heinrich

Let's put it this way with a few succinct facts:

1.) Braking front wheels = safe especially when weight shifts forward under ... braking
2.) Braking rear wheels is unsafe especially when weight shifts forward under ... braking
3.) Lift-throttle oversteer has killed more Porsche drivers than the Black Plague
4.) Any questions?

the flyin' scotsman

I roadraced motorcycles for many years some of the machines being Grand Prix 2 strokes spinning at 15k rpm. Sitting up after flying down the straight, off with the throttle, full brakes, grab the clutch, down shift 3 gears, out with the clutch and throw it into the corner.

On a CBR900cc if you didn't 'blip' the throttle on the downshifts the back tyre would skip/lock.......not fun at 130mph on 2 wheels.

On the street there's little requirement to do similar except to have a little fun........yeah ha!!!!

heinrich

Malcolm what's Yahoo Serious doing in your avatar

SwayBar

On a roadrace course, using engine-braking to slow the car down is a complete and unnecessary waste of time, which means the guy who solely uses his brakes to slow the car will beat the engine-braker.

As for street-driving, brakes are much cheaper to replace than an engine.

the flyin' scotsman

James Hunt...........a former Formula 1 world champ from the '70's who partied a little too hard and left us at the tender age of 45. Loved his driving skills and his rebellious attitude. Infamous for punching out a press member who dared to try and interview him after his car expired while leading a race.

What can I say; its freezing cold and we're all getting a little cabin fever.........normal service shall resume in ........a few months

mark kibort

double clutch = silly, no reason. we are not driving 1950 pickup trucks

engine braking = dont worry, just leave the car in gear so its in gear and you are not making your clutch and transmission work over time.

Brakes= Cheap!! as was said, brake pads can be found for about $25 and take 20min to change.

Clutch= use it as least often as you can. this eventually wears the pressure plate as well as the discs, not to mention, throw out bearing.

The engine braking power pales by comparison to the power of the brakes
it is nice to have some engine braking through turns on a race course, as it plants the rear end and also keeps the rears from locking up on threashold trail braking. (racing concern only)

Just drive and have fun!

Let me ask the field, do you put the clutch in and keep it in gear at a stop light??
If you do, youre multiplying your throw out bearing wear by 10x. put it in neutral as you just approach a stop. you then only use a quick cycle of the clutch, and the throwout bearing is used for less than a second. leave it in gear, and keep the clutch engaged at a stop, the presure plate is flexed, and the T/O bearing is spinning! you can count the number of seconds the holbert car has used the throwout bearing. (seconds x shifts). Most folks this can be seconds x time spent at a stoplight.

Mk

mark kibort

One fact further, under racing braking, engine braking is a non-factor. more concern will be with rear wheel brake bias. as i mentioned, deep deep trail braking relies on a type of "engine braking" in the sense that it helps the rear wheels from locking up, as the inside rear corner has very little weight on it and can lock and upset the car's handling.

as far as #3, i dont think its lift throttle oversteer in 911s that has been a problem. I cant tell you the number of 911s, new and old ive chased. The matter is good driver vs bad driver!

mk

ew928

Leaving SITM one year, flew by a trooper who'd stopped a motorcycle for a nice chat. I was trying to catch up to the pack after getting stopped at a light.
Few minutes after catching the school of sharks, I see this crown vic on fast approach from the rear. Get on the Motorola FRS radio and warn the others. Drop tranny into 3rd gear and slow from 70's down to 56mph. Cruiser drops right on my tail. He sees no brake lights but I'm just at the 55mph limit. Think this was killing him as he knows I'd been going faster but no way to prove it in court. He then proceeds to drop behind each of the other 3 sharks but he nets zero kill.

Engine braking worked great that time.
And brake pads are a lot cheaper and easier to change than a clutch.

Ernest (NYC)

heinrich

Mark I wasn't saying 911 specifically and I can't imagine that you would be unaware of the fact that lift-throttle oversteer is the number one killer of Porsche owners since the first one was made? It's a Porsche historical fact, which is exactly why the Weissach axle was invented and used. Every performance driving school out there will teach you this.

aguk928

I was taught advanced driving by a top rally driver and engine braking was a big thing as you have more control of the car in all aspects from steering to being ready to accelerate or having greater braking if needed with the pads as well also wear on the clutch is minimal when done properly, brake fad is reduced and times lap and course time can be improved as you ready to accelate earlier. May be not for all, it does takes feeling and work but from what I was tought it is worth it.

UKKid35

Engine breaking doesn´t wear the clutch

Changing down a gear (or two) without double de-clutching does wear the clutch

Brake pads aren´t that much cheaper, and with our wonderful ally calipers that corrode, its often not that much easier to change them

fabric

Using the clutch wears it out. It's much less for upshifts and well matched downshifts, but it wears it nonetheless. If you shift up *and* down, it's going to be at least double the wear, probably more because you're not going to smoothly downshift every time.

Modern gearboxes don't need to be double-clutched either.

There's nothing wrong with just leaving it in the gear and slowing down there, and then using the brakes as needed, and putting it into neutral at the appropriate time. The engine will still assist in slowing, although not as much as if you downshift as you go. Engine braking has nothing to do with downshifting per se. It's great to be in the right gear to accelerate, but most of the time for road driving, you're slowing down to stop, or aren't going to need maximum acceleration when you startup again. I think there's a happy middle ground of doing it for fun and to be in the appropriate gear when in the twisties, but there's truly no need to row back down through the gears everytime you are slowing down.

Engine braking also decreases fuel economy, particularly if you are rev matching. This isn't a huge deal, although if you are being truly aggressive it's probably not insignificant.

tomcat

Ok, a modified double clutch to match revs during downshifting. I'd rather coast for as long as I can than ride my brakes. Coast longer in a lower gear. Yeah, brakes are cheaper to replace. But I believe by matching revs during the downshift, the wear on the clutch is minimal.

On the street you're mostly slowing down for traffic or stop lights/stop signs. If you have time/distance to slow down, I'd rather be in a lower gear ready to go (with my foot on the gas), or downshift and let off the gas for the engine brake. Just my preference and hasn't been detrimental to my clutch or tranny in my experience. One reason I hate autos - I have to use my brakes more.

James-man

I have never heard of anyone clutching-in for brake zones. The guy that solely uses brakes in a brake zone ahead of a turn and does not downshift in there somewhere will SURELY be slower than the guy that does the engine braking downshift (along with brakes of course).

A huge part of this is balance. When turning in after a brake zone you do not want to unsettle the car by dinkering around with shifting AFTER braking. If you shift right before turn in you are futzing around with balance where the car and the driver need to have things settled. In most cases, the balanced car negotiates the turn faster.

If in mountain twisties, I think it is a good idea to downshift earlier (hitting higher RPMs) in the braking zone so that you can have a safe turn and be in the right gear coming out of it. At the track, it is just something that you do.

Just my 2 cents.

Jim is right though. Brakes are inexpensive and Xmissions are not. You have to have a good reason to be hard on the drivetrain of your car, but I suppose that FUN qualifies as a good reason?

heinrich

Let's not confuse engine braking with matching revs with the wheels so we're i nthe right gear and the right engine speed for torque through the turn