Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th March 2012, 04:01 AM   #81
a.wayne is offline a.wayne  United States
diyAudio Member
 
a.wayne's Avatar
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by wahab View Post
The numbers contradicts your sayings..

Besides , european carmakers have the best diesel engines
because this fuel is the most used in this part of the world
and that subsequently most of the research effort has been
made in this area with petrol engines relegated as second
rate market and as such , minimal improvements were
made theses past years.

This comparison chart for diesel and petrol engine cars
show clearly that once you have accounted for the higher
density of diesel comsumption is the same...

http://fiches-auto.fr/articles-auto/...t-le-moins.php
Diesels have poor emissions vs gas ....

Quote:
Originally Posted by Charles Darwin View Post
I very much prefer straight sixes to V8s.
One of the reasons being that straight sixes are inherently balanced and run very smooth, the only thing smoother is a V12.
Sadly they are getting rare as most manufacturers use either V6 (a nightmare, without various balancing shafts they would shake themselves to pieces) or V8 because of their shorter blocks.

Also the regulations of the german touring car chIampionship stipulates 4.2L V8 engines.
It would be a complete waste of money to design a high-performance V8 for racing and a completely different one for the M5. The V10 was designed when F1 used 3L V10s but they have gone to 2.4L V8 too so there is no marketing advantage to having a V10 road car.

Mind you there is still Audis stonking 6L V12 TDi which is based on their multiple Le Mans winning 5.5L V12 TDi race engine. Since '06 no petrol engined car has won there.
V6's make for better packaging and are inherently stronger than straight 6's . If the intention is racing then the v6 makes for a better power plant ..

Quote:
Originally Posted by tvrgeek View Post
The inline 6 is just too heavy. An old mechanic friend used to say the V6 was invented by the patent holder for the engine hoist. Lancia actually. With the magic of balance shafts, we have narrow angle 6's, 5's and who knows what unbalanced monster. But they work. None are as elegant as the XK or Alpha 1.8 were. Just plain art. A V12 is not necessary any smother. It depends on how it is built. There is a stronger argument for a flat 12 to counter the crank whip an I6 gets.
A v12 is inherently smoother because it has an firing event every 60 deg. Vs every 120deg for a 6....
  Reply With Quote
Old 10th March 2012, 04:31 AM   #82
a.wayne is offline a.wayne  United States
diyAudio Member
 
a.wayne's Avatar
 
Join Date: May 2008
Location: Front Row Center
Quote:
Originally Posted by tvrgeek View Post
I got only a few years on you, and yes, the same criteria. Thanks to advances in technology, my GTI is quicker, faster, more precise, better poised, and gives better feedback than any of the "sports" cars I have owned. I can drive it quickly if I choose, sedately if not. The only car that could do this better was a second generation M3. Big square 4-door sedan. If you drove it like a luxury car, it behaved as such. If you got on it, it was a monster that could tax anyone's skill. Too bad they trashed the 3's. In both cases, those who boo-hoo their capabilities I suggest have not actually driven the cars, or do not know how to drive. I am sure there are many other examples I am not familiar with. To put things into context, A Caravan can/has beat an XKE around Limerock. I am sure the Jag feels better doing it, but technology is what it is.

The larger gate resistors, and further changes to the compensation finally got the DH-120 dead on solid. Then a clip fell off setting the bias and I blew it up again. Poor old circuit card. The VAS CCS sure is fragile.
Unfortunately VW cant overcome their poor build quality , poor shifters , falling roof lines,window regulators , coils, dire plastic trim and electrics..


Quote:
Originally Posted by dvv View Post
I don't know of any other way to express engine efficiency. Perhaps you can point out another method.

Of course, just sticking an engine into a car will not maintain that power, because of inevitable losses on the trasmission system and the the gearbox. It not unusual for these losses to be in the -12...15% region. Every now and then, along comes somebody who claims 200 bhp and and say 300 nM of torque, and rolling road measurements show he has actPually 1 to 3% more than stated, but that is rather rare.

My own little fun car is a good example. The engine delivers 142 bhp on the test table, but on the wheel, the measured value is 126 bhp, i.e. a loss of some 13%. My Deawoo is rated at 133 bhp, but on the wheels, it delivers 117 bhp, a loss of also 13%.

For a comprehensive list of such tests, see Welcome to Rototest Research Institute . Some very interesting results, see BMW lose 58 bhp in the transmission process, and observe FIAT beat its own spec.

Of course torque has much to do with it all. Diesels are driven on torque more than on bhp, given their naturally large compression ratios, further boosted by turbochargers, their torque figures are impressive. Unfortunately, the effective span of that torques is as narrow as their effective power bandwidth, they generally do their best in the 2,000-4,000 rpm span. By comparison, VW's 2 litre FSI turbo engine delivers 211 bhp and 320 nM torque at just 5,100 rmp, but it maintains both very well indeed over a span of 2,000-6,000 rpm - DOUBLE the bandwidth of a diesel.

But ultimately, it all boils down to the power to weight ratio. The less kilos each horsepower must move, the better the performance. There are no two ways about it. Top speed though is effected by aerodynamics of the bodywork as well; it has long been recognized that above 100 km/h (62 mph), progressively more and more power is being used to overcome air resistence. The omnious Cx factor. Which is, surprisingly enough, much better for a Yugo than one would expect, mostly due to its small front surface area.
U
As for modern lightweight materials, they are just that, Kamaterials. Carbon fibre is very fashonable at the moment, but I don't trust it, I'll take a standard sheet metal car over it any day.

And the logic of lightweight bodywork fitted with a reasonably powerful engine is a lesson we have had since the early 60ies. France's Alpine had a very successful Renault mechanics based rally coupe, weighing in at just 620 kilos (app. 1,350 lbs), powered by a 1.6 litre engine delivering 150 bhp. Then of course, the unavoidable Colin Chapman and his Lotus, from model 7 onwards - that was always Lotus' philosophy and approach. Not to vene mention such models from Reliant and many other UK small car makers, and from East Germany, the immortal Trabant, a.k.a. Trabi. It may be funny, but that little car sure made a lot of people VERY happy.

About the FIAT engine, I don't know, I haven't driven one, and so far, I haven't come across any test of it, since it's a relatively new engine. But, Italians always had the most expensive fuel in the EU and always made cars which use up a lot of it. That is changing only now, about two decades after the Germans. Anyway, its consumption will also depend on the model of car and its weight, so there is no clear cut answer.

You like diesel, I don't. But I'll look up some figures for you tomorrow, it's late over here just now.
Transaxle cars -12- 15%
Rear driver - 18%

In the 70's Fiat made the best performing small cars 125S , 124 sport coupe , OK BDA Escorts were the dangles , but horrendously expensive ...

Very few modern cars excite , most are pretty good but , meh, exceptions of course, basic transportation newest is best , driving cars I favor most prior to 2000. Again there are some exceptions , few ...





Quote:
Originally Posted by SoNic_real_one View Post
My take on that: The only limited resource in this world is your time on this Earth. If you choose to spend it crammed in a tiny car, slowly dragging your body from point A to B just to claim "good gas milage" it's... sad.
At lest in a V6-V8 that eats 15mpg you feel that your are alive.
Agree


Quote:
Originally Posted by tvrgeek View Post
1974, V4. It was painted BRG with gold pinstripe. My real excitement in it was coming down I-70 and realized I had not locked the freewheel. By putting up the headlights andO rolling down the windows, I kept it under 80 all the way down until the breaks worked again. I left it locked after that and did not worry about no clutch shifting!

I used to leave class in Golden at exactly the same time as a 914. I could take him on the hill, but he would blow by me as soon as he got going. That old railroad refrig motor had wonderful torque. I never went much above 65 intentionally as the transmission wine was louder than the exhaust. It held together though.
Really ...... Very poor 914 driver ........
  Reply With Quote
Old 10th March 2012, 07:48 AM   #83
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
Quote:
Originally Posted by a.wayne View Post
Diesels have poor emissions vs gas ....
In fact, quite the opposite is true, at least in modern cars. Don't be fooled by what you see and smell as the black cloud behing a big truck. Almost all, except for the cheapest entry models, cars made in Europe today have particle filters installed, and their CO2 emission levels are typically lower to much lower compared to an equivalent petrol engine.

The recent trend of downsizing, which means many more petrol turbo assisted engines, have reduced petrol emissions to much lower levels, but even so, cc per cc, the diesel is still better, even if only by little.



Quote:
V6's make for better packaging and are inherently stronger than straight 6's . If the intention is racing then the v6 makes for a better power plant ..
A MOST questionable view. A straight six has 7 bearings, and a V6 has five. More bearings means smoother operation and less vibration. Try a BMW straight six - you actually have to look at the instruments to make sure it's turned on.

Quote:
A v12 is inherently smoother because it has an firing event every 60 deg. Vs every 120deg for a 6....
Again, a questionable assertion. V against straight - straight almost always wins because of more bearings. Of course, the V is used simply because haing a straight 8, let alone a straight 12, is simply highly impractical, as it would be far too long.

The V configuration is not better, it's simply much more practical. You should also look closely at boxer motors, which have a "V" of full 180 degrees; one could argue that they are the best because their cylinders and hence forces are directly opposing.
  Reply With Quote
Old 10th March 2012, 09:14 AM   #84
dvv is offline dvv  Serbia
diyAudio Member
 
Join Date: Sep 2004
Location: Belgrade, Serbia
@Charles Darwin

According to the latest edition of Germany’s „Auto, Motor und Sport“ annual yearbook, listing all cars sold in Germany, Alfa Romeo’s 1750 engine develops 235 bhp at 5,500 rpm, with 300 Nm at 4,000 rpm. It powers a new Giulietta car (Golf class), weighing 1,395 kilos and does 0-100 km (0-62 milies) in 6.8 seconds, hitting 150 mph max, with an average fuel consumption of 7.6 litres and an emission of 177 mg CO2.

Since BMW just did a lot of engine changing, throwing out some older models and introducing brand new ones, I could not find a direct comparison any more, except for the series 5 limo. Their 2 litre engine produces 170 bhp at 6,700 rpm, with 210 Nm at 4,250 rpm, powering a car weighing 1,445 kilos from 0-100 km in 8.2 seconds, with a top speed of 142 mph. Consumption is claimed at 6.4 litres average, and exhaust is claimed at 144 mg.

From the figures, it’s fairly obvious that the BMW naturally aspirated engine is cleaner and uses up less fuel, but at the cost of considerable power, the Alfa’s engine being a solid 38,2% more powerful.

But, let’s try to compare nominal power for power. The same model is offered by Alfa Romeo with 170 bhp, i.e. the same as BMW, but from a turbo blown MultiAir 1.4 litre engine. Alfa states that this 1,368 cc engine, with just one OHC but still 16 valves, delivers 170 bhp at 5,500 rpm, with 230 Nm of torque at 2,250 rpm. It propels the 1,365 kg heavy car to 136 mph, doing 0-100 km in 7.8 sec. Nominal fuel consumption is 5.9 litres, and exhaust is 137 mg CO2.
This is one of the FIAT groups latest generation of engines, much cleaner and more cost effective than their old ones. They are slowly withdrawing the old generation and replacing it with the new – this same engine is available in several version, ranging from 120 to 170 bhp.

To make things more even, here’s a test result of BMW’s latest turbo blown 2 litre engine, installed in their X1 x-Drive 28i model. It delivers 245 bhp at 5,000 rpm, with 350 Nm at 1,250 rpm. The car, weighing in at 1,620 kilos, was propelled 0-100 km in 6.1 seconds, to a top speed of 150 mph.
BMW claims an average fuel consumption of 7.9 litres, but test results show that this was 10.8 litres. BMW cailms CO2 emissions as 210 mg, test results show 183 mg, considerably better than claimed, this is one VERY clean engine (as engines go).

Their model 320 sedan has a 2 litre diesel engine. It delivers 184 bhp at 4,000 rom, and 380 Nm of torque at 1,750 rpm. It is claimed to satisfy the future Euro 6 standards on emissions. The car does a very respectable 0-100 km sprint in 7.5 seconds, with a measured top speed of 146 mph. BMW sways the average fuel consumption is 4.7 litres, measured value is 7.1 litres. BMW claim emissions of just 129 CO2, measured value is 125 mg.

So, as we can see, diesel engines, albeit with a multitude of built-in filters, are in fact cleaner than petrol engines where it really matters. On the other hand, they are not nearly as economical in terms of fuel consumption as they are hyped up to be – for some reason, practically all manufacturers lie about their consumption much more than with their petrol counterparts.

This should not surprise anyone. From a humble barn workhorse, the diesel engine has been elevated to an almost racing status even in regular passenger cars, and with them, just as with their petrol bretheren, performance costs money. You wants lots of power, you have to pay, period.

Since I understand that all European governments have caught on to the diesel engine, and refusing to be diddled out of their tax income have now made diesel fuel equally or even more expensive than the regular Euro 95 petrol, the economy of the diesel has been lost to a very large extent. Yes, they use less fuel, but the initial purchase price difference, where diesels cost more almost like 1.5 metric TONS of petrol, the breakeven point has been raised much higher. So, for a low mileage per annum driver, a diesel version may actually be more expensive than the petrol version – I am such a driver, at least on the big car. After 8 years and 81,000 km on the clock, if I had a diesel, I would be about the breakeven point now. If however I was a taxi driver, or a travelling salesman, then a diesel would make sense, but not as much sense as natural gas, which is way cheaper than all of them.

A car will use up about 40...60% more natural gas for the same effect measured in litres, but its purchase price is below one half of the next cheapest fuel, so when you work it all out, it comes off as the cheapest ride around. However, differenet governments have different tax rates on natural gas, so what may make for good economy in one country may not be so in another.

Locally, since Serbia is a direly impoverished country, natural gas is all the rage. The government does not dare increase its tax rates, or they will face some serious troubles on the street, and besides, they would cripple half the country. The general elections (for president, parliament and local authorities) are on in May, reason more to play possum for the time being.

In closing, I must pat myself on the back. In 2002, I bet six of my friends that the future of automobiles in Europe lies in small displacement PETROL engines, which will get all the niceties thus far reserved for bigger engines (e.g. direct injection, allowing for higher compression ratios and better fuel efficiency) and will be turbocharged as is from the factory. By I reckon 2015, anyone with a 2 litre engine under the bonnet will be a rich man, because he’ll have about what he has today with larger capacity 3+ litre engines. The biggest engines will be long gone by then, perhaps one or two remaning for the richest among us. A good example is Nissan’s 3.8 litre engine, with twin turbos it delivers 480 bhp.

Anyway, I won the bet hands down. Today, small capacity turbocharged engines are the norm even in the economy class, or perhaps I should say especially in the economy class. Look at FIAT's latest economy engine - two cylinder, 900 cc, turbo blown engine, which behaves like it was a regular 1,600 cc engine, but uses less fuel - European engine of the year 2012.

Literally everybody who is anybody in cars in Europe is switching over. The VW groups (VW, Audi, SEAT, Škoda) has introduced a new 1.2 litre, SOHC 8V turbo blown engine, delivering 105 bhp, as their economy version. Renault of France has such a 1.2, 1.4 and 2.0 engines. Peugeot/Citroen group and BMW have their 1.6 normal and turbo versions of their jointly built 1.6 litre engine, as installed in the Mini, Peugeot, Citroen and just now into BMW Series 1 cars. The FIAT group (Fiat, Alfa Romeo and Lancia) are pushing their MultiAir technology. GM/Opel already have 1.4, 1.6 and 2.0 turbo blown, DOHC 16V, engines, ranging from 120 to 245 bhp. Ford Europe has new series 1.6 and 2 litre turbo blown engines, 150 ... 240 bhp now, soon with more power.

The Far Easteners, Japanese and Koreans, are thus far resisting the shift. Mazda has just announced its latest series of both petrol and diesel engines with a compression raio of 16.5:1, claiming that there is still much to be gained from developing the regular engines, no need for turbos just yet. In my view, they are mistaken, if for no other reason, than for sheer marketing power - they will end up being the only ones left behind. What is often missed is the fact that turbo engines recycle exhaust gasses to a point, providing for cleaner engines, easier able to keep up with rising Euro X standards.

And of course, there are the hybrids ...

I don’t think you Yankees will fare any differently, really, the downsizing will only come slower to you, but no less inevitably. It’s already started – Chevy Cruze is offered with a 1.4 turbo blown, 138 bhp engine from Opel’s Astra range. Oddly enough, that same car is being sold in Europe ONLY with a 1.6 124 bhp, 1.8 141 bhp petrol and 2 litre 163 bhp diesel. The 1.4 litre turbo engine is reserved for its European counterpart, Opel Astra (used to be sold in the US under the trade name of Saturn).

GM is in a bit of a rut here, they want to push both Chevy and Opel, but can’t afford to have them competing against each other in house. The 1.8 litre Cruze costs € 15,200 locally, with everything but the kitchen sink built in, while an equivalent Opel Astra, with the 140 bhp 1.4 litre turbo engine costs € 19,300.

Guess which sells better ...
  Reply With Quote
Old 10th March 2012, 10:44 AM   #85
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
re VW: For 2009, I would agree 100%. That was why I bought the Mini, it was the second worst car out there. I have zero complaints about my 2011. Zero.

re: bearings: Not all. The TR-6 had 4 mains. It would whip like a snake over 6000, or 6500 if you put in the short GT-6 crank. Group 44 could keep them alive at 8000 just long enough to win a race. BTW, Wally is not doing well. A great wrench and good guy.

re: smooth at idle, my RSX I had to look at the tach at idle. I-4. The TR-6 that was originally in the TVR, no. ( the 350 HP 5.0 that I replaced it with was smoother ) Still if you want smooth, it was a Rolls I-6 that made famous balancing a nickel in the valve cover.

re diesel vs gas: Now we finally have the "clean" small modern diesels here, they still stink, still puke soot, and the cost of diesel is about the same per mile as gas. They are far better than they were, but far from gas and the small soot has been shown to be very very bad for you. Understanding the pump price is largely set by tax rates in most of the world. I looked at the TDI as the torque was nice, but no diesel at my local station to next to my office.

We are only a few years from electrics that will work. As an electric produces max torque at stall, they have big advantages. It's the batteries. In the lab, there are several developments that have the energy density to give us the US market required 300 mile range. It is just about bringing it to durable production. You lose a lot in conversion, but the power plants burn the fossil fuel at about 90% efficiency. Even with the 40% line loss, you are ahead. charge rate is a problem, but that could be solved by liquid electrolytic exchange. We still need to get the weight down. My GTI weighs twice what several of my older cars did. We need to get back to 2000 Lb and less. It's that old mass times distance thing.
  Reply With Quote
Old 10th March 2012, 10:51 AM   #86
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
A.Wayne,

If you don't know the old V4, it was an industrial engine designed for rail car coolers. It had very low peak HP, but monster torque. The Sonnet was lighter and had far more low end torque, so the steep long grade out of the lot gave me an advantage. The 914 had a lot more tire, wider, and more gear, so he could get me after the first curve. Don't confuse the later 2.0's. Much faster. The Saab had 165-80-15's, so not much total grip.
  Reply With Quote
Old 10th March 2012, 11:11 AM   #87
Sin Bin
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 84
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
Quote:
Originally Posted by tvrgeek View Post
You lose a lot in conversion, but the power plants burn the fossil fuel at about 90% efficiency.
Nope, typical Btu/kWh run from 10,000 to 6,000 : expressed as efficiency that tops out around 54% with the most modern gas-fired supercritical steam boilers. See:

http://www.npc.org/study_topic_paper...efficiency.pdf
  Reply With Quote
Old 10th March 2012, 11:22 AM   #88
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
Quote:
Originally Posted by wahab View Post
The numbers contradicts your sayings..

Besides , european carmakers have the best diesel engines
because this fuel is the most used in this part of the world
and that subsequently most of the research effort has been
made in this area with petrol engines relegated as second
rate market and as such , minimal improvements were
made theses past years.

This comparison chart for diesel and petrol engine cars
show clearly that once you have accounted for the higher
density of diesel comsumption is the same...

http://fiches-auto.fr/articles-auto/...t-le-moins.php
Don't like the numbers go on wiki and fix them.
According to wiki the energy contained in 1L of petrol is 34.8MJ and for diesel 38.6MJ. For comparison for BioDiesel it's 35.1, Ethanol 23.5, Kerosene 37.6, liquified natural gas 25.3 and liquid hydrogen 9.3.

As for diesel being popular in Europe that is because it is cheaper to run a diesel. It used to be that it only worked out once you've done 20 000km a year. In continental Europe diesel is a cheaper than petrol but the govs impose taxes based on engine size (you pay x amount for every 100cc) and fuel type (let's say a petrol engine is taxed at $15 per 100cc, a diesel would be taxed at $30 per 100cc for example. That at least was how the german tax system worked last time I had a look)) but the advances possible with diesel economy far outstripped the advances in petrol economy despite the manufacturers best efforts.
And that boils down to the ignition system I guess. One could conceivably build a self-igniting petrol engine but this would not be an incredibly efficient petrol engine. It would by definition be a petrol powered diesel engine as a diesel engine is not restricted to the fuel type but the fact that ignition is achieved by compressing the fuel mixture enough to cause it to self-ignite.
Either way diesels have become popular in Europe because of the new engines, the engines did not come about because diesel was popular already as you stated.

My 18-year old Audi TDi still produces pretty much exactly the numbers stated by Audi for the car when it was new.

Someone else mentioned diesel producing dirtier exhaust fumes but the emission regulations, which are comparable to many US states except California, are the same for both. However this does require high quality diesel fuel which appears to have so far been unavailable in the US.
  Reply With Quote
Old 10th March 2012, 11:31 AM   #89
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
Quote:
Originally Posted by benb View Post
No. It is the most powerful, the most efficient is the MAN S80ME-C7.
  Reply With Quote
Old 10th March 2012, 11:53 AM   #90
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
Quote:
Originally Posted by dvv View Post

The V configuration is not better, it's simply much more practical. You should also look closely at boxer motors, which have a "V" of full 180 degrees; one could argue that they are the best because their cylinders and hence forces are directly opposing.

Note that not all flat engines are boxers. For example Ferrari never made a boxer engine and despite the cars moniker of 512 Berlinetta Boxer the engine it used was in fact technically a 180deg V12.
Essentially in V engines opposing pistons share a crank pin while in a true boxer they don't.
Porsche at times made both: The 911 motor was a boxer while the one from the 917 race car was a 180deg V.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Let's talk about FLHs... Brian Steele Subwoofers 9 15th May 2010 12:37 AM
Hello and could I talk to a mod? markdesmarais Introductions 2 10th March 2009 11:07 AM
Let's talk about the concerts we saw! Bricolo Music 62 19th April 2008 02:29 PM
Let's Talk Capacitors speakerguy79 Parts 3 12th October 2006 01:42 AM


New To Site? Need Help?

All times are GMT. The time now is 03:40 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2