Brian1037

Because our cars have fuel shutoff, I can take my foot off the gas completely, push in the clutch and before the revs drop to idle, downshift, and use no gas in the process. correct?

jponto07

I keep hearing this around the forum, but honestly it doesn't make any sense...how would the engine keep running without ANY gas?

sdaidoji

iTrader: (1)

if car is geared, engine will be spinning. Maybe there is a minimum amount of fuel injected?
Anyway, ever seem a prius moving only on electric power? then suddenly the petrol engine starts running wihtout cranking? same thing, no starter is required. Software is a flexible thing. Hardware not so much

MPG numbers should prove the point anyway.

Muirsy

op dont quite get what you are trying to say. the prius dosent use a starter because the electric motor is an oversized starter motor and the engine is still turning there is just no fuel or air going inside the engine until the computer allows fuel and air into the engine.

Brian1037

I read around here that we have fuel cutoff when we release the gas pedal, because the momentum of the car will keep the engine running as long as the car is in gear (ie not in neutral and at idle revs while "rolling" down the highway).

So lets say I'm cruising down the highway, and I know my exit is right up ahead, and instead of using the brakes, I want to know if I can:

• Release the gas to engage the fuel cutoff (the car will stay at around 3000 RPM at 110km/h
• Disengage in the clutch. The revs will start dropping from 3000 to idle
• But before the revs reach idle, shift into 4th and engage the clutch, so that the car never gets to idle, and effetely doesn't need to turn off the fuel cutoff because I still haven't touched the gas and it didn't drop to idle.
• Continue down shifting like this until 2nd gear or until I come to a stop or need to touch the brakes.

gearbox

iTrader: (95)

key word momentum. the car is already moving and the crank is turning.

sl33pyriceboi

iTrader: (3)

you will have one hard down shift and a crap ton of jerky.ness.

it does more bad than good, and here's why:

you will blow ur front motormount our faster due to the hard shift in engine

and

you will wear out clutch faster (compared to rev matching)


any time u downshift, you should be rev matching your gear weather it is blipping the trottle or head/toeing.

sl33pyriceboi

iTrader: (3)

so therefore its not really worth saving a few vapors of gas to achieve your "not wasting gas goal."

it's completely pointless

sdaidoji

iTrader: (1)

sl33py, guess you are sleepy

Brian1037

I just looked some stuff up and it turns out I wasn't downshifting properly. Thanks sl33py, now I'm aware of how to properly do it. Good thing I wasn't doing it this way for too long.