Some time ago we talked about race engines and why manufacturers preferred using gasoline to diesel. Diesel provides more energy out of the same amount of fuel than gasoline, yet we speculated that due to its longer molecular structure, it takes longer to break down and hence is not practical for race application where high revving engines are the norm.

So here comes Audi, with their newly developed 5.5 litre twin-turbo V12, yes, you guessed it, turbo diesel. It produces its peak power betweek 3,ooo and 5,ooo RPM, outputs 650 bhp, and 810 lb-ft of torque.

Not only did their car win 6 of the 7 Le Mans races, they reported of great power delivery and exceptional fuel economy. What else is interesting, is that this engine is reported as being VERY QUIET compared to gasoline counterparts. Didn't the tides turn, diesel quieter than gasoline? Of course, revving betweek just 3 and 5K while racing has much to do with this, I'm sure, as well as silencing that the two turbos provide.

Their challanges were to beef up transmission to handle this amount of torque, and during the last race, one of the Audi cars had to be pulled in, where transmission was replaced in 10 minutes.

Just more FYI, that indeed it is possible to use diesel-powered engines in race applications.

Some links:

Info on the car from Audi

Article from BBC on Le Mans race results

Excerpt from the article:

"Audi led every lap as the diesel cars, as expected, enjoyed greater fuel economy but also proved quicker than their petrol-powered rivals."

 

My guess would be that some of the rules might be rewritten regarding diesel engines in the seasons to come at Le Mans. Right now, diesel engines seem to get some breaks regarding their gasoline cousins. Someone correct me if I am mistaken, but doesn't the Audi car have more of a fuel capacity over its other P1 (I think thats the class it runs in, if not P2) gasoline counterparts? Does that not seem strange?

 

ACO regulations for the 24 Heures du Mans for 2006 shows the following:

Supercharged Gasoline engines with more than 2 valves per cylinder:
Max displacements: 4000 cc
Maximum supercharging pressure: 1500 mbar
Air restrictors: 45.3 / 32.4
Fixed internal turbo geometry

Supercharged diesel engines:
Max displacement: 5500 cc
Maximum supercharging pressure: 2940 mbar
Air restrictors: 55.9 / 39.9
Variable internal turbo geometry allowed

 

Its amazing what an additional 1.5 liters of displacement, twice the boost, less restriction, and more advanced turbo's will do to an engine.

 

No kidding.

 

... and at the same time delivering better fuel economy

The thread was posted more as FYI, like I said, to show that diesel does or can find its way into racing.

 

Then I think we should include the Gale Banks engineering race Duramax's in the discussion!

I wonder what the Duramax could do in the racing series?

 

*What* racing series is the question. I think we can safely say that Audi's LeMans oil-burner is just a wee bit lighter than the 'max. I'd love to see GM field a serious racing diesel prototype, though - maybe as the centerpiece for a revival of the Caddy LeMans program.

I'm fine with racing rules that tilt in favor of new technology, because I'm getting damn sick of seeing a bunch of incremental improvements to race-only gassers that stand little chance of making it to production vehicles. It's time to see some real innovation in racing, which in my opinion is sorely lacking (it's said when the parking lot outside of many/most motorsports events contains more technology than the vehicles on the track).