| Author | Message | ||
     Xbolt12 |
Why is it that I still haven't seen a single dyno result of an xb12 that surpasses stock levels by any significant amount? I check the KV and all I ever see are the tuber results from 50 years ago or a few xb9 results. Is it that the 12 just can't put out any hp without the race ECM, or is simply that nobody has the money for dyno runs? Frankly I am beginning to suspect that an xb12 even with porting, cams, TFI, and exhaust still won't improve much at all. Still wondering if it's time to defect to Ducati..... xbolt12 (bored gearhead who doesn't want to waste anymore time searching the KV for no-existent information) | ||
| M1combat |
I posted one that indicated I think 90 at 6000RPM with a Drummer, PCIII and chopped airbox... | ||
| Typeone |
I'll have dyno runs posted after next week for my 12, just made an appointment today. I'm more interested in finding out more clues to my ping under load than HP/TQ numbers but I'll post what I get. The bike will be setup with the following... Drummer, K&N, no snorkel, stock inner airbox, re-routed breathers, race ECM and TFI with settings of 4--8:30--6--8:25 | ||
| Jerseyguy |
Xbolt12 go to http://www.badweatherbikers.com/buell/messages/3842/144656.html?1126282942 I have posted this chart on no less than 5 threads. | ||
| Rageonthedl |
and i have posted my Bikes Dyno many times | ||
| Fullpower |
the two limiting factors with the twelve are: 1) throttle body size 2) rev limiter without addressing these two issues, horsepower is not going any higher. | ||
| Wheelsleaning |
I'm trying to find a dyno in Austin with O2 sensor. Harley of Austin wasnt much help. I still need to dial in my Techlusions. | ||
| Buellerx |
Tq x rpm / 5250 = HP 78 x 6800 / 5250 = 101HP 78 x 7200 / 5250 = 107HP 78 x 7800 / 5250 = 116HP HP isn't a measure of anything really. It is a formula that calculates torque over a given RPM range. That is how the Japs sell the new inline 4's to the squids every year. They raise the RPMs using lighter and cheaper parts. Then they claim MORE HP FOR 06'. People too stupid to know any better run out and buy the "latest and greatest" RR, GSX, ZX or whatever it is this year. Then they are surprised when I beat them off the light. What they don't understand is that unless you increase Torque you are not getting more acceleration, just more top end speed (where it isn't needed on the street). If you get 77ftlbs of tq and near 100HP at the wheel on a Buell, you will be able to out accelerate most bikes up to about 80MPH (although that isn't true for a lot of the new liter bikes). Unless you change the gearing or raise the RPMs on your XB, you will never see anymore top end speed no matter how much HP the dyno sheet says you have. All you really stand to gain is acceleration (which you already have plenty of). | ||
| M_singer |
Buellerrx, You are wrong when you say that HP isn't a measure of anything. HP is actually much more meaningful then torque. The torque numbers from a dyno run are nothing more then the hp that the motor puts out a 5252 rpms. Take one engine that makes 100 hp at 12000 rpms like a Jap 600 super sport. Then take a Buell that makes say 90 hp at 6800 rpms. The gears ratios of the 600 will multiply torque more then the Buell gears will. The 600 will put MORE torque to the rear wheel then the Buell will! It is NOT torque at the crank that accelerates the bike. It is torque at the rear wheel that accelerates the bike. Peak torque at the rear wheel for any given road speed will always be when the motor is spinning at the peak HP rpm NOT the peak torque rpm this is due to the torque multiplication due to gearing. Torque is multiplied by the transmission and drive sprockets. Motors that spin faster can take advantage of greater torque multiplication through gearing. If you geared a Buell like a jap supper sport your top end would be around 65 mph. You would be on the rev limiter in top gear b/4 you were going fast enough to get a ticket on the interstate. In other words if your Buell is running at 60 mph with the tach at 6k rpms and a jap bike is also running at 60 mph with the tach at 12k rpms the jap bike’s gears will be multiplying the torque by twice as much as the Buells gears will be. The Buell needs double the torque at the crank just to keep up with the higher revving motor Bottom line more hp = more rear wheel torque. Diesel engines make tons of torque, but they are not very fast. I’m not trying to beat up on Buells. I test rode an XB12s last fall and it would be my favorite bike in the world for the twisty roads that I ride. The power delivery is great for mountain riding which is what my understanding is that Buells are all about. I’m here to learn more about Buell’s b/c some day I hope to own one. Not to be smart or anything, but have you ever rode a late model jap sport bike? I suspect that you have not. | ||
| Dana P. |
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| Buellj79 |
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| Dagwood |
Can soul be measured on a dyno? | ||
| Nevar |
Yo Dag! Can soul me measured at all? Tim in Tucson | ||
| Nevar |
I was just out in the garage and my 03 XB9S is sitting next to my 04 Duc ST4S and I think the XB9S is a better looker than the Duc - and it's worth about 1/3 what the Duc is worth. The XB9S is a FINE lookin bike! Tim (Message edited by nevar on September 21, 2005) | ||
| Bayview |
You don't ride a spec sheet. | ||
| Dagwood |
Tim, They say that when you die your body instantly loses exactly 28 grams... I wonder how much weight is lost every time a squid dumps his yamahondakawazuki. LOL (Message edited by dagwood on September 22, 2005) | ||
| Xbolt12 |
Ok, I agree with you guys about all the qualities of the Firebolt and xb's, which is why I love mine. The problem is I've been to the track and had pin it everywhere to not get left behind on the straights and even on the street I am often pushing the engine to its limits to get decent acceleration and frankly the power is getting a little boring (riding with the throttle pinned a lot of the time). I just would like to see some mods that are street-able and not make the motor grenade and put out rwhp figures in the 100-110 range (ok more torque if you must  In other words, mods worth the money for more than noise an a little power. This must be possible because some of the race bikes have it. However, I have heard a lot of talk of big-bore kits, phase three heads, etc, but not many (any?) dynos to back up the results. Whats really odd is that the people selling cylinders, etc post some impressive tuber hp figures in that range. Maybe Fullpower is closest to the truth. However, if torque increases in the engine then of course so would hp at a given rpm.... | ||
| Buellerx |
I have been wrong before but unless I am missing something it looks like the Buell puts out more tq at the wheel. It also looks like it makes more HP until it hits redline at which time the 600's pass it because they are able to rev higher.    XBOLT12: My point wasn't that HP doesn't mean anything. What I was trying to say was unless you change the gearing ratio or increase the RPM before redline, you will still be hitting the rev limiter. You will just hit it faster when you increase the power. A bike the will do 160 in top gear is still going to walk away from you on the straights. My understanding from talking to one of the guys at Hals is that their race bike revs to around 8000RPM. How they keep it together at that RPM I don't know. | ||
| Alex |
There were two things mentioned to be the limiting factors: 1. rev limiter This one is true when considering two other things: first You talk of limits in gains in top speed, not horsepower (I can make a Buell engine put out more horsepower at the same rpm). Second Your bike hit the rev limiter in top gear. If Your bike does not because it lacks of power to hit the limiter in top gear You will surely find some more mph with more horsepower (at least until You found enough to hit the limiter). 2. throttle body size: forget about that. The size is way enough to feed at least 110 horses at the wheel. I normally do a Stage I head job (stock valves, ports reworked, combustion chamber reworked), combine it with a FAST intake system and a more free flowing muffler to get above 100 rwhp. No need for hotter cams or big valves. You want a dyno sheet? Sorry, I only trust in my flowbench sheets and the customers´faces when they come back from a test ride.  Best regards Alex M-TeK Engineering | ||
| Nevar |
They say that when you die your body instantly loses exactly 28 grams... Hey Dag! Isn't there a movie with that theme? I've had bikes with way more power than my XB9S and I could never come close to using it. And even with the lower power of my XB, I still can't use it. I salute the riders who can push these bikes to their limits! Tim | ||
| M_singer |
Xbolt12, IMO it sounds to me from what you are saying that the Buell isn't the bike for you. You are not going to get the kind of hp from a buell that you are from a jap liter bike, and if that is what you are after then maybe you should consider one. I ride a Bandit 1200 which has the original Suzuki GSXR air oil cooled engine in it with milder cams, lower compression and a displacement increase from the 1127-1157. The bike makes about 100 hp and 70 something ft-lbs or torque in its castrated stock trim. I added a jet kit and full exh system and it now makes 120.5 hp at about 8250 rpms. It wouldn't be hard to get it up to 150 hp if I wanted to. Just drop in GSXR cams, bore it to 1216 and drop in 10.5-1 pistons and do some head work. Buells just don’t have that kind of easy power gains to be had. I don't bother with more engine mods b/c it already has more power then I could use on the tight twisty roads that I ride most. I would be faster on a Buell due to the lighter weight and quicker steering etc. I think that the Buells have tremendous Soul and character and while they are not impressive on paper they are much underrated as back road weapons where being fast isn't about big hp. Like someone already said we don’t ride on a dyno. | ||
| M_singer |
Bullerx, You are missing the point probably b/c I didn't do a good enough job explaining it. Below is an excellant web page that I am sure will make the hp & torque clear http://vettenet.org/torquehp.html After youy read the above you will understand why it is better to make torque higher in the rpms b/c you can then take advantage of gearing to produce more rear wheel torque at any give road speed. HP is how much work can be done in a period of time. The more hp the more work you can do in any given period of time. It is not an arbitrary formula. You are only doing "part" of the math my freind. Please take the time to read through that link for the rest of the story. Oh BTW my bike makes over 80 ft-lbs of torque. (Message edited by M_Singer on September 22, 2005) (Message edited by M_Singer on September 22, 2005) | ||
| M1combat |
Well... the dyno's in question measure HP at the rear wheel. The gearing and RPM's don't matter squat. 100HP at the rear wheel is 100HP at the rear wheel. 100HP is capable of accelerating a certain mass to a certain velocity in a certain amount of time. That doesn't discount the benefits of torque multiplication though and yeah, for a race track, a high revving engine is typically a better choice (although not ALWAYS, check out the FIA GT Championship...). http://corner-carvers.com/forums/showthread.php?t=24722&highlight=explain | ||
| Buellerx |
Yup What he said makes sense. On a drag strip or at the salt flats you want your peak tq number at a high RPM because that gives you the most top speed and delays your shifts. That is why I-4s rule on an open stretch of highway. It is also why I can pull away from them at every light or on a twisty back road. Having that torque at 15,000 RPM only helps you when the bike is at 15,000 RPM. My point in posting the Dyno charts is that the Buell makes more tq than the I-4s at every RPM. Yes, on a straight road, over a long enough distance, higher revs win. The japs keep increasing the RPMs and the claimed Top HP numbers. I dont consider that "usable HP" if I have to rev to 25,000 (exaggeration) rpm to get it. M_singer I'm not arguing the math. that article is correct in the examples he gave. I am just saying that it doesn't necessarily equate to what's practical and useful in riding on the street. Which is why guys on 600s with claimed HP numbers much higher than mine are shocked when I pull away from them at the light or when I snap the throttle and pull the front up without having to rev it high and dump the clutch like they do. We can just agree to disagree on this one (Message edited by buellerx on September 22, 2005) | ||
| Fdl3 |
So, if the XB12 engine is already at the maximum limits for producing reliable power, wouldn't a better modification be to change the gearing? Either for more acceleration (of which it already has plenty), or more top end (trading off "excess" acceleration)? | ||
| Buellerx |
I have a 29 tooth front pulley and I was kicking around the idea of putting it on to replace the stock 27 tooth. It would make the gearing "taller" but I think it would throw the speedo off since it is driven off the transmission. I don't know by how much. Also some others seem to think there isn't enough slack in the belt to accommodate the larger pulley. The 29t came off my S2T. I am not sure why Buell chose the ratio they did for the XB. maybe they thought the bike wouldn't be stable at higher tops speeds because of the short wheel base and steep rake. | ||
| M1combat |
You can get LOTS of power out of a twelve. The main modification needed (both for a nine and a twelve) is re-machining the left side case for a temkin bearing. I hear they'll only support about 115 ft/lbs with the current bearing setup. I've heard that 140HP with an 88" kit is doable. I would imagine that if you pulled that down to about 120HP you would be pretty reliable. There are people working on superchargers as well. My goal will be to shoot for about 120HP with a 1250 kit or just leave it at 1203 and leave the gearing stock, but take the rev limiter to about 7500 for those days on the track. | ||
| M1combat |
"maybe they thought the bike wouldn't be stable at higher tops speeds because of the short wheel base and steep rake." I think the FX bikes use the stock rake but a little more wheelbase and they seem stable up to what... 190-195? | ||
| Spike |
This has nothing to do with XB12 dyno charts, but here is one of the best horsepower/torque articles I've ever read: http://www.yawpower.com/tqvshp.html The short answer is that horsepower wins. Torque at high RPM isn't an advantage just because you can take advantage of gearing, it's an advantage because it means you have more horsepower. | ||
| Spike |
Xbolt12, I know what you mean about the lack of big horsepower XB12s out there, but I don't think there's any reason to think that the XBs can't make as much power as the big horsepower tubers out there. I think it's just that XB's aren't at the age where most owners are willing to hack them up yet. Anyone who purchased an XB new is likely still making payments on it and that makes it hard to justify tearing down the motor. The other big issue with XBs is fuel control. We have the TFi and some have had luck with the PCIII for X1s/S3s, but frankly I would be afraid to use either on a serious motor. It would be *really* nice if we could get some sort of dumbed down version of the factory race ECM. The FX bikes idle smoother than any other XB I've ever seen. |
