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View Poll Results: petrol or diesel for performance ?(read post before vote)
Petrol 126 68.85%
Diesel 57 31.15%
Voters: 183. You may not vote on this poll

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Old 22nd March 2010, 16:28   #46
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Originally Posted by A350XWB View Post
Voted for Diesel, after watching the WTCC and Le Mans series. And diesels have immense potential to grow, which is untapped even today.
Ok. So Somebody else watches F1 and votes for Petrol.
Everyother thing other than an egoist's thinking, has potential to grow in this world - whats the big deal ?

C'mon guys - Rather than comparing speculations, Compare science.
If anything on this world is going to run on Petroleum gas - This is going to be even faster than a same Cubic Capcity - Same Technology Petrol Engine.

Going by what few people are saying, i think a Kerosene powered, 4L CRKi ()engine with a twin sequential Turbo charger that is also a Variable Geometry Turbine(yeah both of them), is a better performer than a 3.0 L Turbo Diesel .


Any Comparison must be based on a point of reference. Whats your POR here ? Is it Volume ? Is it a Turbo ?. Hence at any particular point of reference a Petroleum gas'ed engine will perform better than a Petrol engine, which will peform better than a diesel engine, which will perform better than a Kerosene powered Engine.

Getting it now ?

Last edited by Mi10 : 22nd March 2010 at 16:33.
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Old 22nd March 2010, 16:44   #47
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Originally Posted by Mi10 View Post
Chill off Guys.

What you are comparing are only cars of different make / model / genre.

When you ask, 'Petrol or Diesel for Performance' ? What I interpret here is a fair, just and more importantly equal comparsion of cars - one Running on Petrol and the Other Diesel).

Forget all manufacturers, Forgot all Techologies and Forget your Jargon on Torque and BHP. Just Consider the below example:

A Car A that has an Inline 4 Naturally Aspirated 1.5 L Engine that runs on Gasoline and
Car B that has a 4 Cyl, 1.5 L Naturally Asipirated Diesel - (without a Turbo).

Which do you think will perform better ?

Obviously Petrol - Simply because its much more refined than Diesel. If you consider the Petroleum Refining Process, Petrol comes out much before Diesel Comes - Meaning A Petrol is much more easily combustible than a Diesel. Which again means - A Diesel without a Turbo and without your CRDI is not going to take up a similar Petrol Engine.

No Point in Comparing Products of different Manufacturers - Its is not going to get the answer for this Question. If Your Diesel is so good on Performance, why not a Diesel powered Aircraft - Now Answer that (lol.. Just Kiddin)

I hope i made my point - Its basically the inherent nature of fuel which makes Petrol engines deliver more perfromance than similar Diesel





engines.



Do you not you know air crafts are kerosene powered(aviation grade)
( just a bit more refined than your what you get at home,to remove particulate matter and TAR so that nozzles of Jet engine does not get clogged).it is far cheaper than diesel.Moreover turbines can almost use any kind of oil for power production(petrol/diesel/kerosene/soya) only calibration of injection system needs to be done according to new fuel.




And why to compare a 1.5l petrol with 1.5l diesel without a turbo(after all you get 1.5l turbo charged diesel engine in same price as 1.5l petrol.
If you can get 1.5l turbo petrol in same price bracket,no one is stooping petrol ones from getting that turbo use) its just that turbo for petrol is many times more expensive!
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Old 22nd March 2010, 17:04   #48
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Originally Posted by Mi10 View Post
Ok. So Somebody else watches F1 and votes for Petrol.
Everyother thing other than an egoist's thinking, has potential to grow in this world - whats the big deal ?

C'mon guys - Rather than comparing speculations, Compare science.
If anything on this world is going to run on Petroleum gas - This is going to be even faster than a same Cubic Capcity - Same Technology Petrol Engine.

Going by what few people are saying, i think a Kerosene powered, 4L CRKi ()engine with a twin sequential Turbo charger that is also a Variable Geometry Turbine(yeah both of them), is a better performer than a 3.0 L Turbo Diesel .


Any Comparison must be based on a point of reference. Whats your POR here ? Is it Volume ? Is it a Turbo ?. Hence at any particular point of reference a Petroleum gas'ed engine will perform better than a Petrol engine, which will peform better than a diesel engine, which will perform better than a Kerosene powered Engine.

Getting it now ?
I think what you are missing here is horses for courses.

I am deeply involved in the development of technology and I have been close to murder bean counters in design departments.

Additionally you have to understand market situations.

It costs about 1,000,000,000USD to develop a new car. It costs 100s of millions for new engines. Car manufacturers need to see a return and markets have to be developed.

The majority of the world's population still thinks only tractors some smelly trucks and a few farmers have Diesel engines.

If Ferrari would built a Diesel powered car thatoutperforms anything else in the world - how many people would buy it? Ferrari hasn't got the technology to do so. The only people in the world are Peugeot and Audi.

When we can with a few rather basic modifications get a 1900cc turbo Diesel from a standard 150bhp to 270bhp and nearly 700Nm of torque, what do you think the factories can do when they make the hardware stronger?

The disadvantage of Diesel engines is that it needs materials that are much stronger than petrol engines. To achieve this at acceptable cost with today's technology it means more material, which in turn makes the engine less desirable.

What most of you people forget is that Diesel engines did not have the attention until the late 1970s. Till date it is necessary to invest a lot of money to make advances.

Why should car manufacturers provide expensive normally aspirated Diesel technology when turbo Diesel engines can be made for a fraction of the cost?

What you also need to understand is that we have changing markets. The petrol engines you are driving are soon a thing of the past. Every manufacturer is now changing from normally aspirated engines to forced induced engines due to emission regulations. And they figure out tha it is cheaper to produce turbo engines then n/a engines with the same power output.

Too many people are hooked on the bhp figures. The torque delivery on most Diesel is excellent. Petrol engines can only deliver such torque characteristics with a lot of expensive effort.

The question of the original poster has been diluted and looked at most in a totally theoretical way not aiding anyone.

I personally do like petrol engines and use them too, but the better concept for performance is Diesel engined cars and I am involved in racing. But as long as people are talking down Diesel engines, the industries will not spend money to oppose it and rather supply technology that people ask for.
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Old 22nd March 2010, 17:21   #49
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Quote:
Originally Posted by Mi10 View Post
Ok. So Somebody else watches F1 and votes for Petrol.
Everyother thing other than an egoist's thinking, has potential to grow in this world - whats the big deal ?

C'mon guys - Rather than comparing speculations, Compare science.
If anything on this world is going to run on Petroleum gas - This is going to be even faster than a same Cubic Capcity - Same Technology Petrol Engine.

Going by what few people are saying, i think a Kerosene powered, 4L CRKi ()engine with a twin sequential Turbo charger that is also a Variable Geometry Turbine(yeah both of them), is a better performer than a 3.0 L Turbo Diesel .


Any Comparison must be based on a point of reference. Whats your POR here ? Is it Volume ? Is it a Turbo ?. Hence at any particular point of reference a Petroleum gas'ed engine will perform better than a Petrol engine, which will peform better than a diesel engine, which will perform better than a Kerosene powered Engine.

Getting it now ?
Ok, we will talk science.
"When burnt, diesel typically releases about 38.6 MJ/l (138,700 BTU/US gal), whereas gasoline releases 34.9 MJ/l (125,000 BTU/US gal), 10% less by energy density, but 45.41 MJ/kg and 48.47 MJ/kg, 6.7% more by specific energy."
(Ref: Diesel fuel - Wikipedia, the free encyclopedia)
More : Diesel automobile racing - Wikipedia, the free encyclopedia
So, speaking science, diesel has more specific energy than gasoline.
Diesel technology was ignored by many compared to petrol because of the usage pattern. Diesel was mostly used in trucks, buses and such heavy haulage applications until recently. But, with demand for diesel engines in passenger cars, this is slowly changing and more and more companies are investing in diesel technologies.

For F1, as somebody already rightly mentioned, it's because forced induction is not allowed. It's a limitation placed by the governing authority.

More references:
Energy density - Transwiki
Diesel cycle - Wikipedia, the free encyclopedia

And I totally agree with the points of CPH above.

Last edited by A350XWB : 22nd March 2010 at 17:33.
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Old 22nd March 2010, 17:46   #50
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And hey I forgot to add,about 70% less pollution from modern diesel engines as compared to petrol ones
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Old 22nd March 2010, 17:53   #51
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Thumbs up Diesel

Quote:

Diesel fuel has a higher energy density than gasoline. On average, 1 gallon (3.8 L) of diesel fuel contains approximately 155x106 joules (147,000 BTU), while 1 gallon of gasoline contains 132x106 joules (125,000 BTU). This, combined with the improved efficiency of diesel engines, explains why diesel engines get better mileage than equivalent gasoline engines.

Diesel fuel is used to power a wide variety of vehicles and operations. It of course fuels the diesel trucks you see lumbering down the highway, but it also helps move boats, school buses, city buses, trains, cranes, farming equipment and various emergency response vehicles and power generators. Think about how important diesel is to the economy -- without its high efficiency, both the construction industry and farming businesses would suffer immensely from investments in fuels with low power and efficiency. About 94 percent of freight -- whether it's shipped in trucks, trains or boats -- relys on diesel.
Source :

HowStuffWorks "Diesel Fuel"
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Old 22nd March 2010, 18:34   #52
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Originally Posted by mxx View Post
Considering that unlike before the newer generation diesels are more responsive and give better performance

1. When you have a choice of petrol or diesel, which one would you choose from a purely for performance? I repeat purely from performance perspective costs including fuel costs are NOT an issue for the choice.
And consider cars above the 25lakhs mark because below that there is no choice of good petrol and good diesel within same model.

2. Why is it that with all the advancements in diesels, petrol is still used in racing circuits? If I am not mistaken only audi has a successful diesel in the racing arena. And no track or street racers prefer diesel.
I think this thread has deviated from the original question. Price is not a consideration in the question above.
For question No: 1, my answer is a diesel
For question No: 2, the answer is, there are more forms of racing which uses a diesel (eg: WTCC, Le Mans) and they are winning the championships also. There are other forms of racing (eg: F1) where there are restrictions imposed (eg: no turbocharging) thereby making a diesel entry difficult.

These are purely the answers for the original questions from my perspective.
"And no track or street racers prefer diesel" -> this statement is plain wrong as WTCC and Le Mans championship winners are TDIs and I don't think people don't prefer winning cars.
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Old 22nd March 2010, 18:35   #53
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I do not understand Why is every one going GAGA over TURBO being used on diesel? It is just the way a diesel engine is suppose to be made to achieve best possible factors that you expect from an Engine!
Turbo diesel or crdi system is not something that some one has got it done aftermarket! to enhance its performance, it is the way the engine is supplied by the manufacturer,it is the way the engine has been designed, so why are people asking to get off the turbo and then compare it with similar petrol one??
I mean diesel heads could say " hey your petrol engine uses lighter crank shaft, n lighter connecting rods,lighter pistons, put on the heavy one from a diesel engine and then compare CC to CC" its just not going to work that way! or is it?
In fact diesel heads could say, hey your petrol engine uses Spark plugs,take them off and see which engine produces what performance! trust me its going to be ZERO BHP.
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Old 22nd March 2010, 18:43   #54
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Looks like a never ending argument. Torque in diesel is addictive but in a very limited range (about 2k to 4k range in the diesel DZire) while got to love the free rev'ing nature of the petrol and the sound it makes. As someone said, it's not just about 0-100 timings (though it's a big part), it's also about revv'ing the nuts off the engine and enjoying the noise it makes during the course of it which only a petrol can offer. Of course, it's just my opinion.
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Old 22nd March 2010, 18:53   #55
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Petrol engines are superior in performance any day. Diesels are good but not hard core performance. If you take 0-100 sprint, 0-top speed run, the petrol engines will easily overpower the diesels. Formula One cars, WRC etc all use petrol, so there we go, mystery solved. For performance, go for petrol!
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Old 22nd March 2010, 18:55   #56
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seems like this has gone to a fight between few members.

When I first started this thread, in my first post I mentioned that this discussion is above cars above rs.25lakhs mark. That was for a reason which was also mentioned.
I will repeat again. Below that point there are no good diesel and good petrol (good means from a car enthusiast view with respect to performance) offered in the same model from the manufacturer. But we do have that in the luxury segment starting from superb, which has a good diesel and a v6 petrol. going all the way to beemers and mercs and even porsche cayenne. This segment also has turbo petrols. So, let us compare with what is there rather than making this a speculative thread.
"If we do this, petrol will beat diesel, if we do that, diesel will beat petrol" sort of discussion serves no useful purpose.
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Old 22nd March 2010, 18:58   #57
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Petrol all the way... its subline to hear a V8 engine revving at 9000 rpm!

P.S. The engine I am talking about above is the Ferrari 458 Italia V8
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Old 22nd March 2010, 19:11   #58
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Some people prefer torque and some top speed.

Just curious to know if any diesel in same 'category' can take on a 911 turbo. lol..just kiddin
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Old 22nd March 2010, 19:35   #59
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Originally Posted by Mi10 View Post
Some people prefer torque and some top speed.

Just curious to know if any diesel in same 'category' can take on a 911 turbo. lol..just kiddin

Maybe a tuned version of the VW 6.0 V12 Tdi in an R8 could have done it.
But the have ditched plans for the V12 TDI R8. If it can take the 2.X tonne q7 in 5.5 seconds, a sub 4 sec 0-100 timing might have been possible with the R8.

We have the tech for free revving diesels. What we need is high revving ones.
Just my opinion.

Last edited by mithunkb : 22nd March 2010 at 19:38.
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Old 23rd March 2010, 09:33   #60
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Default Another perspective on performance

Isn't the main aspect of performance about cutting your miles (or kms) faster? For this aspect, wouldn't the "standing kilometer" (seconds taken to cover the first 1000 meters) be a better measure? It is not just about how you get to your top speed but also about how you stay there.

I personally am more exposed to petrol engine cars and never extensively driven any diesel engined cars. So I will refrain from commenting on the comparison. But the BMW site (BMW India : 5 Series Sedan : All the facts : Technical data) does give the following:

Standing kilometer timings:
Petrol 530i - 26.4s
Diesel 530d - 27.1s

Some other standing kilometer timings for Lamborghini cars can be found at: Lamborghini cars, the enthusiast site

May be someone can pitch in with the standing kilometer timings for diesel cars.
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