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Old 20th November 2009, 19:23   #16
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Thanks for solving my doubts, guys. Interesting comments. What I gather:

1. Too much potential torque.

2. Weight.

3. There are some V8 diesels, as some of you pointed out, but they are better off serving ladder frame trucks & SUVs.

4. Limitations of that torque being used in a monocoque.

5. Weight.

6. V6 diesels have more torque than even V8 petrols. Sufficient already.

Could also be that the traditional flagships (e.g. S500) will be overshadowed & outperformed by an S500 CDI?

EDIT: One flagship sedan does offer a V8 diesel. The Audi A8. 4.2 L V8 diesel 322 BHP & 650 NM of torque @ 1600 rpms! Wiki says 0 - 100 in 5.9 secs!

Quote:
Diesels have huge torque and lesser horsepower, to go faster one needs lots of power, unfortunately diesels cannot provide it.
I'd disagree with that. Most German common rails today are faster than their petrol counterparts (e.g. 530d versus 530i).

Quote:
one will spend more time in shifting than enjoying it..
Actually, you shift less with a diesel thanks to all that low-end torque.

Last edited by GTO : 20th November 2009 at 19:27.
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Old 20th November 2009, 21:50   #17
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GTO. the folks over at the thread I posted to think that Inline Sixes are the way to go, and that they have more torque, and lower down than the average V 8
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Old 20th November 2009, 22:23   #18
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If one is trying to achieve better refinement with the V8, then surely, petrol V8s will do the job better. And hardly anyone buys a diesel V8 for economy. When it comes to performance, petrols are way better than diesels. Diesels may have more torque, but when it comes to sheer driving pleasure, high revs and power, a petrol is miles ahead.
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Old 20th November 2009, 22:36   #19
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1: Gearboxes to take this torque are few and far
2: Torque from 6 cyl more than adequate
3: V8 dielses are heavy affecting handling
4: Limited market so why bother
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Old 21st November 2009, 03:38   #20
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Quote:
Audi V8 diesel has bore x stroke 83 x 95.5 mm, 4134cc, 16.5 compression ratio, twin turbo and two intercoolers, 322 bhp and 77.55 Nm of torque. That is, 18.759 Nm/ltr! Very nice for such a large engine.
I think you got confused between "nm" and "kgm". 77.5nm is what you'd expect from a 800-1000cc engine.

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Old 21st November 2009, 04:07   #21
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In a petrol the V8 has a unique growl that luxury customers look for. In a diesel you just get clatter anyway so why bother I guess.

Both Merc and BMW made V8 diesels for last gen S and 7series...both were low volume and almost handbuilt. Customers prefered the 6 cylinders and now both are dropped.

For 2010 two brand new V8 diesels will be launched in the US by Ford and GM for pickup trucks. The Scorpion and the Duramax.

Last edited by Mpower : 22nd November 2009 at 00:42.
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Old 21st November 2009, 11:25   #22
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Quote:
Originally Posted by Mpower View Post
In a petrol the V8 has a unique growl that luxury customers look for. In a diesel you just get clatter anyway so why bother I guess.
The clatter is only at idle if any. Once you getting the revs rollings you get a nice growl from todays modern diesel engines. Infact the inline 6cyl BMW engine has a slight/muted v8 find of rumble in the mid range.
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Old 21st November 2009, 12:18   #23
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Quote:
Originally Posted by McLaren Rulez View Post
If one is trying to achieve better refinement with the V8, then surely, petrol V8s will do the job better. And hardly anyone buys a diesel V8 for economy. When it comes to performance, petrols are way better than diesels. Diesels may have more torque, but when it comes to sheer driving pleasure, high revs and power, a petrol is miles ahead.
hi
but experince is totaly diffrent
infact most new generation diesel engine car i have sat in europe have give me more pleasure
than any petrol car i have sat in
for example i was sitting in front seat in audi a6 3.0 after 2nd 3rd gear the car just shoot
i felt like i was sitting in 747 jumbo with the kind of torque it generated
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Old 21st November 2009, 13:19   #24
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Quote:
Originally Posted by greenhorn View Post
GTO. the folks over at the thread I posted to think that Inline Sixes are the way to go, and that they have more torque, and lower down than the average V 8
Thanks, did read through last evening and saw the comments in favour of the inline sixes. Probably a reason why BMW sticks to inline even for the 730 / 740d?

That said, I don't see any lack of low end torque in the Merc V6 diesels!

Quote:
Originally Posted by McLaren Rulez View Post
but when it comes to sheer driving pleasure, high revs and power, a petrol is miles ahead.
wholeheartedly!

Quote:
Originally Posted by Mpower View Post
In a petrol the V8 has a unique growl that luxury customers look for.
So obvious now that you mention it. The sheer engine & exhaust note of German V8s are to die for.

Quote:
Originally Posted by Sahil View Post
Once you getting the revs rollings you get a nice growl from todays modern diesel engines.
Still not a patch on the music that a BMW 6 / 8 petrol makes!
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Old 21st November 2009, 14:03   #25
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take this scenario. you have unlimited money to buy and run an s-class. your choices are:

1) S Class V8 petrol, say 4.2 Litres making 450 bhp and 40 Kgs of torque @ 4500 rpm
2) S class V8 diesel, say 4.2 litres, 300 bhp and 80 kgs of torque@ 2000 rpm

what will you t-bhpians buy? The diesel does not make economic sense here as those buyers wants luxury and silent petrol engines. The Economy consious buyer will rather buy and s-class with a 3 litre diesel engine. Diesel still is for the economy concious buyer. Add to that all the technical issues like added weight, need for stronger transmission, chassis, torque steer etc.

It makes sense on a SUV as they are not bought as luxury cars (eventhough it has turned out to be a luxury buy these days, and indeed it is luxurious than some saloons). A bigger diesel engine makes sense when you need more torque at low rpms, resulting in longer life. So you see them more often in earthmovers, boats, ships etc.
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Old 21st November 2009, 16:15   #26
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[quote=GTO;1593317]

I'd disagree with that. Most German common rails today are faster than their petrol counterparts (e.g. 530d versus 530i).
QUOTE]

i am talking about the rate at which it reaches the top speed..
Diesel will reach similar top speed, but will take time, isnt?

Quote:
Originally Posted by GTO View Post

Actually, you shift less with a diesel thanks to all that low-end torque.
You are right, We shift lesser with a deisel, but only at lower speeds..
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Old 21st November 2009, 19:16   #27
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Quote:
Originally Posted by GTO View Post
Thanks for solving my doubts, guys. Interesting comments. What I gather:

1. Too much potential torque.

2. Weight.

3. There are some V8 diesels, as some of you pointed out, but they are better off serving ladder frame trucks & SUVs.

4. Limitations of that torque being used in a monocoque.

5. Weight.

6. V6 diesels have more torque than even V8 petrols. Sufficient already.
......
Hi,
Topic caught my eye. Went through the thread. And the US link.

Is the conclusion that for a given displacement, the I6 has more torque than the V8? Why?

What would the weight difference be like? Once again, for the same capacity.

How many turbos do the Vs have?

Regards
Sutripta

PS: always thought that the rpm limit in a diesel was injection/ combustion process related rather than mechanical (as in conrod through block).

Also might be interesting to ask Cummins how many VT1710s (V12) they sell compared to KT/ KTAs (I6) and why.
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Old 21st November 2009, 19:27   #28
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Quote:
Originally Posted by VEA View Post
1) S Class V8 petrol, say 4.2 Litres making 450 bhp and 40 Kgs of torque @ 4500 rpm
2) S class V8 diesel, say 4.2 litres, 300 bhp and 80 kgs of torque@ 2000 rpm
Well, tough choice. But since we don't have a V8 diesel in the S Class or 7 series available, I'll take the easy way out . Between the 530i and the 530d, I'd take the diesel any which day!

Quote:
what will you t-bhpians buy? The diesel does not make economic sense
I don't think its only about the economy. The diesels offer double the torque which is useful in the city, or when quick overtaking on the highway.

Quote:
Originally Posted by r@CYR@y View Post
i am talking about the rate at which it reaches the top speed..
Diesel will reach similar top speed, but will take time, isnt?
Not really . Again, I take the example of the BMW 5 series. The 530d is quick in a 0 - 100, a 0 - 160 and a 0 - 200. I'm not even bringing up the mid-range where the 530d will eat the 530i for breakfast.

Quote:
You are right, We shift lesser with a deisel, but only at lower speeds..
Again, I beg to differ. Even at higher speeds, the torque ensures you don't need to shift down at all. In my C220, on the expressway, the 6th gear is good for the 120 - 240 kph range. In gear acceleration is WAY superior with a diesel (mid-range).
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Old 21st November 2009, 21:21   #29
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Quote:
Originally Posted by VEA View Post
take this scenario. you have unlimited money to buy and run an s-class. your choices are:

1) S Class V8 petrol, say 4.2 Litres making 450 bhp and 40 Kgs of torque @ 4500 rpm
2) S class V8 diesel, say 4.2 litres, 300 bhp and 80 kgs of torque@ 2000 rpm

what will you t-bhpians buy? The diesel does not make economic sense here as those buyers wants luxury and silent petrol engines. The Economy consious buyer will rather buy and s-class with a 3 litre diesel engine. Diesel still is for the economy concious buyer. Add to that all the technical issues like added weight, need for stronger transmission, chassis, torque steer etc.

It makes sense on a SUV as they are not bought as luxury cars (eventhough it has turned out to be a luxury buy these days, and indeed it is luxurious than some saloons). A bigger diesel engine makes sense when you need more torque at low rpms, resulting in longer life. So you see them more often in earthmovers, boats, ships etc.
hi
first a person or a company who buy s class benz any were in the world yes i say any were in the world does think of economy or something like this because this s class is for the higher economic or higher end of the market
now if u ask what would u choose a petrol v8
or new generation deisel v8
my answer would 100 percent deisel
why?
because the kind of pickup and a torque u get in new generation diesel engine a petrol cannot match also for example u say 0 to 100
in 10 seconds and 0 to 100 in 12 secounds
for a car which use in road 0 to 100 1 or 3 secound does not matter because u are going to use car in a road not for racing
but if i had deisel car it has more torque
so less gear changes better pick up
increase driving pleasure
also a deisel give better fuel economy than petrol imagine u have v8 s class with approx 80 liter fuel tank full tank can give u may be 700 km range but same car
in deisel with 80 liter fuel tank can give 1100km range so u donot have go offten to fuel station offen this what makes new diesel better in my opinon but is last more about personal taste
narry

Last edited by GTO : 23rd November 2009 at 11:07.
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Old 21st November 2009, 21:38   #30
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Ive seen quite a few Touraeg V10 TDi s in Delhi.
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