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Ccryder
Posted on Sunday, April 01, 2001 - 09:19 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Wow, torque curves don't get much better than that! The HP curve ain't bad either. Wish my X-3's curves looked that good.

Neil S.
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Aaron
Posted on Tuesday, April 03, 2001 - 12:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Neil: yep, you're right! But what I really like about this guy's result is that it shows where the constraint is, and more importantly, where it isn't! The fact that he can achieve a result like that with basic head work and matching pistons, and yet leave the stock cams and carb and ignition in place, speaks volumes.

BTW, I forgot to mention it, but the gentleman who put this motor together should get some credit, he really did a nice job. His name is Mike Frieburg (sp?), he was a Buell tech at Chicago HD/Buell, went to work for Thunder Mountain last year, but I think (?) he went back to Chicago recently. I only met him a couple times, but he struck me as a sharp guy and a damn good tech, and he did a real clean job on this bike.

AW
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Rocketman
Posted on Tuesday, April 03, 2001 - 03:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

OK I'll jump in on this one because I also get 100 RWHP.

Mmmmmm, so I think, na these Yanks can't be right. They're hitting high horse numbers and getting big bangs for a few well spent bucks whilst Rocket has a few thousand pounds and all the best bits in his motor and has just about the same bang !

Here's what I think. After careful consideration, and studying dyno results from various bikes, and different sources, I'd like to ride Mike Frieburg's (sp) handy work. I'd also like to bet , despite what the dyno says, that if you rode my Buell you would really feel the difference in power.

Mine WILL rip your arms out. I don't know about the Mike bike, but reading the dyno chart and looking at what his engine has in\on it, I doubt it would be anywhere near as powerful as mine on the street and that's where it counts most, right ?

There simply must be an advantage to installing big cams and carbs, flowing the heads and running the race kit and god knows whatever else. I've always believed my motor was put together with the right bits and I still believe that's true today and I would say that everything we put in my motor was a good choice. I also have one other weapon in my 100 horse defense and I'd like to see the Mike bike do the same and that's to put a 200lb rider on board and post an 11.25 ET on his first attempt. I'm confident my Buell will run in the 10's given the right pilot but the 100 horse Buell's you guys talk of, I doubt it .

Rocket in England
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Aaron
Posted on Tuesday, April 03, 2001 - 05:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I was wondering when we'd get a rise out of you! Thanks for not letting me down .

I think there's a lesson to be learned here. Maybe a couple of them. I'm worried that if I try to rationalize it instead, I'll miss the lesson. But hey, whatever floats yer boat!

AW
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Rocketman
Posted on Tuesday, April 03, 2001 - 10:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

:
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Rocketman
Posted on Tuesday, April 03, 2001 - 11:00 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aaron : I wasn't baiting anyone , rather, I was addressing the board in general. I don't for one moment want to put down or disclaim your great efforts or anyone else's and I know you speak with no forked tongue. Never the less, the more I see horse power quoted anywhere these days, I can't seem to draw a relative line between power, performance and capability between differing models and manufactures.

I read specifications like 90deg V twin liquid cooled 999cc 8 valve dohc with F.I . Then I spots the horse power curve, a pretty steep rise from 4 grand and about 40 brake horse then peaking at 7 1/2 grand with a paltry 125 horses. This thing weighs like 440 lb too and its torque is nothing to write home about either, compared to a Buell that is, but what I can't figure is why this RC51 can rip the quarter in 10.5 and hit 140 MPH at the end or go on to a 170 MPH flyer.

I dunno. The motor is smaller but a lot lot more high tech and yet it has only managed a mere 25 BHP more than my Buell and yet it will beat my Buell hands down in all the specification and performance categories. Well, if you look at it realistically, the RC51 has 25% more BHP than my Buell which in turn is a quarter more of the power I've got and there's nothing mere about it at all. In fact, the high tech is what got it there so OK maybe that explains the RC51's dominance but what about this.........

Are the Japanese wizards ?

Consider a 125 BHP Buell. Nothing strictly high tech compared to the RC51 spec sheet. More a hotted up tractor motor, but to be fair let's assume it's performance is on a par with the RC51. Well, now we have a Buell turning in some really fantastic performance (the likes, by the way, of which I've never seen). RC51 performance. But what price that extra 25 BHP above the hard earned 100 you already bought ?


Then, someone else comes along with a nice healthy 90 horse Buell motor. Someone else slings a couple of jets at it and spends an hour or so on the dyno, and for a few measly dollars, grabs 10% more horse power than was started with, right outta the sky.

Is this dude a greater wizard ?

What in effect will this do to the now said 100 HP machine ? Will its power and performance be identical to mine and if so, will that in turn indicate that I perhaps have made the wrong choices with my chosen performance goodies or I just haven't extracted all that's on offer to me from those goodies ?

Just what kind of relativity are we talking ?

The proof must surely be in the riding and that was the point of my first post and I'm standing by it. There's 100 horses and there's 100 HORSES, or is this just mythology because if it is, I've got a Mikuni HSR 42 for sale, Crane single fire, some fat cams, some performance catalogues and s...o...m.....blablablablablablabla ?

Now I've got that lot sold I'll not make a mistake like that again in a hurry. .

Rocket in England
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Aaron
Posted on Wednesday, April 04, 2001 - 12:02 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Susy's S1

Here's my bride's '96 S1 ...

Mods are:

- t-storm conversion (including standard t-storm header) - no head work
- thin shim gaskets
- Mikuni HSR42
- race kit air cleaner
- V&H carbon fiber muffler

STOCK:
- ignition module and coil
- Lightning cams

The top end has about 18K miles on it. I've seen it pull a little more than this but this is a typical pull when it's tuned reasonably.

AW
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Aaron
Posted on Wednesday, April 04, 2001 - 12:19 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Rocket: appears you've abandoned your "American dynos read higher" theory and replaced it with a "some horses are stronger than other horses" theory.

I'm going to resist the urge to say something sarcastic here, I'll try to be good ...

A Dynojet dyno is a dirt simple device. It just measures the time it takes a bike to spin up a big heavy drum, and gives a result that's been mathematically converted to this thing we call "horsepower". It has no knowledge of how much money was spent on the bike, and there's no place to type that into WinPep. It's as objective as it can be.

Now I'm not the sharpest knife in the drawer, but I guess I have a hard time with the notion that two bikes spin this drum up at the same rate, but somehow one bike is stronger than the other in a way that the dyno isn't showing. You'll have to explain that to me a little better, I need a theory that makes sense to me.

There, I was pretty nice, wasn't I?

AW
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Airborne
Posted on Wednesday, April 04, 2001 - 01:29 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Price VS Horsepower. Cool discussion. I did two dyno runs in the same day once before and got an extra 8 HP for only $50.00. I replaced the stock air filter with a K&N switched from the 6R12 plugs to the 10R12 and tightened the secondary belt back to correct tension. Changed the oil. and aired up the tires back to correct pressure. Just the K&N and oil cost the $50.00 everything else was free. I figure I gained 3 HP from the correct belt tension and tire pressure. Another 4 HP from the air filter change. The last 1 HP from the new plugs and oil. The last 5 HP from the oil, plugs and air filter was gained not because of a better product was put back in but because they were fresh and clean VS dirty. By the way I came in second with just 89 HP the winner in the 1200cc class had a Hot Rod XL 1200 Sportster with slide carb, V&H drag pipes and stock heads re-worked by a local race shop for only $200 (good cheap deal) He had a 95 HP run that day.
My $50.00 gave me 8 HP. His $200.00 gave him somewhere around an extra 15-20 HP over what he had before the re-worked heads.
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Mikej
Posted on Wednesday, April 04, 2001 - 08:48 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I think I understand somewhat what Rocket is saying, two bikes with similar dyno curves can feel different somehow. Sort of like coffee, two cups might have the same caffeine content, but one will have a bunch more bite to it (I said "sort of like").
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Jmartz
Posted on Wednesday, April 04, 2001 - 09:00 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Rocketman:

I have a contribution to your RC51 dilemma. I believe that for any amount of power (ie. two bikes making say 100 RWHP) the bike that makes it at the higher rpm will go faster regardless of torque.

I have chased a Honda 600 in the N. Georgia mountains. This one made 100 RWHP and as you know about 45 lbs. torque. I could ride up his back wheel in the tight curves but he would always put distance between us in the short straightaways.

Our bikes have an advantage from stand still to 400 ft. then the higher rpm motors overtake them. My best riding buddy has a 916 with a few tricks dynoes at 116 HP. When we get behind a car beacuse of the double yellow line and we make a run for it I can always pass him as he attempts to pass the car. Pisses the hell out of him.

Then, just as I get to 70 mph he whizzes by.
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Aaron
Posted on Wednesday, April 04, 2001 - 11:09 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sorry, I flat reject this notion that horsepower is not an accurate indicator.

Rpm is a component of horsepower, it's already factored into the number. hp=(rpm*torque)/5252

Torque at the rear wheel, after gear reduction, is ultimately what moves the bike, and horsepower is an accurate indicator of how much torque you'll have at the rear wheel after gear reduction.

Example: bike A is spinning 10,000 rpm & making 50 ft/lbs of torque in the process. Bike B spinning 5,000 rpm and making 100ft/lbs of torque. Which is stronger?

If we just compared the torque of those two bikes, we'd think bike B is much stronger. But actually, they're identical. After 2:1 gear reduction, bike A's rpm will be 5,000 and it's torque will be 100ft/lbs, just like bike B.

Both of these bikes are making 95hp. Horsepower is the better indicator for comparison purposes because it's already got the rpm component factored in.

With respect to the comparisons between two bikes with equivalent horsepower and different acceleration rates, keep in mind that there are other components to quickness besides horsepower. Weight and gearing come to mind. 6-speeds make a damn big difference.

AW
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Travis
Posted on Wednesday, April 04, 2001 - 12:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I hate to jump into a room in the midst of a fire fight, especially when i am holding a butter knife.

But what i think the point is (and i dont want to put words in anyones mouth) that if two bikes have the same PEAK horsepower/torque numbers, they could have drastically different curves and actually peak at a different RPM. Therefore the two bikes would "FEEL" different.

Warning - Anecdote:

For instance, my buddy has an R1100S Beemer. Aside from the asthetic differences and drivtrain (shaft v. Belt) his bike and my buell offer simmilar peak HP/TQ numbers. although i would say that i like my bike much more because it feels like it pulls harder, and i always beat him.

Now, we have not had these bikes on a dyno in more than a year, and never on the same dyno. So like i said, that is anecdotal as i do not have any graphs or such to compare yet.

Anyway, now that i have muddied the water with spread butter, I will let you take from this what you will

Trav
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Axtell
Posted on Wednesday, April 04, 2001 - 01:18 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Figure the torque at the rear wheel with the ACTUAL gearing the bike has.
The high rpm engine can carry much more gearing leverage and ends up with MORE torque at the rear wheel over more of the power band.
Aaron is right in his example BUT the bikes won't have the same gearing---If they did the lower rpm bike would be running 1/2 the ground speed of the high rpm bike ie: 100mph vs 200 mph!
axtell
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Jmartz
Posted on Wednesday, April 04, 2001 - 01:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

There is one thing we have not considered and that is the weight of the reciprocating assembly. For example, between an S2 and an S1 with similar peak HP, the S1 will always accelerate faster (asuming weight parity) beacuse it can reach peak HP quicker.

Aaron: Physics notwithstanding (and you are correct in you assesment) converting the engine's energy output into forward motion seems to be better modulated with high rpm applications and more gear options.

I would be willing to bet that with a 6 speed baker with the proper ratios (and the present raios are not those) I could outrun my buddy's 916 perhaps to 80 mph but if the race isn't over soon, he'll pass me.
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Buellistic
Posted on Wednesday, April 04, 2001 - 01:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ATT: ALL the BUELLERS in BUELLDOM
IF you haven't raised the point where torque
and horsepower cross at 5252 you have not done
a BUELLSCHITEN thing!!!!!!!!!!!!!!!!!!!!!!!!!!!!
In buelling
BUELLISTIC and/or Hardley-Harley
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Aaron
Posted on Wednesday, April 04, 2001 - 01:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I don't think Rocket is talking about "feel" at all, he was very specific in referring to measured performance as it relates to horsepower. As was Jose.

Mike introduced the concept of "feel" but he referred to two bikes with similar dyno curves, and I believe he was misinterpreting Rocket. Actually, he's right though, gearing and weight and rider position will all radically affect "feel". For example, take two bikes with identical gearing and weight and dyno curves, but one bike has lower bars and a more rearward seating position. The acceleration will act on your body more through your posterior than the upright bike, which will yank on your arms. They'll feel very different under similar acceleration.

AW
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Court
Posted on Wednesday, April 04, 2001 - 02:11 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ron:

While yoiu guys are discussing this, may I have the 200mph bike for a little bit?

I'll be back by the time the discussion ends.

Court
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Mikej
Posted on Wednesday, April 04, 2001 - 02:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I always misinterpret Rocket, which is easy to do since he rides sitting backwards in the rain. :) Hmmm, maybe that's why his bike feels different.

MikeJ 'thunk' ouch, where'd that brick come from
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Aaron
Posted on Wednesday, April 04, 2001 - 02:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ron, I wasn't trying to describe two actual bikes, I was only trying to illustrate why comparing horsepower is the right way to do it since rpm is already factored in and gear reduction is used to make torque. I didn't mean to imply that those two hypothetical bikes would be geared the same.

Yes, of course, if you want to know why a 916 or RC51 outruns a Buell, those calcs could be done with the actual power and gearing info and that would be better.

"There is one thing we have not considered and that is the weight of the reciprocating assembly. For example, between an S2 and an S1 with similar peak HP, the S1 will always accelerate faster (asuming weight parity) beacuse it can reach peak HP quicker."

Reciprocatiing weight will show up on the dyno sheet. If the curves are the same, the S1 will not be quicker (assuming weight parity and same gearing)

"converting the engine's energy output into forward motion seems to be better modulated with high rpm applications and more gear options."

Yep, what those closer spaced gears do for you is they let you keep the motor closer to your hp peak as you run through the gears. So you're maximizing the torque that's reaching the rear wheel.

"I would be willing to bet that with a 6 speed baker with the proper ratios (and the present raios are not those) I could outrun my buddy's 916 perhaps to 80 mph but if the race isn't over soon, he'll pass me."

Didn't you say he's got 116rwhp? And probably a fairing too?

AW
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Travis
Posted on Wednesday, April 04, 2001 - 03:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I did not consider the differences in Actual riding positione. But that is interesting, and most likely true.

This is a good discussing, i learn a bit from this board.

And if i misinterptred Rocket, my apologies.

AW:

Reciprocatiing weight will show up on the dyno sheet.

Would this be shown by a curve that aproached its TQ peak in a small RPM range then continued through the rest of the full range? (Blue line in the rough example below)

Rough Example

And on the other hand something that reaches its TQ Peak slowly, (Red line above) would have a larger Reciprocatiing weight?

do i understand right?
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Doncasto
Posted on Wednesday, April 04, 2001 - 03:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sir Aaron:

I ran into Mike Frieburg yesterday at High Country HD/Buell in Longmont, Colorado. He has been working there for about a week and hired on after discovering the new ownership is very pro Buell. This is in contrast with both Mike's and my former employer where I got the distinct impression the dealership is actively discouraging any and all Buell business. Mike will be doing the torn isolator replacement/product upgrade on Roz next Thursday.

To any Colorado area Buellers that either came to appreciate Mike's work at his previous (and un-named in my personal pledge for a more diplomatic BWB presence) or are looking for both an excellent Buell tech and a Buell friendly dealership I heartily recommend contacting High Country HD/Buell, 800 S. Main St., Longmont, Co 80501 Phone 303-772-5252

They are still very new to Buelldom and are still minimally stocked with Buell P&A, but are willing to order in anything a customer wants as they are coming up to speed.

Don

PS. Although the might be a few sharper knives in some drawer somewhere, your mentally agility always manages to slice me to ribbons. I guess that's what comes from realizing I will never make it out of the ball peen hammer drawer.
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Rocketman
Posted on Wednesday, April 04, 2001 - 03:50 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I understand how monumental it was for EB to produce say 90 HP from an S1W race kitted Buell and make it rideable and reliable (for most of us anyway). All the more so when we take in to consideration the origins and development history of the Sportster motor and the sort of power the Sporties are\were producing.

I also remember how this board, me included, had talked of how difficult it was to produce a motor that would surpass the magic 90 HP without serious work. I say magic because that was the original HP allowance in the Lightning series in which the competitors installed Buell Race Kits to achive this target. Given that the first 5 or 6 bikes across the finish line were dynoed to enforce the 90 HP rule, I'd assume the competitors also dynoed their own Buell's pre-race.

What did these racers do ? De-tune ?

Now it would seem that anyone with a fairly healthy Buell motor can achive near on 100 RWHP from a carb tune and a 1 tick adjustment on the timing plate. If this is true, and I've no doubt it is, does this mean N9 cams are a total waste of time ? Did the HSR42 bring nothing to the party ? Is Dick O'Brien suffering from Alzheimers ?

By my reckoning, based on the nearly 100 horse Buell that Aaron tuned, I should be hitting 110, maybe 115 RWHP. However, I'm not !!!

In love, not war, your 100 against mine. That I'd like to see. Wouldn't you ?

Now I'm gonna talk to my torque curve. Perhaps he can explain to me something you guys are missing on. I just can't belive a nicely tuned S1W putting out near 100 RWHP can match my hottly tuned S1W with very similar RWHP when we take 'em both for a back to back burn !

To conclude might I ask a question...........

This dude, Merlin, (for he is a Buell wizard) go's in to a Buell Dealer where he sees two, more or less identical, used S1W's for sale. You know these two Buell's already :). One has a hot rod motor and the other is well up on performance but without a lot of the hot bits the other one has. Both are in fine condition and optimally tuned and both put out similar RWHP. Even if the hot one was more expensive, money isn't an issue.

The question is Which one do you buy ?

:)

Rocket in England
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Jmartz
Posted on Wednesday, April 04, 2001 - 03:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Now I am really confused but in any case, the fundamentals of the problem lie in the rate of energy depostion to the ground. Empirically speaking, I am convinced that it will happen better with a higher rpm motor although I realize that the overall quantity of deposition can be the same for different mechanical configurations.

As my 916 friend says: I'm always th fastest no maater what bike I'm on. Not exactly true but he believes it.
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Aaron
Posted on Wednesday, April 04, 2001 - 03:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Trav: When you roll a bike onto a Dynojet, you're mechanically connecting the drum to the flywheels (and primary drive and clutch basket and secondary drive and wheel and everything else that's contributing to the reciprocating weight). It's just like adding weight to the drum. The motor has to spin all that stuff up, and the torque/horsepower that the dyno sheet shows will reflect that extra spinup time required as a lower level of torque and horsepower. The engine isn't making any less horsepower than one with light flywheels, but less is reaching the back wheel, which is what the Dyno is measuring.

Ron's the motor guru, but as I understand it, torque is a function of cylinder pressure and mechanical advantage on the crank (stroke).

Don: thanks for the tip, I'll stop by there and say hello to him! Glad to know he stayed in the neighborhood. And that's BS, you're one of the smartest people I know. That "fat boy in Iowa" (as he calls himself) may be number 1, though, he has an uncanny ability to turn things around and look at them from different angles.

AW
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Rocketman
Posted on Wednesday, April 04, 2001 - 04:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

So, what does the dyno tell us ?

I'd say Merlin should buy the other Buell, and not this one,

Rocket Stat

based on the torque curve.

Rocket in England
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Aaron
Posted on Wednesday, April 04, 2001 - 04:32 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I dunno, Rocket, that's why I posted Roger's sheet. I thought it was damn interesting that it could approach the century mark with stock cams and carb. BTW, we never touched his jetting, only his timing.

'Course, when I talked to Brian about it, all I got was a big yawn. Seems it's not an unusual result, I just live a sheltered life. He said something about customers with injected bikes routinely breaking 100. Keep in mind that he's someone who cuts on these t-storm heads all day every day, and he's been making steady improvements. I'd quote numbers but I think I've openeed enough worm cans lately.

Actually, I posted my wife's sheet for a reason, that wasn't a coincidence, and only one person picked up on it (he e-mailed me). There's a definite trend with overachieving t-storm motors. All of them seem to have something done to tighten up the squish. The factory setup is fairly sloppy. It is, after all, a production motor. This is what I'm getting at ... I want to learn from this stuff, if I ignore the laws of physics and rationalize it away that won't happen. Now maybe I'm jumping to a conclusion, but it's worth further investigation.

How did the squish come out in your motor? Was anything done to tighten it? Was it ever measured?

Another question: have you ever put that beast on the dyno and spent 2-4 hours *carefully* tuning it? I'm not talking about a rush job, I'm talking about very careful changes, lots of testing to see what's really going on, carefully controlling temps, retesting to make sure you're not getting fooled, trying your damndest to get it as close to perfect as possible. Doing a good job at this is really time consuming, I don't think most shops (outside of say a Cycle-Rama) would do it thoroughly.

Rarely do I go to tune up a bike without being able to find 3-4hp. We found 9 on Don's. I found 10 on my S2T. We found 4.5 on Roger's without ever touching the carb.

Put that boat anchor in a box and ship it over here.

AW
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Jeffb
Posted on Wednesday, April 04, 2001 - 04:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

This is a very interesting conversation that is going on. I think I have had it before with people, but I don't remember which side of the fence I was on! Thinking back to Calc. 1 and integrals, a given rpm band of a power curve with more area under the curve than a different power curve will be able to produce a larger total force, ie. greater acceleration (F=ma). Using that logic, if two engines produce the same peak torque and HP, their accelerations could still be different (one will rip your arms off and the other will just snap your neck)if one produces that peak torque value for a greater rpm band than the other engine. I will stop rambling now, sorry.

I don't know if I have ever proven this to myself for sure, or if I have seen it proven. I might be missing something, but it makes sense to me.

What do you think?
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Hans
Posted on Wednesday, April 04, 2001 - 05:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

One question is never answered:

"hp=(rpm*torque)/5252"

Is that the rpm and the torque of the engine ?
I suppose so.
But there is always spoken of rearwheel HP. And there are different formula`s to convert the measured power on the rearwheel to engine power: DIN and SAE used mostly but they are different. And these factors are used to correct for losses in the gearing but also for a waterpump and a shaft drive.
Have you adjust the Dynometer if there is not a waterpump or shaftdrive ?
And if you measure the uncorrected power on the drum of the dyno then you can`t say that "hp=(rpm*torque)/5252" if you speak about the engine.

If you come with different formula`s (DIN, SAE) with estimations to engine Horse Power you can`t say horsepower is horsepower.

But if there is only used the SAE formula:
It is then, to say the least, difficult to believe that somebody can come to the same HP with minor modifications as Rocketman with the finest parts and the witchcraft of a British tuning doctor.

Found this one: "In the end it doesn't really matter, because the purpose of a dyno is not to stroke squid's egos, but to aid in tuning a motorcycle."

Hans.

PS: Rocketman, You got me: It is your ultimate goal to get you Buell shipped by the now totally upset Americans to the States to proof that your Buell gives the 165 HP on their Dyno`s wich you needed to ride 178 MPH with your back in the wind.
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Aaron
Posted on Wednesday, April 04, 2001 - 06:25 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

JeffB: I agree completely.

"hp=(rpm*torque)/5252
Is that the rpm and the torque of the engine ?"


That's a universal formula that applies to any rotating power source.

"But there is always spoken of rearwheel HP. And there are different formula`s to convert the measured power on the rearwheel to engine power: DIN and SAE used mostly but they are different"

Those correction formulas don't convert rear wheel to engine power. They are used to correct for environmental conditions, so that dyno results from different environments can be compared. It's the method by which I can compare my results, here in CO at 5300' elevation, to say Pammy's results, at near sea level (and be disappointed, BTW).

"It is then, to say the least, difficult to believe that somebody can come to the same HP with minor modifications as Rocketman with the finest parts and the witchcraft of a British tuning doctor."

Well, I guess if you believe that buying the "finest parts" guarantees the most power, then yes, that's really difficult to believe. BTW, how do you know which parts are the finest?

But not everyone looks at it that way. Another school of thought is to identify and put your effort into the thing or things that are really constraining the motor, and ignore the other things.

AW
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