Something Random
- Thread starter ddrueding
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Stereodude
Not really a
That all depends how many HP the other engines are putting out. In general it requires a certain amount of fuel to be burned to get a certain power output. If you want 300HP it doesn't matter how you go about getting it. With an internal combustion engine you're going to use about the same amount of gas regardless of the number of cylinders or displacement. Roughly speaking a 300HP V8 uses the same amount of fuel as 300HP V6 or a 300HP 4 cylinder if they're all generating 300HP.
ddrueding
Fixture
Exactly. But if this car is able to perform as advertised, mainly keeping up with cars that have twice the power, than it will indeed be sipping gas.
There must be some efficiency gains in an engine with fewer cylinders generating the same rated HP as an engine with more. My thought is that with fewer moving cylinders, there is less internal drag, less oil to move around, less total weight. The increase in efficiencies may be minor, but I'm guessing there must be some. Also, the added bonus of reclaiming some of the energy lost as heat through the use of a turbo might help a little.
Yeah, I bet. I don't think Mother's Day is a real holiday.
The efficiency gains happen in how well the engine scales down to say 40 or 60 HP output when cruising. Even in something as simple as my car I can see anywhere from 13mpg to 33mpg.
The other concern is how drivable are these engines, is it a super peaky small displacement forced air engine where the torque curve looks like an upside down ice cream cone or is it a large displacement flat as a pool table torque curve? Lots and lots of tricks going into the small displacement engines to cover up that natural tendency to be peaky. Smaller displacement forced engines have a lot of expensive technology surrounding them to make them drivable.
Again on the other side there are tricks to make the big displacement engines have some efficiency. Take a car I am familiar with like the Lincoln MKVIII and the multi valve 4.6l v8. They have a short/long intake runner arrangement for each cylinders two intake valves and at low rpm they close the short one. The long one then generates more swirl and efficient burning at low rpm. Now because you have twice as much cylinders and twice the displacement you can use the above trick to successfully run the engine at half the typical cruising rpm of an engine with half the cylinders and displacement would need to spin at. You can quite often be cruising at 50mph and have the engine turning well below a thousand rpm and getting 28mpg or more.
time
Storage? I am Storage!
AFAIK smaller displacement per cylinder = flatter torque curve, i.e. it extends higher up the rev range. Larger displacement per cylinder results in a bigger torque peak in the low to mid rpm range, but it's a ski slope rather than flat.
A 1500cc 4-cylinder engine is definitely not peaky. And when coupled with a sensible vehicle weight, it works just fine. The problem is coupling very small engines with very heavy vehicles - that's when you need to start talking about hi-tech turbos to smooth out the user experience. I'd assume that's why Ddrueding loves his turbo Audi, it's designed to deliver consistent torque from very low rpm.
I'm fairly sure that non-diesel engines are sub-optimal below a thousand rpm, unless you're talking about a no-load situation such as backing off or going down a hill.
I'm not powertrain expert but I'd say your premise is correct, overall. Of course, it's alot more complicated than that. I think you kind of get stuck in a somewhat circular mass loop though. Mass begets mass. Larger cylinders weigh more & have more inertia. More interia means they can't reciprocate as fast w/o putting more stresses on the moving components. More stresses mean stronger/heaver components or some type of alloy must be used to acheive the strength. But you're probably stuck with more weight unless you get into advanced materials that are expensive. There's a sweet-spot depending on the desired output and induction technology used. My guess is most cars are probably there in this day & age.
Then you add in the issue of balance and NVH as another variable. That's probably the most difficult one to overcome when you're playing around with the number of cylinders you have. In that respect, I think Rotary engines are cool.
That's another angle that I wasn't considering but I think you are correct. But again it doesn't make for an efficient or even inexpensive engine when you move up to eight ten or twelve cylinders to meet the needed power requirements if you want to keep the small displacement per cylinder.
I was referring to what it takes to maintain speed on the level highway, it really isn't much.
Bozo
Storage? I am Storage!
Chewy509
Wotty wot wot.
Mmm... Engine for a new Monster Truck!
ddrueding
Fixture
Quite. Running the engine above ~3500RPM in traffic is uncivilized, particularly when ~2250 is all you need to pull away from the unsuspecting suburban. Massive torque at low RPM is why I'll be adopting electric earlier than most.
Any engine that requires multiple tiers of guard rail is freakin' awesome.
Santilli
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The driving force in engine design for F1, and this kind of car, the wing, is aerodynamics. Flat 12's were designed because they created a better wind signature then a similar V 12. In this case the height of the 4 works to the advantage of the car
in creating a wing effect, and in narrowing the rear end, allowing for bigger tires.
The problem with large displacement cylinders, and engines, is they can require large components, like valves, that put more stress on things like springs, and wear them out quicker. Also, it is easier to accelerate
a lighter piston then a heavier one. So more cylinders often means quicker response time. This might be critical in F1, but for Lemans, or CART it's not nearly as much.
Turbos generally allow for a much flatter torque curve, sacrificing high end revolutions, and peak horsepower, for flexibility. The irony is the turbo cam shafts are the reason for the even torque curve, not so much the turbo.
A turbo cam, with proper natural aspiration, or even injection, can give the same flat torque curve as the same setup with the Turbo, and be less peaky, and more driveable, since it doesn't depend on the Turbo pressure to be built
up by exhaust pressure. In other words, no lag.
in creating a wing effect, and in narrowing the rear end, allowing for bigger tires.
The problem with large displacement cylinders, and engines, is they can require large components, like valves, that put more stress on things like springs, and wear them out quicker. Also, it is easier to accelerate
a lighter piston then a heavier one. So more cylinders often means quicker response time. This might be critical in F1, but for Lemans, or CART it's not nearly as much.
Turbos generally allow for a much flatter torque curve, sacrificing high end revolutions, and peak horsepower, for flexibility. The irony is the turbo cam shafts are the reason for the even torque curve, not so much the turbo.
A turbo cam, with proper natural aspiration, or even injection, can give the same flat torque curve as the same setup with the Turbo, and be less peaky, and more driveable, since it doesn't depend on the Turbo pressure to be built
up by exhaust pressure. In other words, no lag.
Santilli
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"Also, the added bonus of reclaiming some of the energy lost as heat through the use of a turbo might help a little."
Ah, no. The problem with turbos is how to get rid of the heat. To reach maximum results from each bang, you have to cram as much fuel and air as possible into the cylinder. This is what they do in drag racing, with very high boost, and with turbos.
The heat generated with a turbo is counter productive to this goal, since gases expand as they are heated, and therefore have less gas to actually burn. Ideally, you would cool your air gas mixture prior to blowing it into the cylinder.
In fact, many of the street car companies put massive coolers on their turbos to keep heat down, at the cost of weight. Also, since you are no piping hot gas around the engine block, it requires more extensive cooling solutions, that usually cost weight, and create aerodynamic problems for designers.
Don't forget that the actual ACT of compressing air creates a lot of heat.
When you get up around 145 miles an hour, you run into a giant hand, called wind resistance. To break this barrier it requires geometric increases in horsepower, and the worse the aerodynamics of the object you are trying to push through the air, the steeper the curve becomes to increase speed vs. adding horsepower. In my day, given the designs, this was one of the reasons there were no mid-sized engines to speak of. Given the body types, once you got into the 350-400 HP range,
to create more top end it was a waste of time to go to a 350. Hence the jump usually from small to large block, with the doubling, at least, in horsepower, for more top end.
Ah, no. The problem with turbos is how to get rid of the heat. To reach maximum results from each bang, you have to cram as much fuel and air as possible into the cylinder. This is what they do in drag racing, with very high boost, and with turbos.
The heat generated with a turbo is counter productive to this goal, since gases expand as they are heated, and therefore have less gas to actually burn. Ideally, you would cool your air gas mixture prior to blowing it into the cylinder.
In fact, many of the street car companies put massive coolers on their turbos to keep heat down, at the cost of weight. Also, since you are no piping hot gas around the engine block, it requires more extensive cooling solutions, that usually cost weight, and create aerodynamic problems for designers.
Don't forget that the actual ACT of compressing air creates a lot of heat.
When you get up around 145 miles an hour, you run into a giant hand, called wind resistance. To break this barrier it requires geometric increases in horsepower, and the worse the aerodynamics of the object you are trying to push through the air, the steeper the curve becomes to increase speed vs. adding horsepower. In my day, given the designs, this was one of the reasons there were no mid-sized engines to speak of. Given the body types, once you got into the 350-400 HP range,
to create more top end it was a waste of time to go to a 350. Hence the jump usually from small to large block, with the doubling, at least, in horsepower, for more top end.
Santilli
Hairy Aussie
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The odd part about this Delta Wing is it's been done before, of sorts, as a result of the CanAm spinoff 917-30 etc.
That, and the car looks a LOT like a landspeed record car.
That said, the real problem with todays' cars is weight. I envisioned long ago that cars would all be under 3000 pounds, or at least the vast majority, and many around 2000. Thanks to government safety standards, and the solutions
designed by Detroit, everything is heavy, and big. I really don't see why a roll cage based car can't be built, and be both safe, and light. However, Detroit didn't go this way, so we end up with 3500-4000 pound 'compacts', and, the land
of the SUV. It is also possible to build a large, roll caged based car, that weighs in the 3000-3500 range, for family types, etc.
Put simply, the more the car weighs the more power to get it to speed, and the bigger the brakes to bleed off the speed. Lighter is just more fuel effective, period. This approach has pretty much escaped Detroit, and, hence we
have tons of Japanese cars which are sort of on board, but don't exactly optimize the weight to power ratios either.
That, and the car looks a LOT like a landspeed record car.
That said, the real problem with todays' cars is weight. I envisioned long ago that cars would all be under 3000 pounds, or at least the vast majority, and many around 2000. Thanks to government safety standards, and the solutions
designed by Detroit, everything is heavy, and big. I really don't see why a roll cage based car can't be built, and be both safe, and light. However, Detroit didn't go this way, so we end up with 3500-4000 pound 'compacts', and, the land
of the SUV. It is also possible to build a large, roll caged based car, that weighs in the 3000-3500 range, for family types, etc.
Put simply, the more the car weighs the more power to get it to speed, and the bigger the brakes to bleed off the speed. Lighter is just more fuel effective, period. This approach has pretty much escaped Detroit, and, hence we
have tons of Japanese cars which are sort of on board, but don't exactly optimize the weight to power ratios either.
ddrueding
Fixture
Don't forget all those amenities that folks like me insist on. I don't know what a heated seat or a navigation system (or even air conditioning, power steering, assisted brakes, etc) weigh, but I'm sure it is a bit.
Or turkmenistan of five five passengers and their belongings, etc. I would never own a vehicle under 3500 lbs. 4000-5000 is preferable for driving in the real world with other vehicles on the road.
ddrueding
Fixture
I would take a 2000lb car (with my amenities) any day. Active safety (avoiding an accident) has served me much better than passive safety (airbags, seatbelts, etc).
BingBangBop
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Active safety has its limits for there are always others on the road that you have no control over.
ddrueding
Fixture
My brain translates this to "If you were a sitting duck you might need your seatbelt when someone hits you" No thanks.
ddrueding
Fixture
Of course, and my car got pretty good safety ratings and has a million airbags, but I'd rather not be in an accident in the first place.
CougTek
Hairy Aussie
I think I share Dave's philosophy regarding driving speed. Statistics tell us that the more time you spend on the road, the more likely you are to be killed in an accident. So I drive the fastest that I can to spend the least time possible driving. When people I pass yell at me, I just answer : I'M JUST TRYING NOT TO GET KILLED!!!
ddrueding
Fixture
I guess it comes from commuting on a motorcycle in traffic in a big city. Simply assuming that no-one sees you is being too optimistic. You need to assume that they are out to kill you and actively deny them that opportunity.
This principle was taught in the MSF course I took.
The bumper stickers that read: "Motorcycles are Everywhere." makes me laugh. It needs to be the other way around (cars are everywhere), much like you've described. It's unfortunate that so many of the motorcycle riders I see on the road are complete cockbags in how they drive. I can honestly see why other motorists would be out to kill them. This really leaves a bad name to the rest of you who ride properly. I remember a few years back driving down RT2 towards Fitchburg/Gardner with two lanes in the road where a few crotch rocket riding fellows were following close and weaving in an around cars. It came up to me and I didn't let them through the car to my right as I was passing them (albeit slowly due to traffic/congestion). I honestly didn't care to let them through anyway...and when barely enough room opened up to let the one guy squeeze through on the right, he immediately passed me and the went right back in front of me within in a foot or so only to slam on his brakes. Seriously? Who did he think would win this situation? I'm not going to sacrifice my car or well being into a guardrail to avoid hitting this twatstick. We both slowed, as did the dozen cars behind me. As if that wasn't enough, he then pops a wheely in front of me in some kind of ritual to show how great he was on the bike? I would not have felt the slightest bit of remorse had he fallen off and then got run over by a few of us.
Mercutio
Fatwah on Western Digital
I really think anyone who needs to ride a bike with an amplified exhaust system should be castrated and used for some kind of painful medical experimentation. At least the asshats who weave in and out of traffic tend to eliminate themselves from the gene pool just fine on their own.
I found a McDonald's that had Rainbow Dashes. Finally. Now I have eight of them. This is probably the only thing I'm going to accomplish all day long.
I found a McDonald's that had Rainbow Dashes. Finally. Now I have eight of them. This is probably the only thing I'm going to accomplish all day long.
Completely agree. I actually went out of my way to get quieter pipes on my ride. I still rode with earplugs though, even wind noise while wearing a helmet I feel is enough to damage hearing after a couple hours at freeway speed. I could actually hear better with them in anyway, less noise.
ddrueding
Fixture
This is true even on my bicycle. Above 30MPH for sustained periods is awful noisy.
Santilli
Hairy Aussie
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I'll take this a bit further. Pretty much every accident I've been in, and that's like one, would have been avoided if I had a lighter car, bigger brakes, and tires, more agility.
I was driving in San Francisco, coming down a hill, and on the right side, two girls were walking down the street, with see through tops, and giant breasts. As I watched, two cars ahead, someone slammed on their
brakes, put their heads down, as did the car that was between us, both waiting to see if I could brake hard enough, and fast enough not to rear end the other car. Not quite, but close. Pretty sure it was an insurance scam, since
right after this, the car that had slammed the brakes disappeared, as did the girls, pretty much instantly. Also the single guy in the car I bumped was very calm, too calm, like he'd done this before.
A number of other near accidents were avoided simply due to the ability to either accelerate, or move right or left quickly, or with my old mustang, brake quickly.
I find higher speed driving keeps you engaged with driving, and focused on that, rather then the millions of other things they put in cars so you crash, and they can sell you a new car.
Also the one thing that I do that gets me closer to getting hit is changing lanes left, looking over my shoulder, checking the blind spot, and then starting the move. At this point
Someone going 30-40 miles an hour faster decides to dart into my blind spot, as I move left. So far, they have never finished the act, but, if I had a faster car, that wouldn't be a problem.;-)
Loud exhaust noise scares people, and attracts LEO, and hurts your ears.
I was driving in San Francisco, coming down a hill, and on the right side, two girls were walking down the street, with see through tops, and giant breasts. As I watched, two cars ahead, someone slammed on their
brakes, put their heads down, as did the car that was between us, both waiting to see if I could brake hard enough, and fast enough not to rear end the other car. Not quite, but close. Pretty sure it was an insurance scam, since
right after this, the car that had slammed the brakes disappeared, as did the girls, pretty much instantly. Also the single guy in the car I bumped was very calm, too calm, like he'd done this before.
A number of other near accidents were avoided simply due to the ability to either accelerate, or move right or left quickly, or with my old mustang, brake quickly.
I find higher speed driving keeps you engaged with driving, and focused on that, rather then the millions of other things they put in cars so you crash, and they can sell you a new car.
Also the one thing that I do that gets me closer to getting hit is changing lanes left, looking over my shoulder, checking the blind spot, and then starting the move. At this point
Someone going 30-40 miles an hour faster decides to dart into my blind spot, as I move left. So far, they have never finished the act, but, if I had a faster car, that wouldn't be a problem.;-)
Loud exhaust noise scares people, and attracts LEO, and hurts your ears.
paugie
Storage is cool
Now if this were a Facebook Post, it would probably get a million "likes" the first being mine. ;-)
CougTek
Hairy Aussie
Always glad to entertain the crowds.
Stereodude
Not really a
The explanation I've heard is that a noisy motorcycle is hard to ignore so car drivers are likely to notice it. That's the same sort of excuse I've heard offered for why many crotch rocket riders are so aggressive and flagrantly bad "drivers". Specifically that they get noticed by driving aggressively.
Personally, I think both are bunk.
ddrueding
Fixture
I'll second that. An exhaust is mostly noisy behind you, where it doesn't matter. And the ricers aggressive driving includes driving on the shoulder, and merging into tight spots without signalling. Not safe no matter what. I always stop at stop signs, always signal, and never tailgate. Compared to that, the speed itself is not particularly dangerous.
I thought that they were mostly self-centered assholes. Now the interesting part would be if one of those loud motorcycle idiots meets up with the loser in the crappy, little old car with the suspension practically on the ground and the giant exhaust pipe. Maybe they could crash and cancel each other out. 
BingBangBop
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Read this again, replacing bike with bicycle and then ask yourself what is an "amplified exhaust system" in that context.
:lol::rofl::lol:
Bozo
Storage? I am Storage!
This is a boring night. Writing all zeros to hard drives before I through them out. I watched 'I Robot' to kill some time.
How does that work when the state troopers or Mounties, or whatever they have up there stop you?