midiwall

So...

I've gotten into "engine braking" the last view weeks and it's now a habit. (this is where you drop down a gear or two to slow down instead of using the brakes)

I wanted to be sure that what I thunk about this was true... That being, since my truck is EFI, and my foot is off the gas when I drop down a gear, then I'm _not_ blowing an incredible amount of fuel as the engine revs up to 4000 RPM and beyond - right?

And then the other side of the question is... how hard is this on a tranny with 124k on it? (no valve body upgrade or other form of "shift kit").


Thanks!

Mark

Dr. Zhivago

When coasting in gear, the engine goes into "Fuel Cut" where all fuel supply is stopped. So, to answer your question, no you are not blowing out a bunch of fuel. How hard is that on a tranny? Depends on how hard you slam it into gear. But the road speed governor in the transmission which determines when it upshifts/downshifts along with other parameters, will limit some of the forces on the transmission. I don't think you'll hurt anything.

My .02
G

midiwall

Kewlio!

I'm back to being in Speed Racer mode!

With all the traffic I'm driving in these days, I'm also spending a lot of quality time in 2nd with my foot on the gas - now I KNOW that's burning fuel, but the torquey feeling is so much fun!


I need an S/C... I need someone to pay for an S/C for me... C'Mon Veygahs... C'Mon Lotto!


Thanks G!

bulldog-yota

Dr Z is spot on with the fuel issue or non issue as it might be the case.

Do you have an auto or manual? Manual should have no issues with regular i.e. non abusive engine braking. I dont know if high speed engine braking with an auto is a good idea at 120k miles or at any point. It just doesn't feel right if I think about the limitations of towing an auto, torque converter, oil pump, etc,etc. Rotors and pads sound very cheap suddenly comapred to an auto tranny.

midiwall

It's an auto... And the cost break is an interesting side. okay... maybe only engine braking under 30 then. No more slaming it into 1st at 70.


(yes, I'm kidding)

Churnd

Several brake jobs are still cheaper than a rebuilt tranny.

I used to engine brake with my truck too, until I thought of that.

85runner

If you double clutch on the downshift you will alleviate the torque in the drivetrain and substatually reduce the wear on the trans. I don't do it between all gears, but I do do it between 3rd to 2nd because the torque there is at its highest. I learned this from some old racecar drivers.

bulldog-yota

I dont know but the last time I checked it was pretty hard to find the clutch pedal on an auto

Dr. Zhivago

I know you were joking, but: Your auto tranny_won't_downshift into 1st gear at that speed because of the aforementioned road speed governor. It's kind of a safeguard against over-revving the engine and drivetrain. You'd get 2nd at the very least and most likely 3rd until you dropped below 55 or so.

Dork.

G

Birdman

I think Bulldog had it right. Pads and shoes are cheap compared to Auto tranny and/or clutch replacement. Not to mention engine wear. I used to do this a lot until I thought it through. When stopping with my 5spd I generally downshift all the way to 3rd and then it's all brakes. No more down shifting into 2nd or 1st for a simple stop. When downshifting for turns and whatnot, I always double clutch to save on wear as well.

midiwall

Thanks again all..

Brake pads here I come!

85runner

Oops. I don't know how I missed that.