engine off and coast question

[figit090]

Originally Posted by jedi_sol

bump starting really depends on the speed at which your driving.

if im going 20mph...then i'll bump start in 4th
if im going 40mph...then i'll bump start in 5th
if im going 50+mph...then i'll bump start in 6th

Anything slower than 20mph, then i'll just use the key/starter because, like you said, i dont want to prematurely wear the clutch because bump starting at such a slow speed causes the car to jerk a lot.

Therefore, engine off coasting is mostly beneficial at speeds faster than 25mph

Nice thank you again! Looks like I might be looking into a starter button AND a kill button for my next car's shifter, if there's room.

[elhigh]

Hey figit,

You'll hear some arguments going either way but I think the general tenor is that bump starting is, at worst, only slightly more wearing on your vehicle than regular starts.

I said it before somewhere else on this forum: I've had the truck for over 200,000 miles, been hypermiling and engine-off coasting all that time, bump starting quite a lot. I just replaced the clutch back in the spring. For the first time, I replaced the clutch.

It might add a bit of wear, but it might not be enough to really be noticeable.

[jcp123]

I had a clutch go out on my SVT Focus at 36k miles. I did some bump starts. The two were not related. Design flaw in the little Getrag 6-speed. I may have been misinformed, but I believe the Minis which used the same trans were similarly affected. Rare was the person who broke 50k miles on the factory clutch.

Too bad, it was a nice car...just not a good car.

[cowmeat]

When I'm at speed during P&G I generally bump start in fifth gear at 30-35 mph, and I barely feel it. I ease the clutch pedal out partially until it fires up, then release it all the way, and it doesn't jerk, shudder, or anything like that, so I don't see that it's putting a lot of wear on anything.
If I'm coming up to a 4-way stop and I can see there's no traffic on either side, I'll bump start it in second right before the sign at about 5 mph. Once again, I barely feel it budge during the re-start, and I'm saving my starter.

The only time it's awkward is that when I EOC up to a light and end up timing it to where I have to restart about 20 mph. For whatever reason it doesn't like bump starting in third or fourth gear, and shudders in either gear, so I try to avoid restarting at that speed, and will key start it i.l.o. bump starting it.

[Frank Lee]

I always bump from top gear, no matter the speed. If it was from too slow a speed to accelerate in top gear I downshift right after the start. That is going to be the easiest on everything- clutch, trans, motor mounts.

[cowmeat]

Nice one, Frank!

Guess it does make the most sense when you think about it. I'll try that on the way home, and if it works, I'll be bumping from fifth from now on.

[figit090]

Originally Posted by frank lee

think about it some more.

whoops.

Bahah.. :d

[cowmeat]

Been bump starting in fifth 100% this entire tank since you gave me that heads up, Frank. I don't know about everybody else's cars, but it definitely works best for the Festiva!

Thanks for the good tip, Frank!

[campisi]

My Subaru bump-starts smooth as silk in 5th gear (5spd trans) down to <20mph. No issues whatsoever with bucking. Just gotta be quick with the clutch and then downshift to whatever gear you need after she's running again. When it gets below about 10mph I key-start it.

[user removed]

I bump start my manual Ranger in reverse down a 5% grade in a parking lot, in 10 feet, and I have a lifetime guarantee starter motor. The cranking speed is around 300 RPM which if your RPM at 60 is 2100 works out to 60/7 or less than 9 MPH in 5th gear, still equals your normal cranking speed. If you know your engagement point of the clutch just let the pedal out to slightly less than the engagement point where you get some friction and it should work fine.

Edit;

I advise against EOC in automatic transmissions, just leave the engine on and anticipate your forced decelerations better and when that does not work, use DFCO.

regards
Mech