I'd say there's a difference between rubber tires and a cerametallic surfaced clutch disk..
I'd say there's a difference between rubber tires and a cerametallic surfaced clutch disk..
We need a little InSim app connected to a scent bottle that releases the scent of burning clutch as you start to over heat it.
You see, I dont really see too much of an issue in that SPR. The first lap you clutch kick a bit and the revs at full on while you do it, no real heat build up.
I only starts to get some heat when you really abuse near end of second lap before your tyres pop.
Even so you tyres pop before the clutch overheats.
Ok, so you drift with a car custom built to drift. Here are some question that interest me...
What is the clutch in that car, standard or some heavy duty multi plate clutch?
If NOT the original clutch, why did you change it?
How often have you glazed the clutch disks?
Exactly, there is no real issue and only reason for clutch to heat is that I kick clutch at too low rpm, so there is too much grip on tires that overcomes clutch grip.
When objects move and when they are on rest there is different friction, maybe lfs clutch it is same friction? Only thing to improve there, imo. But still it is not a problem, even I use it very badly in spr.
That video doesn't show you doing flat upshifts all merely going sideways. I want to see a pedal cam of proper 'flat shifts'
Automatic transmissions use lots of clutches.
I have no issue at all:
auto-clutching + flat shifting causes minor heat, but nothing spectacular unless it's a longer race
manual clutch + flatshifting causes a bit more heat but still nothing worth killing anyone over,
complete manual clutch + lifting, I generate less heat than using auto clutch + lifting.
I think people just need to adapt, seeing even me, with my shitty style of driving, have no issues, even when I try to beat on it.
http://www.autoracing1.com/markc/000802ShiftWithOutLift.htm
http://www.geartronics.co.uk/flatshift.htm
http://en.wikipedia.org/wiki/Semi-automatic_transmission
http://en.wikipedia.org/wiki/E ... aulic_manual_transmission
http://www.hewland.com/svga/gearbox_range_current.htm
Click on markets & products, then motorsport: http://www.xtrac.com
There are multiple clutches, one for every gear combination.
After some web searching, clutch disks don't glaze like brakes do. The friction materials are designed to wear away before they glaze. As an extreme example, top fuel dragsters output close to 7000hp, and a large part of this power is dissipated as heat by the clutch during the first part of a run, where the clutch is essentially a torque limiter used to keep the tires from spinnning. In a funny car, the cockpit will get filled with clutch dust during a run.
After a lot of web searching, it appears that clutch slippage (as opposed to wear) due to overheating simply doesn't exist in the real world. My guess is that this is because a clutch can dissipate more power (as heat) than the engine the clutch is designed for can generate, and that clutches are designed to simply wear away rather than slip at excessively high temperatures, meaning that the friction surfaces wears off before losing a significant amount of coefficient of friction.
Strange, after no real searching I found this...
http://www.exedy.co.jp/english/service/measure2.html
"As the engine and clutch become hotter, the tendency to slip becomes more marked."
Also, just searched "Clutch glazing" on Google and got 250000 results? It DOES exist and WILL make a clutch slip. It is possible to drive very gentle for a few 100 Km and clean up a clutch with slight glazing but there are limits to what you can recover from
The top fuel drag cars you talk about have clutches BUILT to take the force.
BTW. You never answered me. So I will ask again
Does your drift car have the original stock clutch and if not WHY did you change it?
Most of the hits on clutch glazing refer to handbags, or purses, which are also called clutches. Try doing a web search on "clutch fade" and "brake fade" and compare the results. It's common to have brake fade with street cars, and for racing purposes, a lot of street cars will need brake upgrades to prevent this. In real life, flat shifting would probably break drivetrain components, but it would never generate enough heat to cause a clutch to start fading.
Unless there's a defect, it's going to take a fairly long period of continuous clutch slipping to get the sufaces to glaze, like slipping the clutch to hold a car still while on a hill, and even a glazed clutch will normally fully engage and not slip during gear shifts, only becoming an issue when taking off from a standing start.
I'm not the person with the drift car.
You do realise that such clutches has absolutely nothing in common with what we have in LFS. Those are based to automatic gearboxes that have oil which cools 'clutches' as you call them.
You can burn automatic gearbox too, just stand on brake and push throttle so that box is slipping, keep at it and not very long until you need to repair your stock automatic gear box.
Automatic box with shifter kit has almost nothing common with manual box in terms how clutch behaves.
I just watched the video again to make sure I saw what I had thought I had seen before. The timeing is a bit off but he lifts on all(every single) upshift. I know what hes is doing on down shifts, its heel & toe, I am no idiot. As you can see in my avatar,
<---------- I have a three pedal setup . I have to use heel & toe to break and down shift properly, just like how I do in my car.
Edit:
<---(It's put together in 4 seperate photos because I dont have a digital camera, and my web cam doesn't have a cable that is long enough)
In the BMW video again you can see his knee lift as he upshifts. As for the F1 video you can't tell if he is or is not lifting because teh camera if far away.
i shift 2-3 3-2 3-4 4-3 like a million times in that video...
The gearboxes aren't automatic, typically most of them don't even have a transmission in the normal sense (except they can back up), just a single gear, no shifting. The clutch slips for the first 1/8th of a mile because the engine produces more power than the tires can handle (see 2nd quote below):
From the link below:
"Unquestionably, the clutch is the most crucial element for Top Fuel success, so much so that the Schumacher team has added a dynamometer specifically for developing this component. The car has no transmission, so the five-disc clutch is set up to slip just enough to keep the tires from breaking traction
http://www.popularmechanics.co ... ports/1268936.html?page=2
From the link below:
"It's simply impossible to transmit the engine's full brutality to the pavement at a launch without inducing time-wasting wheelspin, so the clutch slips continuously to keep the tires on the edge of adhesion. Near the 1/8th-mile mark, the downforce generated by the rear wing has given the rear tires sufficient bite to finally transmit the full power from the raging supercharged V8 ... 8000hp"
http://www.edmunds.com/insidel ... Features/articleId=120159
These shifters wouldn't be called "no lift" shifters unless they literally meant upshifts occur without the driver lifting on the throttle. It's not humanly possible for a human to get off and back on the throttle in the 30ms to 50ms it takes for a no-lift shifter to shift. In addition, the dog type gears (as opposed to syncro-mesh gears used in passenger cars) need to be shifted as quickly as possible, as they will get damaged from slow shifts.
ShiftWithOutLift.htm
"The cars are equipped with 6-speed sequential no-lift shift gearboxes":
http://www.brandonmerrell.com
From the link below
"Successful upshifting ... will be achieved by fully moving the dog ring as rapidly as possible from one gear to the next, preferably with the engine's driving load removed until the shift is completed. (The opposite is true of a synchromesh gearbox as used in passenger cars, where slow movement helps). It should be remembered that it is not possible to damage the dogs when fully engaged (in gear). The damage can only take place when initiating contact during a shift, (the `danger zone`) therefore this element must be made as short as possible. If a driver moves the gear lever slowly, or if the linkage is not rigid and effective, dog wear will occur. "
http://www.hewland.com/svga/help.htm
This is getting a bit off topic. The point here is if a typical automotive clutch would actual fade and slip due to overheating from flat shifting. It's my belief that this simply isn't possible in the real life, unless the clutch is defective. In LFS the brakes don't fade on cars similar to real world cars, and most real world cheap econobox like cars will have serious brake fade issues if raced with the stock brakes. At the same time, I don't believe any of these cars would ever suffer from clutch fade due to flat shifting (although drivetrain breakage would be likely). The springed hub in a clutch and the engine mounts are designed to give a little to reduce the shock of changing engine rpms too quickly during a shift, but there are limits to this protection, and drivetrain damage is still possible.
It is possible to overheat clutches and even glaze them, but this would occur from continuous abuse, like slipping a clutch while moving slowly or not at all uphill, riding the clutch in stop and go traffic, or if an engine was souped up and simply producing too much torque for the clutch to hold.
http://videos.streetfire.net/v ... 339-b6f5-98aa00fe0ac1.htm
talks about clutches and heating and clutches in general
talks about clutches and heating and clutches in general
Good video. What was hinted at but not directly stated, was the cause of the clutches heating up. If an engine produces more torque than a clutch can hold, the clutch will slip and overheat. Assuming that it's not a design flaw, this only happens when the engine is souped up and exceeds the torque specs of a stock clutch. This is why the clutch maker representative mentions that the higher peformance clutches will handle more power. The actual issue is handling more torque, clutches and transmissions are rated by torque, not power.
You'll once loose your tire if touching another car with formulas or loose your front wing when slightly touching another from behind, for realism's sake.
However I'll keep my gas down.
However I'll keep my gas down.
www.zoomclutch.com ls1 twin-plate.
i've had it out several times, its got some hotspots but its in great shape still, and has outlasted two ENGINES. my $2k retail clutch has outlasted two of my ENGINES. not just one engine, TWO.
and my car still has less suspension adjustability than an XRT.
the XRT from my expereince has the same clutch issues as a stock mazda miata with a 150k stock clutch that came from the factory with a turbo kit on it.
Well done you've surpassed yourself...
...they all use some system of cutting ignition or closing the throttle :doh:
Yes it does. I've seen it happen in racing (rarely), autotests and most commonly production car trails.
I'm sure you do but I can't see your footwork and don't believe you.
Well yeah, that's the point, the computer does it for the driver, the driver isn't doing any throttle movement, because a human can't release and push back on the throttle in the 30ms to 50ms that the computer can.
The systems don't close the throttle, but they do cut off the fuel injection to a few cylinders very briefly, reducing power just enough to do the gear change. It's probably not good to cut off the ignition and end up with unburnt, explosive fuel coming out of the engine.
Ok, change this to overheating and clutch fade due to flat shifting rarely occurs in the real world. The most likely case for problems is when an engine is enhanced, and ends up producing more torque than the clutch is rated for.
Anyway, it seems that the goal here is to reduce or elminate flat shifting, but inventing clutch fade as the solution seems like a poor choice to me. Drivetrain failure due to flat shifting would have been realistic, but it's not in LFS yet.
In the meantime, flat shifting could have been better handled by forcing a somewhat extended auto-cut and shift whenever a flat shift was detected. Think of this as self-protecting ECU in the car. As a real life example, a Corvette Z06 has a torque limiter in it's ECU that cuts fuel if torque at the clutch exceeds some fixed amount. Z06 drag racers report that it's noticable during an attempt to powershift (like a partial flat shift) from 1st to 2nd gear when using drag radials.
Street cars don't slip clutch, then explain THIS (Turn three, shifting 2nd -> 3rd)
Clutch is new, I lift foot from clutch quick and completely but I'm bit too eager with throttle so it slips. Clutch should be ok with 300nm of torque, car has 170nm at max.
How street car's new clutch* slips there? I say it is perfectly possible, more like likely to slip, at least if car is LFS era Japanese or European car.
* New clutch has driven around 1000km, normal easy driving on streets before.
Clutch is new, I lift foot from clutch quick and completely but I'm bit too eager with throttle so it slips. Clutch should be ok with 300nm of torque, car has 170nm at max.
How street car's new clutch* slips there? I say it is perfectly possible, more like likely to slip, at least if car is LFS era Japanese or European car.
* New clutch has driven around 1000km, normal easy driving on streets before.
Go Volvo! It was clearly done to spice up your track time and add some excitement to it. I hope you have a special agreement with the track organizers to pay on a "per lap" basis rather than a timer. :P
It was 50 euros a day, now it is 60 euros per day
Even slow, still much more fun than sitting in front of your monitor and "driving on track" with your tiny plastic wheel
But that is quite irrelevant to subject here
60 euros for 5 laps is kinda pricey.
However, to get back on subject - on the comments of that video you mention you have a problem with the linkage on that car - wouldn't that contribute to your clutch slipping in general (possibly because it would overheat by you slipping it when you're trying to get into 2nd)? Although I didn't hear any gear hiccup at the point you mention.
Assuming the slow rpm drops were due to slipping clutch, then wow, it was slipping quite a bit. I've experienced this on an old motorcycle (Norton 850) with a worn out clutch, but not in a car, at least not that much.
I have experienced clutch slippage in some cars when trying to take off from a stopped position using high rpms. The clutches in some cars don't grip well if there's a huge differenece between flywheel and friction plate speed, perhaps to protect the drive train. Coefficent of friction does decrease with a difference in speed, and the dynamic friction of some clutch friction material is significantly lower than the static (non-slipping) friction. To take off fast in these cars, it's best to drop the clutch at a lower rpm and let the tires spin.
Then again, there is the other extreme, a Porsche 911 Turbo can be run up against the rev-limiter, throttle pegged, clutch dropped, for a somewhat scary all wheel spinning launch that combined with relatively low gearing produces an incredable 0 to 30mph time of 1.1 seconds.
I'm not sure how clutches are rated, dynamic (slipping) friction, or static (non-slipping) friction. It would seem that since a clutch is intended to be slipped, then it would be a dynamic friction rating. Even though the engine produces 170nm of torque and the clutch is rated at 300nm, it's possible that flywheel momentum could generate more than 300nm of torque on the clutch, but this would be an rpm issue more than a throttle issue.
In your case, did the clutch continue to get worse, or did it stay about the same during that run? Did the clutch get hot enough that you could smell "burnt" clutch?
How realistic is clutch overheating?
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FGED GREDG RDFGDR GSFDG