1. Don't pop the clutch when you downshift
2. Don't downshift so that engine RPM's go into redline
3. Don't downshift at a rate that causes rear wheels to lose traction

 

i definetely haven't done any of those three, but i appreciate the input. i grew up driving my dads 58 corvette (carburated) so i didn't know if running a fuel injected car had any difference as far as downshifting goes. my dad trained me on his car to downshift alot so i am in the habit of downshifting alot. thanks

 

You shouldn't have annything to worry about b/c I do the exact same thing when I'm driving.

 

Good question. I was taught that downshifting causes unneccesary strain (and wear) on the drive train. If you think about it, downshifting to lose speed puts an opposite load on your transmission gear and diff, in effect loading the "back side" of the gears.
I've always doubted the premis and it sure hasn't prevented me from using engine compression to help reduce my speed but I'm curious.

Has anyone seen any real data to support downshifting (or not)?

Dan

 

well i have heard that during break-in, it's actually a GOOD idea because it puts force on the other side of the rings... makes sense i guess...

 

well if your rev-match the gear before you downshift, then yu're really not putting much more "strain" on the drivetrain. The only thing it would cause more wear on is the clutch, but it is pretty much negligible. I don't think downshifting into 1st is ever a good idea, yes it can be done, but you are going slow enough at that point to where it is of little help. I usually like to downshift so that my next lower gear comes out at about 3K rpms. Hence into 3rd gear at 40mph, 2nd @ 30.

Blipping the throttle in between shifts is enough to match the revs without causing the unconfortable lurch when letting out the clutch.

 

i downshift all the time, its just habbit i guess.... usually at low rpms. when i get to 2k i drop into the previous gear and it usually jumps to around 3k, and do that throughout the gears.

when i first got my car i had an issue with it stalling so i was forced to downshift all the time and keep my RPM's up by giving it a tiny bit of gas. since then ive fixed the problem but the downshifting stuck.

 

downshifting prevents you from becoming lazy.if you want to drive lazy,why did you buy a 5 speed?if downshifting correctly,you will not put premature wear on the clutch,and the Z32 tranny is pretty darn tough.that stuff about wearing out the clutch was probably started by a lazy driver.

have you ever been driving along and you suddenly find yourself in the wrong gear?you're rolling along at 45 MPH in 5th,and youre coming up to a light and it turns yellow. youre at the point to where youre pondering whether to go for it or stop.after a split second decision,you decide to go.if you were not in the proper gear,when you give it the gas,it will take a moment to hit the powerband(doesnt matter if you have an NA or TT),that second or so will make the differences as to whether you run a redlight or not.if youre driving in the correct gear,you will have power on demand.if you have to downshift you will not make it.

the beauty of the manual tranny is that you the driver can easily keep the engine in its powerband.

 

It does place wear on the synchros.

I was adviced not to do it by some knowledgeably people on the board.

Mario

 

Everybody has an opinion.... I have always done it, I don't think your driving a stick unless you do.

 

by wear on the clutch, i meant the normal wear that would be caused by 2 to 3 more shifts as opposed to throwing it in neutral. . . just to clarify.

 

the only thing that down shifting will put more wear on is your clutch. See back in the day when cars first came out there brake where not that good. so the designer planned on using the clutch as a nother way to slow the car down. now a days with hydraulic brakes thay dont biuld them with that in mind. So you may shorting the lift of your clutch a little.
PS i down shift all the time but half the time i rev mach and let the engine slow me down

 

i do every time I stop unless in an emergency braking situation. Downshifting saves your brake pads by almost 50%.

 

"you give it the gas,it will take a moment to hit the powerband(doesnt matter if you have an NA or TT),that second or so will make the differences as to whether you run a redlight or not."

if your that close to red, then you should have stopped in the 1st place. yes i understand that many people have lives that are so incerdibly important that 30 seconds @ a light could destroy them. too bad the person who gets the pleasure of being broadsided by you doesnt get that choice to stop or go....

-that being said, i know what you meant, it just wasnt a good example. if you have time to stop.. stop. if you dont have time to stop then chances are you dont have time to think about the gear your in anyways.

- my wife is form europe, she says that over there they preach to NOT downshift to slow your car down. she says it wastes petrol. anyways, i downshift (not in my Z its an auto) when i can. it just sounds cooler haha.

 

wastes petrol? I don't think it wastes any more than being in neutral?!! the gas pedal is in the same position when downshifting as it is at a dead stop. The slight blip of the throttle is a neglible about of gas. . .I don't think any fuel is being fed to the cylinders. . .otherwise you'd be making power causing acceleration.

 

engine revs = gas consumption. but not necc. combustion.

petrol = gasoline.

and i seriously dont think it matters - the savings would be negligible if any.



Post Edited (Jan 18, 10:45pm)

 

"iyes i understand that many people have lives that are so incerdibly important that 30 seconds @ a light could destroy them. too bad the person who gets the pleasure of being broadsided by you doesnt get that choice to stop or go...."


f you did understand what i wrote,you would have noticed the little part about being in the correct power band for the engine.(see your owner's manual).if you ARE in the correct power band,you wouldnt need to downshift.and if you wish to stop at a yellow light,so be it.


and while transmission synchros do wear out,downshifting prevent the driver from doing something much worse...like lugging the engine which beats the **** out of the main bearings.tell your wife that its better to waste petrol than hammer the main bearings of the engine.

 

Down shifting shouldnt cause wear on anything more than the clutch. exceptions would be if you are jamming the shifter into gear, grinding gears, popping the clutch, etc.

every time the clutch is disengaged and reengaged some wear of the friction plate occurs. extra wear would occur to the clutch if you are downshifting at high revs where the sudden high torque could cause the clutch to slip somewhat as it engages.

I honestly dont think the designers "back in the day" intended the driver to use downshifting as suplementary braking. the problem with older braking systems is not a matter of enough braking power, it is a matter of controlling the power. old systems tend to lockup, new systems allow you to accurately apply maximum braking power without lockup. Also old transmissions do not have synchros, therefore you cannot really downshift unless you double clutch.

downshifting does not waste gas at all unless you hit the gas pedal, the increased rpms does not cause the engine to consume any more fuel than if the car was sitting still at idle. if it consumed more fuel, the car would not slow down, it would maintain the same speed.

I dont think "saving the brake pads" is a very strong defense for downshifting, as the cost and difficulty of brake replacement is far less than that of clutch replacement. I would rather replace many sets of brakes than 1 clutch . . . especially in a Z.

i personally do downshift quite often, but I do this only because i like the way the car feels and sounds, and i feel more in controll when i do it.


-matt

 

I downshift all the time. I did in my 280zx, I do in my 200sx, I will in a 300zx when I find one. I feel much more in control, it's kinda fun and it sounds awesome in a Z. In my little 4 cylinder 200sx it's not as cool...

 

Downshifting does add wear to the transmission. I imagine something else will break or wear out long before the gears do though.

Not that it is necessary but I cannot heel and toe in the Z in normal shoes. If you want to be the least lazy you should be matching revs.

 

to go along with Seattle's post...


starting your engine adds wear too.does that prevent you guys from driving?

 

Def. If you downshift just by letting the clutch out and having the engine catch back up to the drivetrain, I would be concerned. I, personally revmatch every downshift I do. Have for about 8 years, and will continue for the next 80 (If I live that long). You don't put as much strain on the clutch as you would if you didn't, you don't really put strain on much of anything except internals. And even that is comparing one quick 0-60 romp to a years worth of downshifting daily.

 

Gravy!