Geez, man! Did PETA get to your hampsters?

 

I disagree. In order to get the engine to spin sufficiently for a start in 3rd or 4th gear, you would need an entire olympic bobsled team pushing, much easier in first or second, the smaller the gear, less "torque" needed to crank it.

 

Interesting....half this topic is about hamsters.....

John

 

Well, they do deserve a little recognition once in a while.

 

I got to say that you want 2nd gear instead of 3rd/4th for not the reason you mentioned. The lower the gear, the less torque needed for the engine to drive the wheels but it's the exact opposite for the reverse. It takes more torque for the wheels to drive the engine on lower gears. You get MORE torque from 3rd/4th gear driving the engine by the wheels, but then the problem is that the higher the gear, the higher the speed you need to push the car up to.

For older carburetted cars that need a few more cranks to start normally, your best bet is to push the car faster (more energy reserved) and pop clutch in a higher gear. For newer fuel-injected cars that start in less than a full engine rotation, a lower gear will save you energy by not needing to push the car up to speed as much.

Except for my S and BMW, I've push-started all my previous cars for one reason or the other. My miata was so easy to push-start that it took just about a car length on a flat road to get up to speed and pop the clutch in reverse to start.

 

Agreed, I meant to say "speed" rather than "torque". But you knew what I meant. The point is that it does not make sense to push start in 4th gear, pleeeaaassse.
Now let's get back to one of the most neglected parts in our cars, THE HAMPSTERS!

 

Not so. Think about your gearing and ratios, etc. In a higher gear, for every revolution of the drive wheel/tire, you get about 1 rev of the engine. In a low gear, for every rev of the drive wheel, you get far fewer revs of the engine. When trying to bump start a car, you want to spin that engine as fast as you can with the minimal road speed possible. What you have to contend with is a balance between fighting the engine compression in a low gear and not going too high a gear such that when the engine fires, it doesn't stall because it can't rev high enough while the clutch is out. I'd say 2nd would be just "ducky" (or hampstery in this case).

EDIT: I'm leaving the highlighted sentence above as is to show my obvious "brain fart". The corrected part should read: "you get far MORE revs of the engine".

 

Did you mean to say the opposite?
Very true. But... for an older car (hint: carburetted) that requires more than 1 revolution of the engine to fire up, a lower gear (implies lower wheel speed required) doesn't have enough energy to go a few engine revolution before all the road speed is used up. Remember higher speed = more energy stored. Also, the lower the gear the more deceleration you get from the engine compression. If you're talking about "bump" starting using another car to keep pushing, that's a different scenario because you get unlimited amount of energy (well almost) to crank the engine so you don't need to store as much kinetic energy from the higher road speed.

My 1st car was an '80 Honda Civic 5-speed that required pulling the right amount of manual choke at the right moment to get the engine fired up. I tried 2nd gear and low road speed to push start. Wouldn't do. The long-cranking-required engine would just eat up all the road speed and stop. I had to have higher road speed and higher gear to get that thing push-started.

 

Nope. Think about the gearing.
Start with the engine driving the wheels ........................................
Let's talk about 1st gear. At any given rpm, the drive wheels turns "X" times. Now, we shift to 2nd. At the same given rpm, the drive wheels are turning faster (more than "X" times).
3rd gear, even faster and on and on till we get to 6th gear, which, for most cars is an overdrive, but for the sake of argument, is 1:1 (or direct drive).

Now, let's talk about the wheels driving the engine (as in the case of "bump starting) ...................................
So, "reverse" think the above. In 6th gear, we get 1 rev of the drive wheel for every rev of the engine, then 5th gear would get more than 1 rev of the engine for every rev of the drive wheel. For 4th, even more, etc, etc, till we get to 1st, where you would get the most movement (in terms of revs) for the engine per rev of the drive wheels.

To put it in more real terms: If you're engine is running at say, 1000 rpm, in 1st gear, the rear wheels are turning at much less than 1000 rpm. Then 2nd, the rear wheels turn a little faster at the same 1000 rpm of the engine. Continue till you get to the direct drive gear of (again for the sake of argument) 6th (it's actually 5th for AP1 and 6th is even more "overdrive") where you will be turning 1000 rpm for both engine and rear wheels.

 

I know and of course agree exactly what you mean, but that doesn't match what you were saying here:
That's what I was bugging you about.