So what I'm wondering is say I'm going down the road 45 mph, and I see a red light a third of a mile a head of me. I'm in 5th gear, will I save more gas by letting my foot off the gas and leaving it in gear, coasting down to like 25 in 5th, then to like 20 in 4th, et., or is it better to just pop it into neutral and let it truly coast? In gear it slow down a lot slower, as the revs drop very gradually, but also the engine runs very inneficiently when idling. I kinda think just coasting with it idling is better, but I wasn't really sure so I wanted to know if someone here knows better than me. Thanks!
Your probably better off coasting in neutral. As you weed through the gears you are getting some amount of deceleration fuel cut off (dfco) but you would have also had to keep on the gas for at least 1/6 of the mile anyway.
Of course if you shut your motor off.....
edit: I see you have a 93, it is very possible that your fuel injectors don't cutoff on deceleration. You will definitely be better of coasting in neutral.
__________________ 2005 Impulse Red 4x2 Access cab 2.7L 5-speed SR5.
Last edited by worthywads; 07-22-2008 at 07:13 PM.
i would just coast in gear until you get to about 20-25 mph, then drop it into neutral. no reason to downshift however, just let your current gear run down your rpm and when it gets low, drop into neutral and get on the brakes. if youre going down a hill in neutral at 45 mph, chances are you will accelerate, which may not be safe if you need to stop all of a sudden.
at the same time, if the red light turns to green while your engine is at idle rpm at 30 mph, you would need to shift back into gear and rev match to avoid unnecessary wear on your clutch. unless you do this perfectly every time, you will either over-rev and possibly chirp your tires, or under-rev and force your clutch to do more work getting the engine up to the speed that it's supposed to be.
i hope i am making sense
__________________
three liters est. 1992
1.5 liters est. 2006
i would just coast in gear until you get to about 20-25 mph, then drop it into neutral. no reason to downshift however, just let your current gear run down your rpm and when it gets low, drop into neutral and get on the brakes. if youre going down a hill in neutral at 45 mph, chances are you will accelerate, which may not be safe if you need to stop all of a sudden.
at the same time, if the red light turns to green while your engine is at idle rpm at 30 mph, you would need to shift back into gear and rev match to avoid unnecessary wear on your clutch. unless you do this perfectly every time, you will either over-rev and possibly chirp your tires, or under-rev and force your clutch to do more work getting the engine up to the speed that it's supposed to be.
i hope i am making sense
Not much reason to rev-match, just poke it into the gear that will get you near 1200-1500 and everything is smooth. Engage the clutch and the engine will increase from idle to 1200-1500 without any fuss but be prepared to give it some throttle to accelerate away.
Why would you think 45+ in neutral might be unsafe. In a "sudden stop" situation anyone i know that drives a stick hits the brakes and the clutch at the same time so as not to kill the motor. There is no benefit to being in gear with the clutch engaged during a sudden stop. In gear engine braking only assists on steep or extended inclines where you would be riding your brakes anyway.
To knj27, your best guide is do whatever makes you use your brakes the least, followed by your throttle.
__________________ 2005 Impulse Red 4x2 Access cab 2.7L 5-speed SR5.
Not much reason to rev-match, just poke it into the gear that will get you near 1200-1500 and everything is smooth. Engage the clutch and the engine will increase from idle to 1200-1500 without any fuss but be prepared to give it some throttle to accelerate away.
Why would you think 45+ in neutral might be unsafe. In a "sudden stop" situation anyone i know that drives a stick hits the brakes and the clutch at the same time so as not to kill the motor. There is no benefit to being in gear with the clutch engaged during a sudden stop. In gear engine braking only assists on steep or extended inclines where you would be riding your brakes anyway.
To knj27, your best guide is do whatever makes you use your brakes the least, followed by your throttle.
Quote:
Originally Posted by ryuji16
i would just coast in gear until you get to about 20-25 mph, then drop it into neutral. no reason to downshift however, just let your current gear run down your rpm and when it gets low, drop into neutral and get on the brakes. if youre going down a hill in neutral at 45 mph, chances are you will accelerate, which may not be safe if you need to stop all of a sudden.
at the same time, if the red light turns to green while your engine is at idle rpm at 30 mph, you would need to shift back into gear and rev match to avoid unnecessary wear on your clutch. unless you do this perfectly every time, you will either over-rev and possibly chirp your tires, or under-rev and force your clutch to do more work getting the engine up to the speed that it's supposed to be.
i hope i am making sense
but i get what youre trying to say as well.
__________________
three liters est. 1992
1.5 liters est. 2006
i leave it in 5th until i'm about to stop or see that i will be going, in which case i throw it into the proper gear for that spepd
it seems to me, the engine really doesn't provide much in the way of stopping power unless you get the revs way up there.
True, if I engine brake I just feel like I'm using more gas and wearing my cluthch more. Neutral it is for me though, cuz I slow down faster going towards a stop, so I avoid the gas and the brake pedal until I'm ready to go.
And if your going 30 in neutral, you don't really need to rev match and you certainly won't chirp the tires, at least not on my little 110hp wonder w/ 31's. You just pop it in 3rd and your good to go.
True, if I engine brake I just feel like I'm using more gas and wearing my cluthch more. Neutral it is for me though, cuz I slow down faster going towards a stop, so I avoid the gas and the brake pedal until I'm ready to go.
And if your going 30 in neutral, you don't really need to rev match and you certainly won't chirp the tires, at least not on my little 110hp wonder w/ 31's. You just pop it in 3rd and your good to go.
Not sure why you think its using gas to engine brake?? When you are engine braking, its the momentum speeding up the engine...even if the engine revs to 4000, its NOT using gas to do it.
I'm not saying yoiu're wrong, but it seems to me that anytime the speed of your engine increases it would have to burn more gas in order to do so. Which now I'm kinda confused cuz how is it that the speed of the engine can increase without pushing the throttle, how does the engine run at a higher speed without any more fuel?
Hell yes you'll save gas as the engine is not running higher RPMs as it provides braking during the downshift process. I've always been a believer in taking the car out of gear and coasting. Also, since a manual vehicle is not in gear (unlike an automatic transmission) there's no additional force for the brakes to work against, and thus your brakes last longer. In all the manual vehicles I've driven I've always averaged 50,000 to 60,000 miles before needing brake pad replacement. One last thing. Not downshifting saves on the clutch too, and if there's one imutable lesson I've learned with clutches and that is when you have one repaired/replaced, it ain't EVER the same. My advice...take it out of fifth and coast....
TrailDust
__________________
-------------------------
2008 Highlander Base 4WD
2002 Avalon XL
1987 Suzuki Samurai 4X4 - Treading where no Jeep can follow....
The engine is running at a higher RPM because the momentum of the car, causing the wheels to spin, which drives of the tranny, which turns the engine. The Engine has a higher resistance to spinning at higher RPMs hence engine braking.
Now, newer Toyota engines have a fuel cut at around 1400-1500 rpms. That means when the engine is spinning above that RPM, and you do not apply throttle, there is almost no gas going into the engine because it doesn't need anything to keep it running. I'm not sure if its in older Toyota engines, but I don't see it being too hard to be applied so it should be.
The acronym "DFCO" is a recent event, but I'm not sure how far back it's been in use. Maybe it's always been around but the parameters are different.
It usually is in effect before 1200 rpms. under 1200, the engine gets fuel again.
An example:
For yaris *US models*... many 07s, dfco only kicked in when you were in 3rd gear or lower. Then in 08, Toyota implemented it in all the gears, you just had to be coasting in gear.
One way to tell...If you have a manual, go into 2nd gear, speed up to 25 or 30, which ever makes you surpass 3k rpms. Coast. When you start to get down to the 1k rpm range, if you feel a slight give-- I would describe it as seemingly to go neutral for a split second (as experienced in my yaris). You may have DFCO.
An easier way to tell is with a scan gauge. Set your meters to read gph, rpms, lod, mpgs. You're mainly paying attention to gph (gallons per hour). If your SG reads this: GPH: 0.00 OR 0.02 RPMS (ABOVE 1200) LOD: (UNDER 20) AND MPGS SHOOT UP OR READ 9999 ACROSS, ---- Then you have DFCO.
GPH may read 0.02 in older versions of SGs.
__________________
**ADAM! A/C button for Gen 5.5 Camry (2005 LE) !! Por favor!
Brake lights aren't broken, I just don't brake.
--Can honestly go to a parts counter and ask for brake shoes for the front brakes.
--Likes long walks on the beach.... once it's lit by a massive bonfire.
Last edited by RningOnFumes; 08-05-2008 at 06:40 PM.
^^ How new are we talking about? Would the Gen 3 Camry have such a mechanism? I always coast in gear unless I'm going downhill.
I'm not 100% sure, but my Camry did a weird thing with the RPM when I coasted between pulsing glides on the gas so I pretty confident that the 3VZ had it. When I let off the gas, the RPMs would drop and dip a bit and go back to normal.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
ToyotaNation.com is an independent Toyota/Lexus enthusiast website. ToyotaNation.com is not sponsored by or in any way affiliated with Toyota Motor Sales, USA, Inc. The Toyota, Lexus and Scion names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.
2005 Impulse Red 4x2 Access cab 2.7L 5-speed SR5.
You just pop it in 3rd and your good to go. 
Linear Mode
