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#21
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>just take the V-12 from Lambo, and tune it for a luxo sedan.
> It's not that simple. The Murcielago's V12 wouldn't have fit in the A8. Plus, they can't produce them in great enough number for A8 application. >I understand the width & length angle, but what are any benefits, between >some savings in development time, and small size. FITMENT. The A8 wouldn't have accpeted a V-12 of that displacement. > they seem to be a little >low on power compared to a "traditional" layout, This is the result of Adui's tuning, not the engine type. > and they seem to have a >little more harshness vibration. > B.S. I've ridden in a W12 Pheaton and it was incredible. |
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#22
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Steve Grauman wrote:
>>when GM >>converted it's cars from using V-8 engines (which are best balanced with >>a 90 degree configuration) >> >> > >Most V6s are 90 degrees, AFAIK. > > Many American V-6's _are_ 90 degrees for the reason I stated in my earlier post including the very popular GM 3.8 liter, now in it's 3rd or 4th generation. That engine was fitted with balance shafts in the mid '90s and it ran pretty smoothly in a rental car I drove. But most modern V-6 engines that are developed from scratch will have a 60 degree angle. Even modular engine families, such as the one Ford developed in 1996 (which spawned a V-6, several V-8s, and a V-10) use a 60 degree angle for the 6 and a 90 degree angle for the others (even though 72 degrees is ideal for a V-10). http://www.mustangheaven.com/2005mustang/powert.htm Honda's 240hp V-6 is 60 degrees and is used in the Accord, Odyssey, Pilot, others? The 3.5L V-6 Nissan/Infinity puts into almost everything is 60 degrees. I may be mistaken by saying that the I-6 was the configuration with the fewest cylinders that is inherently balanced. While writing this response I found a site that says all boxer engines, even the H-4 are perfectly balanced because the cylinders move in the same plane at the same time. But I think the H4 has second order harmonics that make the I-6 smoother. I do know that the H-4 in my WRX, while quiet and powerful, isn't as smooth at idle as the I-6 engines I've test driven. By the way, this page http://www.ukcar.com/sframe.htm?/fea...ech/engine.htm is pretty interesting. And this page http://autozine.kyul.net/technical_s...ne/smooth1.htm has some of the physics behind it. The 5th page of the article has info specific to the VR6, W8, and W12 engines. For a fairly in-depth engineering explanation, check this site out http://www.thrashercharged.com/tech_...ne_design.shtm |
#23
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In article >, Steve Grauman
> writes >>no, not all engines are the same, if you drive a W-8 back to back with a V-8 >>the W-8 will not be as smooth, it has odd firing sequence. > >What the hell does the engine's firing sequence have to do with smoothness? Err, everything! Smoothness is all down to the movement of the pistons relative to each other. They need to fire in a sequence such that their momentum relative to each other balances out. -- Toby |
#24
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>Smoothness is all down to the movement of the pistons relative to each
>other. They need to fire in a sequence such that their momentum >relative to each other balances out. I'm having a fit of dumb**** and not following. I'm well aware of how the standard combustion driven engine operates but I'm not sure as to how a 4-cylinder with a 1-2-3-4 firing order could be any more or less smooth than one with a 1-3-4-2 firing order, or any other variation. Beyond that, I've ridden in a W12 Pheaton and found it to be quite smooth, so I find Ghee's claims (as usual) to be obnoxious. |
#25
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>Many American V-6's _are_ 90 degrees for the reason I stated in my
>earlier post including the very popular GM 3.8 liter, now in it's 3rd or >4th generation. That engine was fitted with balance shafts in the mid >'90s and it ran pretty smoothly in a rental car I drove. I seriously dislike the GM 3.8. I've driven an N/A version as well as two supercharged units (a 2001 Bonneville SSEi and a 2004 Grand Prix GTP) and disliked both. The supercharged version has a ton of torque but it did very little to help get quick 0-60 times from the bloated Bonneville. The 3.1 in the Malibu was worse, although I've not driven the new version. But 170Hp from a 3.1 litre V6 is stupid to say the least. > Even modular engine families, such as the one Ford >developed in 1996 (which spawned a V-6, several V-8s, and a V-10) use a >60 degree angle for the 6 Does this include the unit (2.5 litres?) used in the Contour or just the 3.0 litre used in the Taurus? I always liked the Contour, for what it was. I thought it was Ford's best sedan with the possible exception on the 2nd Gen. V6 powered SHO. >Honda's 240hp V-6 is 60 degrees and is used in the Accord, Odyssey, >Pilot, others? The Accord is a 3.0 litre. The Odyssey and Pilot have a 3.5 litre engine, as does the 3.5RL, but the Acura's is different. I drove a Pilot and liked the 3.5, a friend's 2004 Accord is nice too, but a little more torque could be useful. >I do know that the H-4 in my WRX, while quiet and >powerful, isn't as smooth at idle as the I-6 engines I've test driven. The H-4 is the WRX felt a bit gruff to me. But the boxer-sixes in Porsches are made of automotive dreams. ;-) |
#26
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>>Even modular engine families, such as the one Ford >>developed in 1996 (which spawned a V-6, several V-8s, and a V-10) use a >>60 degree angle for the 6 >> >> > >Does this include the unit (2.5 litres?) used in the Contour or just the 3.0 >litre used in the Taurus? I always liked the Contour, for what it was. I >thought it was Ford's best sedan with the possible exception on the 2nd Gen. V6 >powered SHO. > > The engine family I referred to is the one used in the Mustang and their truck lines. The duratec engines, which started with the 2.5 60 degree V-6 in the Contour, and was expanded to 3.0 in the Taurus and the 3.4 60 degree V-8 (a 2.5 with 2 extra cylinders) in the last SHO. The 60 degree V-8 pretty much killed the SHO - along with its high price. There's a new duratec 3.5L V-6 coming out within a year. > The Accord is a 3.0 litre. The Odyssey and Pilot have a 3.5 litre > engine, as does the 3.5RL, but the Acura's is different. I drove a > Pilot and liked the 3.5, a friend's 2004 Accord is nice too, but a > little more torque could be useful. You're right. But they're all 60 degree V-6s. >>I do know that the H-4 in my WRX, while quiet and >>powerful, isn't as smooth at idle as the I-6 engines I've test driven. >> >> > >The H-4 is the WRX felt a bit gruff to me. But the boxer-sixes in Porsches are >made of automotive dreams. ;-) > > If I coulda I woulda... 'course I tried to get into a used '00 S4, but the new '02 WRX fit so much better into my budget. |
#27
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>The engine family I referred to is the one used in the Mustang
Yuck. They could've gotten the same power output and better fuel economy from a 3.0 litre motor. A twin-cam, multi-valve setup would've been nice too. >The 60 >degree V-8 pretty much killed the SHO - along with its high price. That car was pitiful. An overpriced P.O.S. as far as I'm concerned, not to mention ugly and not particularly fast if memory serves me. >There's a new duratec 3.5L V-6 coming out within a year. I hadn't heard about that. I know that something based on the Futura concept and built on the Mazda 6 platform is set to replace the Taurus and Sable. A 3.5 would be nice, if it's done right. But even the 3.0 in the 6 would be an improvement over the current Taurus mill. >If I coulda I woulda... 'course I tried to get into a used '00 S4, but >the new '02 WRX fit so much better into my budget. I came very near getting a 944 Turbo instead of my VW. But the high maintenance and insurance costs put me off and the 968 would've been the same scenario with a higher buy-in price. I thought the WRX was a great bang for the buck but I thought the VW was more comfortable and already more than quick enough to get me in trouble. I've been pondering buying a Grand National from a local guy who's selling his, but I think it'd be a stretch and I fear the car would spend most of the time in the garage thanks to gas, insurance and registration costs. |
#28
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Steve Grauman wrote:
> > I'm having a fit of dumb**** and not following. I'm well aware of how the > standard combustion driven engine operates but I'm not sure as to how a > 4-cylinder with a 1-2-3-4 firing order could be any more or less smooth than > one with a 1-3-4-2 firing order, or any other variation. The firing order will have an effect on the frequency distribution of the vibration, thus affecting the peak intensity which is what will be perceived by the human. A 1-3-4-2 order should, hypothetically, produce vibrations of twice the frequency and half the amplitude that would be generated by a 1-2-3-4 order. (This is one of the reasons why 1-3-4-2 or 1-3-2-4 are more commounly used than 1-2-3-4.) > Beyond that, I've > ridden in a W12 Pheaton and found it to be quite smooth, so I find Ghee's > claims (as usual) to be obnoxious. Indeed. Car & Driver's recent writeup of the W12 Phaeton uses words like "completely silent", "won't even realize it's running", and "no vibration transmitted through the steering column" or some such. That's low enough in vibration for me. -- Mike Smith |
#29
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Byron wrote:
> > But most modern V-6 engines that are developed from scratch will have a > 60 degree angle. Even modular engine families, such as the one Ford > developed in 1996 (which spawned a V-6, several V-8s, and a V-10) use a > 60 degree angle for the 6 and a 90 degree angle for the others (even > though 72 degrees is ideal for a V-10). Then again, there are some modern weirdos, like the SAAB/Opel 3.0 V6 that was used in the Saturn LS2/L300 - it has a 54-degree angle. Go figure. -- Mike Smith |
#30
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In article >, Mike Smith
> writes >Indeed. Car & Driver's recent writeup of the W12 Phaeton uses words >like "completely silent", "won't even realize it's running", and "no >vibration transmitted through the steering column" or some such. That's >low enough in vibration for me. Indeed. I've worked a fair bit in the production plant at Crewe where the Bentley Continental GT is manufactured, and those things can really sneak up on you, they're so quiet. -- Toby |
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