|
|
Post by jim2jags on Oct 24, 2017 10:30:04 GMT
I see Bentley (probably not a surprise) are claiming that downsizing to smaller turbocharged engines is not the answer to better economy or emissions in the real world compared to lower revving large capacity normally aspirated engines of similar power. I know Mazda have a similar philosophy and a few other manufacturers are questioning whether downsizing really produces better efficiency and a better car to drive.
I have an interest in all this, not just because I have a 5 litre n/a engine in the XK but also had a 1 litre 125bhp ecoboost Fiesta for a short while, which road testers rave on about, but I absolutely hated to drive due to its on-boost/off-boost character. Also, if revved as it had to be to deliver good performance, I found the economy very disappointing (less than 40mpg).
I accept there is a difference between petrol and diesel in this respect, but just wondered what you guys thought?
|
|
|
|
Post by etypephil on Oct 24, 2017 13:27:07 GMT
More or less nail on the head Jim, forced induction has much the same effect as an increase in swept volume.
An exhaust driven supercharger (turbocharger) is eminently suitable only for diesel engines, because they have good low speed torque (when a turbocharger is ineffective), but naturally aspirated, run out of power as the engine revolutions increase, when a turbocharger become effective, boosting power when it is most needed. Conversely, petrol engines produce most of their power at higher engine speeds; the smaller the engine, the more true this is (a few years ago, I had a 1,002cc motorbike which produced 197 bhp, @ 13,500 rpm, but insufficient power to move the bike at less than 2,500 rpm). Fitting a turbocharger exacerbates this unpleasant power delivery. A crankshaft driven supercharger typically provides boost from tickover to the rev limiter, in direct proportion to engine speed.
I suspect that manufacturers of small engines concentrate on turbocharging, rather than conventional supercharging, even though turbochargers are much more expensive to manufacture, and are much less reliable than conventional superchargers, has much to do with the flawed EU fuel consumption tests, rather than real world efficiency, as exemplified by your 1.0 litre turbocharged Fiesta fuel consumption being less than 25% better than our 5.0 litre supercharged XFR, despite the Jag weighing almost twice as much as the Ford, and delivering rather more in the way of performance.
|
|
|
|
Post by OBC John on Oct 24, 2017 17:01:38 GMT
Power and engine speed are directly proportional. If 1 rpm = 1 HP output then 100 rpm = 100 h.p. With or without a turbo or supercharger. Its a straight line graph.
|
|
|
|
Post by etypephil on Oct 24, 2017 17:35:10 GMT
|
|
|
|
Post by OBC John on Oct 24, 2017 17:55:24 GMT
I don't need to consult the interweb on this one. I have a degree in mechanical engineering with a thesis written on heat transfer and heat engines.
A dynomometer will produce a curve . . . . but the underlying fundamentals of a heat engine are that shaft power and engine speed are directly proportional.
There is no argument/discussion to be had here.
|
|
|
|
Post by etypephil on Oct 24, 2017 18:08:26 GMT
I don't need to consult the interweb on this one. I have a degree in mechanical engineering with a thesis written on heat transfer and heat engines. A dynomometer will produce a curve . . . . but the underlying fundamentals of a heat engine are that shaft power and engine speed are directly proportional. There is no argument/discussion to be had here. Yes John, I know that you have a degree in mechanical engineering, that does not mean that your received wisdom is correct, and that all dynamometers are wrong.😎 |
|
|
|
Post by OBC John on Oct 24, 2017 18:15:54 GMT
I don't need to consult the interweb on this one. I have a degree in mechanical engineering with a thesis written on heat transfer and heat engines. A dynomometer will produce a curve . . . . but the underlying fundamentals of a heat engine are that shaft power and engine speed are directly proportional. There is no argument/discussion to be had here. Yes John, I know that you have a degree in mechanical engineering, that does not mean that your received wisdom is correct, and that all dynamometers are wrong.😎 But that's not what I said, is it? I said "A dynomometer will produce a curve". For a reason. Google it. |
|
|
|
Post by etypephil on Oct 24, 2017 18:17:59 GMT
Yes John, I know that you have a degree in mechanical engineering, that does not mean that your received wisdom is correct, and that all dynamometers are wrong.😎 But that's not what I said, is it? I said "A dynomometer will produce a curve". For a reason. Google it. Yes, a dynamometer produces a curve because it records what actually occurs, rather than what occurs in the head of an academic. |
|
|
|
Post by RS5litre on Oct 24, 2017 18:26:40 GMT
I have a degree in mechanical engineering...... Yeah, you lost me at this point. 😊 |
|
|
|
Post by OBC John on Oct 24, 2017 18:44:35 GMT
Let's leave it here, shall we? Lest we fall out. :rolleyes:
|
|
|
|
Post by etypephil on Oct 24, 2017 19:05:10 GMT
Let's leave it here, shall we? Lest we fall out. :rolleyes: Fine, although I must express surprise that one with a degree in mechanical engineering does not know how to spell dynamometer, commonly shortened, incorrectly, to "dyno".  |
|
|
|
Post by OBC John on Oct 24, 2017 19:09:29 GMT
Let's leave it here, shall we? Lest we fall out. :rolleyes: Fine, although I must express surprise that one with a degree in mechanical engineering does not know how to spell dynamometer, commonly shortened, incorrectly, to "dyno". Well, there you go. I strive for perfection but there's always a clever dick to bring you down.  |
|
|
|
Post by RS5litre on Oct 24, 2017 19:26:44 GMT
I’ve been in and around engineering for 36 years. My experience of those who boast about having a degree is that that is their ultimate undoing. There are exceptions of course, but it should be kept to one’s self, and not put on a business card in the form of “BSC Mech Eng Hons”. When I see that, I think ‘dick’.
My o/h has a degree, but she has gotten the respect she deserves based on her growing industry experience rather than spouting about a qualification she got 25+ years ago.
|
|
|
|
Post by OBC John on Oct 24, 2017 19:45:17 GMT
Or "if you ain't got it you can't flaunt it".
And my experience of more than 45 years in engineering, (starting with a 5-year apprenticeship in heavy engineering) and working my arse off over many years at night school to gain my degree, is that those without any qualifications seem to think their "experience" trumps any academic qualification. Whereas in truth, it absolutely don't!!
Ignorance isn't a virtue.
|
|
|
|
Post by RS5litre on Oct 24, 2017 20:02:15 GMT
A degree is just a certificate that you attended an establishment where you were taught by those who couldn’t hack the real life, and took a few exams.
After 5 years in work, your degree becomes irrelevant, and any initial advantage the degree gained over those who chose experience has gone. Those who think it’s still relevant are a bit sad and maybe disappointed at their progression through professional life because they thought they were better than most.
If you’re still flaunting if after that many years, then I know which camp you’re in, sadly.
think of it as two sides of a five year square. Degree vs experience. The outcome is the same.
|
|
|
|
Post by etypephil on Oct 24, 2017 20:04:17 GMT
Ignorance isn't a virtue. Quite. |
|
|
|
Post by OBC John on Oct 24, 2017 20:11:59 GMT
I am unashamedly proud of my degree. Much as you are clearly proud of your ignorance. Celebrate it!
|
|
|
|
Post by RS5litre on Oct 24, 2017 20:24:43 GMT
And I’m am unashamedly proud of the experience I’ve gained in engineering without a degree, and now able to operate as a consultant to coach those better ‘qualified’ than me.
Don’t put people down because you have a bit of paper.
|
|
|
|
Post by etypephil on Oct 24, 2017 20:25:08 GMT
I am unashamedly proud of my degree. Much as you are clearly proud of your ignorance. Celebrate it! John, you are wrong, and you know it, just as you are about "clean, economical diesels". BTW, I don't scream about my formal qualifications, because I don't need to; I used them as a foundation on which to gain fifty plus years of practical experience, building my own engines, modifying those of others, machining my own parts, and testing the results on dynamometers, and the racetrack. |
|
|
|
Post by OBC John on Oct 24, 2017 20:33:20 GMT
And I’m am unashamedly proud of the experience I’ve gained in engineering without a degree, and now able to operate as a consultant to coach those better ‘qualified’ than me. Don’t put people down because you have a bit of paper. Then don't you come over all superior because you haven't been able to. I don't appreciate being alluded to as a "dick" by anyone. God preserve us from the self-righteous. "He's got a degree! Must be a dick." Sheeesh. |
|
|
|
Post by RS5litre on Oct 24, 2017 20:40:51 GMT
And I’m am unashamedly proud of the experience I’ve gained in engineering without a degree, and now able to operate as a consultant to coach those better ‘qualified’ than me. Don’t put people down because you have a bit of paper. Then don't you come over all superior because you haven't been able to. I don't appreciate being alluded to as a "dick" by anyone. God preserve us from the self-righteous. "He's got a degree! Must be a dick." Sheeesh. 😂😂 I don’t recall calling you a dick, but if you have that kind of wording on your biz card at your age, then perhaps you may be. |
|
|
|
Post by OBC John on Oct 24, 2017 20:43:14 GMT
I am unashamedly proud of my degree. Much as you are clearly proud of your ignorance. Celebrate it! John, you are wrong, and you know it, just as you are about "clean, economical diesels". BTW, I don't scream about my formal qualifications, because I don't need to; I used them as a foundation on which to gain fifty plus years of practical experience, building my own engines, modifying those of others, machining my own parts, and testing the results on dynamometers, and the racetrack. Phil, I'm I'll inclined to explain myself to anyone but here goes. I mentioned my degree because it was relevant. In this particular case I didn't need the internet. What winds me up is the self-righteous of this world who are clearly threatened by anyone more intelligent than themselves and so have become loud and boorish to compensate. You and he know who I mean. And you saying "you are wrong" doesn't make it so. I am not. |
|
|
|
Post by etypephil on Oct 24, 2017 20:43:52 GMT
And I’m am unashamedly proud of the experience I’ve gained in engineering without a degree, and now able to operate as a consultant to coach those better ‘qualified’ than me. Don’t put people down because you have a bit of paper. God preserve us from the self-righteous. "He's got a degree! Must be a dick." Sheeesh. I thought that you don't believe in God. Irrespective of that, may we be preserved, by all forces available, from those who having listened to others and read about their thoughts, accept said thoughts, without question, and are rewarded with a piece of watermarked paper, believing that anyone not in possession of such a piece of paper, doesn't know what they are talking about, and should always defer to those holding said piece of paper, especially when those holding such paper are talking through someone else's arse. |
|
|
|
Post by OBC John on Oct 24, 2017 20:45:02 GMT
Then don't you come over all superior because you haven't been able to. I don't appreciate being alluded to as a "dick" by anyone. God preserve us from the self-righteous. "He's got a degree! Must be a dick." Sheeesh. 😂😂 I don’t recall calling you a dick, but if you have that kind of wording on your biz card at your age, then perhaps you may be. Consultant? People who live in glass houses shouldn't throw stones. |
|
|
|
Post by OBC John on Oct 24, 2017 20:51:04 GMT
God preserve us from the self-righteous. "He's got a degree! Must be a dick." Sheeesh. I thought that you don't believe in God. Irrespective of that, may we be preserved, by all forces available, from those who having listened to others and read about their thoughts, accept said thoughts, without question, and are rewarded with a piece of watermarked paper, believing that anyone not in possession of such a piece of paper, doesn't know what they are talking about, and should always defer to those holding said piece of paper, especially when those holding such paper are talking through someone else's arse. This getting surreal. What??? |
|
|
|
Post by PsiFox on Oct 24, 2017 21:25:38 GMT
As an aside what do we all think of the price of cod this week?
|
|
|
|
Post by OBC John on Oct 24, 2017 21:30:55 GMT
As an aside what do we all think of the price of cod this week?  |
|
|
|
Post by etypephil on Oct 25, 2017 5:08:19 GMT
As an aside what do we all think of the price of cod this week? It seems reasonable enough to me: Fresh Fish Price List Fresh Price Unit Bream Gilthead £9.00 per kg Brill Small/Medium £15.00 per kg Cod Fillet £12.00 per kg Coley Fillet £7.00 per kg |
|
Deleted
Deleted Member
Posts: 0
Member since: January 1970
|
Post by Deleted on Oct 25, 2017 7:06:50 GMT
As a marine biologist, I proffer to you Phil that you are wrong  FISH PRICES AT PETERHEAD MARKET 24/10/2017 8Boats &6Consignments Landed 4891 Boxes SPECIESBOTTOM PRICE (£ per Kilo)TOP PRICE (£ per Kilo) COD A1/A2 3.30 4.50 COD A3 3.20 3.80 COD A4 3.20 3.50 COD A5 3.00 3.50 HADDOCK LARGE 2.80 3.00 HADDOCK MEDIUM 2.30 2.80 HADDOCK SELECTED 2.80 3.20 SEED 2.15 2.50 CHIPPERS 1.75 2.25 METROS 1.50 1.80 ROUND HADDOCK 1.20 1.60 |
|
|
|
Post by etypephil on Oct 25, 2017 8:16:26 GMT
As a marine biologist, I proffer to you Phil that you are wrong FISH PRICES AT PETERHEAD MARKET 24/10/2017 8Boats &6Consignments Landed 4891 Boxes SPECIESBOTTOM PRICE (£ per Kilo)TOP PRICE (£ per Kilo) COD A1/A2 3.30 4.50 COD A3 3.20 3.80 COD A4 3.20 3.50 COD A5 3.00 3.50 HADDOCK LARGE 2.80 3.00 HADDOCK MEDIUM 2.30 2.80 HADDOCK SELECTED 2.80 3.20 SEED 2.15 2.50 CHIPPERS 1.75 2.25 METROS 1.50 1.80 ROUND HADDOCK 1.20 1.60 A chacun son metier; I know a little about vehicles and buildings, my knowledge of fish is limited to retail purchase and consumption. Now I know something else.😎 |
|
