I haven't seen another thread like this so I assume it bothers only me. The shift light in Y is very wrong. As it is now in almost all cars (I haven't tried the 1.0L ones TBH) the shift light is somewhere around 100-200rpm below the limiter. In the faster cars this means that it might as well be right on the limiter. Defies the whole purpose of having it, since when you see the light you've already hit the limiter. The light should come on a bit earlier, or as someone else suggested in another thread the limiter should be moved a bit upwards. No real car (street or racing) has the limiter right at the max HP point of the curve. It's usually around 400-800rpm above that.
Wrong shift light?
Firstly the rev limit and power curve are completely unrelated. The rev limiter is set according to the cars redline. The redline is the maximum speed the engine can safely rev to a car like the MRT has a restricted turbocharged bike engine which shifts the torque curve down the rev range so whilst the engine can safely rev to 13000 rpm peak power is at around 7000 and the ideal shift point is at around 8500 depending on gearing. On the flip side some, mostly older racing engines produced more power above the redline, resulting in cars having to shift bellow peak power to reduce the chance of the engine falling apart, the Merc W196 is a good example of this. Most modern racing engines are still peaky and produce power near to the redline. They need to be geared so that the optimum shift point, which is the point the light comes on at in LFS, is bellow the redline.
Food for thought: A race car wouldn't need a limiter if there were no need or temptation to rev that high.
My Saturn is an automatic, but the manual version actually has a shift light. To the people who say "shift lights only come on at a certain RPM," they are very wrong. Stock shift lights suggest when to shift, not at a preset RPM.
the rev limiter isnt really there for that, its there to clean up the mess that humans can make missing shifts and stuff.
Those people shouldn't be driving race cars
...humans? hah... well, you know the kind.
I doubt that, although they may have a very vague load variable programmed in to adjust it a bit. I've not heard of a shift light (or ECU) in which the torque curves (for all throttle openings), wheel diameters, and gearing are used to generate a real time wheel torque graph from which the shift point can be found. Racing cars just have an RPM based light.
In a sequentially shifted car, possibly that is the purpose. The real reasoning behind a rev limiter though is to prevent mistakes, either by getting carried away in close competition or missing shifts on an H-gate gearbox. The single seater my dad races has a lightened engine and no rev limiter, if you miss a gear which in a racing situation isn't hard to do you will normally have floored the throttle pedal by the time you realise, the result is retirement and at least a new set of valves. This is a real problem for everyone using this engine, the other engines, which either have rev limiters or bike 'boxes don't have this issue.
It's a road car, it is unlikely to be advisable to be shifting anyway near the engines optimum shift point let alone the redline. For this reason you get a small computer to tell you when you'd be better off in a different gear. Someone I know who runs a garage once had an American turn up in a hire car complaining of lack of speed, poor fuel economy (by American standards!), noise and smoke pouring out the bonnet. They'd somehow managed to drive 30 miles in first gear when they forgot they had to change gear :doh:
Most racing cars now have a set of shift lights like those in the FBM or a digital tach like in the FOX. I have only ever seen the light(s) set at pre-defined revs. Whilst an ideal shift is theoretically possible you'd have to reprogram it everytime you changed gear ratios.
Hmmm.... The engine's peak power and the RPMs at which it is produced have nothing to do with the gear ratio. Furthermore, in all kinds of engines, based mostly on the materials used, a certain RPM is defined through study/tests, above which the engine can be damaged. The limiter can then be set a little below that, and the engine can be tuned to produce it's max power a little below the limiter.
Limiters are adjustable ajp71. In road cars and racing cars. As is the engine's power curve. There's no reason for a car, be it a racing or road car, to produce it's max power at some RPM that the engine will be damaged. There is also no logic to having the limiter way up there, since there is no point to rev high above max power. For example, a racing car could produce -with a certain setup- it's max power at 9000RPM. Why would anyone want to put the rev limiter at 14000RPM then? No point. Or, a given engine cannot exceed 9000RPM without damage. Why would anyone tune it for max power at 12000RPM? Again, no point in that. Of course, at 12000RPM it will produce more power than at 9000, but what's the meaning if the engine breaks down all the time? The limiter and the max power RPMs are *completely* related (not mechanically but in the way an engine is designed/tuned), and they are also related with the max safe RPM, both in a racing or road engine where both (limiter and power curve) can be tuned either from the team or from the factory.
But even so, this has nothing to do with my question. My question was about the shift light. It should be at about the max power RPMs. So in patch Y where the light comes on at the limiter, either the shift light comes on at the wrong RPMs (above max power, where you might want to rev if the next gear is too long as you suggest, but the light still has no business up there), or the limiter is too close to max power RPMs.
Limiters are adjustable ajp71. In road cars and racing cars. As is the engine's power curve. There's no reason for a car, be it a racing or road car, to produce it's max power at some RPM that the engine will be damaged. There is also no logic to having the limiter way up there, since there is no point to rev high above max power. For example, a racing car could produce -with a certain setup- it's max power at 9000RPM. Why would anyone want to put the rev limiter at 14000RPM then? No point. Or, a given engine cannot exceed 9000RPM without damage. Why would anyone tune it for max power at 12000RPM? Again, no point in that. Of course, at 12000RPM it will produce more power than at 9000, but what's the meaning if the engine breaks down all the time? The limiter and the max power RPMs are *completely* related (not mechanically but in the way an engine is designed/tuned), and they are also related with the max safe RPM, both in a racing or road engine where both (limiter and power curve) can be tuned either from the team or from the factory.
But even so, this has nothing to do with my question. My question was about the shift light. It should be at about the max power RPMs. So in patch Y where the light comes on at the limiter, either the shift light comes on at the wrong RPMs (above max power, where you might want to rev if the next gear is too long as you suggest, but the light still has no business up there), or the limiter is too close to max power RPMs.
The ideal shift point has everything to do with the engine power curve and gearing. The taller the next gear the lower the revs will be after shifting so the further after peak power you need to rev before it's the ideal moment to shift.
As for the engines, normally the regulations produce the engine like it is. In the examples we've discussed there's nothing a team can do to change it. The MRT (a formula student) uses a formerly high revving motorcycle engine but due to intake restrictions in the rule book there's no point in making the engine rev to anywhere near the powerband of the stock engine. The Formula BMW on the other hand has the rev limit set at 9250rpm and non-adjustable, possibly it would be faster without a rev limit but that'll result in redlining the engine and increase costs so the factory ensure that nobody is at a disadvantage if they decided they'd rather not consider engines a consumable component. Other cars I mentioned, like the W196 could produce more power higher up but due to the limits of technology couldn't safely rev there for more than a few seconds a race.
The reason why your shift light doesn't come on until the limiter is because you've got a badly geared car. Your next gear is too tall (too much higher than the current gear) so even past the maximum power of the engine you've still got more power available in the lower gear, power curves don't just stop at the peak and in some engines you can safely rev miles past the peak power point, usually completely pointlessly.
As for the engines, normally the regulations produce the engine like it is. In the examples we've discussed there's nothing a team can do to change it. The MRT (a formula student) uses a formerly high revving motorcycle engine but due to intake restrictions in the rule book there's no point in making the engine rev to anywhere near the powerband of the stock engine. The Formula BMW on the other hand has the rev limit set at 9250rpm and non-adjustable, possibly it would be faster without a rev limit but that'll result in redlining the engine and increase costs so the factory ensure that nobody is at a disadvantage if they decided they'd rather not consider engines a consumable component. Other cars I mentioned, like the W196 could produce more power higher up but due to the limits of technology couldn't safely rev there for more than a few seconds a race.
The reason why your shift light doesn't come on until the limiter is because you've got a badly geared car. Your next gear is too tall (too much higher than the current gear) so even past the maximum power of the engine you've still got more power available in the lower gear, power curves don't just stop at the peak and in some engines you can safely rev miles past the peak power point, usually completely pointlessly.
And that does a nice wrap to dispell all the miss information that caused this thread in the first place.
Misinformation? My friend it is you who is misinformed.
ajp71, you are right on a few parts, I didn't explain them correctly in my previous post. However what you are saying are not exactly true either. For example, the MRT example may be valid, but it's a rather special case isn't it? Since as you say they use an already existing engine designed for sth else. Please tell me, why would someone want to make the max power point, max safe rpms, limiter and shift light at way far apart points of the rpms? In an engine designed for a specific reason, not using a random engine that was available.
Please tell me why would it be reasonable for any car to have it's max power at 7000, it's limiter at 6800, it's shift light at 6770, and it's max safe rpm at 6500 (or at 12000). I'm surprised really, because I've been studying (and tuning in my cars) internal combustion piston engines for about 10 years, and if a mechanic told me that we'd build my engine in the way you say I'd laugh and leave. I've also been studying racing regulations for various types of racing, and I've yet to see a race series where the engine was like you said. Either made that way by the regulations, or by the team given a certain freedom of tuning by the regulations. All engines I've ever seen in my life, road, racing, bikes, boats, armoured vehicles, aircraft piston, turbo, jet engines, all are designed and built along a standard pattern: maxpower -> rev limiter(when there is one) -> max safe rpm, in that order and usually quite close together. If the W196 as you say had the max power point above the limiter then it was wrongly tuned. I'm talking now about a REAL max power point, like the engine was tuned to produce it there. And since most racing cars have a peaky power curve if for example it was tuned for max power (let's say 220hp) at 6200 and the limiter was at 5500, at 5500 it could very well make a little over 130-140hp. If on the other hand it was tuned for max power at 5200, it could make ~180hp there. I suspect you're talking about the theoretical max power at higher rpms than the limiter. If so, all engines have the potential for more power at higher rpms than they work now, if tuned properly for the more air and higher rpms. But that's theoretical, it doesn't mean that if they went above the limiter as they are now they will make more power. They won't.
have you seen many racing cars where the max power is below the limiter? Or the limiter is 5000rpm above max power? Or any road car? For example, my old car had max power at 6200rpm, and the limiter at 7000. My new car, is the same car only the newer model, ad it has the same engine, only improved. It has more power and torque, but now the max power is produced at 5200, and the limiter is at 6000. Since it's the same engine, and even more with improved internals you'd expect that the previous 7000 limiter was fine. So why didn't they leave it up there? Since max power was now lower it didn't make any sense to leave the limiter almost 2000rpm above even if it was a safe rpm for the engine. Yes, 7000 was safe, but 6000 is safer. And if the power is at 5200 you don't need to go above 6000. You don't even need to go at 6000. Bad gearing as you say is a factor, but not that much. For example, my third gear is quite higher than the rest. So instead of my usual 5200 shift point, I change second at 5500. And that's what's needed. I don't need to go to 6000 to make up for the taller gear, since above 5200 the engine already starts to drop the power fast, and I would actually lose time high above that. Of course that depends heavily on the torque and power curves but still. My engine is pretty peaky for a road car, and third is quite a bit taller than the other gears.
Anyway, the ideal shift point has indeed everything to do with gearing, but the shift light does not. If as you say my car was very badly geared (which it isn't anyway), if one gear was very short and the next very tall, then yes, the ideal shift POINT could very well be above the limiter. But the shift light should come on regardless. If it's programmed to come on at 7200 and the limiter is at 8000, no matter what the gearing is like, it WILL come on at 7200. Even if I completely change the powercurve and the way the engine performs, if I don't change the shift light it will still come on at 7200rpm. So as you can hopefully see my thread is completely valid, and the shift light comes on late.
And BTW all power curves I've seen, and in all cars I've driven, the curve does actually just drop after max power. You might have more ACCELERATION in the lower gear because it's short, the power will be less.
ajp71, you are right on a few parts, I didn't explain them correctly in my previous post. However what you are saying are not exactly true either. For example, the MRT example may be valid, but it's a rather special case isn't it? Since as you say they use an already existing engine designed for sth else. Please tell me, why would someone want to make the max power point, max safe rpms, limiter and shift light at way far apart points of the rpms? In an engine designed for a specific reason, not using a random engine that was available.
Please tell me why would it be reasonable for any car to have it's max power at 7000, it's limiter at 6800, it's shift light at 6770, and it's max safe rpm at 6500 (or at 12000). I'm surprised really, because I've been studying (and tuning in my cars) internal combustion piston engines for about 10 years, and if a mechanic told me that we'd build my engine in the way you say I'd laugh and leave. I've also been studying racing regulations for various types of racing, and I've yet to see a race series where the engine was like you said. Either made that way by the regulations, or by the team given a certain freedom of tuning by the regulations. All engines I've ever seen in my life, road, racing, bikes, boats, armoured vehicles, aircraft piston, turbo, jet engines, all are designed and built along a standard pattern: maxpower -> rev limiter(when there is one) -> max safe rpm, in that order and usually quite close together. If the W196 as you say had the max power point above the limiter then it was wrongly tuned. I'm talking now about a REAL max power point, like the engine was tuned to produce it there. And since most racing cars have a peaky power curve if for example it was tuned for max power (let's say 220hp) at 6200 and the limiter was at 5500, at 5500 it could very well make a little over 130-140hp. If on the other hand it was tuned for max power at 5200, it could make ~180hp there. I suspect you're talking about the theoretical max power at higher rpms than the limiter. If so, all engines have the potential for more power at higher rpms than they work now, if tuned properly for the more air and higher rpms. But that's theoretical, it doesn't mean that if they went above the limiter as they are now they will make more power. They won't.
have you seen many racing cars where the max power is below the limiter? Or the limiter is 5000rpm above max power? Or any road car? For example, my old car had max power at 6200rpm, and the limiter at 7000. My new car, is the same car only the newer model, ad it has the same engine, only improved. It has more power and torque, but now the max power is produced at 5200, and the limiter is at 6000. Since it's the same engine, and even more with improved internals you'd expect that the previous 7000 limiter was fine. So why didn't they leave it up there? Since max power was now lower it didn't make any sense to leave the limiter almost 2000rpm above even if it was a safe rpm for the engine. Yes, 7000 was safe, but 6000 is safer. And if the power is at 5200 you don't need to go above 6000. You don't even need to go at 6000. Bad gearing as you say is a factor, but not that much. For example, my third gear is quite higher than the rest. So instead of my usual 5200 shift point, I change second at 5500. And that's what's needed. I don't need to go to 6000 to make up for the taller gear, since above 5200 the engine already starts to drop the power fast, and I would actually lose time high above that. Of course that depends heavily on the torque and power curves but still. My engine is pretty peaky for a road car, and third is quite a bit taller than the other gears.
Anyway, the ideal shift point has indeed everything to do with gearing, but the shift light does not. If as you say my car was very badly geared (which it isn't anyway), if one gear was very short and the next very tall, then yes, the ideal shift POINT could very well be above the limiter. But the shift light should come on regardless. If it's programmed to come on at 7200 and the limiter is at 8000, no matter what the gearing is like, it WILL come on at 7200. Even if I completely change the powercurve and the way the engine performs, if I don't change the shift light it will still come on at 7200rpm. So as you can hopefully see my thread is completely valid, and the shift light comes on late.
And BTW all power curves I've seen, and in all cars I've driven, the curve does actually just drop after max power. You might have more ACCELERATION in the lower gear because it's short, the power will be less.
As already stated the shift light is programmed to tell you when you will get more power in the next gear. It DOES NOT say when you get max power.
Read the next bit because this is what you fail to understand....
If you change the relationship between your gear ratios it WILL change when the shift light comes on.
The shift light is NOT the max power point it is the point where you gain more benefit if you change gear.
That's probably it. Here's the section of the manual on the shift light:
Now some funny misc. stuff from the section about the manual transaxle. Funny warning in a big yellow box that says "CAUTION":
Seriously, if someone is going to shift from 5th to 1st, then they should have their license taken away.
A "notice" in a light-blue colored box:
But, if you blip the throttle and match the revs of the lower gear, then won't you have a lower risk of damaging the clutch? Maybe they don't think that people buying Saturns know how to drive properly.
BTW, ajp71, I get about 34mpg in my Saturn when I drive at a constant speed of 65mph over a distance of about 20mi. I'm going by the fuel gauge, which isn't very accurate. So, I could actually get anywhere between 28 and 38mpg on the highway. When the tank is full, the needle goes past the last tick. Not accurate at all, but meh. Last time I measured it, I was doing 3/4 throttle starts away from traffic lights. It was a highway with traffic lights. It's hard to explain.
The most economic way to drive is to accelerate as hard as possible using full throttle to your cruusing speed, then modulate the throttle stay there. Accelerating gently means you spend long 'accelerating', and you burn off more fuel that way. To save the planet, floor it.
Your shift light is for economy, and it's entirely made up. It has nothing to do with tractive efforts, or power curves, or anything.
In England you are now taught to not change down the gears 5-4-3-2-1, but to stay in whatever gear you were in whilst braking, then changing to 1st when you come to a stop, or to whatever gear required at the speed you slowed too. This is on the basis that brake pads and discs are cheaper than gearbox internals and cylinder bores. But personally, I think it gives you less control, less smoothness, and doesn't allow you to nuture skills like heel and toeing (which no one wants to anymore anyway) and stuff like that.
Your shift light is for economy, and it's entirely made up. It has nothing to do with tractive efforts, or power curves, or anything.
In England you are now taught to not change down the gears 5-4-3-2-1, but to stay in whatever gear you were in whilst braking, then changing to 1st when you come to a stop, or to whatever gear required at the speed you slowed too. This is on the basis that brake pads and discs are cheaper than gearbox internals and cylinder bores. But personally, I think it gives you less control, less smoothness, and doesn't allow you to nuture skills like heel and toeing (which no one wants to anymore anyway) and stuff like that.
As everybody has a explained to you the shift light in LFS comes on at the ideal time, not a pre-set rpm.
Of course the curve has to drop after max power for it to be the maximum point. That doesn't mean that shifting up will give you more power. In this quick example if you're at 6500rpm (past peak power) and shifting up will mean a drop to 5000rpm you have more power available in the lower gear.
Interesting you say that, my driving instructor taught me to go sequentially down through the gearbox whilst braking.
That's what I do half of the time. An automatic transmission is just a manual where the shift lever is the gas pedal. Whenever I floor it, I usually let off around 5000rpm until it shifts up. By then I am usually going about 45mph, which is what most of the speed limits around where I live are. Next time I go on the highway, I'm going to accelerate to the top speed of the car I think the governer is set at 115mph, but I haven't been that fast yet. I've been near 80mph, but I didn't want to accelerate past that because over 80mph is reckless driving where I live, and I didn't feel like being arrested. Although they always park in the left shoulder, and it was a LONG straightaway after the crest of a hill. I could see 2mi down the road, and there were no cops. But I decided not to test the top speed of my car. Besides, the brakes are total crap. If someone cut me off going that fast, I would have to swerve into the shoulder to avoid rear ending them.
The new "Highway Code handbook, sponsored by Kwik-Fit"?
Then it is just plain wrong. IRL shift lights come on at preset rpms. I'm talking about shift lights in race cars not "economy shift lights" or whatever.
I'd like to see it changed as well but it is entirely possible to make a system like this if you know the power curve and gearing. To my knowledge no car IRL uses a system like this.
I say we do away with the shift lights altogether in most or all of the non-race cars. (an old plea)
What system are you talking about?
+1 to that.
The current LFS system. I see where I cunningly tricked you though by quoting one thing then talking about something completely different
I'd like to see a system of LEDs at preset revs in the race cars (like the FBM has) and no lights in the road cars myself
ok now I understand 
and I agree with your suggestions.There is plenty of reason to go past Maximum power RPM on the road and the track if the next gear will put you out of the power band. This is most noticeable on grades in lower gears (where the difference between ratios is greater) when exceeding the HPMax mark will reduce power but not so much as taking the next gear. Rev until engine power output is less than or equal to output in the next highest gear for the given speed. And yes; it would be very easy to make a shift-light operate this way with known gear ratios and engine output (considering the math above it about all it takes) but I agree, it doesn't belong in the UFR.
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Wrong shift light?
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