Quote :

The thing I dont understand is that you keep going on about the GTR and BF1 cars.

I only mention their real world equivalents to explain current technology. I also mentioned dual clutch transmissions, which effectively are always flast shifted, and put in all those car divisions of Volkswagen as listed in previous posts.

Quote :

If you can get the clutch to overheat in them ...

I've already mentioned it's not an issue for me, as I programmed auto-cut and auto-blip via my joystick driver. Every shift is a perfect shift with just the touch of a button. My point is that drivetrain breakage is a realistic consequence of flat shifting, clutch overheating isn't.

Last edited by JeffR, Tue 1 Jan 2008, 09:48.

Quote :

Quote :

Dual clutch transmisstions, seamless shift transmissions, ...

All those systems remove the position of the throttle pedal from controlling the output of the engine during a gear shift.

No throttle cut is done on dual clutch systems, they are simply designed to use clutch slippage to reduce the shock of shifting gears, so in fact they are effecively being flat shifted on every gear change. It's essentially the same as an automatic transmission, but without using a fluid clutch.

In the case of a Formula 1 cars, there's over 1 g of aerodynamic drag at high speed, so any time spent without power during a 6th to 7th gear shift would slow the car down faster than maximum braking on a road car. Modern seamless shift transmission usage for Formula 1 started in 2005. The point of seamless shift transmissions is to apply a smooth torque transition during a shift, not only to minimize shift time, but also to reduce the shock on the drivetrain during such fast shift times. The torque at the driven part of the clutch remains about the same as full throttle output of the engine during a shift. Fuel cut off only occurs during the brief period where the engine inertia due to drop in rpms produces more torque than full throtttle application. This technology also involves some computer controlled slippage of the clutch on every shift. There's no period of reduced output torque to the drivetrain during a shift, the goal is to minimize any transitions in torque into the gearbox during a gear shift. This is not the same as lifting on the throttle during a shift, which would introduce a huge transition in torque (off and back on again) into the drivetrain.

back on topic - Again my point is that with Patch Y, it's not about driving methods, but that LFS now has road cars with brakes that never fade, drivetrains that never break, but clutches that fail due to overheating due to very brief periods of slippage caused by flat shifting. It may be a quick and dirty "fix" to reduce flat shifting, but it's not realistic. Now it's obvious that cars being raced will have their brakes upgraded if the stock brakes fade under racing condition. It's also obvoius, that weak or poorly designed clutches are going to be upgraded as well. The weak link on any real race prepped car will always be the drive train if a driver truly flat shifts, and drive train breakage is what should have been implemented to discourage flat shifting.

I'm not opposed to discouraging flat shifting, I just belive that drive train breakage would be a lot more realistic than having clutches that fade. I do feel that auto-cut and auto-blip should have been left in the game as an option. After all it is a game, with a wide range of player abilities and controllers.

Last edited by JeffR, Tue 1 Jan 2008, 03:18.

Quote from tristancliffe :

Whilst the materials are 'harder', the higher coefficient of friction means that when slipping they generate a lot more heat.

The amount of heat is proportional to the power consumed by the clutch, which is somewhat independent of the coefficient of friction. A clutch with a higher coefficient of friction will just require less plate pressure to consume the same amount of power and generate the same output torque than a clutch with lower coefficient of friction.

Clutches that operate at higher temperatures dissipate their heat faster because of the higher difference between their operating temperature, and the ambient temperature outside.

Quote :

There isn't a clutch in real life that can withstand several seconds of high rpm, high slippage, large torque transfer over and over again. Drag cars (that use a manual clutch) let them cool, or even change them every run.

If you've ever watched the show pinks, the finals require that cars be run 3 times in a row, without a cool down period. These aren't top fuel dragsters, but they have a lot more power than most of the cars in LFS.

Top fuel dragsters are slipping the clutch for the about the first 3 seconds of a run (about 1/8th mile), limiting the torque from a 8000hp engine so the tires don't slip, reaching a temperatures over 1000 degrees Farenheight, yet they still fully engage and don't slip for the final part of a run. The clutch parts are replaced after every run due to wear.

Quote :

There isn't a clutch in real life that can withstand several seconds of high rpm, high slippage, large torque transfer over and over again.

Which doesn't occur when flat shifting, because the time period of slippage is very short (few tenths of a second), unless the clutch is defective or simply too weak. Unless a driver slowly releases the clutch while power shifting, which isn't flat shifting, there isn't going to be a heat issue, but it's likely that the drive train will be broken.

Quote :

Road cars are getting "smarter" these days.

Torque limiters in the ECU auto-cut power (fuel cut), if excessive torque is sensed at the clutch plate to protect the drive train. High peformance cars like the Corvette Z06 have these.

Dual clutch transmissions (DCT's) are used on Volkswagen cars these days: Audi TT and A3. Bugatti Veyron 16.4. SEAT Altea, Toledo, and León. Škoda Octavia. Volkswagen Passat, Golf GTI/R32, Touran, Eos, Golf, Caddy, and Jetta/Bora.

BMW offers SMG's - Sequential Manual Gearboxes - on some of their cars.

As time goes on, intelligent transmissions in both road and race cars will elminate any issues associated with flat shifting, to allow faster shift times without drivetrain damage, and for minor improvement in fuel econonmy in city driving. By the time S3 is released, flat shifting in road and race cars will no longer be an issue for most of those cars, except for a few racing classes that won't allow it.

Last edited by JeffR, Tue 1 Jan 2008, 01:21.

Quote :

A racing clutch is far more likely to burn up than a road clutch, because it needs to be light but also as soft as possible.

Racing clutches are made out of more heat resistant materials than road cars clutches. The friction materials are carbon - kevlar fiber or ceramic, which are very heat resistant, and have a much higher coefficient of friction than road car clutches.

Quote :

soft

These are clutches, not tires, high friction clutch materials aren't "soft", ceramic is stickier and "harder" than a road car clutch.

Quote :

overheating clutch ... spinning out and not clutching in in time or staying in a high gear

Spinning out and not clutching in time kills the engine (usually causes an engine to spin backwards), why would it cause the clutch to overheat, since it's not going to slip when a car spins out? Maybe if it was a slipper clutch as used on some motorcycles, but the FBMW uses a Sachs single plate dry racing clutch, not a motorcycle like multiplate wet slipper clutch.

Quote :

dual clutch gearboxes

Every shift with a dual clutch gearbox is a flat shift, and the clutches don't overheat. For road cars, these typically use wet multiplate clutches, but dry clutches are under development, and some race cars already have dry clutch based dual clutch gearboxes.

http://auto.howstuffworks.com/dual-clutch-transmission.htm

Quote :

Seamless shift gearboxes

"A modern F1 clutch is a multi-plate carbon design with a diameter of less than four inches (100 mm), weighing less than 2.20 lb (1.00 kg) and handling 900 hp (670 kW) or so. ... introduction of the new seamless shift gearbox, a type of dual-clutch transmission which nearly eliminates the brief power interruption during a gear change."

During a shift on a seamless shift transmission, power from the engine may be cut very momentarily, but only while the engine inertia is driving the gears at the equivalent of full power (or more). Some systems rely on momentary clutch slippage or have reverted to shocks / springs in the drive train to reduce the shock during a near instant gear change.

With seamless shift gearboxes, the next gear is enaged before the current one is disengaged (at least on upshifts). In the case of Formula 1, all the car makers have their own proprietary method of implementing these, so there aren't a lot of details.

http://en.wikipedia.org/wiki/Formula_One_car

http://www.speedtv.com/articles/auto/formulaone/42017

Last edited by JeffR, Mon 31 Dec 2007, 13:07.

Quote from xaotik :

My opinion is that it (clutch overheating) was implemented based on Scawen's track experience with the FBMW.

That's hard to believe. Formula BMW is based on a motorcycle engine, BMW's 1.2 liter inline 4 @140hp, with a sequential shift Hewland racing transmission and a Sachs racing clutch. The car only weighs 1001 lbs. Clutch overheating isn't going to be an issue with anything but deliberate abuse.

http://www.formulabmwusa.com/technology_technicalspecs

http://www.hewland-engineering ... svga/productrange/ftr.htm

Again, my point is that for most cars, especially those being raced, flat shifting breaks drivetrains, and doesn't cause the clutches to fail from overheating. The clutch in these cars is never the weak link in the drivetrain.

Well the main argument that clutches rarely overheat would be that automatic transmissions "flat shift" on every shift, and don't fade. In an automatic transmission, there is a separate clutch for every gear combination, and a pair of these clutches is deliberately slipped at the same time to smooth out the shifts, even when at full throttle. The time period of this slippage is much longer than any flat shift would be, and yet the clutches don't overheat.

So the real issue is whether or not clutches for manual transmissions in cars similar to ones in LFS could ever overheat due to flat shifting. Maybe there are some real world cars with weak or defective clutches that would suffer from this, but I don't imagine these cars being run in stock form in a competitive race.

So with patch Y, we now have cars with brakes that never fade, drivetrains that never break, but clutches that fade from flat shifting. Are there any cars in the real world with this combination?

To me this isn't an issue of players learning to drive properly, it's an issue of realism in LFS. In my opinion, clutch overheating and failure due to flat shifting was a quick, dirty, and unrealistic change made to LFS in an effort to discourage flat shifting. The fix for flat shifting should have waited until it could have been implemented properly, which would be drive train damage, which is what would happen in real life.

Quote from geeman1 :

Auto-blipping I can just borderline understand if you have combined axis, but auto-cutting I don't. Seriously how hard can it be to lift the throttle?

Considering the cheesy plastic pedals that come with the cheaper wheel and pedals sets (I have a Momo racing wheel and pedals, and the pedals seem flimsy), wear and brakage of the pedals is a true concern. I would also find it fatiguing to constantly have to lift and press the throttle pedal quickly, because unlike a car, sitting in a normal chair doesn't provide ideal pedal movement the way it does in a car. I rarely use the wheel and pedals, because it's a pain to have to clamp it on and hook it up, so I use two joysticks on a clipboard instead, that I just set to one side of my desk when not in use.

NFS did one smart thing in it's current verion of ProStreet. Collision (and drafting) is off on cars that are a lap or more down to your car, although they can still draft and collide with each other. I thought this was a pretty clever idea. For LFS, it would keep the late joiners as well as slow or damaged racers from being an issue.

Huge grids on public servers is going to be an issue. It was for Nascar Racing Season 2003, where grids up to 40 players on a high speed, restrictor plate race forced players to stay in packs to take advantage of the draft. There was usually one pile up per race.

Quote :

However I have not much experience from US market cars, only what I have read and heard, so that is bit of question marks to be honest.

It would depend on the car, and not just those made in USA. I would assume that most higher peformance cars, regardless of where they are made, England, Germany, Italy, Japan, USA, ... are going to have stronger clutches. My only experience with burnt clutch was with a 1987 Mustang GT, while it was backed up a long, steep driveway, with the clutch slipping the entire time. It was enough to produce smoke, but even so, the clutch showed no signs of increase slippage while backing up, and worked just fine immediately afterwards. The clutch may have lost about 5000 miles off its lifetime in the process, but it's grip wasn't noticably affected.

So at least in the case of that old Mustang, clutch fade was non-existant. I've never experienced clutch fade in any of the cars I've owned, but I've never flat shifted either, although I have powershifted by slipping the clutch in 2nd gear. I have even launched from a standing start in 4th gear once or twice, and clutch overheating wasn't an issue, but I wasn't doing this repeatedly either.

Quote :

no lift shifters - ignition cut

Note that most no lift shifters cut off fuel, not spark, otherwise the fuel mixture would end up igniting in the exhaust, which is not good. The point about the no lift shifters, especially the fast ones, is that even with the fuel cut, engine rpms aren't going to drop that much during the 50ms down to 30ms shift times just due to the fuel cut, there will be a short period of clutch slippage to rapidly reduce engine rpms during a shift. The clutch, and the remainder of the drive train is designed to deal with the excess torque generated by the rapid rate of decrease in rpms.

Quote :

There has to be an ideal temp for the clutch/flywheel surfaces

Probably, but clutches should be designed to have more than enough grip to function well at any reasonable temperature. Personally, I've noticed that clutches on both my car and motorcycle tend to be a bit grabby when cold, so the grip is probably higher when they are cold. I'm pretty sure that grip will remain strong well below freezing.

This isn't an issue for me, I use two CH USB joysticks for driving, one to steer, one for throttle / brake, like the old style radio control car transmitters, and they have a user programmable driver, and I've already programmed auto-blip and auto-cut to trigger when I use the shift down and up buttons. I'm starting to see similar utilities being made for some wheel and pedal sets.

Last edited by JeffR, Sun 30 Dec 2007, 04:51.

Quote from Gunn :

Fast laps were not possible two car lengths off the circuit. Maybe your definition of "circuit" and understanding of "car lengths" are inaccurate?

I was exaggerating, and I've since updated my post. The cars do go completely beyond the curbing at quite a few spots at Blackwood. A video of the BF1 at Blackwood, driven by MacEST.

lfsblf1.wmv

Last edited by JeffR, Sun 30 Dec 2007, 04:20.

Quote from JTbo :

Street cars don't slip clutch, then explain THIS (Turn three, shifting 2nd -> 3rd)

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?

Last edited by JeffR, Sat 29 Dec 2007, 14:13.

Quote from xaotik :

I like being able to flat-shift a few times for the advantages it gives.

In real life racing, would flat shifting give a significant advantage?

Quote :

Quote :

no lift sequential shifters

They all use some system of cutting ignition or closing the throttle

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.

Quote :

Quote :

it appears that clutch slippage (as opposed to wear) due to overheating simply doesn't exist in the real world.

Yes it does. I've seen it happen in racing (rarely), autotests and most commonly production car trials.

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.

Last edited by JeffR, Sat 29 Dec 2007, 13:38.

I can't think of a good reason for removing auto-cut or auto-blip. If it's not giving players who use it an unfair advantage, then leave it alone. It it was giving an advantage, then increase the auto-cut / shift time to remove the advantage.

As the original posted stated, players with combined throttle / brake axis have a good reason to want auto-cut and auto-blip in the game. Despite the goal of realisim, a lot of players are using controllers with combined throttle / brake axis, and they shouldn't be penalized.

In my opinion, auto-cut should be automatically triggered by the game when a flat shift is detected, to eliminate the advantage of flat shifting.

Personally, it's not an issue for me. I use CH USB joysticks. CH makes a user programmable software driver for it's USB devices, and the driver can be programmed to auto-blip and / or auto-cut, which I've now done for LFS.

I don't play LFS that much, but I did try out the updated BL1 track, and liked it better, but mostly because I didn't like the idea of going beyond the curbing for a good lap time. I don't know what the real world rules are, but for most racing sims, it's at least two wheels on the track / curbing, and fast laps on the old track was more like two carlengths away from the curbing.

So count me as one who prefers the new layout.

Last edited by JeffR, Sun 30 Dec 2007, 04:18.

Quote from lalathegreat :

http://videos.streetfire.net/v ... 339-b6f5-98aa00fe0ac1.htm

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.

Quote :

Quote :

top fuel dragsters

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.

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

Quote :

he lifts on every single upshift

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.

Last edited by JeffR, Sat 29 Dec 2007, 07:08.

Quote from Woz :

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?

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.

Last edited by JeffR, Sat 29 Dec 2007, 03:26.

Quote :

What is a 'no-lift' shifter? Care for a link?

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

Quote :

I thought automatic transmissions used torque converters, which are not anything like clutches

There are multiple clutches, one for every gear combination.

Quote :

How often have you glazed the clutch disks?

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.

Quote :

clutch overheating / slippage isn't real

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.

Last edited by JeffR, Sat 29 Dec 2007, 02:42.

Quote :

more heat = less grip

This isn't true, unless temperature reaches the point that it literally melts the friction surface, causing it to glaze. Once glazed, the glazed surface will have to be worn off before the brakes (or clutch) work again.

If more heat = less grip then why do drag and high end road race vehicles preheat their tires? Drag racers do this via burnouts, road racers use tire heaters. Obviously tires can get overheated, but hot tires stick better than warm or cool tires. More heat does not mean less grip.

The materials used in brakes and clutches can handle a lot of heat.

As I just posted, automatic transmissions do worse than flat shifting on every shift, yet it's not a problem.

Try doing a web search for "clutch overheat" and all you'll find are articles about pre-mature clutch wear, or clutch chatter (warped plate), and nothing about clutch slippage due to over heating. A warped clutch will cause a lot of vibration, but it will still engage. Do a web search for "brake overheat", and you find a lot of references to brake fade. If you do a web search for "clutch fade", the hits will mostly be fluid related, or travel problems due to thermal expansion, but not due to friction material geting overheated and lowering it's coefficient of friction.

Last edited by JeffR, Fri 28 Dec 2007, 08:41.

Quote :

Quote :

LFS cars are being raced on tracks, not fun runs, but actual wheel to wheel racing. I'm not aware of any wheel to wheel racing based on bone stock road cars without some modifications, even if just for safety reasons.

Last time I checked, XRT had all comfy interior parts and no roll cage or anything like that, this would indicate rather different story than what you are telling here.

Maybe it's different outside the USA, but in the USA, all santcioned road races require roll cages, external battery cut-offs, water instead of radiator fluid, no usage of air condition (no dripping of water on the track), ... For track days, where drivers are not competing with each other, but just doing fun runs on a track, then roll cages are not required, however, there are still rules about using water instead of coolant in the radiator, ...

Quote :

So you are basicly saying that clutch should slip only when temp is going to be bit higher than sun's surface temp?

No, but it's going to have to get as hot as failing brakes would before it would start sliping, since the materials are similar, and flat shifting simply isn't going to generate that amount of heat, since it can't be maintained for anywhere near the time that the brakes are applied, and the power involved is much less. Brakes can decelerate at 1g or so at all speeds. Few cars can pull 1g in first gear, and virtually no street car can pull 1 g in second gear, and shift times are much smaller in duration that braking times. Flat shifting involves much less power involved over a much shorter time compared to braking, so the heat generation is relatively small by comparason.

automatic transmissions always "flat shift" and don't overheat

Maybe a better point to make is the fact that automatic transmissions have clutches that are "flat shifted" on every shift. In order to smooth out the shifts, the clutches for the two combinations of gears involved in a shift are delibrately programmed to slip simultaneously for a smooth transition. This is a huge amount of clutch slippage compared to flat shifting with a manual, and yet automatic transmissions don't experience clutch failure due to heat.

Last edited by JeffR, Fri 28 Dec 2007, 06:05.

Quote from legoflamb :

If you look at the pedals you can clearly see that Tsuchiya lifts throttle on upshifts.

He's lifting on downshifts (shifter is auto-blipping for him, but he's also trying to brake smoothly), but not on upshifts, at least not most of them. Another no lift sequential shifter example, BMW 320i STW from www.supercarchallenge.nl. Turn down the sound as the rear end is really loud.

Assen-bmwSTW.wmv

or a 2002 Formula 1 car, fully automated computerized shifting, David Coulthard in a McLaren at Spa:

spaf1.wmv

Quote :

The road cars in LFS are not highly modified drift or pimped rides for street racing.

LFS cars are being raced on tracks, not fun runs, but actual wheel to wheel racing. I'm not aware of any wheel to wheel racing based on bone stock road cars without some modifications, even if just for safety reasons.

Quote :

You appear to believe that you cant kill a clutch.

I believe that the tranny, drive shaft, axles, or differential will break long before a clutch ever does because of flat shifting. Compare the amount of energy dissipated by the brakes versus clutch where every shift is a flat shift and braking energy dissipation will be many times that of the clutch energy disspation, and the clutch components are huge in comparason to the brakes. So better stated, I don't believe a normal clutch can be made to slip due to overheating from flat shifting, and that only by wearing the clutch down will it ever slip. If I recall correctly, the LX6 lap record at Blackwood was done using only 3 of the 6 gears on the car, that's not a lot of shifting.

The point of my thread is that real clutches aren't going to slip due to the heat generated by flat shifting. Obviously, flat shifting is likely to break powertrain components, but the clutch isn't going to be the weak link here, and failure isn't going to be a slipping clutch. Many street car clutches are designed to slip to protect the transmission during a launch, but even repeated runs at a drag strip doesn't worsen the slippage until the clutch is physically worn out. Actually in cars with such a clutch, it's better to launch by dropping the clutch at a specific rpm and let the tires spin, a common method used by magazine testers when doing time to speed or time to distance runs for car testing.

Last edited by JeffR, Fri 28 Dec 2007, 05:29.

Quote :

Does anyone think less of Greg Stewart or Greger Huttu because they flat shifted on their record runs for Grand Prix Legends?

An update - hot lapping in GPL is done with damage off (not "hardcore mode"), so no engine or drivetrain damage. In GPL, with damage on, it was the engine or drivetrain that failed, not the clutch, when flat shifting. There's also a small random chance of engine or drivetrain failure even if a driver does nothing wrong on a long race (not sure if this was edittable in the player.ini file). Note all the laps aren't small, Nordschleife world record is around 7:45, and takes over 8 minutes for most players. Spa is over 3 minutes long.

In GPL, most online play was done with damage on, with the possible exception of the 1000km, 44 lap races at the 1967 Nordschleife that lasted over 7 hours with the required 40 minutes of break time (car in pit). These were a once a year event, and surprisingly, didn't result in any divorces.

Anway, the point about flat shifting in GPL, is that players accepted it for hot lapping, or damage off races. In my opinion, engine and/or drivetrain damage (like loss of a gear) would be better than clutch overheating.

Quote from Mazz4200 :

GPL - can't find the CD

Download the GPL 2004 demo, it's all setup, all cars, but just one track. You'll have to get the other tracks from your cd if you can find it. Sold out software (online store) may still have them for $5 (USA).

Quote :

Seriously can you not work out the reason why there aren't loads of videos of 'flat shifting' on the web?

Every race car with a "no-lift" shifter is technically being flat shifted. The main and syncro clutches are just designed to handle the abuse.

Last edited by JeffR, Thu 27 Dec 2007, 23:27.

Personally, I don't see the issue of players flat shifting justifying the creation of an imaginary clutch that overheats due to such shifting, since it doesn't happen in real life. This is a case where the clutch has been given imaginary limitations to prevent flat shifting, and I would have just left the flat shifting as it is, since it's been around for along time, and I don't recall anyone complaining about it.

Does anyone think less of Greg Stewart or Greger Huttu because they flat shifted on their record runs for Grand Prix Legends? It's my opinion and others that GPL and NR2003 have better physics than the current LFS. Players of GPL do use clutches and proper shifting in GPL, but almost all the world records are done via flat shifting, even though the game was patched to allow quicker shift times for the manual clutch players.

Obviously, no NFS game is going to compete with LFS or any other sim oriented game for it's reality, but most of the NFS series are fun and challenging in their own way.

The main differences between ProStreet and the previous 3 NFS games: Tracks are independently located at "legal" venues, with the supposition that the former street racer in the game has now gone legit. Tracks are scatter out through the world, as opposed to being marked off streets of relatively large city maps. The former games had very large city maps, included a free roam mode that allowed a player to cruise around in the city, and get involved in pursuits if caught speeding. So free roam and pursuits (as evader or cop) are gone. Drag racing is back (Carbon didn't have it). Drift is more realistic. Speed mode is new, basically cars driven almost pegged at the speed limiter speed of 250mph, although only one car in the game, the 911 Turbo, can run the Nevada tracks at that speed without going airborne and most likely getting totaled, in a cool (for the first few times) slow motion outside view.

This is the first NFS game with some tracks based on real world tracks. I'm not sure how accurate these tracks are or if they were "smoothed" out for ProStreet. Like most NFS games, ProStreet limits power induced oversteer, steering induced understeer, and exaggerates peformance of the cars.

Power induced oversteer is prevented for most cars (except for drift mode). For the lower powered cars, it's pretty obvious that the engine power is cut when taking turns, which I found a bit annoying. It's less obvious with higher powered cars, especially the rear wheel drive cars like the Ford GT.

Steering induced understeer only occurs on front wheel or all wheel drive cars and only when combined with braking or downshifting. Excessive steering inputs on rear wheel drive cars (or cars setup to oversteer) result in a mild oversteer that scrubs off speed; this can be used to stuff some of the rear wheel drive car into turns at higher speeds.

Peformance is greatly exaggerated. Real world lap records at Willow Springs are about 1:06 for a CART (Indycar) and F1 race car, set back in 1987. The fastest car in ProStreet, the Zonda, when fully souped up, can do a lap just under 46 seconds, pulling over 5 g's by my estimate, and hitting the in-game speed limiter of 250mph on the two "straights".

There are a large number of cars, but not the huge number of tracks, in the previous NFS games. All events occur on race days held at various locations: Autobahn, Autopolis, Chicago Airfield, Ebisu, Mondello Park, Nevada Highway, Portland, Tokyo DockYards, and Willow Springs.

The career mode isn't as progressive as previous NFS games. It's not clear when to upgrade or buy new cars because of the ingame handicapping. There are "tier" levels of cars, but the game will handicap the AI cars based on what the player is driving up to a point, requiring a faster car only in the latter stages of career mode. With 52 race days, and 9 locations, there's quite a bit of repetition in career mode.

Online play is based on the same single location race days used in career mode, which is pretty restrictive compared to previous games where any track could be chosen while with a group of players. The result is that there aren't a lot of online players (at least for PC).

Offline and ranked (online solo mode) scoring is done via a handicapped points system, so rather than choosing the fastest car, the most points are accomplished by using a car with a relatively high handicap. Head to head online play is still based on the fastest car / player, and points are ignored in this case.

Sample videos:

The most important feature, the slow motion "totaled" sequences, which are fun the first dozen or so times:

npcznd.wmv

Stage 3 Lotus Elise at Willow Springs, "incredible" speed.

npwslte.wmv

Stage 4 Zonda at Willow Springs, "ludicrous" speed.

npwsznd.wmv

Stage 4 911 Turbo at Nevada C (speed mode):

nps911.wmv

Drift mode (RX7):

npdrift.wmv

Drag mode (Zonda):

npdchiznd.wmv

Wheeli mode (supra no-nitrous drag, followed by Charger wheelie):

npdwchg.wmv

Last edited by JeffR, Wed 26 Dec 2007, 17:43.