| Author | Message | ||
     José_quiñones |
148 hp at 15,000 rpm? Impressive considering where it started:  | ||
| Blake |
JQ, Not sure the peak HP is at 15K, just that the bike is capable of spinning to 15K rpm reliably for more than race length duration. Yes it is impressive, but no more so than what we are likely to see from the IL4's or hopefully, the Buells. Since the announcement of the new 749, Jeff has been extremely excited about the racing prospects for the Duc middleweight twin in classes that permit performance head work and the like. The heads of the 749 are much more suited to performance enhancement and racing than the old 748 heads. I should also clarify that I (dumbass) failed to get clarification on whether the 148HP was at teh crank or rear wheel. Racers though are almost universal in referring to HP at the rear wheel, so I feel safe in assuming that it is indeed rwhp. That and knowing that the 999 factory racing machines are making near 200 HP. Interesting side note. Jeff was on crutches with a cast on his left foot/ankle. I asked if he had been out on the track again. He sheepishly confided that the injury was a result of a skateboarding spill. | ||
| Blake |
I also asked Jeff about the eventuality of AMAPR allowing the Duc 749 into the Supersport class. He replied in an exasperated tone that "They will never allow that to happen." I was shocked. I pryed further but it was clear that he was not willing to divulge specifics other than to name two names, names of individuals at the very top of AMAPR. Draw your own conclusions. Keep in mind also that Jeff told me last year that he agreed with Erik's statements from his heated interview with RRW on the frustrations with AMAPR management. But hey, maybe FX will rise up and relegate the SS class to a backseat third tier support class. I still don't see supebike going away as the premiere class. Oh one other interesting thing that Jeff mentioned. He said that he was astounded at the initial Superbike class rules proposed, that they included no provisions whatsoever for maintaining parity between twins and the new class leading IL4 literbikes. He said that it was obvious that AMAPR management had no interest whatsoever in maintaining twin cylinder bikes in Superbike. Jeff along with others had to fight hard to get the rules in place for 2004. He feels that they are fair and equitable, more so that any in recent history. I mentioned that Mladin didn't feel the same way. We all had a good laugh about that and Jeff made a comment to the effect that Matt will need some excuse when Eric Bostrom is kicking his ass next year. I'll be watching with much interest. Oh, I meant to respond to another assertion made here concerning my prediction that in 2003 the GSXR1000 would walk away with the championship or win all the races or some claim along those lines. I did predict that, yes. It largely came to pass. The only losses suffered by the big gix were attributed to tire failures. The tire failures were in turn attributed the the massive increas in HP that the big gix was dishing out. I'm confortable in the accuracy of my pre-season assessment JQ. Considering the honest results of the season, to argue against the overall dominance of the big gix in AMA Superbike is a bit, well, ridiculous isn't it? | ||
| José_quiñones |
You're moving the goal posts, Blake. You predicted they would not lose another race. They did not win them all, so your prediction was incorrect. Simple, really. Did you ask Jeff why he voted against dissolving the AMA Pro Racing board when he had the chance at Barber? Did you ask him how Ducati manages to get an engine with a 54mm stroke (the 749R) to spin reliably at 15,000? What's the piston speed for a 54mm stroke at 15,000 rpm, Blake? | ||
| Jscott |
It looks as though Formula Extreme is going to be the coolest class next year - What's the word from Buell? Is Hals, Kosco, or Tilley's going to participate? | ||
| Blake |
Yep I was wrong again. Pitiful is me. However pitiful my powers of prognostication might be, the fact remains that the big gix was woefully dominant in 2003 AMA SBK once the racers and Dunlop figured out a way to make the tires hold up under all that HP. That just ain't debatable. Now this year there will be another IL4 literbike, and it, the CBR1000RR, is looking to be a possible contender with it's dual injector stock throttle bodies. But if Mr. Nash is happy with the rules, then I'll keep the faith that a liter twin without the stock throttle body restriction will be able to challenge the liter IL4's in AMA SBK. Go Ducati! Go RC51 racers! Can you believe that I forgot about the dissolving the board question, I was stricken with momentary senility, but I sure did want to ask him that. I knew there was a question I needed to ask him about one of his votes, but my brain froze up on me. I'll definitely ask next time I talk to him. As to how Ducati achieves the amazing performance that they do out of the 749R factory racing machine, I have no idea. Probably an extremely well ported set of heads, high compression pistons, well tuned/balanced cams and exhaust tract, and of course that wonderfully efficient desmo valve train. No I've not calculated piston speed for a 749R at 15K rpm. You think Jeff is mistaken? I heard the 998 and 999 Superbikes were spinning near 18K rpm. I would NEVER bet against the powertrain engineers at Ducati. Them's some smart fellers. Happy Thanksgiving. | ||
| José_quiñones |
Thank you, hope yours went well too. You may or may not know this, but most pistons have a hard time surviving anywhere above 4500 ft/min average piston speed. You like math, go figure out the piston speed for the stock 749R stroke of 54mm, at 15,000 rpm, then tell me if it's possible to run the pistons at that speed "all day" as Jeff claimed to you. The only reason their MotoGP bike can rev over 16,000 rpm is because the stroke they are using is extremely short, about 45mm. To compare, the stock stroke for a 999R is 58.8mm and it redlines at a little over 11,000 rpm. If your excuse then becomes that they must be using a shorter stroke engine, then they could not put that particular engine in a 749R for World Supersport or AMA FX because the rules require stock bore x stroke for liquid cooled twins, so don't go there. edited by josé_quiñones on November 28, 2003 | ||
| S320002 |
The Math: 54mm/25.4=2.13" x 15,000rpm x 2 strokes per rev=63,800" per minute/12" per ft = about 5,317 ft per minute | ||
| José_quiñones |
The Buell equivalent would be to spin a stock 3.125" stroke XB9 engine to 10,250 rpm and live to tell about it..... | ||
| Blake |
JQ said (on another thread)
Your attitude is unfortunate. Let's deal with the facts shall we?... What is the piston speed in a NASCAR engine. You know, the ones that can run flat out for 600 miles in the middle of Summer? JQ, 5,000 fpm mean piston speed is the norm for racing engines these days. 5,317 fpm certainly is not outside the realm of possibility, especially for Ducati. These are racing engines, not street engines that are expected to run without incident over the course of years and years and miles and miles of variable operational conditions. The Buell engine even in racing form has other issues to overcome besides piston speed limitations in trying to achieve engine speeds approaching the level you mention. | ||
| M1combat |
Didn't Ducati have help from Ferrari on the 749? I don't know what the stroke of the F2003-GA V10 is, but I'll bet it's piston velocity is bleeding edge at the least  ">. edited by m1combat on December 03, 2003 | ||
| José_quiñones |
My attitude? I copied your response to Rocket on the other thread! Look, until we see an article somewhere explaining how Ducati has their 749R achieving "all day" higher average engine piston speeds than their MOTOGP bike, you have no credibility in this area. 5,317 feet per minute average piston speeds are unheard of outside of top fuel drag racing, for good reasons. | ||
| Blake |
Jeff Nash told me that Ducati has their 749 racing machine putting down 148 HP and revving to 15K rpm reliably for extended periods, his words were "all day." I repeated the number somewhat incredulously, "fifteen grand?" He confirmed it. That is good enough for me. That kind of info is likely proprietary information that only a select few are privy to. He was kind enough to share it with me. You are free to believe as you wish. What are these "good reasons" JQ. Please enlighten me. | ||
| Blake |
RE: Your dyno plot above. Why not post a dyno of a stock GSXR750, then exclaim how impressive it is that in Superbike form they make 180 HP? Racing engines are not street engines. They spin faster, breath deeper, and pull harder and include all kinds of tricks to reduce parasitic HP loss at high revs. From the stock 12K rpm on the 749R to 15K rpm is a 25% increase in engine speed. What is the stock rev limit of the V-8 engine in a stock Chevrolet? What is the rev limit of a NASCAR racing engine? Way the hell more than 25% greater than the stock engine. No? Now, granted the 749 was designed from the start to support a racing platform unlike the Chevy V8. I believe Jeff. | ||
| Benm2 |
Buell PT Bike, 3.6" stroke, 5317fpm = 8860 rpm. RRW article said shift point "somewhere around 8000 rpm". It's 4800fpm at 8000rpm. It's 8370rpm with a stock-stroke 1200, and over 10,000 rpm for an XB9R motor. Anybody shift at 8370? If Ducati & NASCARzzzz.... sorry dozed off there. If they can hit 5317fpm, and the Evil Empire can, Buell will have their hands full in FX. | ||
| Blake |
I agree. A Buell team will indeed have their hands full trying to compete against a full blown HRC team and others. It sure will be interesting though. I'm not expecting miracles the first year. | ||
| S320002 |
"5,317 feet per minute average piston speeds are unheard of outside of top fuel drag racing, for good reasons." A NASCAR engine with a 3.5" stroke running at 9,000 RPM would average 5,250 FPM. 5,317 FPM piston speed is not unheard of or even that unusual in racing engines. | ||
| José_quiñones |
According to the original Road Racing World article, Mike Ciccoto shifts his XB1350R at 7500 rpm, or 4500 feet per minute. Now back to the 5317 feet per second 749R: Ducati's own MotoGP bike does not reach these piston speeds. Ducati's website mentions here an average piston speed of 25 meters per second, or about 4920 feet per minute. Impressive, but not quite the 5,317 feet per minute Blake/Jeff are claiming for the racing 749R. | ||
| Blake |
JQ, Okay, so you are saying Jeff Nash is a liar? If so, I strongly disagree. And you are basing that on information taken from statements that are prefaced with the likes of...
Nascar can do it, but Ducati cannot? Right. It is a racing engine. I don't think you comprehend the difference between a racing engine and a street bike engine. Same as the difference between running 20W50 and 0W oil. | ||
| José_quiñones |
I understand the difference just fine. I also understand the difference between a development engine spun on a dyno and an engine in an actual road race bike designed to last a full race. Those don't reach 5317 feet per minute piston speeds. When the World Supersport season starts next year, we'll find out how high the Factory 749R revs to, my bet is that it will be around 13,500, not 15,000 rpm. | ||
| Blake |
The 749 racebike that Jeff told me about wasn't just run on a dyno to 15K rpm. It was per Jeff, run all day around a track, I think he said in Germany. I don't know where the rev limit for the 749 will be set. I just know that Jeff Nash told me that the factory 749 racing machine has been run on a track, "all day" at engine speeds up to 15,000 rpm. You want to take issue with Mr. Nash, I suggest you talk to him yourself. I for one, have absolutely no reason to doubt him. He is an honest man as far as I can tell, and everyone else that I know who also know him speak very well of his integrity and character in general. The bottom line is that 5317 fpm is nothing unheard of in a racing engine, especially for a Ducati racing engine. What does the 999 superbike engine spin too? I believe it reportedly revs to 15K as well. Same stroke no? If so, it too reaches the same piston speed no? But that's impossible cause you say so? Ask Steve Madden (Steve2) what his latest performance endeavor does. What would a 4.25" stroke at 8200 rpm net in piston speed? You conveniently ignore the NASCAR data. Surely if a pushrod racing engine can endure 600 miles of 5000+ fpm piston speeds, Ducati can achieve the same for less than 300 miles. | ||
| Featheredfiend |
"Same stroke no?" No. 58.8mm vs 54mm for the 749r I think JQ is spot-on with 13.5k. At 15k "all day" the question won't be piston speed but the valve train. feathered | ||
| José_quiñones |
Now you lowered that to 15K, ok fine. The info I have says that they only rev to 13000 at the World & Brittish Superbike level. | ||
| Turnagain |
Whoa there Vern! You've got me confused w/ Steve Madden (smadd) or some other gear head -- I just like shootin' sheet w/ my cam.  edited by turnagain on December 09, 2003 | ||
| Blake |
Steve, My bad. I'm terrible with names, and apparently with numbers too. He just posted the other day about sharing his info when he returned home. Who was that? Oh well, I probably shouldn't be blabbing about it anyway... 210 rwhp S1 Okay JQ, the only number I'm sure of is the one that Mr. Nash provided. However, if a bigger bore longer stroking 999 racing engine is setup to run at 13000 rpm (5016 fpm), it sure doesn't seem like much of a leap to make a smaller bore, shorter stroke 749 version of that engine run an additional 300 fpm, just a 6% increase. Why is that so unbelievable? You seem to think that there is some mystical limit to mean piston speed. There isn't. It is limited by stresses, stresses that are induced by mass, the masses of the piston and the rod and the crankshaft. It is limited by strength, the strength of the piston, rod and crankshaft. Decrease one, increase the other and you can increase the allowable piston speed accordingly. It isn't a one to one ratio, the stresses induced by inertial forces increase proportional to piston speed squared. So to double piston speed one would need to quadruple strength or quarter mass or some combination of the two. Racing engines typically use the very lightest and strongest materials and parts conceivable for the engine's top end. I wouldn't be surprised if Ducati is using metal matrix composites, fiber reinforced ceramics, or even some exotic carbon fiber polyemide composite material to fabricate their racing engine connecting rods and other top end components. That could save a LOT of weight and still provide excellent strength. Duc runs a desmo valvetrain on their MotoGP bike which is rumored to spin well above 16K and supposedly to 18K+, so I wouldn't think the valvetrain is the factor limiting the 749 racer's rev limit. | ||
| Turnagain |
That could've been me -- just got back from Florida where I shot the (what I like to think of an) S3, but I'm not good with numbers either. (wonder how it'd do on a road course  )  you two carry on, but play nice as I know y'all just enjoy the hell out of a good debate. Steve(2) | ||
| Featheredfiend |
"Duc runs a desmo valvetrain on their MotoGP bike which is rumored to spin well above 16K and supposedly to 18K+, so I wouldn't think the valvetrain is the factor limiting the 749 racer's rev limit." Is it fair to compare a GP motor to a SBK just because they're both Ducatis? Do not believe they share the same valvetrain geometry. The GP has a 16k rev limiter. Knowing how poorly the 748r's valvetrain held up, it would be a quantum leap for the 749r to maintain 15k "all day". I'm skeptical. feathered | ||
| Sportsman |
Moto GP is a place to try anything. I'm going to go with, they must of learned something. Just wish they'd teach it to HD.  | ||
| José_quiñones |
Except for the small detail that the World Supersport rules don't allow any of that fancy stuff if it's not stock on the bike, you would be correct. The 749R does have titanium valves, guides and connecting rods, which help it to rev faster and higher, but I still don't think you'll see the Factory WSS race bike rev up to 15,000 rpm when it hits the track. We'll just have to wait and see. The reason the MotoGP bike revs past 16k is because the stroke is around 41mm. | ||
| Blake |
The conversation was concerning Ducati's possible participation in AMA FX. Yep, but I only brought up the MotoGP engine speed, and I'm sure it can rev to well over 16K, to counter the claim that valvetrain would limit the 749 to less than 15K rpm. We are al kidding ourselves if we think we actually know the rev limit of any of these high end racing machines, especially MotoGP machines. That is likely highly guarded confidential information. They may tell us a number, but that is not likely the whole story. I wouldn't be surprised if the Duc MotoGP bike is capable of reving well past 16K rpm. I see Guzzi is running some tests trying to decide if they can make a go in FX. I hope they do. Still no word on Buell or Ducati participating though. Jeff Nash said he would need a minimum of a half million dollars to make a serious run in FX. It's going to be extremely tough to beat some of the top names and especially the HRC/Duhamel contingent in FX. Seems awfully strange that Honda would forego SS in favor of FX. |
