Pot to Kettle, Pot to Kettle… You are black, over.
thanks for keeping me awake at work educated.
i agree with what you said, i just don’t know if i agree with how you said it. some of your examples that you compare against each other can’t be compared in my opinion because there is no fixed reference. Allow me to expand on this and waste more of my company resources 
Ref 1
“The faster you stop, the more heat and noise that is produced over a shorter period of time and distance.”
Ok so let’s say you stop with force F1 over a time period of t1 and distance d1.
Ref 2
“It’s more efficient on all of your braking components, and tires, to dissipate the kinetic energy of your vehicle movement over a longer distance and period of time.”
for this, we’ll label things similar to Ref 1: F2, t2, d2.
now, since you’re comparing, which are you holding constant to see a difference? this is where I started to lose you since you haven’t stated any fixed references.
I was looking for something more like this: let’s say 100m from the light you know you’ll have to stop, for both scenarios. in both scenarios both cars enter the 100m zone with the same velocity and no accel (v1=v2, a1=a2=0).
Ref 1 – 100m from the light, traveling at v1, you maintain v1 until you brake hard in the last few meters, coming to a dead stop exactly at 0m.
Ref 2 – 100m from the light, traveling at v2, you begin to decal proportionally until you come to a dead stop exactly at 0m.
What can we say about F1, F2, t1, t2, d1, and d2?
We know that d1 = d2 first off, so there’s our fixed reference. Let’s work with this. We know that t1 < t2, and F1 > F2 when d1 = d2. Also note that v1 = v2, and v1f=v2f=0 (dead stop). The fact that decel1 > decel2 is due the imbalances of time and force (which are inversely related).
If you sum up the force distribution across the whole 100m span, I’m sure you’ll find that for the same brake setup, the sums should be relatively close.
Yes there’s heat and all that jazz that account for the “relatively” part in “relatively close”, but for street driving purposes and the variance with brake setups, it is better to hold this constant as well and just deem it as negligible so we can see the big picture.
So bottomline, the total amount of force input required to stop a vehicle from a set speed will always be similar across different timespans and distances. I think the only aspect of your argument that we really can’t quantify right now is how heat affects efficiency in daily driving. Taking that aspect out, I’m just stating that I think that there really is no difference.
I’m sure I have a few things that are unclear here and there too. I’m just typing this up in word to kill some time for discussions sake and make it look like I’m working. Tgif.
braking should be avoided at all costs, hard braking wears out tires, tires cost more than pads on most cars (unless you have exotic pads but then they’ll wear super-quick anyway)…
Hawk HPS’s front and rear, front 12.2" wilwoods dynalite calipers, rear 11.4" z31 upgrade.
I didn’t think that this topic was going to get as technical as it has. I’m happy with what I’m doing with my brakes and my habit of driving on the roads. It does effect me on the track though as some of those habits come up during unnecessary times…
Because of my larger braking system I don’t really have to worry about excessive wear, a small touch of the brakes and I’ve reduced a lot of my speed already. I’m just curious about the habits of others.
^To answer your question, yes I do that all the time too. Infact, I consider it good driving practice, and see people that don’t do it as bad drivers. I have only one friend that doesn’t, and he always late brakes and makes sudden stops. We all make fun of him and call him a n00b.
ditto. <3 engine braking.
LMAO to kimmerkaze
wasting time at work LOL
u rock:thumright:
if u know how do drive standard properly, ur brakes should last 50,000-80,000kms, and your tranny will last forever
plus, rev-matching sounds cool 
uphill braking > engine braking 
everything wears with heat.
yes. heat does that. apparently.
lol awesome thread, thanks guys
nothing wrong with stopping a lil early man
for the record
when you use compression braking, your injectors are still firing. at leasto on 240s. they dont feature overrun fuel cut.
the difference between fuel use during idle and fuel use during compression braking is negligible anyway.
not to mention, sometimes you dont need compression braking because that will cause -too much- deceleration for the situation
oh and solarian, you are as guilty of flaunting your technical knowledge (and making sure everyone knows you are an engineer) as anyone else on this board
In the past, I don’t do it anymo’ fo’ sho’ 
mike, you may or may not be right about the 240 thing, but i read in a C&D recently that under engine braking your injectors do not fire and I specifically asked dustin if the inj. duty cycle goes to 0% under compression braking and he said yes, they do.
whether or not that is accurate, I do not know.
i was just testing this on the way home with datascan
it didnt go to 0
Out of curiosity, what did it go to? More or less fuel being used than idle?
I guess my information was specific to the VQ, but I was under the impression that it applied to most/all FI cars.
i dont remember
maybe the fuel -is- cut off and datascan just shows the minimal value it can
either way the differences are negigible!
I’d be curious to know how much fuel is actually being used at idle… it’s come up a few times where people are telling me I shouldn’t be letting me car idle because I’m wasting gas or whatever… I don’t have anything to go on, but I have a feeling that if I idle for like 5 minutes I would use about the same amount of gas as if I were to accelerate once up to 60kph
PS - Mike, UPDATE SIG! 