Lack of Engine Braking

JP08

PasturesNew wrote: »

It's probably just because of where you're used to driving... as the only hill in the whole county is the 400 yards descent from the Shire Hill down to the traffic lights, real hills will have made your brain think "Ooh 'eck" (yes, your brain changes accents when you drive) .... ".... this is scarey/different...."

It's just typical flat-lander thinking when presented with an actual hill.

A valid theory - but I'm afraid an assumption too far

This is the third vehicle I've had the pleasure of pootling round the Dales in over probably a dozen trips up there in the last seven years - as well as excursions to the delights of Snowdonia and Exmoor.

The first was a Mitsubishi Galant 2.0 Auto, which was an excellent tool for the job - in contrast to some of the comments about automatics on this thread. Would even kick down on descending, so it understood engine braking too. Great for those steep hill starts after the inevitable stop to give way on the single track 1:5s.

The second was a Skoda Octavia 2.0 manual diesel. Again in contrast to the comments on this thread, engine braking was very much in evidence. I'd go so far as to say that of all the cars I've owned over the years it was probably the most "brakey" of all of them.

It's only the Auris that behaves like it has lobbed the engine out at the top of the pass and is going "wheeeeee !!!!" and coasting down like a demented Red Bull Soapbox contender ...

reeac

[QUOTE=EssexExile;72488687

Drive a traditional automatic the you get used to little or no engine breaking.[/QUOTE]

I use engine braking on my automatic simply by manually changing down ....not many hills here in Suffolk but plenty of bendy country roads. Gives a nice smooth ride.

Norman_Castle

JP08 wrote: »

The first was a Mitsubishi Galant 2.0 Auto, which was an excellent tool for the job - in contrast to some of the comments about automatics on this thread. Would even kick down on descending, so it understood engine braking too. Great for those steep hill starts after the inevitable stop to give way on the single track 1:5s.

The second was a Skoda Octavia 2.0 manual diesel. Again in contrast to the comments on this thread, engine braking was very much in evidence. I'd go so far as to say that of all the cars I've owned over the years it was probably the most "brakey" of all of them.

It's only the Auris that behaves like it has lobbed the engine out at the top of the pass and is going "wheeeeee !!!!" and coasting down like a demented Red Bull Soapbox contender ...

The first two are bigger engines which presumably have engine braking related to their capacity while your new car gets a larger proportion of its power from the turbo which would add nothing to engine braking.

JP08

Norman_Castle wrote: »

The first two are bigger engines which presumably have engine braking related to their capacity while your new car gets a larger proportion of its power from the turbo which would add nothing to engine braking.

Which was my suggestion b) in the original post. Hence there question whether anyone else had noticed this with other turboed small engined for their size cars (eg Focus 1.0 Ecoboost) ? Or is the Atkinson cycle engine the main reason ? Or just making it worse ?

almillar

Turbo engines give less engine braking. I'll not go into the science, but they do. Automatics (ignore the flappy paddles/manual overrides) don't really do engine braking either. You're making your motion on the road, turn the engine over, instead of exploding fuel to keep it going. Higher revs means more 'braking'.

JP08

almillar wrote: »

Turbo engines give less engine braking. I'll not go into the science, but they do. Automatics (ignore the flappy paddles/manual overrides) don't really do engine braking either. You're making your motion on the road, turn the engine over, instead of exploding fuel to keep it going. Higher revs means more 'braking'.

I'd guess in crude terms that, under engine braking, air (and not exhaust gases) is being expelled from the cylinder, driving the turbo, hence forcing more air in the inlet. Positive feedback ?

Which brings me back to the Atkinson bit - this surely means that there is less compression due to the inlet valve being open longer, therefore less resistance to the piston on the compression stroke, therefore even less engine braking ?

Re the old fashioned autos. I can only repeat that the 1990's designed box (sorry got a bit muddled and said it was an Aisin Warner one - that was the slushbox in the Volvo 240, can't track down the Mitsubishi suppliers name - Jatco/Nissan?) in the Galant would certainly change DOWN under off power descent conditions if the speed built, and would do "proper" engine braking. To be fair it's the only auto I've driven that did that - the 1960's Borg Warner in the Humber and the AW Volvo 240 one weren't that bright. Maybe it was designed with Japanese mountain conditions in mind.

kmb500

agrinnall wrote: »

I'm going to have to experiment now, but I think you may be right: I think that the engine braking effect is less in my 1.0 Ecoboost Fiesta compared to my previous normally aspirated 1.25 engine, and as a result I use brakes more on a descent than I would have in the past. I don't think in my case it's a particularly significant difference, but perhaps if you've come from a car with a very different engine/weight configuration you might notice it more.

I've just got a Fiesta yesterday with one of Ford's "Ecoboost" engines and compared to my previous car that was naturally aspirated, my ability to slow myself using the gears is much less now, and I'm finding myself using the brakes more than I used to. Haven't driven enough cars for long enough to really know the difference between cars but I've definitely noticed that. Wonder if it has anything to do with the car being turbocharged.

Exemplar

I use brakes. That's because they were designed for that......

oldagetraveller

"my ability to slow myself using the gears is much less now,"
Which will be cheaper to replace if you continue to use your gears to slow down?
A worn gearbox, a worn clutch or worn out brake pads/shoes/discs/drums?

JP08

oldagetraveller wrote: »

"my ability to slow myself using the gears is much less now,"
Which will be cheaper to replace if you continue to use your gears to slow down?
A worn gearbox, a worn clutch or worn out brake pads/shoes/discs/drums?

Why would you get any significant wear in the gearbox ? Compared to the hundreds of thousands of miles it would take when the car is being accelerated / driven ? It wouldn't even be wearing the same surfaces.

And why would it wear the clutch ? You're not changing gear or slipping it.

If you really were an old age traveller you'd remember the days where you came down a hill in low gear engine braking cos otherwise you had no braking ability at the bottom due to brake fade from your poor old drum brakes ...


(and yes - I'm old enough to remember that, although in my case it was due to me leaving the handbrake on on my first car, a Fiat 127. It says something about the effectiveness of said handbrake that I didn't notice anything different for 10 miles or so of normal A road driving ... until I had to slow for a speed restriction - thankfully not a junction or an emergency - and the brake pedal went to the floor with no resistance due to the brake fluid having boiled.)