| Author | Message | ||
     Dj_rider |
hahaha i know...thats why i bought the xb...well if the speedo is off, ••••••••••• looked down for a split second and it was nearly hitting 160mph...on a downward long straightaway  very scarey on those katanas...front end was shakin like crazy!! | ||
| BadS1 |
DJ if your Katana will do close to 160 then I seriously had a slow 1990 GSXR-750 that she would do about 150 mph and that was giving her some room.Mind you it did have a Yosh pipe and filters and stage 2 jetting | ||
| R1DynaSquid |
Another way to look at it is like this...the GSXR750 from the same era which was indeed a race rep bike, was able to hit 161 mph. You may have indeed seen close to the number on the speedo, but typically they can be off by 10 to almost 15% at higher speeds. | ||
| Dj_rider |
why would i bull - ••••... expessialy in a forum full of gearheads and looney tuned speed racers? any time any of you would like to see my p.o.s. katana do 160 come to pittsburgh, id be more than glad to demonstrate it... | ||
| R1DynaSquid |
Hello Wall this is DJ, DJ say Hi to the wall  | ||
| BadS1 |
The 1990 wouldn't do it Dyna no way!!!!I gave her all of Sheridan Road and it wasn't gonna go anymore. edited by bads1 on July 19, 2004 | ||
| R1DynaSquid |
Dana...a 95 model GSXR750 would. | ||
| Blake |
So Greg, to clarify is it your contention that top speed and acceleration in the 150MPH+ realm are governed by power to weight ratio? If so, When you compare power to weight ratios, what weight are you using? | ||
| R1DynaSquid |
WTF are you yakking about? I dont recall ever even insinuatuing that top speed & acceleration are governed by hp to weight & nothing else. Aerodynamics come into play, gearing, etc. Without the HP all the gearing in the world wont net you squat & without gearing the hp wont do you much good & if the bike has the aerodynamics of a brick its going to need more of both. | ||
| Blake |
Greg, WTF are you yakking about? I dont recall ever even insinuatuing that top speed & acceleration are governed by hp to weight & nothing else. You no read good. What me say was...
"Governed" mean "restrained" or "limited" or "controlled". Me no say "& nothing else; you say those words. Me no say those words. You no read good. You no remember good what you say. The above was in response to your prior answer to my question... Where you said...
I asked a simply question and get attacked. Not very nice. I'll try again... So Greg, to clarify is it your contention that top speed and acceleration in the 150MPH+ realm are governed by power to weight ratio? That's a yes or no question. I should clarify that I am talking in relative terms concerning the ZX12R and any other sport bike. If so, When you compare power to weight ratios, what weight are you using? Again, a simple polite question. Try again grumpy. | ||
| R1DynaSquid |
Dearest Blake, read above post for answer to question. Love Dyna  | ||
| Mikep |
It really does take all of the following: HP. Appropriate aerodynamics. Reasonable weight. Appropriate gearing. These two guys posted the correct answers. Posted by Blake: The AMA supersport bikes are exceeding 160 mph on a regular basis. They supposedly put down around 120 RWHP though I wouldn't be surprised if the top factory machines were closer to 130 RWHP. You can make that kind of power with your Buell bumped to 1249 cc's and with a well matched and tuned set of heads, pistons, cams, EFI augmentation, and exhaust. I'd say for around four or five grand you could be very close. Not sure you'd need a six speed either, just a change in final drive or primary drive ratio. Consider that it takes 35% more power to achieve 160 mph versus that required to achieve 140 mph. If a stock XB12R with proper gearing could achieve 140 mph, which it very well may be capable of doing, it would take an additional 33 rwhp to make 160 mph, or around 124 rwhp. Definitely doable. Posted by Lightisright: Roadracing World August issue has a profile of the Hal's FX bike. They interviewed crew chief Terry Galagan and Eric Buell. EB says the FX bikes run in two configs, both with a 96.5mm bore. One is a short stroke 79.4mm revs to 8500rpm and the long stroke version is an 88.2mm revving out to only 7500rpm. EB also says the short stroke engine makes around 120hp and 135 for the long stroke on a dynojet dyno. At Road America, Ciccotto had the 4th fastest FX trap speed at 161.9mph on the AMA's official timing. Galagan said (on the Hal's radar gun) the best they had Duhamal (FX CBR) was 168mph w/o the draft and Ciccotto at 165mph. Said their bikes weigh 360-365lbs (class min 350) but they are working on it. Also said a competent Harley tuner could make a competitive engine for about $5000 and have a total cost in the bike of 20k+. | ||
| Blake |
Greg, You no read good. You no answer question. In the world of sport bikes, there is one absolute factor that no matter the gearing governs top speed. One. Do you know what it is? It is the only thing opposing further acceleration and speed of any sport bike no matter its power to weight ratio. | ||
| Glitch |
Engine speed? | ||
| R1DynaSquid |
I would say its aerodynamics/wind resistance. if the bike cant make a clean path thru the air, adding more power or gearing isnt going to help it. | ||
| Lightisright |
Wind resistance rises with the square of the speed. | ||
| R1DynaSquid |
Well? | ||
| Blake |
Dyna, You are right. Also, consider that with all else equal the HP required to achieve a peak speed goes up proportionally with the ratio of peak speed cubed. In other words, to double peak speed requires eight times the HP. To increase peak speed from 150 mph to 180 mph requires (180/150)3=1.728 or 72.8% more HP. That's a lot of HP for just another 30 mph. I figure it takes around 100 rwhp to make 150 mph on a fully faired motorcycle. If that is about right, then it would take 172.8 rwhp to reach 180 mph. Why does required HP go up with speed cubed when wind resistance only rises with speed squared? Anyone? | ||
| Phillyblast |
So what you're saying is all things being equal it wouldn't even hit 160 if it was, as originally suggested, dropped from a C130, due to wind resistance limiting terminal velocity? And why is it the only thing I can ever remember in metric is 9.8 m/sec2?? | ||
| Starter |
I can assure you there are no stock busas out there with that much power but they can get to a genuine 186mph stock with the limiter removed. GSXR600 are pushing 158 mph this year with just 100rwhp. Top speed really has more to do with the aerodynamics of the package rather than engine power. If you want the quickest speed from a given engine you need to gear it so it uses all of it's revs in top. | ||
| Mikep |
Starter, We do have to agree that we are talking actual mph, not speedometer indicated. The speedos on many motorcycles (if not all) are quite optimistic. If you run your bike on a SuperFlow chassis dyno that has been calibrated you will see that your speedo can be as much as 15% optimistic. This puts the GSXR600's 158 mph indicated at an actual of 134 mph. The GSXR600's HP is, as you will find out, also optimistic by about 15%. Your calibrated SuperFlow may show 85 rwhp. If you can accept my words, that puts us at 85 rwhp on a faired bike providing 134 mph (actual mph). mikeyp | ||
| Lightisright |
SportRider gives a GSXR600 ('03) 103hp (don't know if they use a SuperFlow eddy or a dynojet intertia) and 158mph top speed on radar. | ||
| Firebolt020283 |
but is sport rider useing there own test or is it using the factory test cuz most factory test are at flywheel not the rear wheel because as i recall buell boast 103 for the 12 but as we all know from dynos that anint so (my thinking is that the gsxr and the 12 are close) i also belive they cant be that much different being as i have freind that has a 96 gsxr and my 9 runs pretty even with his bike (but im no professional im just stating my thoughts and experiances) | ||
| Blake |
The current crop of IL4 600cc machines put down right at or just over 100 rwhp. Mike, The crankshaft values are always higher. Mucho power is lost during transmission from crankshaft to rear wheel, most often around 15%. That goes for Buells and any other motorized wheel driven vehicle. After reading the recent MCN article on the tricks that certain factories play with pre-production test bikes, I don't put much stock in magazine tests of new models. I do believe that a stock GSXR600 will do 150 mph and that with proper gearing an XB12R would easily do 140 mph. | ||
| Socoken |
why is it the only thing I can ever remember in metric is 9.8 m/sec2?? that is the rate at which gravity accelerates objects, without factoring in wind resistance. | ||
| Mikep |
Blake, "Why does required HP go up with speed cubed when wind resistance only rises with speed squared? Anyone?" Look here for your answer: http://en.wikipedia.org/wiki/Drag_equation I think what I understand from this is that: 1. The Force due to aerodynamic Drag goes up as the square of the velocity, and . . . 2. The Power required equals this Force times the increase in Velocity. Is that were we get the cubed rise in power? mikeyp | ||
| Wyckedflesh |
Getting back to Tatsu's original intent of producing 160mph on his XB...If you aren't worried so much about off the line acceleration, you could switch to a chain kit and play with gearing until you just simply can't get it to go any faster, then work on the power output. As has been pointed out, the XB12 is still rising in power when it hits the revlimiter. Until someone removes that revlimiter and puts the stock engine on a dyno, letting it run til she stops no one really knows just how much top end the bike really has. On the couple dyno's I have done, both times the power was still climbing, I mean going up at a good angle and not just tapering off. Both times its been indicated 94rwhp right before the revlimiter started kicking in. I honestly think, larger injectors, a better exhaust with the Race ECM and PCIII or maybe as FP said a dyna ignition and a megasquirt could be a good foundation to get the bike sorted enough to utilize better gearing. I think the power is there in the stock XB12 to be unleashed for a streetable with enough room ability to hit 160mph with those changes. We aren't talking hit 160 at the end of the front straight at RA, we are talking having a mile or two to get there. More like what would it take to get the XB12 to hit 160 at Bonneville or MAxton. | ||
| Mikep |
Wyckedflesh, I wonder how long an XB12 would last at 8000 rpm where it might be producing 100 rwhp? Probably last a reasonable length of time. mikeyp | ||
| M1combat |
You mean a constant 8K? I don't think it would last too long. Just my guess though. | ||
| Wyckedflesh |
I don't think it needs to run at 8000, I think setting the soft at 7000 and the hard at 7500 might be all it needs. I will see if I can find the dyno sheets, but seriously even the techs running the dynos thought 100rwhp was there just out of reach due to the revlimiter. I also think it would be possible to set up a staged revlimiter so from 1st thru 4th its the standard limiter, but in 5th you get the additional 1000rpm. |
