I am an mpg nut, so:
1. Is it bad to shift from 1st into 4th, assuming you are not revving 1st too high. My gears are really long...4spd std?

2. Is it bad to coast in neutral?

3. Is it bad to coast with engine off, and bump start?

Thanks Guys!

 

1) I recommend either shifting to neutral and letting out the clutch to rev match fourth gear or push in the clutch, shift 2-3-4, and let out the clutch. It is easier on the synchros.
2) It is OK to coast in neutral. Make sure the clutch is out to keep the input shaft spinning. This ensures lubrication. I usually coast for shorter periods by depressing the clutch with the transmission in gear. For longer periods, I shift to neutral.
3) Don't bump start. You can really stress the axles. If you do bump start, use the highest gear. Coasting with the engine off also cuts your engine lubrication. So, you are restarting each time. It is not as bad as a cold start, but I don't recommend it.

 

In regards to bump starting, are axles substantially stressed if bumped with a really high gear at a lower speed? And, what exactly is missing lubrication while coasting with engine off? THANKS.

 

1) Chances are you will save more gas by shifting normally through all your gears and not bogging your engine down.

2) Fine to coast in neutral with clutch up. Everyone does it.

3) Never coast with the engine off. You lose all your power brakes. Not to mention it is pointless. I think, not too sure, if you are coasting the ECU cuts gas from the injectors. It is an unsafe thing to do.

If you wish to save gas check your tire pressure, have a clean air filter, and good plugs. That will go a long way.

Cheers.

 

If I do not have power brakes/steering, what specifically is bad about coasting with the engine off? What in particular is not being lubricated on a 91 manual civic? Thank you all for your input! Frank.

 

you have power brakes

leaving the car in gear while coasting essentially shuts off the injectors so you are not going to get better mileage by shutting off the engine

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by budomove &raquo;</TD></TR><TR><TD CLASS="quote">If I do not have power brakes/steering, what specifically is bad about coasting with the engine off? What in particular is not being lubricated on a 91 manual civic? Thank you all for your input! Frank.</TD></TR></TABLE>

I suppose that coasting in neutral for short periods is far different than flat towing for a long period. The manual cautions against flat towing. Check and see what difference in mileage you actually see. Use MPG not miles per tank, which is essentially meaningless.

 

91 civics have power brakes.

to answer your question as to what gets lubricated with the engine off. Nothing. with the engine off, absolutly nothing gets lubricated at all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 89s1 &raquo;</TD></TR><TR><TD CLASS="quote">
to answer your question as to what gets lubricated with the engine off. Nothing. with the engine off, absolutly nothing gets lubricated at all.</TD></TR></TABLE>


And amazingly enough; nothing needs to be lubricated when your engine is off...lol

 

as far as shifting, moderate/to heavy throttle and short shift through 1-2-3-4. It's not so much how much throttle you use but how long. If you keep intake manifole pressure high, the piston doesn't have to overcome as much of a delta/p (pressure differential) between the intake manifold and the crank case, engine works a little easier.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bdavis &raquo;</TD></TR><TR><TD CLASS="quote">leaving the car in gear while coasting essentially shuts off the injectors so you are not going to get better mileage by shutting off the engine</TD></TR></TABLE>

Exactly. Coasting in neutral wastes more gas since the injectors are now firing to keep the engine alive. Coast in gear instead.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bdavis &raquo;</TD></TR><TR><TD CLASS="quote">you have power brakes

leaving the car in gear while coasting essentially shuts off the injectors so you are not going to get better mileage by shutting off the engine</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

Exactly. Coasting in neutral wastes more gas since the injectors are now firing to keep the engine alive. Coast in gear instead.</TD></TR></TABLE>

The effects of engine braking (pumping losses) will induce a parasitic drag if the car is "coasting" in gear. This drag consumes energy that must be recompensated by burning more fuel. It is much more efficient to allow for the car to idle while coasting in neutral. The new Civic hybrid disables the valves (all closed) when it is operating in electric only mode. Even though the engine is rotating with the electric motor, the parasitic pumping losses are minimized by holding the valves closed.

 

wat is flat towing? is this like flooring it in 5th wen goin slow?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blulude92 &raquo;</TD></TR><TR><TD CLASS="quote">wat is flat towing? is this like flooring it in 5th wen goin slow?</TD></TR></TABLE>

From my understanding it's towing a car with all 4 wheels on the ground rolling.

 

ok well then is it bad to chug the engine along, say 35 mph in 5th gear floored? A buddy and i were discussing this the other day and reached an impass.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blulude92 &raquo;</TD></TR><TR><TD CLASS="quote">ok well then is it bad to chug the engine along, say 35 mph in 5th gear floored? A buddy and i were discussing this the other day and reached an impass.</TD></TR></TABLE>

It's an excellent way to waste gas. There is no reason to do this.

As for bad? Well I don't know if you are actually causing damage or not. You certainly aren't accomplishing anything.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blulude92 &raquo;</TD></TR><TR><TD CLASS="quote">ok well then is it bad to chug the engine along, say 35 mph in 5th gear floored? A buddy and i were discussing this the other day and reached an impass.</TD></TR></TABLE>

It is always bad to floor the throttle at low RPM as it simply wastes gas due to poor fluel mixing. I cruise in 5th at 35MPH in my GSR all of the time. I have plenty of power to keep up with traffic by lightly pressing the accelerator.

 

so ur creating a rich condition when doing this? interesting. i thought the ecu would just give wat the engine can use at that engine speed. guess i was wrong? i hardly ever do this btw but was just wondering

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by old man neri &raquo;</TD></TR><TR><TD CLASS="quote">From my understanding it's towing a car with all 4 wheels on the ground rolling.</TD></TR></TABLE>

lolz