Best speed to bump start in 5th gear.

[kickflipjr]

I just wanted to know what is the best (smoothest) speed to bump start in final gear for your car. For me it is a bit below 40mph, but above 35mph. The engine spins 1,400rpm at that speed.

[kickflipjr]

I put this in the wrong section. Whoops.

[jwxr7]

I bump start using 5th almost exclusively. It works almost undetectably at 55mph all the way down to 15 mph. Coming to stop signs I can usually use 5th right before I stop if it looks like I won't have to wait for traffic. Although I have had several instances when I didnt have quite enough speed for 5th at stop signs where I couldn't see until the last few feet for traffic, so I end up having to use the starter .

[cfg83]

kickflipjr -

I find that between 40 and 25 I can get the softest "bump" for my Saturn.

(good question)

CarloSW2

[landspeed]

I've stopped doing bump starts, because I'm worried about damaging my engine, because the sudden 'bump' happens when there is no oil pressure in the engine, and the cylinders start firing straight away.

I've heard that the Prius spins up the engine before applying spark / fuel, to reduce engine wear by bump starting. So this is what I do!. With the ignition off, I put the car in 5th gear, let the clutch in so the engine spins up (slowly depending on speed). If at 20mph, this still works. After about 2 seconds, I push the clutch in, while starting the ignition. This means the engine starts with oil already circulating!

[trebuchet03]

I avoid bump starting in 5th.... Something about an overdrive gear applying a magnified amount of torque to overcome static friction bothers me.

But I too spin my engine up before putting the key into "run" - but I don't take off the clutch immediatly (unless I'm coming to a stop). I'll have my foot on the gas before I turn the key (the computer seems to be able to handle that).

[omgwtfbyobbq]

Compared to bump starting in other gears, or spinning it over w/the starter?

[rh77]

Just tidying-up the Team Challenge forum...

It gets a free "Bump" -- pun intended :-)

[Bill in Houston]

Originally Posted by rh77

It gets a free "Bump" -- pun intended :-)

Oh please. Don't start.

Heh heh.

[cfg83]

theclencher -

Originally Posted by theclencher

Mine is all just like that, except I have done it down to 11 mph with no trauma.

treb, you are bass-ackwards on the "overdrive" line of thinking. Top gear is the gentlest of all the gears for bump starting.

And, there is no "ignition delay" when key starting so

That has been my experience. From a driver perception POV, when I do it right, I can bump start between 25 and 40 MPH without even feeling the bump. Almost all the other bumps below 20 MPH seem rough to me, but I haven't experimented will all the gears.

CarloSW2