The current issue of RACE TECH magazine (Issue 64) has a most interesting article about F1 engine performance factors with information from Axel Plasse, the project manager for Renault’s RS25 V10 (2005) F1 engine. He discusses peak power vs. area under the hp curve with real numbers on how it affects car performance. Even though the engines run in the 15,000-19,000 rpm range, the curves look very similar to what we see at 1/3 those revs. Unfortunately the absolute power numbers are in percentages, but that is just re-labeling the y-axis.

The main point was that peak power is not always the Holy Grail even for F1. Sure, that’s what folks quote, but Plasse explains how an engine with 25 less peak power (about 2.7% of total), but with a flatter peak area gave the same lap times at Barcelona testing as the +25 hp peaky engine. Similarly, a peaky engine with the same peak power (but less area under the curve) was 0.45 seconds slower. To get the same lap time with the peaky engine, they had to run it 750 rpm faster where it had 33 more hp.

Here’s a quote:

“On average, every percent of power you gain is worth 0.12 seconds (per lap). You can also have in mind that 10 hp is a bit more than 0.12 sec. or 1 hp is a little more than 1/100 of a second.”

Standing start performance is related to “low” rpm torque, as you might guess. While they don’t do 60 foot times, they check time to speed (0-60?) and distance after four seconds. With a an engine that was 2-10% (depending on rpm) more “torquey” below 12,000, but the same above 12K, the car was about 33 feet (nearly 2 car lengths) farther ahead in 4 seconds. Perhaps this accounts for Renault’s great starts during the last seasons.

Interestingly, hard acceleration in first gear gives 6,000 rpm/sec engine acceleration. I’ll bet it takes a good dyno to find that 10 hp lost to inertia at that rate. They did say that they ran about 23,000 miles in track testing and about 92,000 miles of dyno testing during a year! That is more than 250 race miles per day, every day on the dyno(s).

There are many more interesting aspects of engine/chassis/driver discussed. All in all, it is a good read. The cover has silver Audi R10 diesel LeMans car on the cover. Barnes & Noble usually carries the mag.

 

Sounds like a good read!

 

Great... I could have used that for my flight pops! Guess I can check it out when I get back in town.

 

What if you take the area under the race-usable hp curve for each gear for each section of the track. Highlight only 15-16k rpms for 4th gear, if that is what you are actually running and that specific point on the track. Then mutliply it by the time you spend in that gear.
Then do that for each gear at each section of the track and each gear. Then add them up and tune the car to get the highest number.
Would that work? While watching TV I've seen some fancy looking screens and graphs on the laptops the crues use so I'm guessing they have a bit more advanced equations taking torque, turns, and traction into consideration.

 

That's basically what can be done. You then throw in aero and friction drag, grade and traction, track and air temp, gear change time, along with engine torque curve, vehicle weights, perhaps every few kilos (a gallon of gas weighs just under 3 kilos) among MANY other factors, and plug it into a very sophisticated program in some very powerful computers, you could get back gear ratios, shift points, areas where you need to "torque manage", and tons of stuff we can't even guess at. You could then plug in the different engine torque curves you have available to see which works the best. Couple that with having to run the same engine at the next (or last) race, and figuring in the degredation of power as the engine approaches it's 1400 km design life (which might be 5%), and it gets trickier. $200-$400 million budgets allow (force?) you to do this kind of stuff if you want to run near the front.

Imagine a wind tunnel with just the airscoop sticking up into it with the car under the tunnel on a dyno so you can accurately measure hp @ 300 kph. It's being done.

"Development and testing expands to fill the available money."...with apologies to C.N. Parkinson

 

Huh, I didn't think about engine life.
As unrealistic as it sounds, I'm kind of suprised no one has built a hydraulic platform (like airplane simulators, or fancy video games) and stuck a dyno on top of it. You could stick that in a wind tunnel, and maybe change the the temperature in there, and maybe control the air pressure by how much air is able to leave the wind tunnel

edit: This company has a dynamometer that shakes for testing on big vehicles.
http://www.vss.psu.edu/H2VRC/h2vrc_s...ynamometer.htm