Discussion in 'Motoring' started by williemaykit, Jan 10, 2008.
Funny, says R8 V12Tdi on the rear numberplate
And in the engine bay
The R10 is the Le Mans winning diesel from which the engine is basically derived.
The R8 has lost its luggage bay as a result of the larger V12 diesel.
Allegedly de-tuned to 500bhp but still with 1000Nm of torque.
It also adds about 100kg in weight apparently
This is all very confusing. IIRC The original R8 was the Le Mans winning V8 twin turbo petrol engined car. Then they decided to do a diesel version which as Alex points out is the R10, which has a V12 twin turbo diesel.
We now have the road going R8 which has a normally aspirated V8 with 420 hp and 317 torques.
Thre is a V10 petrol version is apparently coming soon, with a an engine derived from that in a Lamborghini Gallardo, although the actual displacement and whether it'll have turbos attached (as in the RS6) is unknown. Some were referring to this car as an R10.
There is also another diesel version planned for 2008 with the 4.2TDi engine used in the Q7.
I remain sceptical as to whether 'supercar' buyers will really want a diesel engined version of their car. A little extra fuel economy isn't really going to make much difference if a) you're wealthy enough to be able to afford on of these, and b) the likelihood of most of these cars not being used all that much. The additional weight of the diesels will adversely affect the handling, which is what these cars are all about, or are these versions built for autobahn-sturming?
Imagine trying to pose around Monte Carlo with a diesel death rattle coning from your sports car engine? (All diesels still do it to some extent, and I'm sure these are no different, it's especially noticeable at low speeds too.)
What'll be really interesting is how they price all these different models.
I recently heard that the V10 won't be that of the gallardo or RS6 but a new engine? Surely that isn't going to be the case though?
Interesting points,although the diesel engine doesnt seem to have held the R10 or Peugeot LM cars back at all.
The diesels are said to be deathly quiet round Le Mans although the comparison is a bit unfair...the diesel has it's turbos,particulate filters etc etc,all of which reduce exhaust noise by comparison with the normally aspirated cars.
I caould see though that selling a diesel supercar will be an interesting proposition,even if the torque and speed are as good as claimed.
Some of the S2000 boys go to Le Mans and it has been mentioned as to how quiet the diesels were.
The R10 is hardly any quicker in terms of lap times than the old petrol R8 (see wikipedia), and if the rules had been the same (same engine capacity/same turbo etc) then the petrol would still have been faster, the additional fuel economy of the diesels balancing things out a bit.
As you say, how racing cars go bears little relationship with road cars.
As for the road-going R8, in most cases the diesel equivalent of a car is more expensive than the petrol version, I'd be very surprised if that were the case here.
It will be interesting once the first few hit the roads over here....I think a lot of petrol supercar drivers will be surprised by the torque.
A few of the AVF boys do Le Mans as well
The LM R10 is a spooky car, far too quiet, the way it pulls though the corners is astonishing. All that torque does not go to waste.
A road going version should be pretty special. As with the race car I assume this is just to prove that it can be done. The whole point of the race car was to develop diesel fuel and engine technology.
If the road car is set up to run on bio-diesel it will decimate many 'true exotics'
But isn't it power that makes a car go fast, not torque...?
And more weight always means worse handling...?
The diesels may have better in gear times, but I suspect the petrols will actually be faster where it really counts with a supercar, through the gears...
AFAIK torque gives you acceleration, horsepower gives you top speed.
This is correct.....there's obviously no competition for having both,but with 500bhp and 800lbs of torque it should be fine.
Also with a sequential or DSG type box,that should ideally suit the diesel's power/torque delivery.
If that's the case, can you explain this? (Data from Parkers/VW)
VW Golf 3d
1.4 GT TSi 167 bhp, Torque 177lb-ft, Weight 1,429kg, 0-62 7.9s
2.0 GT TDi 167 bhp, Torque 258lb-ft, Weight 1,445kg, 0-62 8.2s
The car with more torque accelerates slower - why is this, the weights are virtually the same?
2.0 GT FSi 147bhp, Torque 148lb-ft, Weight 1,392kg, 0-62 8.9s
2.0 GT TDi 138 bhp, Torque 236lb-ft, Weight 1,451kg, 0-62 9.3s
Again, the car with more torque is slower (although there is a bigger weight difference here)
I'm guessing it's to do with gearing but I'm intrigued to find out the answer to this one.
I was bored at lunchtime so did a little more research on BMWs website where they have the power/torqe/weight figures, as well as 0-62 and 50-75 in 4th gear times.
It makes interesting reading, some observations:
The most obvious finding is that the lower torqued petrols accelerate faster than the diesels from 0-62. However, the diesels are quicker in the 50-75 time in 4th gear.
This is borne out in the correlation figures. A correlation of -0.97 between power and 0-62 indicates that power is the main factor in outright acceleration. The -0.94 for the torque/50-75 figure indicates that torque allows you to accelerate quickly if you're in the wrong gear.
However, there is a much stronger correlation between power and 50-75 (-0.75) than there is between torque and 0-62 (-0.47).
The diesel cars are generally heavier (an average of 65kg) which undoubtedly slows them down (and worsens handling/braking of course).
Thoughts/explanation gentlemen, please
i was at goodwood, and they had the audi lemans diesel there, and yes it was scary quiet compared to most of the cars there!
i was expecting louder or atleast the same, but nope, no louder than a jag xkr IIRC
some further details:
Featuring a twin-turbocharged 6-litre V12 diesel engine, the concept R8 produces 500bhp and a whopping 737 lb/ft of pulling power eclipsing the V8 petrol-powered Audi R8 which produces 414bhp and 317 lb/ft.
This means a 0-62mph time of 4.2 seconds and a top speed at well over 186mph, marking the concept Audi R8 V12 TDi as the worlds fastest diesel sportscar.
The monster V12 engine the same unit used for the Audi Q7 V12 TDi is mated to a six-speed gearbox and the diesel R8 will feature Audis Quattro four-wheel-drive system.
But for those fearing the gorgeous Audi will have lost its appeal thanks to a diesel clatter, engineers at the Ingolstadt firm have said the R8 V12 TDi sounds full-bodied and is equipped with energetic overtones.
Official consumption figures have not been released, but Audi claims the diesel R8 will meet forthcoming Euro 6 regulations due in 2014.
The concept R8 is distinguished by a glass roof and engine cover, larger wheel arches, bigger air intakes, more pronounced side-skirts and an aluminium spoiler.
I wish someone would ask them "Does it sound as good as the 4.2V8, or the planned V10?"
Has to be the gearing....my current (diesel) is geared for 38mph per 1000rpm in 6th whereas my last equivalent petrol car was geared for about 28mph/1000rpm.
Obviously its partly a product of the diesel's inability to rev that high,but the very tall gearing will blunt the acceleration.
Thanks, does that therefore mean that the torque/power at the wheels is affected by the gearing?
For example 2 cars
Petrol 8000rpm max 180hp, 100 torques
Diesel 4000rpm max 180hp, 200 torques
Both cars geared for 80mph in 3rd gear at max rpm.
Travelling at 40mph
P has 4000rpm but gear ratio of 1000rpm:10mph
D has 2000rpm but gear ratio of 1000rpm:20mph
Would this mean that all else being constant/equal, both cars would accelerate at the same rate from 40mph?
You've got me there...my physics was never very good.
All I can say is that torque was explained to me by the race engineer who built the engine on my Cosworth as the single most important factor in midrange acceleration.
BHP he said does govern top speed,but it's torque that would allow you to outrun a potentially faster(top speed) car on a road where it wouldnt have a chance to use that.
Anyway...seemed to work!
Now of course I drive a diesel,and it's still amusing to see something "sporty" trying to keep up at times.
My 200+ bhp would monster your car off the line. Rolling in 3rd or 4th, I would not be so confident. The weight difference between the Audi and the Cupra would be cancelled out .
And my weedy 153 lb-ft will beat all of you at any speed up to 150mph
bikes are cheating
It's not a bike...
Now I remember, mr S2000 240 horses straight out the box
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