anewconvert

The article in question on wikipedia states that the engine was kept to a redline of 9000 rpms due to concerns of longevity during a 24 hour endurance race. It gones on to state that an engineer (doesnt state WHICH engineer) who worked on testing the engine stated that at a redline of 10500 rpms the engine was producing over 900 hp. Also stated that after LeMan they tore the engine apart and found it to be in almost prestine condition and capapble of running another 24 endurance race.









BC

j9fd3s

the last part i can corroberate. we had a chance to talk to koby in 01 or 02, since we were standing next to the 787, we talked about it, wear on the apex seals was .0004". he said it could have gone ANOTHER 24 hours

jwteknix

thats ******* insane

heretic

That's pretty impressive then, considering that, according to the SAE paper submitted by Mazda, the horsepower curve was nearly a straight line from approximately 405kw at 6300rpm to roughly 500kw at 8500, then flattening to 515kw at 9000. For it to build so smoothly, then taper off, then shoot up by over 150kw in the space of only 1500rpm is an incredible feat of engineering.



If the sarcasm isn't obvious, I believe the 900hp claim to be complete and utter bullshit.

The Ultimate 7

When you build a rotary with a dry full sump oil system, multi piece e-shaft, (which gives you additional bearing points to help keep the shaft from flexing) a lightened clearenced and balanced rotating assembly, ceramic apex seals, ceramic coated housings and plates, and an intake that allows the engine to breath at those stratospheric levels, you will get these kinds of results. I'm not surprised at all by the durability, however over 900 hp? That would mean a 2 rotor would have to make 450 or at least 400rwhp to be believable.

anewconvert

LIke I said, I CAN NOT corraborate the article, Im just reporting on what it said.



Straight from the wikipedia article: "Engine speed (RPM's) were deliberately kept low for longevity under the extreme stresses incurred during a 24-hour endurance race. The 787 was reported to have a redline around 9000rpm. However, interviews with Mazda's 787 race engineers revealed that the power of the quad-rotor increased dramatically above 9000rpm. One engineer stated that the car could develop more than 930hp with a redline around 10,500rpm. Engineers also commented that during the post-race inspection and tear-down of the quad-rotor engine they discovered that all aspects of the engine were still in excellent condition and could have run another 24-hour race"





Dont shoot the messenger.





BC

anewconvert

http://en.wikipedia.org/wiki/787b





Just for reference.



BC

j9fd3s

i think mechanically the 4 rotor's capable of higher revs, but there was also a big push to get the output from 600ish hp to the 750ish level

mazdaspeed7

Anyone can submit a definition to wikipedia, and generally, the definitions are not checked for accuracy. Take what you read there with a grain of salt. Mazda has released plenty of technical papers, with tons of great information in them.



The 787B won le mans due to its durability. Im sure mazda could have pulled more rpm's and more power out of the engine, but you cant argue that the engine didnt serve its purpose, and serve it well. I believe Mazda is still the only japanese manufacturer to win the fabled le mans 24 hrs.

heretic

Actually, it won due to its fuel efficiency. Anybody can run for 24 hours, anybody can run hard for 24 hours, but it takes a special something to run hard while being limited to a certain amount of fuel.



More fuel efficiency = you can drive it harder = you're faster.



Incidentally, the graph that supplied the power figures I quoted had two power curves. There was a "best efficiency map" curve and a "best power map" curve. I quoted from the best power curve, the best efficiency curve was roughly 30-50kw down on power.



Peak efficiency was at 6300rpm.