Racing Brake Pad / Brake system discussion/questions
09-25-2014, 06:17 PM
#616
20 million years from now this thread will be discovered by some alien race and they are going to have no problem determining why we are extinct. It may be sooner if global warning really kicks in, or if Nancy Pelosi has her way
09-25-2014, 08:45 PM
#617
Rennlist Member
Thread Starter
My understanding of the negatives associated through the term 'engine braking' were due to mistimed downshifts while heel/toeing or even not blipping at all and relying on engine braking to help slow you more than the brakes. That is probably what most people are objecting to in this thread. We've all seen it where someone basically just puts the car in the next lowest gear and releases the clutch whereby the engine revs overly high and sometimes leads to the rear tyres chirping (rwd car).
Of course there is some engagement of the engine during off throttle / in gear moments. We don't knowingly think 'I must use engine braking through this upcoming corner'. We just do it. By balancing the car on the throttle we are using the compression of the motor at these moments. If you want to term that 'engine braking' for the sake of argument, just preface this before beginning discussion and this will save you some R.S.I.
Of course there is some engagement of the engine during off throttle / in gear moments. We don't knowingly think 'I must use engine braking through this upcoming corner'. We just do it. By balancing the car on the throttle we are using the compression of the motor at these moments. If you want to term that 'engine braking' for the sake of argument, just preface this before beginning discussion and this will save you some R.S.I.
anytime you are off throttle, you have engine braking... I think about it, understand it, and try and avoid the brakes (meaning I don't want to over slow if I don't need to), and have confidence that it is there and a force that is pretty significant when you lift, or select a gear that gives you a high RPM to then be able to release the throttle.
09-25-2014, 11:57 PM
#618
Rennlist Member
So you're saying that you make a conscious decision at multiple places on the track to not brake but rely on the compression of your motor to slow you up so that you don't over-slow by using the brakes? Either you're not carrying enough speed into corners that you can get away with that or you mean that by feathering the throttle to balance the car is in effect 'engine braking' and therefore don't we all do this? I think we're all aware that over-slowing via heavy application of brakes is, well, slower...but that's a given. Sometimes some of us use a dab of left foot just to pull the nose down. Especially with aero cars. You don't get the same reaction if you merely come off the throttle. While the nose will drop it is less effective than a bit of LFB especially combined with a continuance of throttle during that process.
Anyway, I think the terminology has created a few extra pages in this thread...interesting as it's been.
Anyway, I think the terminology has created a few extra pages in this thread...interesting as it's been.
09-26-2014, 02:46 AM
#620
Rennlist Member
Thread Starter
then, dive in
what wrong with thread is folks claiming to know something they don't...... yeah, no one uses engine braking yeah, its inefficient and hard on equip.......
09-26-2014, 02:56 AM
#621
Rennlist Member
Thread Starter
So you're saying that you make a conscious decision at multiple places on the track to not brake but rely on the compression of your motor to slow you up so that you don't over-slow by using the brakes? Either you're not carrying enough speed into corners that you can get away with that or you mean that by feathering the throttle to balance the car is in effect 'engine braking' and therefore don't we all do this? I think we're all aware that over-slowing via heavy application of brakes is, well, slower...but that's a given. Sometimes some of us use a dab of left foot just to pull the nose down. Especially with aero cars. You don't get the same reaction if you merely come off the throttle. While the nose will drop it is less effective than a bit of LFB especially combined with a continuance of throttle during that process.
Anyway, I think the terminology has created a few extra pages in this thread...interesting as it's been.
Anyway, I think the terminology has created a few extra pages in this thread...interesting as it's been.
actually, you get near the same weight transfer for the same decal rate, however, the front brakes can give more, for a quick stab and set .
the only thing that LFB will buy you would be keeping turbos spooling up.
it really depends on the turn, but yes, by knowing and trusting the amount of engine braking you can be faster so you don't over brake. many at laguna do this at turn 9. If you are aware of its forces, you can trust it and not tap the brakes that might give a competitor a few feet of run up.
09-26-2014, 09:19 AM
#622
Rennlist Member
Whatever mark.
You argue absolutes about generalities and then generalize about absolutes to fit your arguments. People don't quit the discussions because you proved your point, they quit because there's no point in arguing with a wall...
You argue absolutes about generalities and then generalize about absolutes to fit your arguments. People don't quit the discussions because you proved your point, they quit because there's no point in arguing with a wall...
Last edited by J richard; 09-26-2014 at 09:36 AM. Reason: Gave up....
09-26-2014, 11:39 AM
#623
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My little car has no turbo, so I guess I'll just quit with the left foot now.
When I go rally this winter, I'll remember that also....
09-26-2014, 11:52 AM
#625
Rennlist Member
Sure, it helps turbo cars but LFB is not mutually exclusive to these cars. By all means it's a good thing with lower c/r motors and bigger turbos but I LFB in my crappy n/a dd road car 85% of the time and also use the throttle for more than 50% of that time. It pulls the nose in while still accelerating and steering simultaneously. It really makes for accuracy.
I think there is some truth in what you say about engine braking but nobody sees it as this. It's still throttle maintenance and a subconscious balancing of the car with the gas pedal over the c/r of the motor. Nobody thinks about this in terms of 'engine braking' and I return to what I said about misuse of terms. Let's move forwards.
I think there is some truth in what you say about engine braking but nobody sees it as this. It's still throttle maintenance and a subconscious balancing of the car with the gas pedal over the c/r of the motor. Nobody thinks about this in terms of 'engine braking' and I return to what I said about misuse of terms. Let's move forwards.
09-26-2014, 12:26 PM
#626
Rennlist Member
Thread Starter
Sure, it helps turbo cars but LFB is not mutually exclusive to these cars. By all means it's a good thing with lower c/r motors and bigger turbos but I LFB in my crappy n/a dd road car 85% of the time and also use the throttle for more than 50% of that time. It pulls the nose in while still accelerating and steering simultaneously. It really makes for accuracy.
I think there is some truth in what you say about engine braking but nobody sees it as this. It's still throttle maintenance and a subconscious balancing of the car with the gas pedal over the c/r of the motor. Nobody thinks about this in terms of 'engine braking' and I return to what I said about misuse of terms. Let's move forwards.
I think there is some truth in what you say about engine braking but nobody sees it as this. It's still throttle maintenance and a subconscious balancing of the car with the gas pedal over the c/r of the motor. Nobody thinks about this in terms of 'engine braking' and I return to what I said about misuse of terms. Let's move forwards.
09-26-2014, 12:36 PM
#628
Rennlist Member
Thread Starter
so, here you are with a little projection here. Now, if you are honest with yourself, you will see that you jumped in here, made a statement, made some assumptions, didn't really understand the technology, and also at the same time, validated and endorsed others that also don't understand the forces, or the concepts.
now, if im wrong , chime in and respectfully make your point to the contrary. But, as I see it, and what I know about this clutch and others like it AND the concepts im referring too....... the clutch doesn't work like that. there are no force on decel or accel that stress the return springs (you call them "straps")...... and the engine can handle , with out an issue, both positive and negative torque and forces. the valve train doesn't know what direction the forces are coming from , the crank and driveline don't care and are not skewed for one vs the other........ its all a fabrication of fear that engine braking, used either with or without wheel brakes, is bad or should be avoided in any way. PLUS, there is not a good club or pro that doesn't use engine braking (with or without thinking about it) a good portion of the time when ever decel is required during a lap.
Last edited by mark kibort; 09-26-2014 at 01:16 PM. Reason: spelling
09-26-2014, 12:39 PM
#629
Rennlist Member
Thread Starter
always? Now that's a generalization.
I can tell you many reasons why that isn't true. There is one time where it will be true, and its in a turn or sweeper where you would want less rear brake bias, because that's the net net of LFB. (assuming you have a modern car and a skilled throttle foot)
ill give you one of many examples that are known deficiencies of LFB.
since you drive a car with realtively little power, this might not be an issue...... but say you are coming up to a sweeper, in 3rd gear, at the meat of your hp curve, and you need to slow the car for turn in. by applying the LFB, you reduce the power to the wheels that goes up in some heat, but there is still a lot of power available because of brake bias.... your front stab of the brakes, shifts the weight to the front of the car (a result of decelerating at whatever rate is required) BUT, Instead of removing power to the rear wheels, there is still power applied , and that can break the rear wheels free and greatly upset the car ...... think of it as doing a brake stand burn out, but at speed. There........ that's a condition where LFB is actually bad, and its not uncommon condition.
where its good.... if you know Thunderhill, turn 8. but the faster and more powerful cars might have the problem above. but if you are in a fast Miata or something 10mph faster, like a spec 911, a LFB is an easy way to just slow the car 5mph and have the car take a set, and drive the sweeper..... no real advantage to a lift, that gives the same decal and set of the car. This also depends on the driver capability and feel of the car, as well as preference. If I was instructing someone using LFB and they were doing it well, I would have no comment or preference.
I do see one advantage..... if someone is on your bumper, a brake light can create a pause in their mind..... might gain a few feet on them.
I can tell you many reasons why that isn't true. There is one time where it will be true, and its in a turn or sweeper where you would want less rear brake bias, because that's the net net of LFB. (assuming you have a modern car and a skilled throttle foot)
ill give you one of many examples that are known deficiencies of LFB.
since you drive a car with realtively little power, this might not be an issue...... but say you are coming up to a sweeper, in 3rd gear, at the meat of your hp curve, and you need to slow the car for turn in. by applying the LFB, you reduce the power to the wheels that goes up in some heat, but there is still a lot of power available because of brake bias.... your front stab of the brakes, shifts the weight to the front of the car (a result of decelerating at whatever rate is required) BUT, Instead of removing power to the rear wheels, there is still power applied , and that can break the rear wheels free and greatly upset the car ...... think of it as doing a brake stand burn out, but at speed. There........ that's a condition where LFB is actually bad, and its not uncommon condition.
where its good.... if you know Thunderhill, turn 8. but the faster and more powerful cars might have the problem above. but if you are in a fast Miata or something 10mph faster, like a spec 911, a LFB is an easy way to just slow the car 5mph and have the car take a set, and drive the sweeper..... no real advantage to a lift, that gives the same decal and set of the car. This also depends on the driver capability and feel of the car, as well as preference. If I was instructing someone using LFB and they were doing it well, I would have no comment or preference.
I do see one advantage..... if someone is on your bumper, a brake light can create a pause in their mind..... might gain a few feet on them.