Unless in the case of the XRR, then your just slow With a racecar that you can change the gearing yeah 1-2k is enough. But in a production vehicle your not going to be able to be in that 1-2k all the time.
Still, I am not a fan of waiting and I will stick with my V8's or engines that produce power figures like V8's. American V8's that is =)
The ONLY point to vtec is Environmental. No one, when looking for performance, would choose it. That is my point.
Also Irbdsi, can you learn to spell and punctuate, because I lost you in the middle of your post as it wasn't understandable. For all I know you might have said something clever and correct for a change, and I wouldn't want to miss that event!
Speaking of VTEC and powerbands, I'll like to clarify why a broad and smooth torque band extending from mid to high revs is essential to EVERY form of racing.
Case study 1:
Renault F-1 V-10s. They stuck to 6 speeds because theri beautiful torque bands on't require too many gears to keep the revs within the useful range. Thanks to this, Renaults have the best launch and corner exit perfoemance almost all of the time.
Case study 2:
Rally cars. This is one arena where mid range torque dominates, especially at those super narrow and twisty stages where narrow powerbands allow no room for throttle control since you're too busy shifting gears mid corner.
Case study 3:
Mitsubishi Lancer Evolution XI. A car famous for MAJOR mid-range punch. Since 4WD allows the use of all 4 wheels to generate traction, the wide and powerful torque band is exactly what it needs to make the most of the superb traction.
Case study 4:
Audi R10. 1100nm peak torque, 650+hp. Powerband is from 3000-5000rpm, redlining at 5500rpm. In fact, it's torque band is so wide and powerful that it needed only FIVE gears. The wide torque band is a major reason for its incredible record breaking lap times. Even if its power and torque were doen 5%, it'll still be ultra competitive. Besides, drivers love it because: "It's so much fun to drive!".
Conclusion:
It's area under the power and torque curves that REALLY count, not peak power alone, in real life driving and racing applications.
BTW, VTEC/VVTL-i controllers are brilliant ways to unleash the full performance potential of their respective engines. They allow drivability and economy at lower revs while changing to a full performance cam grind at high revs. A friend of a friend of mine installed a VVTL-i controller to his Corolla Sportivo and in its current setting, easily smokes my friend's fully OEM car despite of nothing more than a change from 195/55/16 to 215/45/17 wheels and tires. It was set by the installers for maximum midrange to peak rpm power. Although peak power was practically unchanged, the car was transformed from gutless to glorious with just some positive changes to the VVTL-i switchover points. Spinning the front tires at 3rd gear at midrange rpms?Definitely impossible with OEM settings.
I was thinking the same thing Whilst he is indeed correct that the area under... is more important, the conclusion could never be reached from the preceeding sentences.
And I wouldn't call Evo's, R10's or modern rally cars cool at all. Not even slightly. A RS200 is cool. A Stratos is cool. A Ford Cosworth is cool. The three he mentioned (one being a generic hold-all) are just computer controlled turds. Quicker - yes. Safer - yes. More reliable - certainly. But cooler? No way. Cool? Nope. Dull and uninspiring - YES!
(eeek, mentioned two Fords on either side of a Stratos - now I'm certainly not cool!)
I'd rather be a consistantly quick driver than "cool" any day.
I don't believe VTEC has any place on a track, aside from track days. It's impressive technology, but impressive doesn't necessarily mean useful.
A race driver needs to keep the car balanced and smooth, at the degree of slip angle you're already at when driving on the limit of acceleration and cornering g force, a jump in power or engine compression, in either direction is going to put you into sever oversteer (RWD)/understeer(FWD), adding tenths of a second to your corner.
If the guy you're trying to pass slows down from peak corner speed mid corner, and you have to lift off, and you drop below your vtec crossover point, you're going to have to change down a gear, concequently by the time you've finished the straight after that corner, you'll be 5 car lengths behind him.... losing.
2 stroke motorcycle engines have had this variable valve technology for atleast 20 years, it's good because of the massive difference of power, with my powervalve (i wish they'd call it something else) shut, I have 12bhp up to 7,000 rpm, at which point it splutters and stops revving any higher, probably a good time to have changed gear by, on the other hand, if I have it open, I have absolutely no power, like 6 bhp up to 7,000rpm, at which point i get up to about 22bhp at 13,000rpm and it will continue climbing to 16,000 (going past 14,000 has only happened a few times, usually when a ponse with a hat and a body kit tries to cut me up, which I don't allow.)
Back to the point, VTEC engines are not 2 stroke, they are 4 stroke, why rob yourself of power at the bottom end of the rpm range? In a race, one day you might need that power, it could win you a championship because you were able to survive the rest of the last lap in 3rd gear and hold onto 3rd place....
No real race car has ANYTHING on it that hurts performance unless the FIA enforce it for safety reasons, or the increase in reliability is worth the trade off, except, I don't think Honda's are any more reliable just because of a change in valve timing, if anything, that's something else to break....
Advantages - fuel consumption, noise level cut down, makes rice boys feel like they have Nitrous Oxide or a turbo because of the kick in power (however mild), but anyone can have a kick in power if they limit the power lower down up to a certain point.
Disadvantages - slower than if you just had a straight four engine with decent valve timing all the way accross the rpm range, heavier than your usual valve system, more likely to break than something simpler...
Conclusion: VTEC doesn't give you more top end power, it takes away bottom end power for noise and fuel advantages.
and by the way, being an SRT4 fanboy is no better than a VTAK fanboy, neither of them are race cars.
Haha Tristan I'll pay that. mmm old school rally goodness. The sound and sight of a Stratos driven in anger would have been magic... even footage of it gets the spine tingling
zerocool - I'm sure somewhere in this thread, at least once, it's been explained that vtec allows a higher state of tune with more driveability at low rpm? It does work just the same as the 2 stroke powervalve, really.
I CAN scientifically prove that cars with fat mid to high range torque tend to be faster especially on the twisty track with megabytes worth of calculations and data, but I simply used RL examples for the sake of clearity and practical context.
I should have mentioned that a broad and fat mid to high range torque curve is what REALLY counts for racing applications. 4000rpm? That depends on what engine you're talking about. For a racecar with a 7000rpm redline, torque at 4000rpm would be considered mid range torque. This rpm region would be very important for corner exits at the slower corners, such as haripins.
IRL, shifting takes time, which slows the car down as no drive is transmitted to the wheels. Which is one reason why a broad torque saves lap times. The only racing transmission with no shift time is the zeroshift, but excess gears are just a waste of space and weight. Besides, attempts to make numerous gears fit into confined spaces tend to end up with less robust gears.
And Tristan, no offense but "coolness" is a "quality" that's simply too subjective on itself. Some people think old morgans are cooler than all other cars, but how's a sphagetti noodle wooden chassis going to help? It just gets nowhere.
Yes, Lancer Evolutions are high tech showcases, but the whole point is simply to extract the most of the car's potential. Computers onboard the EVO help optimise grip and handling, but do NOT break the laws of physics. Besides, its still takes exceptional skill to get the most out of them, unless you think someone like Tomi Makinen is a nancy boy.
I prefer to aprreciate cars for what they are, not via sweeping categorizations. I guess you hate diesels no matter how good they get. Just a hunch.
Blowtus - I understand it's very much like VTEC, I just thought another, perhaps more extreme example might be worth a mention.
Does anyone know how much power does a VTEC engine lose low end with the VTEC stuck in the high rpm profile?
My main point, hence the bolding, is that while it's good for the street, it's bad for performance on the track. Air conditioning is good for street use, but that costs a lot of petrol, and a lot of power, and as such no track car is going to have it. I think since in LFS they are ALL track cars, VTEC doesn't really need to be coded in either. I'd rather the time was speant developing something else.
Zerocool - why is vtec bad for performance on the track? Other than the extra complexity? You're not going to tell me that powervalves are bad for track performance too are you?
Fat mid to high range torque = high peak power. I agree that there is more to a car than peak power, but it's a 'reasonable' and simple indicator for a race engine, whereas a shit indicator for a street engine.
Powervalves are good for the track because without them you simply can't get any more than 12hp out of a 125 2 stroke engine, it will NOT rev high enough.
VTEC engines are bad for the track because as I understand it, VTEC doesn't give you any extra power top end, nor extend the power band further, or give it a higher redline, it takes away power lower down for drivability on the road.
The smoother you drive, the faster you can be, and that changeover will hurt your time in corners, and you will lose out compared to someone driving smoother than you are.
If someone could give me the Dyno charts for a car with VTEC, the same car with the timing always on the first cam lobe, and then another chart with it on the second cam lobe, I can prove VTEC has no track application, for any given set of corners (providing I've got the radius for a constant radius corner, or otherwise, plus the cornering force limit for the car in question, which is probably about 0.7 G)
Last time I checked, AC WILL be COMPULSORY in closed top Lemans cars next year if I remeber correctly, but it'll be so sooner than latter. Only very small (less than 1mm (0.3mm to be exact) for a 25mm restrictor) increases in air restirctor sizes are required to level the performance.
Just to clearify things, VTEC is meant to simply provide multiple cams for one engine, i.e. 2 engines in one. That's the real practical point of it. Unfortunately it does act like an annoying on/off switch. As for increased power, it does so if its high speed cams are of a profile just as aggressive as full blown race cams. The good news would be of docile handling at low (such as below 3000rpm) revs used on the street.
However, the IDEAL cam would have infinitely variable lift and timing settings. Some variable cams such as Ferrari's use a shaft that slides forwards and backwards as such longitudinal regions represent different timings and lifts, allowing an almost infinitely variable cam adjustments in real time.
Last time I checked, the V-8 Renault F-1s were FORCED to adopt 7 speeds as its variable air intakes that helped produce excellent powerbands was BANNED. Hate it when F-1 forces technological mediocrity with the excuse of "better" racing.
rubbish! powervalves dont make the engine rev higher, they do exactly the same as vtec - allow the engine to be useable down low while tuned for higher peak power. pre powervalve highly strung 2 strokes are pretty nasty things to ride by all reports...
I have one of those highstrung two stroke motorcycles, and I HATE IT! It's horrible to ride. so yes, you're right there!
If you had VTEC "kicked in" 100% of the time, you'd have more power low down.
If you have a powervalve open 100% of the time the bike will barely pull away under its own power.
Having the low lift cam profile at all is damaging to the cars peformance, you get less power. Having the lower exhuast exit port on a 2 stroke motorcycle means you can actually pull away without being above 7,000 rpm.
Those are my reasons for thinking they are fundamentally different, the only reason I race my crappy 2 stroke motorcycle is because it's cheap, I can get the engine overhauled for practically no money when I break it.
Some Morgans ARE cool (and I don't like English cars generally), and the wooden chassis is actually a very clever and good idea. All the strength of wood, with predictable flex, low cost and not that much weight. A natural composite - in fact I think a LOT of modern cars would benefit from a bit of woody goodness in their chassis!
Whilst computer controlled cars cannot break the laws of physics, and whilst undoubtedly a good driver is needed to extract the maximum from them, the point of the electronics is to make crap drivers fast. I'm old school in so much as I think crap drivers should either a) not drive b) learn to drive or c) die (yes I think c, even though my brother was killed in a road accident - I'm a firm beleiver that cars should be able to kill, and I don't want a spotty 17 year old programmer deciding that that last mm of throttle travel won't be allowed. It's what gives you an incentive to not push the limits, drive safely and learn what you are doing. No airbags in my car, or TC, or ABS. And a nice flexible chassis to put the engine in my lap - perfect!).
Evo's are, quite simply, for people who can't drive a proper car
Yes I dislike diesels. Mainly because they are worse for the environment, are heavier, more expensive, sound crap, are rev capped, don't have much engine braking, and are considered by some to be the future. Sure they might give you better mpg's on the road, but for every mile you are giving more people cancer. Whooo! On an individual basis I am prepared to accept that aspects of diesels are great, but on a general basis I am against them. When they can produce an unthrottled gasoline engine on an economic scale for better part load efficiency I think we'll see diesels die. And unthrottled gasoline engines are the focus of lots of research, so I think it's only a matter of time
Edit: The only reason I seem to argue with you a lot James is because a) you know your stuff and b) you're as arrogant and opinionated as me. I'm just glad we do agree on some stuff, otherwise we'd just end up hating each other
Didn't you say yours had a powervalve?? powervalved 2 strokes are the best bike engines around! my ktm380 lifts the front wheel with the engine on the verge of stalling lol.
When folk talk about vtec kicking in, they mean the wild cam profile - worse power down low.
I agree with Tristan, in as much as all driver aids should be removed, except for formula 1, because that should be a competition for cars to go as quickly round the track as possible, as such there should be no engine tyre or aerodynamic limits.
In every car with traction control, ESP, whatever acronym that turns up on the latest car door in crappy plastic chrom lettering.... The first thing I do is switch it off. I don't like the idea that any thing can take control away from me as a driver, I've worked so hard to get good at it, and I'm a firm believer in my own ability, and my real world track times are testiment to that, as such, anything taking away from my driving experience is a definate negative. illepall
People don't crash planes very much becase they are lethal when that happens, people survive car crashes every day, me included. Put everything on something far more dangerous than a car, and eventually the crash rate will plummet, everyone who's going to crash will have done it already, and won't do it again!
lol, ok maybe not, but it's an interesting concept.
edit :
I can't find dyno charts for the same car with the VTEC enabled, disabled and normal, plus disabled and always in the wild cam profile. I don't think a conclusion about this is possible untill we find them!
When was the last time chassis flex is good for handling precision? And judging from what you say about cars with computer controlled differentials, professional rally driver in Lancer Evolutions/Subaru Stis/Citreon Xsaras are all crap drivers. A list that includes Sebastain Leob, Tomi Makinen, Marcus Gronholm, etc. Next time you such a thing, you might as say that all the current WRC drivers are no skill hacks of no driving ability.
Just to illustrate that sweeping statements make no sense.
Homogenous Petrol combustion is known to me as well, but the truth is petrol is getting real old. It's dino oil based, and no matter how much oil is currently left, it's FINITE. Even though new sites are found every now and then, ACCESSABILITY WILL be increasingly difficult and *EXPENSIVE*. I wonder if you are willing to pay 10 pounds per liter of petrol before you frigure that it's hopeless to adamantly stick to petrol in the long run. Unless of course you couldn't care less about your future generations.
Diesel, on the other hand, has multiple sources, so it's not utterly dependant crude oil alone.
Oh, while you're away, diesel technology has gone a LONG way from the 70's smokers. As if petrol engine emmisions don't cause cancer at all. The solutions for the NOx problem are now well within reach. Don't be surprised that 5 years from now all new diesels would have no more and possibly even less NOx emmsions than contemporary petrols.
Diesels have NO ENGINE BRAKING? Is this a reverse logic universe? When was the last time a diesel manual car lost to a petrol car with almost all else equal in the engine braking department? Even with taller gearing usually used for diesels, they STILL consistantly beat all petrols in the engine braking department. I guess you've never driven Diesel Off-Road 4WD vehicles before.
On the weight front, diesels have made startling progress thanks to materials and design technologies used for the AUDI R10 , which WILL be applied to poductions cars very soon. Don't be surprised if Diesels will soon be not significantly heavier than contemporary petrols.
Tristan, I'm perfectly fine with opinions as long as they have some valid reasons to back them up, but please, don't resort to categorial hate. And please don't discount new technology that is now widely available before you make an opinion.
But I wish it was that simple. Usually the boyracers drive above the speed limits, have no real idea about what they are doing and in general their car control skills are shite. Plus the obvious that when they crash out, they usually kill/cripple innocent bystanders instead taking their own life.
I think every car sold should be infested with all kinds of safety devices because I don't want to get killed on highway when 18 years-old idiot from the next door tries how fast his punto can go, eventually losing control on straight highway spinning in front of me, making me live the rest of my live in vegetative state while he just continues living. Plus the fact that most people have no idea how to drive on extreme situations.
I have TCS, ABS (no ESP) etc... in my car and they really don't bother me at all. If the deviced were limiting my "performance" - it would be a sign that I'm driving too fast instead of that they limit my skills. Of course it is sad that ESPs and such are used in modern cars to make the handle better making the driver to believe that he can actually drive.
Racing car is a different topic. I want the frame to be sturdy and the car to be safe so in case of a flat rear tire I don't need to learn to drive without feet. But electronics aren't the place for racing cars, the driver should be the only one who decides how deep the loud pedal is pushed or how hard he brakes on corners.
My first car had neither ABS nor any other electric controls. My closest situation to a severe crash was when I was travelling over a twisty downwards section in a town. Travelling at 60km/h I suddenly saw a car standing square right on my lane in a left turn.
Without thinking I opted for an evasive move to the left lane, quickly turned the steering wheel left, tapped the brake, induced oversteer and flicked the rear end around the obstacle neatly.
TC or ABS would never have allowed me to do this. The car would have never gone sideways and I would never have had the time to react to that "unnatural" behaviour. I would have crashed right into the driver of that car.
ABS and TC are made for people who lack understanding of vehicle dynamics. And it's a great protection for them. But everyone who knows how braking while turning influences the grip levels at the wheels of a car will have to visit a street security course with his car to understand what it will do with his (propably senseful) inputs in specific situations.
(Sorry for being offtopic, but I thought I'd share the story. Really, if you never learned how a TC works you can't anticipate it and it will be dangerous if you f.e. expect the car to go sideways. Security courses are really senseful there.)
That’s not true… It’s a little bit difficult to explain… mainly cause of my bad English (I am correcting the spelling and grammar mistakes for about a hour, on ms word)
It is logical that the power extracted by an engine depends on the air (or air mixture) flow of intake and exhaust system including the cylinder head and the valves…
It’s also logical to think that the higher the valve lifts and the more it remains opened the better air flow you have.
The problem is that when engine is working even in low rpm, the speed of the gases mass passing the intake valve or the exhaust valve is much higher than you can imagine… In that condition air (and gases) doesn’t moves as we normally think,
it moves in the form high frequency waves…
Engineers study the behaviour of those waves and tune the intake – valve train –exhaust system to be coordinated in the frequency in which air moves in certain rpm.
Tο determined that frequency in which the engine will have its max efficiency; (max torque) geometric characteristics such as length, diameter of the intake-exhaust system and the valve train geometric-timing characteristics are carefully chosen.
An intake camshaft e.g. 11mm lift and 290οduration, prevents maximum air flow in cylinder head only around 7000rpm with an optimal range of +- 1500 rpm… that camshaft may be full efficient there but when the rpm drop under 3000 the air flow wil be messed up… and in idle the engine will hardly keep working… In low rpm an camshaft with lower lift and shorten duration will be more efficient.
Ideally the best would be that the camshaft geometric characteristics (as also the exhaust ant intake system, but lets stay focused on the valvetrain) could change continuously as the revolution rate of the engine is altered.
Well fore now we have the ability in an engine with logical cost to get only e few modes of camshaft characteristics depending on which rpm the engine works.
Off course for road used cars the timing of the valvetrain and the modes are not tuned for maximum attribution of power in all rpm…
They use the benefits of that technology most for fuel efficiency and lower emissions… and for not having the customers disappointed they give to them a peak power point which comes suddenly 1000rpm before the rev limiter, to play with…
That’s because valvetrain control systems tuned in that way, cant have a good racing performance. (When the wider the power band is the least gear changes you have to make to keep the acceleration high)
Valve timing&lift control systems are used in more racing cars (including F1) than you can imagine…
But not in the way similar systems control the power extraction of a road going car…
(tip: when tuning (vtec,vvti etc) engines you can easily (by reprogramming the ecu) move the “wild cam mode” rpm point in lower rpm such as 5000rpm… and you have a nice wider power band, so you have at least 3000 rpm το play with. (end you don’t even feel the kin of that point…)
And for the reason I mentioned before the wild cams don’t work properly in lower rpm…
As for the valve system tow stroke engines have… its completely different with the one fore stroke engines have… And as for the exhaust port of a tow stroke engine… if you leave it wide enough you may not have power at all… Yes… and there gases gone mad cause off the speed… also hi frequencies, and because we have no cylinder valves the only way to tune the engine to produce more power is to coordinate the exhaust pipe with complex geometry...
And yes. I have omitted a lot theory which I must have reported to prove what I am writing…
And yes my description sucks … so just look for some info about that and you will see.
Lots of times. There is such a thing as a chassis that is too stiff. Chassis flex in cars is a very important aspect of their design, and they don't simply make them as stiff as possible. Gains can only occur when the flex is substituted elsewhere in the suspension, and in many cases low profile tyres and limited suspension travel (yes, on road cars) means that chassis flex is important. Drive any new BMW on run-flat tyres and tell me that the TERRIBLE ride couldn't be improved with a bit of give in the chassis.
I think you'll find that the drivers prefer the mechanical diffs
You forgot the bit after this sentence.
It's not just the finite nature of it, but the environmental impact too. So...
I think you'll find there is a lot more oil out there than we know about
Aha, yes, you can make it from plants too. Which means cutting down the trees to make space for the huge fields of oilseed etc, which means even less trees to keep the atmosphere going. You see, there is no solution that involves burning oil at the moment that DOESN'T harm the environment just as much as any other. Vege oil diesels are no better for the environment than dino oil as you put it.
Yup it has. And it's still awful![/quote]As if petrol engine emmisions don't cause cancer at all.[/quote]Almost negliably compared to diesel emmisions, but of course there is some added risk yes.
Only if petrol technology doesn't improve too. It will, and I firmly believe that diesel will always be playing catch up. And by the time it does we'll have something 'better' like Fuel Cells or something.
The lack of throttle means that there is less work done on the piston crown on overrun, resulting in less engine braking. This is partly, though not entirely, offset by the larger compression ratios and cylinder friction, but I still have yet to drive a diesel with as much engine braking.
Aha, cheap digs at dawn!
All all the vehicles in the world, I would enjoy a diesel (yuck) off-road (yuck) 4WD (yuck) car the least, but yes I have done a bit in the aforementioned excuses for transport. And I felt the off-throttle performance (i.e. engine braking) was stronger, more predictable and easier to modulate in the petrol (throttled) vehicles.
Yeah, in about 10 - 15 years they will be as light as petrol engines.
When, not if, but the when is still a long way away.
James, I perfectly fine with option as long as you have some valid reasons to back them up, but please, don't resort to blind fanboyism. And please don't just love new technology or technology over the horizon just for the sake of it. And please don't hate old technology just because a magazine says something newer is better.
I have nothing against new technology. But it's either trying to gain public opinion ('Wind Power is Good' says government. 'Okay, we believe you' says gullible public), or to sidestep emissions legislation (Use LRP, it's better honest) in many many cases. With regards computer control and driver aids in road cars it's simply because driving standards are falling WORLD WIDE, partly because people are too lazy to learn how to drive, and partly because they don't need to learn because the computers compensate. But then they need more computer aids to compensate for the humans being slightly lazier each time than they expected.
This is a discussion about Vtec engines, and not the rights and wrongs of diesels. Start a new thread if you really want to discuss it, but this is the wrong place.
Kaynd - thank you for your detailed explanation, your english is good, exceptional considering the nature of the technical subject.
I had been aware of the compression waves of fuel mixture before, however I assumed it's affect to be negligable for four stroke engines, due to the fact there is an exhaust valve that shuts to allow compression, where as a two stroke requires back pressure provided by the expansion chamber to keep the mixture in the cylinder and out of the exhaust.
So essentially, while the variable valve timing may exist in motorsport, you would never get the trademark VTEC sound, as the cam profile switches a lot earlier and far more smoothly before a sudden step in power is noticable, and dropping off into an area of lacking acceleration is less likely as it is far lower down the rpm range and the power delivery is smoother than "the loudest vtec crossover ever lolz"
The result I wanted, all be it in a rounderbout kind of way! lol.
Does this mean every VTEC owner with an aftermarket exhaust system requires their VTEC extensively retuned to take advantage of the backpressure frequencies with the new system?
With a racecar that you can change the gearing yeah 1-2k is enough. But in a production vehicle your not going to be able to be in that 1-2k all the time. 
illepall
