like he said... research it people.... sheesh...

 

The engine never "stops firing".... for every revolution of your 4 cylinder 4 stroke engine, you get two power strokes, meaning two cylinders will fire. If you downshift, and then completely lift throttle, your car will of course slow down but it will still be using gas. The throttle body is closed so very little air is getting into the combustion chambers, but some is and spark plugs will still fire and the injectors will still inject gas..... it's just such a small amount that the power made is not sufficient to overcome the other facters slowing your car down. So even at closed throttle, an engine turning at a higher rpm will burn more gas than one turning at a lower rpm. Engine braking will use more gas than braking in nuetral... but you'll never really notice the difference....

And proper engine braking is not bad for anything on your car... as long as you downshift properly, all the components of your drive train are doing what they're designed to do....

 

I still don't understand the concept of downshifting, is the car suppose to rev up high and rock back and forth after you downshift? If not i'm doing something completely wrong, Some one please help me

I'm always putting it into neutral to brake ; at stops, turning and what not. I attempt at downshifting here and there but like I said I think i'm doing something wrong. Say i'm going 35 into a turn, do I shift into 2nd in the turn or aftewards or before the turn!!??! As for the clutch am I suppose to rev match or something!?!?

 

Putting it into neutral to brake.. or downshifting. People have their preferences, I sometimes downshift because it sounds cool and I feel leaving it in neutral is dangerous. Anyways from a 45 into a turn- Visualize this: Release the gas, clutch, shift from 4th to 3rd and release your clutch a bit to rev about 2.5-3.5k (4k if you going too fast) apply some brake if you are going too fast into the turn for support. Still approaching the turn (~25mph), clutch, 3rd to 2nd, then release your clutch to rev around 2-3k (again brake if you don't want to rev too high and to give it support). You will actually "feel" it slowing down and as you approach the turn, now get ready to gas after you have enough to complete the turn, your rpm should be around 2k at the point of completion of the turn -Vrooom take off.

My opinion, I use downshift to control my downhill speed, to tailgate dumb drivers with that ROAR sound. However, most of the time I just let go of the gas leaving it in gear (never switching to neutral- dangerous) to slow down and down shift at a lower rpm, using the brakes as necessary. Down shifting is a racing thing which I don't do on the streets.

 

heel-to-toe!

 

In the old days when cars had carbs it worked like this. When the modern ECU notes the throttle is closed, it shuts off the injectors completely until the engine is down to idle speed.

I'm certainly not trying to say that engine braking is OK though. Really it's rediculously stupid. Y'all just keep on doing it, trashing trannys and blowing out syncros and giving the tC a bad reputation. It'll just cause Toyota to drop the tC's powertrain warranty back down to 36,000 miles too.

The ONLY reason to downshift when breaking is when your actually racing, to get into the gear you need to be in at the appropriate moment just as you are about to enter a curve -- and this is done as a heel/toe maneuver -- with a double clutch if you are trying to not wipe your syncros.

And yes, I was a mechanic for years, and yes I raced too. A long time ago. In fact my first car didn't even have syncros -- double clutching was *required*.

 

I won't argue with the fuel thing. I'll assume you're right as I'm not all that familiar with some of the more modern ECUs.... I still don't see the problems with engine braking... If I'm cruising along and decide to slow down by letting off the throttle, how is this bad for my tranny or clutch??? so then I get to the point where my rpms are too low for my current gear and speed so I downshift... push in the clutch, change gears, blip the throttle, let out the clutch... how is this in any way damaging to drivetrain components whose sole purpose is to transfer powder between my engine and my wheels???

 

thats why its called downshifting i drove the $#!t outta my 5spd man civic for 6 years and never had tranny problems

 

Alright I have been really practicing downshifting lately, now the only problem is how do I come to a complete stop? The slowest I ever get is around 20 some MPH, how do I get to speeds around 5? Thanks

 

i've been manually shifting my max for 3 years+ and put about 80,000mi on original tranny and it still shifting strong. still on original tranny. nissan design automatic with "O/D, 2, and 1" for a reason. if it's bad shifting manually on an auto, they won't even design "O/D,2,and 1" on the car. so it's there for a purpose. i shift my auto proper at correct RPMs and match up with whatever speed i'm at to control my car better.

quoted from maxima.org....

 

i just drop it into neutral always. alwayssssssssssss. that is just me though.
uh i'm pretty sure they created the different gears in an AUTO is if you need to go up a hill or tow something you have that extra power to pull. it is not made for shifting

 

lets resurrect an old discussion. i believe this is the case.
however, i would need proof. the proof would involve downshifting, then switching the car to off. then switching it back on. what would the result be? if no sudden drop in rpm and nothing crazy happens, then this proves the theory

the case for old 97 corolla was different. i had leds hooked up to the signal wires for the injectors. it was an automatic. when i would downshift or let off the gas, the inner 2 injectors, #2&3 would turn off and the outer 2 #1&4 would flash more rapidly.
this only told me that the outer two injectors simply took over the job of the inner two and the same amount of gas was used.

 

I downshift most of the time, but never to 1st. The lowest ill downshift is 2nd. I also only downshift when going around corners you dont have to stop at, if its a straight stop I throw it in Nuetral.

 

Im sure when your foot is off the Gas pedal there is still fuel being delivered. I know most Hybrid vehicles do this, but they actually shut off completely and the car will coast to a stop.

 

Nothing more needs to be said, imo.

 

well not that this applies completely to our engines, but there ARE engines out there that will completely cut-off the fuel.
http://www.jakebrake.com/
installed for large commercial vehicles. (aka BIG trucks)

i believe that even if there is still fuel being delievered to our engines when we downshift and not apply gas, being in neutral will still use up more gas.

especially for downhills... i would strongly suggest downshifting instead of using the brake.

 

on an auto switching to neutral aids your brakes in that they don't have to work against the "impulse" power of your car in first.

 

So much misinformation...

I've been working on this stuff for years as a mechanical engineer. First, all fuel is NOT cut off when you take your foot off the gas pedal in gear. A smaller amount of fuel is being injected, but it is still being injected. The higher the RPMs, the faster that small amount of fuel is injected. If it shut off the fuel completely, you are saying you could turn on the car, put it in gear, and as long as you were always coasting downhill, with the engine running, you'd never need to fill up the tank. Not so...

The only time downshifting for breaking is harmful to your car is when you shift too low and over rev.

I've been braking this way for 13 years and have always driven manuals. I've NEVER wore out an engine, clutch, transmission, etc. And Toyota has never reduced their warranty to 3/36 because of my downshifting in their cars...

peace...

 

I have to agree with everyone that says use your brakes. Brakes pads are way cheaper then a new clutch and by downshifting your using your clutch twice as much. I only downshift when I need to, like going up step hill or not coming to a stop. My tc is my 5th toyota and I've always got around 150,000 miles out of the clutch. Downshifting does not hurt anything, just puts more wear on engine and trans., but's it's your choice.

jjp

 

brakes are cheaper than clutches