Kup4036

just got an 07 civic si a month or so ago. buddy and I debated on coasting in neutral or leaving in gear when coming down a hill or to a stop sign/red light.

2 questions:
1) do u use more gas leaving in gear (since rpms are higher) or coasting (where rpm's are at idle - 800 rpm)?

2) does one do more wear and tear vs. the other?

your help in this debate would be appreciated.
Kup

02BLKCIVIC

iTrader: (8)

Personally I rev match and down shift through each gear till about 3000 RPM's then go to neutral...

Don’t know about the long term effects...

I have heard putting your car in neutral at high speeds is bad because it drains you car of oil pressure don’t know if that’s true or not...

LDB

Leave it in gear, and work your way down through the gears, until you get to no more than walking speed. You have no control in neutral and while you can get it back in gear that takes extra time. You never see a race driver put the car in neutral until they are in the pit box.

M4H

First, the answers:
1. Engine braking (coasting in gear) uses no fuel. Coasting in neutral uses a little fuel - the same amount as idling would.
2. As long as you're not going down through each gear (glares at 02BLKCIVIC and LDB) engine braking will cause negligible wear. Just don't grind your gears.

Now, the EDU:
If you're just coasting on relatively flat ground to a stop sign, just leave it in the current gear - unless you're in 5th or 6th, then pop it down to 4th so you're not in overdrive.
Add regular friction braking as needed - do not cycle down through the gears until you to need to get going again (eg: approaching a red, and it turns green, or the guy behind you in the lifted F-150 isn't showing signs of braking at all)

If you're descending a hill, it's similar - but you may also gear down to 3rd or even 2nd depending on how steep the grade is, and how fast you are currently going/plan to be going at the bottom.

LDB is also correct in that you should not coast downhill in neutral due to lack of control - in fact, it may even be illegal depending on your state/provincial law.

Kup4036

thanks for the tips. however, not understanding the 'lack of control' in neutral u guys stated. how am I 'losing control' of my car?
also, not used to this high revving of an engine. seems all cars I've had 'cruise' around 2K rpm. What do u think ideal 'cruise' rpm's is in the civic si? (i.e., best rpms for both gas conservation and engine running/not stalling).

simplicated1979

gas consuption depends on your driving habbits. for ie: if your in vtec all the time it uses more gas if your under 3k rpms less gas, about the "neutral" thing; let's say your going down a hill very fast and some "idiot" cut's infront of you, if your in a lower gear using engine braking plus your foot on the brake will stop your car faster or you will be able to maneuver your car away from the idiot cuz your in gear....rather than if your in neutral and riding the brake will stop your car slower and because your not in gear it would take you a couple of seconds to get in gear which can result in an accident. And you know how accidents usually can take less than seconds to happen... :thumb: