Displacement vs Cylinders
06-10-14, 09:08 AM
#46
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It's true that a V6, in general, costs more than a regular N/A in-line four to produce, but I'm not completely convinced that it costs that much more to produce than a turbo-four. A turbo four also adds production costs from its added complexity and hardware...and may cost more over its life to service from the need for expensive heat-resistant oils and more frequent oil changes. I addition, though they are much better today than they used to be (and don't require as many precautions about warm-up/shut-down) turbos still don't always last the life of the engine itself.
Also as the technology and design processes become more advanced so will the reliability, cost and complexity. Auto manufactures already have 10 year warranties on their turbo 4s.
06-10-14, 09:40 AM
#47
This is correct. Bore x Stroke vs Compression and RPM will determine the HP/Torque figure. There is only so much you can do to bring it to the border line of efficiency.
Take Example of those F1 Engine. More cylinders and less displacement. It gives off a very unique sound, and loud. But their HP is higher than Torque due to the low stroke spreading across the board of cylinders. Typically they Launch it at a very High RPM, and to get it moving, you will have to tap into somewhere 8-9k RPM at first gear.
Compares the sound of a Diesel Truck vs F1, and you will learn the differences sound of the moving cylinders at speed.
The Technologies you talked about are still being produced by Ferrari and Lambo, and Toyota just did in LF-A. But due to Production for street use (Emission+Reliability+Usable Torque Range) They become so expensive......and can only be considered (Super-Car)
The closest to anything you have spoken off was IS-250. Grab it before they thrash it and replace it with 2.0T
Take Example of those F1 Engine. More cylinders and less displacement. It gives off a very unique sound, and loud. But their HP is higher than Torque due to the low stroke spreading across the board of cylinders. Typically they Launch it at a very High RPM, and to get it moving, you will have to tap into somewhere 8-9k RPM at first gear.
Compares the sound of a Diesel Truck vs F1, and you will learn the differences sound of the moving cylinders at speed.
The Technologies you talked about are still being produced by Ferrari and Lambo, and Toyota just did in LF-A. But due to Production for street use (Emission+Reliability+Usable Torque Range) They become so expensive......and can only be considered (Super-Car)
The closest to anything you have spoken off was IS-250. Grab it before they thrash it and replace it with 2.0T
06-10-14, 10:38 AM
#49
Lexus Fanatic
It's true that a V6, in general, costs more than a regular N/A in-line four to produce, but I'm not completely convinced that it costs that much more to produce than a turbo-four. A turbo four also adds production costs from its added complexity and hardware...and may cost more over its life to service from the need for expensive heat-resistant oils and more frequent oil changes. I addition, though they are much better today than they used to be (and don't require as many precautions about warm-up/shut-down) turbos still don't always last the life of the engine itself.
Where it likely costs Toyota less is that they have made a higher HP more fuel efficient car for the same cost as the outgoing 2.5. Sure there will be less spark plugs and parts, but I doubt that made much of a difference if any.
06-10-14, 11:18 AM
#50
^ getting down in the back country nice. Of course there will always be a large number of people who don't care but you look at Prius and Tesla S sales and there's just as many environmentalists. The struggle continues.
Keiffith, mmarshall, Sulu and Och got it best before this thread turned into a discussion of the IS250's 2.5L V6
. We're asking why V6's are not replaced with smaller V6's rather than engines with less cylinders. I propose the question because of the inherently smoother nature (V6 > I4) especially when it pertains to an automaker. Factors like trends, costs and application seem to restrict low displacement high cylinder engines.
Keiffith, mmarshall, Sulu and Och got it best before this thread turned into a discussion of the IS250's 2.5L V6
. We're asking why V6's are not replaced with smaller V6's rather than engines with less cylinders. I propose the question because of the inherently smoother nature (V6 > I4) especially when it pertains to an automaker. Factors like trends, costs and application seem to restrict low displacement high cylinder engines.
06-10-14, 11:57 AM
#51
There's always been the argument; "no replacement for displacement". Lately due to governemnt regulations and emission standards coupled with social view the trend has been to downsize and add forced induction.
My question is, with all these automakers dropping say their 3.0-4.0 six in favor of a forced induction 2.0-2.9 four, why not downsize the displacement but retain the same cylinder count. Why don't we see 2.0L V6's? 3.0L V8's? (Some exceptions like the Mclaren 3.8L V8 and Lexus 4.8L V10 and excluding racing engines like F1)
Having the benefit of two extra cylinders especially in a luxury car adds/retains that refinement. The 2.5L V6 in the IS may get dinged for being 'slow' but then would you rather have a raspy four which is not as linear. As long as one understands the IS250 is a four cylinder competitor with two extra cylinders for refinement.
Any thoughts? Correlation between Displacement vs Cylinders?
Discuss!
My question is, with all these automakers dropping say their 3.0-4.0 six in favor of a forced induction 2.0-2.9 four, why not downsize the displacement but retain the same cylinder count. Why don't we see 2.0L V6's? 3.0L V8's? (Some exceptions like the Mclaren 3.8L V8 and Lexus 4.8L V10 and excluding racing engines like F1)
Having the benefit of two extra cylinders especially in a luxury car adds/retains that refinement. The 2.5L V6 in the IS may get dinged for being 'slow' but then would you rather have a raspy four which is not as linear. As long as one understands the IS250 is a four cylinder competitor with two extra cylinders for refinement.
Any thoughts? Correlation between Displacement vs Cylinders?
Discuss!
The reason why they don't do it? Cost and weight mainly, packaging reason too. Less cylinders = less hardwares = less cost and weight and smaller engine for easier packaing into the engine bay. The reality is 98% of the population who buy normal car won't notice the refinement benefit of extra cylinders.
BTW, small displacement with high cylinder count = sounds heaven.........3.0L V12 baby!!
06-10-14, 12:46 PM
#52
Lead Lap
The main reason (or at least an important one) to go for more cylinders is piston weight. For argument sake, you can have an engine with a single cylinder and 2 liter capacity with wonderful torque characteristics, but the inertia of the heavy piston will make high revolutions impossible.
The difference in piston weight between a four cylinder 2 liter and a six cylinder of the very same capacity, is of course not that big, but the six, will still pick up refs better. Now you can go for crank lay-out like a boxer six or a V6, that gives a smooth spread of power impulses (a straight six as well). Cost is however, a factor and it is a good question if most drivers even know these intricacies. Will a 3 litre four cylinder outgun a 2.5 V6 (for argument sake all other things equal)?
Can't say, but it is interesting that Porsche tried that route with the 3 liter four in the 944, but despite all the balance shafts and the fact that it was fast, never pursued it further.
The difference in piston weight between a four cylinder 2 liter and a six cylinder of the very same capacity, is of course not that big, but the six, will still pick up refs better. Now you can go for crank lay-out like a boxer six or a V6, that gives a smooth spread of power impulses (a straight six as well). Cost is however, a factor and it is a good question if most drivers even know these intricacies. Will a 3 litre four cylinder outgun a 2.5 V6 (for argument sake all other things equal)?
Can't say, but it is interesting that Porsche tried that route with the 3 liter four in the 944, but despite all the balance shafts and the fact that it was fast, never pursued it further.
06-10-14, 06:24 PM
#53
You are 100% correct, more cylinders add refinement
The reason why they don't do it? Cost and weight mainly, packaging reason too. Less cylinders = less hardwares = less cost and weight and smaller engine for easier packaing into the engine bay. The reality is 98% of the population who buy normal car won't notice the refinement benefit of extra cylinders.
BTW, small displacement with high cylinder count = sounds heaven.........3.0L V12 baby!!
The reason why they don't do it? Cost and weight mainly, packaging reason too. Less cylinders = less hardwares = less cost and weight and smaller engine for easier packaing into the engine bay. The reality is 98% of the population who buy normal car won't notice the refinement benefit of extra cylinders.
BTW, small displacement with high cylinder count = sounds heaven.........3.0L V12 baby!!
truth, few appreciate Cars and the spirit of automobiling
06-10-14, 07:14 PM
#55
personally i dont like V-10's or V12's. if a diesel truck can haul 20 tons of stuff with 6 cylinders, you shouldnt need twice that, unless you really have that much money burning a hole in your pocket.
you may call it "refinement" but murphys law still applies. anything that can go wrong, will go wrong. and more moving parts means more chances of kaboom.
you may call it "refinement" but murphys law still applies. anything that can go wrong, will go wrong. and more moving parts means more chances of kaboom.
06-10-14, 10:18 PM
#56
The ultimate small displacement/high cylinder count engine was the BRM Formula 1 engine from the early 1950's. A supercharged V-16 that displaced 1.5 liters or about 90 cu. in. It was reported to make 550 horsepower! One obvious downside of so many parts is poor reliability which plagued BRM.
Steve
Steve
06-10-14, 10:38 PM
#57
Lexus Fanatic
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The ultimate small displacement/high cylinder count engine was the BRM Formula 1 engine from the early 1950's. A supercharged V-16 that displaced 1.5 liters or about 90 cu. in. It was reported to make 550 horsepower! One obvious downside of so many parts is poor reliability which plagued BRM.
Steve
Steve
06-11-14, 06:17 AM
#58
Lexus Fanatic
The ultimate small displacement/high cylinder count engine was the BRM Formula 1 engine from the early 1950's. A supercharged V-16 that displaced 1.5 liters or about 90 cu. in. It was reported to make 550 horsepower! One obvious downside of so many parts is poor reliability which plagued BRM.
Steve
Steve
06-11-14, 06:28 AM
#59
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3.5L V6 are the best compromise of refinement, performance MPG & durability
Above 4.0L and V6 tend to sound harsh and unrefined
The thing is that the IS350 has an extra 100hp yet it consumes about the same amount of gas as the IS250
Above 4.0L and V6 tend to sound harsh and unrefined
The thing is that the IS350 has an extra 100hp yet it consumes about the same amount of gas as the IS250
06-11-14, 06:36 AM
#60
Lexus Fanatic
Originally Posted by yowps3
The thing is that the IS350 has an extra 100hp yet it consumes about the same amount of gas as the IS250