Dyno Question

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OB_BusaGeek

Registered
Got my 2000 'Busa dynoed today.
Red/Gray, 1800 miles, Micron full system, Ti can, PCII, small air box mod, 42 tooth rear sprocket.

Made up a PCII map by starting with 003 (Micron full system) and doing some tweaking looking at what Dynojet did when they tested the Akro with the small box mod (Mostly partial throttle and low RPM changes).

Biks runs excellent on the street.

Run on a Superflow CycleDyn Dyno. Made wonderfully smooth torque and HP curves, did some fiddling with the PCII and couldn't get any more out of it. The weird thing is that it made --

134.8HP at 9500rpm
92.6ft-lb of torque at 6600rpm
(both SAE corrected).

I've never heard of a number that low. Can anyone guess what is going on here? The bike feels good, I didn't get a test before the mods, but it feels stronger. Bike smokes a little when letting off the gas at max rpm.
 
Something is not right there. As far as dyno differences go, I had my bike on a Superflow and a Dynojet 150 and got the same numbers. I was even in different parts of the country(FL. and Ct.)!
 
Dynos are liars. I pulled 172.9 w/ stock pipe and PC2 on a DynoCrap200, believe that one...
 
I went to CycleDyn's web site today and their stock 'busa made 132HP. Seems to be consistent with this dyno. Puzzling thing is that a ZX-9 made 127HP.

Can anyone tell me what 1.186g acceleration at 6660rpm, 700# inertia, .993 SAE corr. fac., 42t back sprocket comes out to in torque and HP? Maybe the calculation is off.
 
If HP=Torque * RPM /5250, how come my dyno chart at 9668rpm, 81.4 ft lb of torque has 134.8HP? By the calculation above, it should be 149.9HP. What gives?

Where can I find another Dyno in the Buffalo, NY area? The only other one I know of is Fast by Gast Racing and he won't take an appointment until mid July.
 
Busageek,

There is a place with a Dyno in Niagara Falls somewhere, I'll try to find their info.

Unless that is where you took it and got the inconsistant numbers.

I would consider extending your search into the Toronto area, you may find dynos more avaliable up there.

PS were you at Mighty Taco Sunday I heard there were 3 busas there?

If you go up to the Flying Saucer talk to those guys as well they might know of a place in the Fort Erie area.

L8r
 
Mis4tun81,
Thanks for the info. I was at a shop in Ransomville. I'd rather not say the name because I'm not yet sure the info is bad, just not compareable to others. If I had dynoed there before the mods, I would have been at least satisfied with the results.
Yea, I was one of the Red/Gray 'busas at Mighty. Also a black '99 there. You should stop out, It's a good time. That is except for the guys who got nailed for left-on-red in Cananda. (it wasn't their fault, for all of the laws that may have been broken, it kinda sucks getting a ticket for getting caught in an intersection when the light turns red?)
 
This is the BS thing about dynos. They don't measure hp that is repeatable amongst other units.

Imagine if you went to the gas station (or grocery store, ect) and you bought one galone of something (milk, gas, ect). At one store you got 3/4 or a gallon, another store 1.5 gallons and the third 1 gallon. You would cry foul if you got cheated and would love it if you got more. Thats why many places that do testing require that (especially for legal cases) that data be done to a reproducable standard. There is even a givernment agency that makes standards just for this purpose (NIST).

Why can't the dyno manufacturures make a dyno that is correct? I am sure (after reading many testing standards including some SAE) that they have to be repeatable to withing a certian degree and give the correct number. If they can't they cannot claim "SAE" hp as that is a specific set of testing parameters that make testing reapeatable and accurate.

-Dana
 
Dyno's are not liars...truth be told gang, dyno's could care less about truth or not...trust me they have no feelings! Fact is...dyno's are polygraph machines! Liars sometimes are the ones feeding improper weather data for the dyno to calculate the numbers from. Also ego's get in the way. Some time ago I started a post about how people are all so willing to volunteer power numbers. This is a huge problem with us performance shops who want to provide real useable data. I probably lose engine and/or tuning jobs cuz I won't lie or "finesse" a number for the sake of ego or telling someone that their bike is making a lot of power when they have spent a lot of money. I have yet to see a stock Hayabusa make more than 153 rear wheel horsepower. Also to those that are trying to calculate Torque X RPM = HP...remember that with this formula, you are
required to be reading a "strain guage". A strain guage shows a number to times to the RPM that the engine made peak on the strain guage. That strain guage number is what gets
multiplied by 5.252...furthermore, you could be confusing this with engine power and not
rear wheel power. Within the race engine building fraternity there is an unwritten rule about how much horsepower per cubic inch
is required thereby setting goals for a race shop to build engines to. This also exists within the OEM's and this number is very realistic. 1298cc = 79.2 C.I. One needs to make stock engines in the power sportbike industry have approximately 2.15 HP per Cubic inch to be competetive today..anything beyond that is a dividend. This way of figuring will put a Hayabusa in stock configuration at 170.28 ENGINE horsepower and the result by the time it gets to the rear wheel is about a 20 HP loss when the clutch is locking up and the chain is good and the dyno shop didn't put foolish numbers to the weather parameters
and so on. So far from my experience a good running stock Busa makes right around 150 rear wheel horsepower...add 20 to that and viola! True... dyno's are only required to show wether or not there was an improvement, but when you get into the real deep dark recesses of engine development and the need to know if you are competetive with another, these formula's help and discredit or make an engine look good. Peace...Freddie
 
Freddie,

I am a bit confused about your post.

Power is defined by the amount of work produced in a given amount of time. HP does correct out to be torquexRPM/5250 (the 5250 is a scalar for english units while the RPM takes time into account).

A strain gauge measure exactly what it says it does. It is a Whetstone bridge (hence a variabel resistor) that measure starin (the amount of movement in a part). This, along with complex modeling can give a force. A force can then in turn be transfer into power if the force is applied over a given amount of time. This is a very complex (and I would think inaccurate) way of measuring power. The only way I could imagine that power is measured this way would be by the deformation of the shaft going throuhgh the drum. Again very complex.
Also a strain gage has to be calibrated for voltage in vs voltage out and then scald to give the appropriate strain. These are very complex systems.

If so many busas dyno in at about 150rwp how come so many peopel seem to get so much more out of them?

BTW, mine dyno'd at 149.3 stock and the operator sadi that that dyno is 4-6 down on other dynos around.

-Dana
 
Don't get hung up on dyno ###'s. They are only bragging rights. As long as they are consistent measurements, you can use it as a tune/test tool. It doesn't matter to me if a dyno is 10hp low, all I care is WHAT I gain.

Superflow and Factory dyno's read different from Dynojets. This is due to design and software calculations/corrections. Take your bike to another Dyno, or even better, take it to the drags and look at your terminal speed. It is a good measure of HP.

Dave
 
Dana...I am sorry to have confused the issue but I think we are pretty much saying the same thing as I agree with your statements...all of them! Perhaps the only thing is, is that you described what I was trying to say in greater detail. My intent was to make remark on some of the prior posts on this topic in general terms. At the time I didn't think of describing the actual engineering workings of a strain guage. There are also different types of them, but regardless, at the time it didn't seem important to be more elaborate than I was, but you did indeed describe accurate information in good detail...better than I did. I need to get to work now but when I have time I will be back to comment more, but by and large I think we are both on the same page. Freddie
 
Dana,

Good explaination. Typical strain guage has 4 resistive elements in a "wheatsone bridge" config. A regulated DC voltage is applied across. When a deflection occurs, a resistive element changes, thus offsetting the DC out, which is normally zero. This SMALL offset voltage goes into a process control device. A common example would be an Analog Devices 3B16/3B18 module. The output of the AD module can be +-10V, or 4-20mA, depending on config. This values are all calculated beforehand. Typical application is stress/load analysis of various stresses, usually torsional.

To MY knowledge, NO dynos use strain guages to measure power. They use either rotating mass VS acceleration, or eddy current measurements.

Dave
 
On some of the static load engine dyno's, there are still strain guages. They are not too bad either, but there is absolutely a better way from an inertia state. The Schenk Eddy current dynamometers are also very useable and good dynamometers. Fact is...if it works for you, and gets you going faster or running better, it is a good dynamometer.
Dynamometers are only as good as the folks that are capable (or not) of interpreting the data. With regard to formulas...on a static load dyno there will be some type of device depending upon the brand of dyno that will measure torque. A guage is supplied with the dyno for the operator to watch in the case of the dynamometer not having data retrieval capabilities...and do not discount these old
antiquated dynamometers as they are very good
if you are used to tuning with them and still in use today with some good engine shops. I
came up through the ranks of dyno "upgrades" and now really have tremendous luck with a re-made dynojet with a custom drum and other enhancements that make dynoing things like 400 and 500 HP Pro Mod and funnybikes easier
and more productive. The resultant data is very useable as well with powerful streetbikes and other small engines as I make a full line of add on devices to dyno just engines on a dynojet as well as in chassis snowmobile (or out of chassis). The point of my original reply was meant for the average consumer wanting more basic information about dynamometers and trying to put things in "laymans" terms is helpful to those who are not as experienced as the others who have contributed here. The information that was contributed is very good and is helpful, but to get to the original remarks, different dyno's will calculate their number with different formulas and if one knows that math that a particular dyno uses, then it could be calculated quite accurately as to the power generated at the engine. Factory and Superflow dynamometers use different formulas
within the computer to post A NUMBER..this doesn't mean that it isn't accurate...it merely means that the dyno is configured in a different manner. I don't have a lot of experience with Superflows Cycledyn or Factory dynos but I'll bet they are very good tools and if they happened to beat Dynojet to the punch to market dynamometers, the public would be wondering why Dynojets numbers seem off instead of the other way around. Personally I swear by the Dynojet (especially mine) and it is important to use the data supplied and be able to interpret it to the utmost in order to optimize an engines running condition. If there were no numbers and only "hash marks" for instance, or just a graph without the numbers, we would simply be trying to exceed "the last line" accomplished
on the best run...but man are numbers good for the ego! By the way, for all of you guys that don't dabble with 2 stroke technology...
I posted that some good power numbers are realized when comparing horsepower per cubic inch...well a good 2 stroke 500cc engine will make power comparable to a 1200 - 1300cc 4 stroke engine! I have 2 stroke 1000 cc engines on carbs and gas only making 264 HP and they will tear the hinges off hell! Maybe a 2 stroke Hayabusa is in the future...anyone want one? Hope all this helps and thanks to all the good folks for posting lots off godd stuff on this forum. Peace...Freddie
 
On a different note, I always see that on Dynojet printouts they claim to have "SAE HP". I was looking through the testing specification for SAE and I don;t think that a dynojet dyno even comes remotely close to repeating the tests called for by SAE on a dyno (for instance SAE requires that you measure the quantity of fuel going into the engine).

What I figured they may be referring to by SAE HP is that they are reffering to the correction factors that are used as specified in SAE J816 (of coarse the SAE specs are laid out so poorly that i have found the refernce to that specification for correction but not the corrections themselves).

An obscure test that I found in SAE was acceleration test. To make claims accoring to SAE acceleration has to be performed in two directions (imagine trying to get the drag strip to let you run from the opposite end of the track).

There was also a spec for measuring noise from a bike but i didn't read it.

Laters
-Dana
 
Koz,

By correction factors I meant the Humidity, barometric pressure, ect used to "correct" the numbers for standard conditions (as defined by SAE).

-Dana
 
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