Saves gas, but will it kill the clutch?

[DarkNinja75]

So I finally figured out that disengaging the clutch causes your engine to go back to idle speed; good for MPG. Now that I know this I cruise downhill with the clutch disengaged. I'm just wondering if I can do this excessively. Say I'm on level ground, I speed up, disengage the clutch, cruise a little until I slow, re-engage and speed up again, repeat.
Is this gonna be bad for my clutch? Or since I'm speeding up again, is this even gonna save me on gas?

[daniel2002p]

Honeltly I think you MPG will be close if not the same when you let off your accelerator pedal while it is still in gear, altho reanganing the cluth so many times may cause premature wear, I would still not recommend this technique, but that is just my opinion....

D

[daniel2002p]

On top of that cruising downhill with the cluth disengaged will make your brakes do all the slowing down causing them to wear prematurely, while with the clutch engaged, your engine will help keep the car at a reasonable speed

D

[thespud]

Originally Posted by DarkNinja75

Say I'm on level ground, I speed up, disengage the clutch, cruise a little until I slow, re-engage and speed up again, repeat.
Is this gonna be bad for my clutch? Or since I'm speeding up again, is this even gonna save me on gas?

This teqnuique(sp) doesnt work. As accelerating puts more strain on the engine and uses mor gas than cruising at the same speed. It also peeves other drivers off if you cant keep a level speed.

Honestly tho, so long as the clutch is fully disengaged or fully engaged, there should be no less wear than everyday city driving. Think about how many times you change gears from stop/start in traffic, at lights, stop signs in parking lots etc. Just make sure you dont ride the clutch...

But really - if you are terribly worried about using gas on a flat level road - Get yourself a Cruise control unit with a clutch switch. This way, the cruise keeps you at a level speed and turns off as soon as you go to change gears...

[freakinbox]

waste of time. and like said one of the bonus' of standard is using the tranny to slow down or keep a speed down hill, etc. By doing that your breaks will wear out faster and you might as well be driving an auto.

[94_Rolla_Guy]

dont hold the clutch in for more than you have too its pushing the crank down the engine wearing the thrust washers and its also gonna wear your pilot bearing, if you really wanna do this then id suggest bumping it to neutral instead of holding the clutch down!

I did this comming home from camping letting the hills push my car and trailer as far as i could see it did jack shit to my fuel mileage!

[AVANT]

As everyone else said, it doesn't save gas.

Also, ponder this when you are crusing downhill next time. Modern EFI cars do not use gas when engine braking (rpms are still up, but you're not stepping on the gas).

So if u can maintain a speed going downhill with just engine braking, it'll save you gas and brake wear compared to stepping on the clutch to accelerate downhill.

[Flashmn]

It saves gas when you enginebrake, as the fuel injection to the cylinders is cut off. However downside is you're braking so you lose speed aswell.
Though wear on the brakes is minimal if you use them rolling downhill. It does save gas when you just let the car roll down hill, never minding the speedlimit, it will accelerate but it wont use the amount of gas used to accelerate to that speed normally.

Been tested using a economy meter, which calculates fuel consumption.

[freakinbox]

yea but like you said... speed limit.
Think of when you first started to drive and you couldn't keep a steady speed easily, you would adjust the pedal alot. On long trips you would get HORRIBLE milage. Thats what you would get on flat land if you tried this.

[joeking]

If you really wanted to increase your mileage you could shut off the engine and restart it when going downhill etc however for all practical purposes just drive it like you should and dont hold in the clutch to save gas. You will wear out the throwout bearing and sychronizers and you dont want that. Just drive it normallyl.

[daniel2002p]

Originally Posted by joeking

If you really wanted to increase your mileage you could shut off the engine and restart it when going downhill etc however for all practical purposes just drive it like you should and dont hold in the clutch to save gas. You will wear out the throwout bearing and sychronizers and you dont want that. Just drive it normallyl.

True but this would be highly impractical as you would loose two of the most important compenonets of a car, number one power steering and brakes would be hell trying to press them..... for the safety I think its better when going downhill to at least keep the engine running I would keep it in a gear also, but when the engine is running you will have full power steering and full brakes.... ever try to hit a brake with the engine on? Then you know what I am talking about....

D

[07Corolla]

In most states coasting is against the law.

[thisxstyle]

Throwing a quick reply in here...When you disengage the clutch it doesn't move the crankshaft, at all, it just shoves the release bearing on the fingers of the pressure plate therefor allowing the clutch to catch up to the speed of the flywheel.

For best fuel economy and clutch life, pause momentarily in neutral before shifting into the next gear. This allows the clutch time to speed up reducing overall wear, and allows the transmissions syncromesh to adjust for a smooth shift.

[ghost_ryder35]

hard on the clutch, doesnt really save any gas, hard on the clutch hydraulic cylinder, shifter bushings, clutch pedal assembly. Basically I would do it other than yes coasting down hills or approaching a stop.

[REN69]

Originally Posted by thisxstyle

For best fuel economy and clutch life, pause momentarily in neutral before shifting into the next gear. This allows the clutch time to speed up reducing overall wear, and allows the transmissions syncromesh to adjust for a smooth shift.

LOL! Also known as granny shifting.