Bill Ball

Heck, I downshift the AT!

I think you have more immediate control over things with the car in the right gear for the engine speed. It's a small point. You can drive the car either way just fine.

ErnestSw

Ryan,
I see your point, but I think it's a judgement call as to which rev point is chosen with the downshift. If the revs are exactly matched by the computer there's no compression braking. It seems Ferrari has chosen to undermatch and use some compression braking as well.

Namvet

Engine braking is not a replacement for the Brakes! It is about Car Control. Go fast and enjoy!

Garth S

Rev matching on downshifts and compression braking seem to go hand in hand to me when having fun in the twisties - otherwise, brakes are just fine on their own.
With respect to the former, those who have driven agressively cammed high compression motors know how important rev matching is - for if the clutch is dumped on too low revs, the tail end locks up and invites one to go **** up in the weeds ... too bad the 928's are not higher compression, for it would add more zest.

marton

When you slow down then as mentioned 99% of the time you need a lower gear to drive away neatly so there is no extra wear on the synchros since you have to change down anyway.
There should be no extra wear on the clutch for the same reason unless you slip the clutch to get engine braking - which makes no sense anyway - you should engage the clutch neatly then it will not have any extra wear.

marton

RyanPerrella

Ernest,

I wasnt talking Ferrari road cars with F1 boxes, I was talking Formula 1 Cars as made by Honda, Toyota, Williams, BMW, McLaren, Ferrari, Renault etc etc. The point was that racing cars use a form of compression braking. Thats not to say it should be used to replace brakes on your 928. But i dont see anything wrong with doing it. And you will get allot more wear on your clutch disc doing high pm launches then you ever will doing a little engine braking while driving.

To the original question if its ok, if you ask me yeah its ok, its fun, its part of the joy of driving a manual trans car. So do it. Or be on the side of caution and dont do it. I think its safe, others seem to think its a complete no-no.

Okv

Engine braking is mandatory when driving down from mountain passes or other extended descents, like the ones we have here in Norway and down in the Alpes. Selecting the appropriate gear will then keep the speed of the car constant between the hairpins, and you will use the brakes only before the turns or when you catch up with a SUV.

The purpose of this is to avoid overheating and unnecessary wear on the brakes, although on a shark, the brakes are so good you will have more to go on before running in to problems like overheating and fading.

But, actually, a lot of normally applied rules don't really apply to Shark-driving; like when going up on a mountain, the brakes will be used quite heavily before the hairpins because the Shark is equally fast uphill..

danglerb

Engine braking slows you down pretty fast without lighting the brake lights, unfortunately the sound tends to attract the attention of the Highway Patrol even more than brake lights. I like the sound and it assists in pretending I am racing.

the flyin' scotsman

That's why motorcycle manufacturers of big hi comp racing machines developed the 'slipper' clutch.............stop that back end putting you **** up on your head........ouch

ErnestSw

Ryan,
We are in violent agreement with eachother. It's all about chosen shift points.

Charley B

Let's see. Burbling back pressure sounds way cool. Increases clutch and tranny wear.020%. What's the question?

heinrich

no - no sense at all

Panzer9

Nothing like a split second- perfectly rev- matched downshift to make you feel like Buddy Rice!

Marine Blue

So in the grand scheme of things if I'm coming to a Stop Light or Stop Sign either one will do fine.

I agree that in a situation where you need to slow down but you're not coming to a complete stop using the clutch does make more sense as you won't need to select the gear.

Interesting points about F1, didn't know that.

Appreciate the input!

Larry Velk

Very old arguement. As I recall, most of the "braking" from a downshift is said to from the added frictional issues related to the higher internal engine and trans speeds. Much of the so-called compression loss is recovered as the compressed gasses re-expand (not all, but a measureable amt.). On a motorcycle at high driver's event speeds at a track or on surfaces with poor traction, the effect of "engine braking" seems very stabilizing. The bike feels much more under control with a slight drag on the rear wheel and braking on the front only. I imagine a car might "feel" better under some conditions with what, on our cars, is like a little hand- brake-turn effect. I think the old-timer's consensus is the downshift is mostly just to get in the correct gear and in some cases to provide this slight bit-'o drag to "set" the car under certain conditions.