| Author | Message | ||
     Davegess |
A tubo XB now that is interesting. I could see it happening. How well would it work? The collector is pretty far from the intake which give more lag but don't those big cylinders push a lot of air at low speeds so that would give less lag. How about this for a setup? Twin turbos, one for each cylinder, mounted right up near the heads? then since turbos help quiet a motor they can make a lighter muffler so the HP gain goes againest virtually no weight gain. Lets here form all you engineers out there. dave | ||
| Sarodude |
Not an official engineer... Turbo + Aircooled Motor = Eventual Unhappiness Gonna deviate from the Harley world for a bit. Ever wonder why aircooled VWs were SO wimpy yet had SO much apparent potential? The engineers building those motors knew that cooling was a major limitation, so they RESTRICTED the engines power in its initial design. So, what about aircooled Prosche turbos and some aircooled turboed / supercharged aircraft? Well, they have baffling / ducting to help in CONTROLLING the cooling (as did the VWs). Some designs include either manual cowl opening / closing or thermostats to further control stuff. The Porsche's cooling fan could likely propel small jet aircraft (slight exaggeration). All that said, there's also such a thing as TOO cool or cooling too quickly. Now, I don't really have any experience with Harley types of motors, but the designs of all the engines mentioned above share many of the limitations of the aircooled pushrod V twin. They even have the benefits of additional, uh, technologies to CONTROL the cooling. What do we have? 2 cylinders that sit in dirty air - one behind the other. Most guys (myself INCLUDED) can't even tell you what proper CHT should be for the front or rear head. What I've learned is this: You can make all the power you like. How LONG you can make that power and how many abusive heat cycles a motor might tolerate may cause you to build that same motor over a few times. For a PRODUCTION type vehicle, it would likely lead to many headaches for the manufacturer. -Saro | ||
| Blake |
Saro... Notice the new airflow considerations going on in the XB9R? | ||
| Sarodude |
Blake- I haven't read anything truely informative regarding the XB. I remember reading something about a fan arrangement - but such things aren't usually the meat and potatoes of a "Kewl Stuph" type of article. What ARE the airflow considerations, anyway? -Saro | ||
| Blake |
Try reading all the observations within this thread. A few... Extensive ducting keeping the rear cylinder near the same temp as the front. I saw posted somewhere here the actual temperature difference and it was impressively small. Also the forced air fan cooling to aid engine cooling in still air. Also the improved design of cooling fins. Greateer volume of engine oil. An oil cooler. Others...?  | ||
| Paulinoz |
When on the factory tour de force we got quoted less than 1 deg difference front to rear cylinder. | ||
| Court |
I'm certain they'll do it with displacement instead of rpm. | ||
| José_Quiñones |
Turbo? Well since Porche is helping out HD, I could see their expertise being shared with Buell for a Turbo Air cooled motor. But I have two problems with that: HEAT: Can you say nuclear meltdown? You would need an oil cooler the size of the VRODs radiator to control the heat, or enough fans to make the bike capable of taking off vertically like a V22 Osprey. You could hide the radiator and the fans in under the tail but that brings me to the second problem: PACKAGING: Where do you hide this/these turbos? If you do it like Dave said, two little turbos near the heads, the bike will have to be taller, raising the center of gravity and probably the seat height, which means I won't be able to put my feet down! The Firebolt is pretty tightly packed, anything you do to stuff something else in there will change the center of gravity/mass centralization etc. Not to mention you would have to increase the V angle to give yourself space for the extra plumbing, which would probably hurt the front/rear weight bias. So added complexity/heat + packaging problems = just say NO to turbos! __________________________________________________ Ok, That article in Roadracing World about the XB9R was very interesting, as now everybody knows that it takes 7 Highly Modified Buells to beat one "closer to stock" Ducati 748! I believe that Tilley's bikes displace 1340 cc, the maximum allowed in the class. So that might be a 3 13/16" bore with a 3 9/16" stroke, probably spinning at 7500 rpm, as any much more than that and the bike will explode with that stroke. | ||
| José_Quiñones |
But hey, I could be completely WRONG! But Imagine an HD tech at your local dealership, first comes the VROD with Liquid Cooling, valve adjustments, ect, and now a turbo Buell? He'll have a heart attack! | ||
| José_Quiñones |
Aerocharger for Buells/Sportsters How do you hide that? | ||
| José_Quiñones |
Ok I agree with Court & Aaron, they will do it with displacement. If an XB9R generates 92 HP out of 984 cc, that's 93.5 HP per cc of displacement. How much horsepower do you want? 125? then you need 1332 cc. What displacement do the Tilley bikes currently run? 
Coincidence? I think NOT. Now this is a race bike, so the street version will probably have 105 HP at the wheel after the EPA is done with it. | ||
| José_Quiñones |
If you haven't already go out and BUY Cycle World's Power& Performance Harley-Davidson which has no Buells at all on the Cover, but features a great interview with Don Tilley, a review of the 6 speed baker transmission, and a very technical review of the XB9R. here are some nuggets to think about:
Hey Aaron, sounds like they stuck a KrankVent inside the engine, eh?
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| José_Quiñones |
Back on the turbos, looking at those pictures it becomes obvious where you would hide all this stuff, under the engine where the muffler used to be! | ||
| Blake |
But José, do the Aerocharger units require "an oil cooler the size of the V-Rod's radiator"? Let's give Buell a little credit here. If Aerocharger can package a reliable turbocharger on a bike that was never designed to carry one, I'm thinking that the designers at Buell, if they so choose, will be able to do the job from the ground up with exciting innovation and artistic integration. Reliable turbochargers have been around for a while now. Keeping exhaust heat in the pipes is no big trick either. A little intercooler, some ceramic coating and maybe even some adeptly placed insulative wrap, and you are good to go, nice and cool. Just some food for thought. Blake | ||
| Imonabuss |
Jose, The "close to stock" Ducati is a $30,000 race edition with factory engine, probably worth another $20,000. If you want to see how true privateer Ducatis run against privateer Buells, check out the success of Innovative Research's Michael Barnes did against 748's other than Nash and Montano. At Daytona he was in 5th place until he ran out of gas on the last lap. The other fast Ducati of Jeff Nash is not running because he fell off and was hurt at an earlier race. I had to laugh when I saw that his "privateer" Ducatis that were racing against the "factory" Buells are up for sale on AMA Superbike.com by Ducati North America as factory bikes. Ooops, a little miscommunication between the factory PR guys and the bean counters at Ducati. By the way, when Scott Zampach used his one Buell RR-1000 to beat a field of Ducatis for the CCS National Championship years ago, the Ducati riders protested to the AMA and got the rules changed from a minimum of 50 bikes homologated to 200. Since there were only 50 RR's, that guaranteed Ducati could get back to their winning ways. It truly shocks me to see now that Buells are truly running against the Ducatis (7+ time World Champions), we owners beat up on the company, deakers and racers. I believe this is the inherent American tendency to believe everything we do is inferior. It makes me sad for the racers, dealers and factory, who are trying so hard to do a great job and please the fans. |
