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+-- Forum: Technical (https://forum.mmsports.org/forumdisplay.php?fid=4)
+--- Forum: Technical Discussion (https://forum.mmsports.org/forumdisplay.php?fid=11)
+--- Thread: Engine Braking (split from the VR-4 brake thread in FS/WTB) (/showthread.php?tid=2603)
- Maengelito - 08-05-2005
ScottyB Wrote:ah. when you say brake management, are you saying you just ride them too long and/or not utilize engine braking?
stoptech rocks btw.
engine braking is for trucks going downhill and feersty coming from reddish knob. you're fighting your brakes if you use engine braking while braking.
- white_2kgt - 08-05-2005
Maengelito Wrote:ScottyB Wrote:ah. when you say brake management, are you saying you just ride them too long and/or not utilize engine braking?
stoptech rocks btw.
engine braking is for trucks going downhill and feersty coming from reddish knob. you're fighting your brakes if you use engine braking while braking.
exactly, there is NO engine braking in a race enviornment. Pads and rotors are much cheaper and easier to replace than engines and clutches.
John just needs to not be a pussy and get some carbotech pads and brake twice as late
- Mike - 08-05-2005
what pads has he been running?
- JohnC - 08-05-2005
white_2kgt Wrote:John just needs to not be a pussy and get some carbotech pads and brake twice as late
Never run anything but Carbotechs.. As for the late braking, yes I definitely need to step up my game there...
- white_2kgt - 08-05-2005
JohnC Wrote:white_2kgt Wrote:John just needs to not be a pussy and get some carbotech pads and brake twice as late
Never run anything but Carbotechs.. As for the late braking, yes I definitely need to step up my game there...
oh I didn't know you were running carbotech, good man, What compound?
- BLINGMW - 08-05-2005
hmmmm.... let's go WAY off topic here (sorry John, count it as a bump :lol: ), but my first impression of what you guys are saying would be that you're wrong. Are you saying my car would slow down faster going into T1 under full braking if I took it out of gear? Maybe I'm misunderstanding you because I've never seen a race car do this, nor heard anyone say it would be a good idea.
- JohnC - 08-05-2005
BLINGMW Wrote:hmmmm.... let's go WAY off topic here (sorry John, count it as a bump :lol: ), but my first impression of what you guys are saying would be that you're wrong. Are you saying my car would slow down faster going into T1 under full braking if I took it out of gear? Maybe I'm misunderstanding you because I've never seen a race car do this, nor heard anyone say it would be a good idea.
You've never been to a classroom session with Dan Unkelfucker? His argument is that the engine's rotating mass continues to propel the car forward, against the brakes. So, maximum braking is achieved with the clutch in.
- JohnC - 08-05-2005
white_2kgt Wrote:JohnC Wrote:white_2kgt Wrote:John just needs to not be a pussy and get some carbotech pads and brake twice as late
Never run anything but Carbotechs.. As for the late braking, yes I definitely need to step up my game there...
oh I didn't know you were running carbotech, good man, What compound?
P+ for now... Probably something a bit more aggressive next season.
- white_2kgt - 08-05-2005
BLINGMW Wrote:hmmmm.... let's go WAY off topic here (sorry John, count it as a bump :lol: ), but my first impression of what you guys are saying would be that you're wrong. Are you saying my car would slow down faster going into T1 under full braking if I took it out of gear? Maybe I'm misunderstanding you because I've never seen a race car do this, nor heard anyone say it would be a good idea.
if your brakes don't slow you down faster than the engine slows down you need new brakes, plain and simple.
brake hard, clutch in, downshift, blip throttle, clutch out, turn in, let off brakes, apply gas, do that in 1.5 seconds and you got it right
- BLINGMW - 08-05-2005
oh yeah, many times! I either wasn't paying attention or he hasn't pulled that one on me
Hypotheticals:
while disengaged, engine with no throttle falls from 6k to 4k in 1 sec.
4th gear @ 6k = 100MPH
4th gear @ 4k = 70MPH
Scenario:
so I hit my braking point coming into T1 in 4th gear at 6k. Brake. Unless my brakes/tires are good enough to slow the car from 100MPH to 70MPH in one second or less, then isn't the engaged engine helping me?
I would think most cars would experience this. Unless it's some huge engine w/ large flywheel and killer brakes/tires.
*edit for Chad's post*
obviously you think your brakes are faster than your engine, so in your case, yeah, I guess that's true. I guess I'll try to take some real data next weekend for my car. Maybe I'm wrong and most cars are like Chad describes. I can't imagine a car with a lightweight flywheel and fast revving engine would be.
to be a dick: I give you no credit Chad since you've been driving stick for what, like a week? :lol:
- white_2kgt - 08-05-2005
BLINGMW Wrote:to be a dick: I give you no credit Chad since you've been driving stick for what, like a week? :lol:
haha, funny, I bet I have more track time on a manual than you do :roll: :lol:
- ScottyB - 08-05-2005
wow, wish i got to this thread sooner.
when i said engine braking, i meant heel/toe downshifting into a lower gear, because i was under the impression that among other things the engine being forced to spin at a higher rpm provides some help in resisting continued forward movement, despite the flywheel effect that would be present....kinda like what Chan is talking about.
i did not mean letting the clutch out while the engine is at a lower rpm (like shift-locking in drift speak....that's not proper downshifting) or putting on the jake brake :lol:
- BLINGMW - 08-05-2005
no we're all talkin about the same thing, all good
white_2kgt Wrote:haha, funny, I bet I have more track time on a manual than you do :roll: :lol:*stab* *stab* *stab*
- Mike - 08-05-2005
i had the same discussion on s2ki so i went straight to the source:
unclefucker Wrote:chan is wrong
hehe s2ki is down right now, but i'll have the exact text when it comes back up
- Evan - 08-06-2005
technically, engine braking is in fact properly used on track.
its called lifting.
there are many situations where touching the middle pedal will overslow the car, and a brief lift is the best and fastest way.
for the advanced, left foot brake (with gas still pressed) can yield good or better results, but takes skill and is not as consistent for most of us who are not champion openwheel racers.
- .RJ - 08-06-2005
Evan Wrote:left foot brake (with gas still pressed) can yield good or better results
w00t!
- Mike - 08-06-2005
Evan Wrote:technically, engine braking is in fact properly used on track.
its called lifting.
there are many situations where touching the middle pedal will overslow the car, and a brief lift is the best and fastest way.
for the advanced, left foot brake (with gas still pressed) can yield good or better results, but takes skill and is not as consistent for most of us who are not champion openwheel racers.
i think we're talking what will get you to 0 more quickly, not what is the best method to control the car.
- white_2kgt - 08-06-2005
Evan Wrote:technically, engine braking is in fact properly used on track.
its called lifting.
The effect from lifting is more weight transfer than engine braking. When you lift generally you have more traction on the rear tires, upon lift the weight shifts forward removing traction from the rear tires causing them to loose grip and the front tires gain grip, therefore your steering input has more effect causing you to rotate, I really doubt the engine has much if anything to do with getting the car to rotate.
- Mike - 08-06-2005
alright, i got his quote:
unkleficker Wrote:Hi Mike,
Technically, the best stopping capability comes with dipping the
clutch pedal... this way, no forward pressure (even from a motor
declining in RPM pushes the car forward) is 'fighting' the brakes.
Even lightened flywheels push against braking. Try taking your foot
off the throttle going up hill, then dip the clutch - the car should
slow more with the clutch in. As long as the engine wants to turn,
it will require some braking to overcome the inertia of the rotating
parts.
I know that many will use the backpressure of the engine to slow
down, especially using a downshift. But, there comes a point when the
brakes must work against the b/p. As well, you can better modulate
the brakes up to threshold if you're not dealing with the varying
levels of RPM....
You might also think of the friction circle graphic that is often
shown in class. Ideally, the max braking is at total opposite of the
acceleration mode and as long as the engine is turning over, its
purpose is to move the car. And, the brakes are much cheaper to
replace than the clutch if the driver is using the clutch w/
downshifts to slow the car... no matter how smooth the driver is...
Hope this answers the question adequately.
C. Dan Unkefer
High Performance Concepts, LLC
<!-- w --><a class="postlink" href="http://www.hipercon.com">www.hipercon.com</a><!-- w -->
919-683-3167
- Evan - 08-06-2005
no, the slowing is not from weight transfer. getting front end "bite" to turn into a corner is, but im not talking about that. there are many corners where you dont really need to brake, but you need to slow down a bit. depending on your car, hp and grip. T4 at summit may be that way for you, or entering the uphill esses.
the slowing effect from engine braking is the rotational friction and energy required to turn the engine over. The higher your RPMs, the more dramatic your engine braking is. This is the same reason that if you dont revmatch while braking and downshifting, you will lock up the tires.
This really is a concept that you should get familiar with, because if you loose your brakes, all you have left is the engine.
Every event I mentally rehearse what I will do if my pedal goes to the floor.
right foot: continually pump brake pedal
right hand: pull ebrake up halfway and leave it
left foot: clutch in, put in next lower gear, clutch out quickly but not drop it
immediately do it again to the next gear
turn in very early to maximize pavement you have to work with
crank wheel to scrub off speed
all of this is obviously done extremely quickly one after another.
you should think about what you will do if you have zero brakes if you dont already. i even occassionaly practice it in the car with it off to develop muscle memory