. My highest mileage was 108,000 on a toyota tercel mostly city in Dallas. I was a service rep. Any way I almost always downshift, so if the light changes or the traffic starts to move I will be in the right gear to keep moving. When I see that the light has just turn red or traffic is not moving I will just brake. Of course that depends on the speed. I will downshift a higher speeds and not at low speeds.

sroberts · 06-10-2006, 10:38 AM

I used to drive big rigs when I was in my early 20's and always used the engine/gears to slow down, although the yaris doesn't weigh anywhere near a semi so you can't compare the two :) But, its less wear on the brakes and like what boxerboy said you are ready to go if traffic starts moving. If I know that traffic isn't going to move then I would put it in neutral the last 100 ft and use the brakes to stop.

Quote:

Originally Posted by boxerboy

When the engine is running it is burning gas. I have yet to wear out a clutch in any car. My highest mileage was 108,000 on a toyota tercel mostly city in Dallas. I was a service rep. Any way I almost always downshift, so if the light changes or the traffic starts to move I will be in the right gear to keep moving. When I see that the light has just turn red or traffic is not moving I will just brake. Of course that depends on the speed. I will downshift a higher speeds and not at low speeds.

Master2192 · 06-10-2006, 10:51 AM

When you are engine braking, the ECU turns off the injectors until the rpms get down to a certain value (~1500). This is very easy to see on a AFR Gauge or a scanner showing Injector duty cycle.

I rev-match downshift all the time, and it doesn't add anymore wear to my clutch and my brakes last 2x as long. I believe it is a skill that all manual drivers should learn. It is definitely an advantage to be already in gear if you need to start accelerating again.

ricko · 06-10-2006, 11:10 AM

This is a great thread. I had no idea that ECU technology was that "smart"!

Although the original question was in reference to coming to a complete stop, my comment relates to the car's behaviour while cornering. Downshifting and keeping the power on (even very moderately) has the advantage of keeping the suspension under load, which improves the car's ability to make the turn. It is safer to drive around a corner than it is to coast around. The process is: brake to reduce speed, downshift, and drive through the corner (the more skilled can do this all at once). This SEEMS to be especially true for front-wheel drive vehicles, although I have no concrete evidence to back this up. Maybe someone can explain the physics of cornering and braking in better terms for us.

plushDJ · 06-10-2006, 01:44 PM

I'll downshift from 4th to 2nd but that's about it

pennystocks · 06-11-2006, 12:42 AM

Bad news, the yaris doesn't "en-lean" when engine breaking. All the GMs i'v owned you could really feel it kick the fuel flow down when engine breaking. My aurora you could see then MPG increase when engine breaking, it auctually got less MPG when in neutral vs drive for coasting.

My scan gauge shows 0.2 Gallons Per Hour when costing in neutral for the Yaris. I did some engine breaking in 2nd and it was around 0.5 GPH. Also when you feel that slight engine break when coasting (you can slightly feel it kick in and out on my auto) is putting the PCM into open loop for a couple of seconds and the GPH is the same as in neutral. Also coasting it reads about 200-250 MPG and when downshifting it drops to 60-100.

I dont think there's a need for the yaris to enlean tho. I just did a trouble code test on a chicks car at work and her 2000 or so neon 4 banger showed 0.6 GPH at idle. I cant imagine what my aurora was at at idle. So thats round 5 hours for the car to idle out a gallon of gas. and 2 days to idle out a tank, not too shabby :)

So coasting in neutral is the best way in the yaris for MPG. BTW full throttle is around 6-7 GPH and normal driving is 1-3 ish and idle w/ the AC on is 0.3 and auctually shutting the car off while long coasting can add 1 or 2 MPG as long as its done on a normal basis. I have an auto so it kinda sucks to crank the starter 50 times a day. Just think of them as free miles that dotn cost you $$$ :)

03-23-2006, 10:43 AM	#1
wushumasterku View User's Garage Drives: 06 White LE HB 5spd Join Date: Jan 2006 Location: Toronto Posts: 173	down shifting and not coasting Hi folks, I have a question about driving manual. do you downshift all the time? or do you let you car coast to stop and use brakes when necessary? i heard that the "modern" engines don't actually use any gas when you leave the car in gear. now is this same as downshifting (when they say leave it in gear?) but when you let your car coast in neutral, the engine actually uses some gas. I'd like to hear your thoughts on this. thanks __________________ .

03-23-2006, 11:13 AM	#2
DJ_SpaRky Resident Scion Guy Drives: 2008 Mazda3 S Sport Join Date: Mar 2006 Location: Groveland, FL (Near Orlando) Posts: 285	good question, I am interested to know too as this will be my first manual car. __________________ Code: DiabolicJourney_SpaRky

03-23-2006, 05:05 PM	#5
Sp33dY www.OZTOYOTA.com Drives: Toyota Echo Join Date: Feb 2006 Location: VIC, Australia Posts: 239	I downshift 90% of the time ... Depends on what speed im slowing down from :) Sometimes go from 5th to 3rd to N, or 4th to 2nd to N, really dpeends on the road and conditions! __________________ www.oztoyota.com - Australian Toyota ECHO and YARIS Club

06-11-2006, 12:42 AM	#18
pennystocks View User's Garage Drives: 07 Civic Si Coupe(Black Pearl) Join Date: May 2006 Location: Chicago, IL Posts: 159	Bad news, the yaris doesn't "en-lean" when engine breaking. All the GMs i'v owned you could really feel it kick the fuel flow down when engine breaking. My aurora you could see then MPG increase when engine breaking, it auctually got less MPG when in neutral vs drive for coasting. My scan gauge shows 0.2 Gallons Per Hour when costing in neutral for the Yaris. I did some engine breaking in 2nd and it was around 0.5 GPH. Also when you feel that slight engine break when coasting (you can slightly feel it kick in and out on my auto) is putting the PCM into open loop for a couple of seconds and the GPH is the same as in neutral. Also coasting it reads about 200-250 MPG and when downshifting it drops to 60-100. I dont think there's a need for the yaris to enlean tho. I just did a trouble code test on a chicks car at work and her 2000 or so neon 4 banger showed 0.6 GPH at idle. I cant imagine what my aurora was at at idle. So thats round 5 hours for the car to idle out a gallon of gas. and 2 days to idle out a tank, not too shabby :) So coasting in neutral is the best way in the yaris for MPG. BTW full throttle is around 6-7 GPH and normal driving is 1-3 ish and idle w/ the AC on is 0.3 and auctually shutting the car off while long coasting can add 1 or 2 MPG as long as its done on a normal basis. I have an auto so it kinda sucks to crank the starter 50 times a day. Just think of them as free miles that dotn cost you $$$ :) Last edited by pennystocks; 06-11-2006 at 12:53 AM.

03-23-2006, 02:59 PM	#3
celica girl Drives: '00 Celica, '07 Yaris Join Date: Jan 2006 Location: Calgary, Alberta, Canada Posts: 49	Personally I don't downshift unless I'm taking a corner. The way I see it brakes are cheaper to replace than a clutch. Unless you know how to rev-match properly when you downshift I say just pop it into newtral.

03-23-2006, 04:52 PM	#4
echo_hrs Around the universe... Drives: Uber-Evolved Pokemon Join Date: Jan 2006 Location: Top Gear Test Track Posts: 228	Downshift all the way...If you downshift properly you're not going to wear out your clutch...

03-23-2006, 05:11 PM	#6
Idjiit 5 Stars, Bitches Drives: Prius, Silver Yaris Liftback Join Date: Mar 2006 Location: Holly Springs, NC Posts: 451	Heel-toe'ing is half the fun of owning a manual, so you bet I downshift/rev-match. As for the technical question, I would be very surprised if downshifting consumed less fuel, but I suppose it's possible.

03-23-2006, 05:56 PM	#8
SmellyTofu 好多人& Drives: . Join Date: Feb 2006 Location: Sydney Posts: 264	Yes all modern engines from the 90's to now run on no fuel when it's at a certain engine speed so yes, downshifting runs over (general rule of thumb is around 1500-1700rpm for petrol.. lower on diesel) will use less fuel than coasting down but you wouldn't use all that much at idle anyway. It also helps emissions in case anyone really cares.

03-23-2006, 07:01 PM	#10
why? Only Happy When it Rains View User's Garage Drives: Yaris LB Join Date: Jan 2006 Location: harnett county NC Posts: 4,097	I use my brakes as little as possible, but I don't make the engine brake any more either, as that uses fuel. I just disengage the clutch and coast to a stop.

06-10-2006, 05:40 AM	#12
TRD_Yaris Yarii Hunter Drives: 2007 Yaris Liftback and S13's Join Date: May 2006 Location: Austin, Texas Posts: 437	This is an EXTREMELY interesting topic..i've been wondering about this for many years. I love rev-matching on both up and down shifts, and I pretty much coast to slow down for stop lights. but, it would be really cool to use a measuring device to check actual fuel consumption (like in many 90's BMWs)..

06-10-2006, 08:59 AM	#13
boxerboy Drives: WRX ,Tacoma and Yaris Join Date: Apr 2006 Location: North Carolina Posts: 206	When the engine is running it is burning gas. I have yet to wear out a clutch in any car. My highest mileage was 108,000 on a toyota tercel mostly city in Dallas. I was a service rep. Any way I almost always downshift, so if the light changes or the traffic starts to move I will be in the right gear to keep moving. When I see that the light has just turn red or traffic is not moving I will just brake. Of course that depends on the speed. I will downshift a higher speeds and not at low speeds.

06-10-2006, 10:51 AM	#15
Master2192 Drives: 98 Subaru Impreza 2.5RS Join Date: May 2006 Location: Washington Posts: 11	When you are engine braking, the ECU turns off the injectors until the rpms get down to a certain value (~1500). This is very easy to see on a AFR Gauge or a scanner showing Injector duty cycle. I rev-match downshift all the time, and it doesn't add anymore wear to my clutch and my brakes last 2x as long. I believe it is a skill that all manual drivers should learn. It is definitely an advantage to be already in gear if you need to start accelerating again.

06-10-2006, 11:10 AM	#16
ricko Drives: Copper-Orange Yaris RS Join Date: Apr 2006 Location: Georgian Triangle Ont. Posts: 310	This is a great thread. I had no idea that ECU technology was that "smart"! Although the original question was in reference to coming to a complete stop, my comment relates to the car's behaviour while cornering. Downshifting and keeping the power on (even very moderately) has the advantage of keeping the suspension under load, which improves the car's ability to make the turn. It is safer to drive around a corner than it is to coast around. The process is: brake to reduce speed, downshift, and drive through the corner (the more skilled can do this all at once). This SEEMS to be especially true for front-wheel drive vehicles, although I have no concrete evidence to back this up. Maybe someone can explain the physics of cornering and braking in better terms for us.

06-10-2006, 01:44 PM	#17
plushDJ Drives: 2007 3 dr manual Join Date: Apr 2006 Location: Red Deer, AB Posts: 169	I'll downshift from 4th to 2nd but that's about it