Everyone knows that the diesel engines developed by VW and AUDI are by far the best. That is, after all how they managed to win Le-Mans with a diesel for the first time ever, and a WTCC and BTCC race.

Diesel power is still unknown to some people, sure the le-mans rules allow diesels to carry more fuel, but did that change the fact AUDI beat Peugeot anyway?

No. It didn't. I'm not sure what the rules are in the BTCC but surely it's only a power restriction, and some sort of wheel base, weight and production per year regulation based on whether the entered car is actually a produced car in such quantity by so many weeks or months or years by the certain manufacterer.

I can't see or think of any rules that would favour the SEAT in the BTCC, if they were being favoured as the fueltank for one isn't relevant as BTCC cars don't make pitstops for tyres, let alone fuel. Why would they quit? Obviously they were on the verge of being ousted, so they decided to quit whilst they were almost on top of the game.

IMO the thing that makes Seat win is not the diesel engine, the turbo is the answer

Quote from BlueFlame :

sure the le-mans rules allow diesels to carry more fuel

That's not the issue, especially when fuel tank size is 9 litres bigger for gasoline engines, but the displacement which slightly favours diesel. Anyways at least the rule maker ACO finally last month admitted the problem and next year diesel engines get 10.5% overall performance cut (smaller air restrictor and boost pressure). But that still won't mean a combination of aging petrol engine and a chassis that has never been in a wind tunnel* becomes a winner candidate against factory teams with 10x budget.

* Pescarolo


.

Quote from deggis :

That's not the issue, especially when fuel tank size is 9 litres bigger for gasoline engines, but the displacement which slightly favours diesel. Anyways at least the rule maker ACO finally last month admitted the problem and next year diesel engines get 10.5% overall performance cut (smaller air restrictor and boost pressure). But that still won't mean a combination of aging petrol engine and a chassis that has never been in a wind tunnel* becomes a winner candidate against factory teams with 10x budget.

* Pescrarolo

Well that is always going to be the case with any winning team in motorsport, money wins.

Quote from NitroNitrous :

IMO the thing that makes Seat win is not the diesel engine, the turbo is the answer

Diesel cars need a turbo to be even remotely competitive with similar capacity petrol engined cars. So the turbo isn't relevant. What Diesel cars will always be better at, (compared to same capacity petrol engines), is producing low down/mid range (ish) torque. Only problem is, they produce so much torque, (especially in a heavily tuned engine), that they can't put it down without spinning up the wheels all over the place. So they resort to traction control that essentially removes the torque advantage. Anyway it's horses for courses... pretty much the same debate that was had when Ducatis first entered WSB racing with their big capacity twins, they had the edge out of the corners but got passed down the straights by the inline 4 engined bikes.

Quote from gezmoor :

Diesel cars need a turbo to be even remotely competitive..

That´s the key. Remember the race in Mexico, where the Seats owned every other car because the track is about 2500m heigh... I think the turbo is too much advantage and it shouldn´t be allowed, or allowed for petrol engines too.

Quote from gezmoor :

Diesel cars need a turbo to be even remotely competitive with similar capacity petrol engined cars. So the turbo isn't relevant. What Diesel cars will always be better at, (compared to same capacity petrol engines), is producing low down/mid range (ish) torque. Only problem is, they produce so much torque, (especially in a heavily tuned engine), that they can't put it down without spinning up the wheels all over the place. So they resort to traction control that essentially removes the torque advantage. Anyway it's horses for courses... pretty much the same debate that was had when Ducatis first entered WSB racing with their big capacity twins, they had the edge out of the corners but got passed down the straights by the inline 4 engined bikes.

So what you're saying is:

1) Diesel is crap unless it is helped by forced induction.
2) Diesel's only win when the 'playing field' is not level.

Funnily enough, a turbocharged petrol engine would crap all over a similar diesel. But for some reason petrol cars aren't allowed FI.

The extra torque at the flywheel will be reduced via gearing to give very similar wheel torque figures, especially as diesel engines don't rev as high. Thus they don't have any more need AT ALL for traction control to limit the torque (besides, even a 6 year old can control wheelspin with their feet).

The bike equivalent you mention is fair - same capacity, same breathing, same weight limits, same fuel... Just a slightly different concept of whether two or four cylinders is the best trade off. There is no need for equivalency rules in that scenario, but there is for diesels versus petrol.

The REALLY sad thing is that some people actually now think that diesel is a decent, viable and even interesting alternative to petrol. How quiet they'll be in a few years when it's plainly obvious how crap diesels are by their very nature.

Quote from BlueFlame :

Diesel power is still unknown to some people, sure the le-mans rules allow diesels to carry more fuel, but did that change the fact AUDI beat Peugeot anyway?

In case you didn't notice Peugeot also entered a souped up tractor. Few people are bothering investing big time in LMP1 and I doubt the few new privater projects will get much manufacturer backing now a petrol win is almost impossible.

Quote from tristancliffe :

The REALLY sad thing is that some people actually now think that diesel is a decent, viable and even interesting alternative to petrol. How quiet they'll be in a few years when it's plainly obvious how crap diesels are by their very nature.

By their very nature, I'd love to know why you say this. The fact diesels use compression to combust, makes them more effiecient than petrols instantly as petrols need ignition to combust, therefor not producing as much torque. Diesel's sound like tractors thats for sure, but Tristan, Diesels spin the wheels more than petrols do, a friend from work has tuned his TDi Mk2 Golf to about 270hp and that smokes the tyres like a bitch, he can't physically find traction, he makes more torques than an 800bhp Supra and we all know how little traction THEY can pick up off of anything. In my mind, I just see a turbo as helping the diesels curve of power at the top end, it helps the balance more. If you have noticed there are alot more people NOW than there EVER were, supporting, tuning and RACING Diesel engined cars. In a boy racer sense it's the smarter option, because with a nicely tuned TDi motor you can smoke alot of things in a straight line over a 1/4 mile and your mpg is as high as Amy Winehouse even when you ARE caning the bollocks off of it.

Quote from ajp71 :

In case you didn't notice Peugeot also entered a souped up tractor. Few people are bothering investing big time in LMP1 and I doubt the few new privater projects will get much manufacturer backing now a petrol win is almost impossible.

So Peugeot didn't really bother at all? I see, because THAT is true. After all it was a French race anyway, so why would they want to even remotely perform well there, I get it now.

Quote from ajp71 :

In case you didn't notice Peugeot also entered a souped up tractor. Few people are bothering investing big time in LMP1 and I doubt the few new privater projects will get much manufacturer backing now a petrol win is almost impossible.

http://www.americanlemans.com/News/Article.aspx?ID=4733

American Honda thinks differently.

Quote from BlueFlame :

...The fact diesels use compression to combust, makes them more effiecient than petrols instantly as petrols need ignition to combust, therefor not producing as much torque. Diesel's sound like tractors thats for sure, but Tristan, Diesels spin the wheels more than petrols do, a friend from work has tuned his TDi Mk2 Golf to about 270hp and that smokes the tyres like a bitch, he can't physically find traction, he makes more torques than an 800bhp Supra and we all know how little traction THEY can pick up off of anything. In my mind, I just see a turbo as helping the diesels curve of power at the top end, it helps the balance more. If you have noticed there are alot more people NOW than there EVER were, supporting, tuning and RACING Diesel engined cars. In a boy racer sense it's the smarter option, because with a nicely tuned TDi motor you can smoke alot of things in a straight line over a 1/4 mile and your mpg is as high as Amy Winehouse even when you ARE caning the bollocks off of it.

Turbo, turbo, turbo...

Quote from BlueFlame :

By their very nature, I'd love to know why you say this

because you can´t speak about diesels without quoting the word turbo.

Quote from BlueFlame :

*Clueless rambling*

Turbo charged petrol cars now routinely produce power figures the far side of 300bhp in cars that are reliable and reasonably economical. If you start tuning them power figures can easily go into 4 figures, completely irrelevant, so why turbocharged diesel engines producing a reasonable amount of power is anything special is beyond me. In a correctly geared car where the power is produced is irrelevant, so long as the powerband is reasonably large, typically it is a lot smaller in diesels, hence why they need to change gear more often and drivers of 'sports' diesels finding they are not in the powerband when trying to overtake makes them dangerous and impractical when you sell them to idiots thinking they're sports cars.

Quote :

So Peugeot didn't really bother at all? I see, because THAT is true. After all it was a French race anyway, so why would they want to even remotely perform well there, I get it now.

No they wanted to win out right and put a huge amount into developing a DIESEL car to take on the Audi. What I said was nobody was giving full scale backing to petrol cars with the intention of winning outright. I don't think Acura have any intention of winning out right, it doesn't seem to have full Honda backing that would be needed to take the front two on. Having said that there are quite a few contenders for the first petrol car home now the biggest team has gone off to play with tractors, and even better got a playmate to make it a bit less dull.

Quote from BlueFlame :

By their very nature, I'd love to know why you say this. The fact diesels use compression to combust, makes them more effiecient than petrols instantly as petrols need ignition to combust

Diesel needs to ignite to combust. Just one is provided via the compression, the other via a spark. The energy required to ignite it still comes from somewhere.

Quote from BlueFlame :

therefor not producing as much torque.

The type of ignition is nothing to with the amount of torque per se

Quote from BlueFlame :

Diesel's sound like tractors thats for sure, but Tristan, Diesels spin the wheels more than petrols do, a friend from work has tuned his TDi Mk2 Golf to about 270hp and that smokes the tyres like a bitch, he can't physically find traction, he makes more torques than an 800bhp Supra and we all know how little traction THEY can pick up off of anything.

Has he changed the gearing to suit the new output, or is he spinning wheels because of the wrong gearing? If I had a car that had the same amount of torque as a Supra I'd hate to only have 270hp. Just imagine how shit it'll be!!!! Constantly changing gear all the time just to use the tiny powerband! Great!

Quote from BlueFlame :

In my mind, I just see a turbo as helping the diesels curve of power at the top end, it helps the balance more. If you have noticed there are alot more people NOW than there EVER were, supporting, tuning and RACING Diesel engined cars.

You might want to go and study turbocharging a little more. Have you noticed that the number of diesels being sold is falling faster than ever? Have you noticed that there are no diesels in race series that don't give diesel an advantage (e.g. turbocharging)?

Quote from BlueFlame :

In a boy racer sense it's the smarter option, because with a nicely tuned TDi motor you can smoke alot of things in a straight line over a 1/4 mile and your mpg is as high as Amy Winehouse even when you ARE caning the bollocks off of it.

But after a quarter of a mile you lose to all the petrol engines of similar power output. Remember, power isn't multiplied by gearing whereas torque is, and as we're interested in the force at the wheels the best comparison is power. Some tractors develop so much torque, but I've not heard of one winning LeMans. Some ships have more torque than there are numbers in 0.999... but none enter powerboat racing.

The fuel consumption when 'caning' it is actually pretty similar. The main fuel economy advantage of a diesel comes from the fact they don't have throttles (and therefore the restrictions a throttle imposes). In a steady state (motorways) or small throttle openings (towns) they do improve economy. But on a race track where everyone is at full throttle more often than anything else, or on a wide back road where again it's all or nothing, then diesel loses much of it's economy advantage. And is still slower!!!

Quote from NitroNitrous :

That´s the key. Remember the race in Mexico, where the Seats owned every other car because the track is about 2500m heigh... I think the turbo is too much advantage and it shouldn´t be allowed, or allowed for petrol engines too.

Yep, its because (correct me if i'm wrong) there is less oxygen at altitude, so, there is less power from both engines. However the diesel has the turbo which isn't affected by the lack of oxygen so the diesel has more power at altitude

Quote from tristancliffe :

So what you're saying is:

1) Diesel is crap unless it is helped by forced induction.

Yup. Pretty much

Quote :

2) Diesel's only win when the 'playing field' is not level.

Funnily enough, a turbocharged petrol engine would crap all over a similar diesel. But for some reason petrol cars aren't allowed FI.

Depends on how you define level. Obviously if you want to look at it purely from the terms of engine parts, one car having a turbo and another not would seem not to be level. But, when the car that is allowed the turbo is starting off with a distinct power disadvantage because of it's engine type then allowing it to use a turbo to achieve comparible peak power is exactly to level the playing field. Looking at it from the perspective of mechanical parts is simplistic in such circumstances, (and I think you know it :razz.

Quote :

The extra torque at the flywheel will be reduced via gearing to give very similar wheel torque figures, especially as diesel engines don't rev as high. Thus they don't have any more need AT ALL for traction control to limit the torque (besides, even a 6 year old can control wheelspin with their feet).

Fair point.

Quote :

The bike equivalent you mention is fair - same capacity, same breathing, same weight limits, same fuel... Just a slightly different concept of whether two or four cylinders is the best trade off. There is no need for equivalency rules in that scenario, but there is for diesels versus petrol.

Actually it's a far closer comparible than you believe. The Ducatis were not only twin cylinder configurations, they were allowed 33% greater capacity than the 4 cylinder inline bikes. Why? well because despite using a very high tech cylinder head the Ducatis didn't have a hope in hell of achieving a similar peak power output as the inline 4's if they were the same capacity, so they were allowed greater capacity in order to be competitive for peak output. But then they had an even greater advantage of making considerably more low down torque, not only from the intrinsic advantage of their engine layout but also from their extra capacity. Despite this, I don't recall many people claiming the ducatis had an unfair advantage.

Quote from tristancliffe :

Diesel needs to ignite to combust. Just one is provided via the compression, the other via a spark. The energy required to ignite it still comes from somewhere.
The type of ignition is nothing to with the amount of torque per se
Has he changed the gearing to suit the new output, or is he spinning wheels because of the wrong gearing? If I had a car that had the same amount of torque as a Supra I'd hate to only have 270hp. Just imagine how shit it'll be!!!! Constantly changing gear all the time just to use the tiny powerband! Great!
You might want to go and study turbocharging a little more. Have you noticed that the number of diesels being sold is falling faster than ever? Have you noticed that there are no diesels in race series that don't give diesel an advantage (e.g. turbocharging)?
But after a quarter of a mile you lose to all the petrol engines of similar power output. Remember, power isn't multiplied by gearing whereas torque is, and as we're interested in the force at the wheels the best comparison is power. Some tractors develop so much torque, but I've not heard of one winning LeMans. Some ships have more torque than there are numbers in 0.999... but none enter powerboat racing.

The fuel consumption when 'caning' it is actually pretty similar. The main fuel economy advantage of a diesel comes from the fact they don't have throttles (and therefore the restrictions a throttle imposes). In a steady state (motorways) or small throttle openings (towns) they do improve economy. But on a race track where everyone is at full throttle more often than anything else, or on a wide back road where again it's all or nothing, then diesel loses much of it's economy advantage. And is still slower!!!

Diesels are more effecient engines, you cannot argue with this. Sure you are correct when it comes to out and out power flammable fuel is the way to go. My friend has the standard GTi gearbox in his Mk2, he gets 50mpg, which instatistics is the same as a 1.0litre Petrol Mk1 Corsa (Mk2 if your european) I had a 1.9Skoda which wasn't turbo charged, and it was better for fuel consumption, it shifted alrite the only difference was the powerband length towards the top of the rev range. I am in no way arguing that petrol engines are superior in things like racing and to drive a diesel you have to be a skilled pilot to get the most out of it to know when to change gear at the right moment, because hitting the end of the revs will only give you a disadvantage (unless you have a revlimiter quite low down for some reason)

I just get the feeling you and AJP are bitter towards Diesel because you don't want to see it in racing. Have either you ever owned a Diesel car Alex, Tristan?

My first two cars were diesel, one NA the other a turbo. Bought solely for reasons of cost. I hated them.

Bullshit about needing to be a better driver to get the most out of them. You just change gear earlier, and it takes no more skill to do that than to know when to shift in a petrol.

Diesels are more efficient for a few reasons, and the main one is the lack of throttling. And a lack of throttling isn't an issue on a race car. Diesel also has a higher calorific value, so for a given amount of combustion (at a given level of efficiency) then more cylinder pressure is generated, on top of the high cylinder pressures of compression ignition.

On the road the fuel consumption IS better. On a race track the difference is pretty negligable (both engines effectively being dethrottled).

Quote from BlueFlame :

I just get the feeling you and AJP are bitter towards Diesel because you don't want to see it in racing. Have either you ever owned a Diesel car Alex, Tristan?

Never owned a car but have had the chore of driving too many diesels.

Quote from tristancliffe :

My first two cars were diesel, one NA the other a turbo. Bought solely for reasons of cost. I hated them.

Bullshit about needing to be a better driver to get the most out of them. You just change gear earlier, and it takes no more skill to do that than to know when to shift in a petrol.

Diesels are more efficient for a few reasons, and the main one is the lack of throttling. And a lack of throttling isn't an issue on a race car. Diesel also has a higher calorific value, so for a given amount of combustion (at a given level of efficiency) then more cylinder pressure is generated, on top of the high cylinder pressures of compression ignition.

On the road the fuel consumption IS better. On a race track the difference is pretty negligable (both engines effectively being dethrottled).

I said it wrong, I meant that driving a diesel requires a different style than driving a petrol. You can't just redline a diesel, it doesn't work that way and we all know that.
And your Diesel cars were? Ford? Vauxhall? Peugeot?
And what Diesel cars have YOU driven AJP?

Quote from BlueFlame :

And what Diesel cars have YOU driven AJP?

106, 306, 307, VW Transporter, Polo, Corsa, Focus, Fiesta, Bedford CF to name a few. So what diesels have you driven that are completely unlike any of the above?

Quote from ajp71 :

106, 306, 307, VW Transporter, Polo, Corsa, Focus, Fiesta, Bedford CF to name a few. So what diesels have you driven that are completely unlike any of the above?

Nothing, but I was hoping you were not going to name a car from the VAG group so I could flame you about talking about Diesels when in a Seat thread if you never drove a VAG diesel before :P

Peugeot and Ford. But I have driven lots of others that I haven't owned - company vans, commercial vehicles, 'normal cars'.

I never redline any car. If I want to be quick I shift in EXACTLY the same way as in a petrol car - when I have more wheel torque in the next gear than I do in the current gear. It takes about 0.2 seconds of experience at driving to be able to feel this point after a dozen gear changes regardless of fuel.

Some people even say "diesels run away with you at low speed". I've never ever EVER suffered from this, and have summised that everyone who says this either can't drive, is just recounting what someone else said to them, or isn't in proper control of their vehicle.