| Author |
Message |
    
Blake
| | Posted on Friday, August 23, 2002 - 12:52 pm: | 
|
Pete L.,
Are your dyno results corrected for standardized conditions (SAE or STD correction factors for air temperature, pressure, and humidity)? If not, do you know the atmospheric conditions during the testing? If so, or probably even if not, your engine is VERY strong!
You have right at 85RWHP and 83 FT-LB (11.7 Kg-m) of torque pumping out of a stock engine, and at only 5,500 rpm! Wow.
Also, what are the three different traces on each plot, I cannot make out the text.
I see what you mean though; it does seem like the torque takes a very abrupt downturn at 5,500 rpm. Almost looks like a switch is being thrown to purposefully diminish peak HP. Hmmmm... Did you try adjusting the timing? You might find that a few degrees of advance might help improve the top end a bit. See Aaron's Race Ignition Module Dyno Investigation which talks about this phenomenon. I'm totally guessing here, but it seems plausible that the export version stock ignition module may have more severe high rpm retardation than even the domestic version. If you gain top end with significantly more advance, that theory is probably valid. Also, if you don't already use one, a freer flowing filter such as a K&N filter, might help. And routing the breather exhaust outside the airbox will help too.
X1G,
You meant to say that you'd "expect nothing less more", right?  |
Blake
| | Posted on Friday, August 23, 2002 - 01:07 pm: |
|
Pete L.
One more thing. That little dip at 4,000 rpm *might* be better addressed through shimming of the needle which will enrichen the mid range without affecting top end. But hey, if going to a 195 main jet helped the engine run better all around, you might try a 200. I assume that the Fuchs dyno does not offer an exhaust gas analyzer (A/F ratio report)? That is such a great diagnostic tool for optimizing carburetion.
Is your engine stock? The power delivery with 83 FT-LBs torque is astounding for any stock Buell. |
X1glider
| | Posted on Friday, August 23, 2002 - 01:38 pm: |
|
Blake: hehe I guess u got me there!
AW: My cams are 46°. 9.5:1 not enough? thanks for the heads up on D.P.M. Pretty hard to find someone who can do good case repairs. The heads aren't damaged tho, he wants the chambers welded up and remachined so he can get rid of that heavy, mountainous dome of a piston. |
Petel
| | Posted on Friday, August 23, 2002 - 02:16 pm: |
|
Blake:
It`s the first time I`ve run anything on any type of dyno.I`m assuming it`s SAE adjusted as in the top it reads 25-1014hPa-41% G=2095% P=18.5mN.
This would be the air pressure/humidity etc?
Don`t know why there are seperate traces but I won`t be useing a Fuchs again because of the lack of A/F ratio info.This would tell me more about whats happening after 5500 than any trace.
The needle was shimmed using two dynojet washers before these runs.
It`s absolutetly stock apart from the exhaust can and the jets, with 2500miles on the clock.
The 2002 models come with lightning cams (Hi-contact ratio) as standard.
Next on the list is to modify the airbox (open it out and fit a K+N), re-route the breather out of the airbox and into a catch can.I`ll have a look at the ignition timing and think about a race ignition module for it but I really want to keep it a standard as possible.
Saying that I would like to see a clean run up to about 6200rpm which could see it making 90hp.
It looks like a bit of experimenting with the jets after the airbox mods and this is possible:-)
Next time I run it on a dyno I`ll make sure they have an A/F ratio meter!!
Thanks for the input.
Regards,
Petel. 02 M2 |
Blake
| | Posted on Friday, August 23, 2002 - 07:13 pm: |
|
Pete,
I wouldn't assume anything. Best call and ask if and how your run was corrected. Then you will know for certain. I've never seen such high torque numbers from a stock engine. Kinda makes me a bit skeptical. I'll peruse the dyno chart archives and see how many examples I can find were torque exceeds 80 FT-LB (11 Kg-m) between 4,000 and 5,750 rpm with a peak equaling 85 FT-LB (11.7 Kg-m). I'm betting I don't find any. You may have found a unique and very good combination of components. You have a 2" collector on your head pipe right? |
Petel
| | Posted on Saturday, August 24, 2002 - 03:58 am: |
|
Blake:
Morning, (UK poster).
The exact set-up is this:
Standard 40mm Keihin.
Throttle slide drilled,original spring,NOKK needle,Dynojet DET001 emulsion tube,Dynojet #195 main (I might go up to #200 when I find a place than runs A/F ratio`s with their dyno.)
Genuine Harley #45 slow jet.
Standard airbox/filter.Standard breather system.
2" collector (standard 02 M2 UK headers).
G-Force stainless oval race can.
This is a small company in Wales that have just started producing exhausts for Buells.
They supply the connector pipe which plugs into the can.
The can itself is 18" long with a 2" diameter straight through perforated tube surrounded by baffle packing.It was TOOO! loud so I welded a perforated stainless baffle right at the outlet pipe.Maybe this sets up a pressure wave that accounts for the mid-range?? Don`t know myself as most of the original setting up was useing the famous "Seat of the pants Dyno :-).
The quality of the charts is poor so here are the exact figures.
First run. #190 main.
4000rpm 57hp 10.4kgm
83.7hp at 5424rpm 11.3kgm at 4917rpm (83.4ft-lb).
Second run. #195 main.
4000rpm 60hp 10.8kgm
84.9hp at 5456rpm 11.3kgm at 4700rpm (83.4ft-lb).
Changing the main gave an increase of 2hp at top end.No change at all in the torque it just moved it 200rpm down the scale.But it gained me 3hp at 4000rpm and removed the midrange dip.
All I`m after now is removeing the flatline from 5500-6200.However if further changes do that at the expence of midrange I`ll stick with this set-up.It`s the range I use most and I don`t often red-line the bike (much;-)
Can I expect a hp gain by re-routing the breather system?
All the best,
Pete. |
Blake
| | Posted on Saturday, August 24, 2002 - 06:36 am: |
|
Yes, you might see a couple additional HP with removal of the breather exhaust from your intake. If you'll follow the link I posted on that above (yesterday's 12:52 PM post), you will see the comparison testing that Aaron performed. It is quite interesting. |
Forevernow
| | Posted on Sunday, August 25, 2002 - 12:50 am: |
|
hi everyone,i have a 99 m2 w/a forcewinder ,streetfighter exhaust,buell race ignition and a stock carb re jetted.i want to get headwork done(somthing along the lines of nallin stage 2),cams(256/536),an adjustable ignition,and probaly a mikuni.my problem is i dont have the cash to do all this at once and im wondering if i can get away with doing those mods in that order,has anyone here ever ran big valve ported heads with stock m2 cams?also can the thunder storm heads be milled enough to avoid having to run higher compression pistons with a set up like this?i would appreciate any ideas,the bike is making 79 rwhp and 76 lbs of torque as of now |
Blake
| | Posted on Sunday, August 25, 2002 - 09:37 pm: |
|
Forevernow,
You can definitely apply those upgrades incrementally. Not sure about milling the heads, but I'd shy away from that. Nallin Racing provides high quality elevated compression ratio pistons for a reason. If you want to run an elevated CR, I suggest you talk to the experts at Nallin racing. They are reputable and trustworthy folk. |
Petel
| | Posted on Wednesday, August 28, 2002 - 08:04 am: |
|
Attention Blake:
What do you think of this then?
Did the run two hours ago and again I apologise for the poor quality of the scan.
Scale is now 0-100bhp.
This is with the breather mods and the airbox mods I`ve been working on.
Carb remains the same,still running the #195 main jet.
91.1hp at 6093rpm.
12.0kgm at 4314rpm.
Not bad and that`s all folks!
I`m happy with that and I`ll post some images of the process when I get the film developed.(No digicam,I still live in the stone-age;-)
Petel. 02 M2 (Sorted) |
Blake
| | Posted on Wednesday, August 28, 2002 - 02:25 pm: |
|
Petel,
That's a very impressive result! Would you be so kind as to explain what changed since your last dyno test?
Did you obtain an explanation for the three separate traces?
What correction method, if any was used?
What HP is reported (PS DIN or SAE HP)? |
Blake
| | Posted on Wednesday, August 28, 2002 - 02:31 pm: |
|
A quick review of the different power standards...
SAE is The Society of Automotive Engineers, an american technical institution that sets standards for all kinds of technical issues in the US auto industry. Their specifications are regularly "borrowed" by other industries.
DIN is a German technical body (The Deutsche Institut fur Normung) that sets technical standards for all kinds of industries over there.
JIS is the Japanese eqivalent of DIN, AS, BSI etc. etc. and does the same job over there, and I believe sets the spec for PS.
In summary...
One SAE HP is 746 watts/0.746 kilowatts.
One DIN/JIS HP/PS is 735.5 watts.
SAE = Society of Automotive Engineers.
DIN = Deutsche Institut fur Normung.
PS = Abbreviation of German term for horsepower.
JIS = Japanese Institute of Standards.
1 DIN PS = 1 JIS HP = 0.986 SAE HP = 0.986 BSI HP
The term "BHP" simply indicates that the power was measured using a brake type dynamometer rather than an inertial type dynamometer. It has nothing to do with where the power was measured, for instance "at the crankshaft" or "at the rear wheel."
There may be a quiz later. |
Reepicheep
| | Posted on Wednesday, August 28, 2002 - 03:27 pm: |
|
Great synopsis Blake... But lets continue to explain why in many ways "the emperor is wearing no clothes"... at least regarding the whole dyno testing thing. Anything correct here is attributable to things Aaron has helped me understand, all errors are mine
1) The power produced by an internal combustion engine can have significant changes due to temperature and barometric pressures. Many dynos attempt to correct for this by applying various fudge factors, but they are just that, educated guesses as to corrections.
2) Many dynos are inertial, which allows the bike to spin up a drum of known mass (and thus known inertia). They simply measure the rate of change in the spinning drum, and attempt to work backwards to the power being put out by the engine. This again is a kludge though, a bike with a heavy flywheel and lots of other rotating mass will be bleeding a lot of power into spinning those things up and it will never show on the dyno. A GSXR-1000 will test much higher then a big twin, even if both were making exactly the same power.
3) It is measuring a transient response (spinning up the drum in a fixed amount of time). I have to believe this will cause transient carb or FI response to be the significant driver in power produced. On the street, steady state responses may "feel" much more significant. Also, the rate at which the drum will spin up is fixed for a given power curve, but likely won't match the way the bike would actually change speed at that same power level. It seems to me this could really misrepresent how a bike actually feels on the street, depending on how big the difference is between the rate the drum spins up versus the rate at which the bike actually changes speed on the street. Transient versus steady state responses would be weighted totally differently.
4) Brake type or eddy current dynos may solve some of these problems, but probably create others.
Dynos (IMHO) are very useful for before and after runs on the same day in the same place on the same dyno with the same bike. Do a pull, change the jets, do another pull. Change the exhaust, do another pull. Dial it in. Add an air / fuell meter, and an exhaust gas analyzer, and they become even more useful.
But to say "my GSXR-1000 pulls 150 horses on my dynojet, but your stupid Buell only pulls 80 on yours" shows a huge misunderstanding about what the a dynojet can actually tell you and how important it's answers are (not to say the Gixxer does not kick the Buells ass, but thats another topic )
I have a lot of experience in electronic instrumentation for jet engine test (150 hp? Chump change... how about 90,000+ pounds of thrust ). People not in the industry would be amazed at how many adjustments, assumptions, corrections and kludges have to be applied. It is REALLY HARD to measure this sort of stuff accurately even at the same facility, and even harder to do so in a remotely repeatable fashion.
Additions? Corrections? Anybody have enough runs on enough different dynos to give a percentage error (5%?, 10%?, 20%?) I bet its at least 15%... |
Petel
| | Posted on Wednesday, August 28, 2002 - 03:56 pm: |
|
Ok!
As far as my quest for power goes:
I could`nt find anywhere within 50miles of me that ran a dyno with an A/F ratio meter.So I went back to RGS who at least had the last three runs stored.I took the last chart with me and explained ultimate bhp was not the target but I was looking for a smooth curve from 5500-6200.
Kill it at 6500-6700 as I know it would`nt make power after that.
Before the run the guy said this is optimised for their F3000 and Touring Car set-ups.Ignore everything but the red line on the graph.
The current air temp/pressure/humidity is printed in the top lefthand of the graph.
The computer allows for changes so it is corrected to the current conditions.
In the right of the graph it shows the max.bhp in hp and the max. torque in kgm. DIN.
I don`t show this as it contains the Buells VIN no. and number plate(licence plate?).
The changes from last time?
Nothing in the carb.(still running #195main but I did turn the pilot jet down 1/4 turn as it was running rich at tickover).
Completely re-routed the breather system out of the airbox into a catch-can and vented to the atmos.
Took the back out of the K+N filter BU-1297 and the back out of the airbox,screened it with stainless mesh (bug-stopper).
This now allows a cross-flow with the filter still protected by the suitcase.
The internal snorkel is still in place and the carb vent still goes into the pressurised airbox as standard.
I think this is where the forcewinders fall down.
Bowl venting is still in the vacuum area inside the suitcase but air flows from both front and back of the filter.Kind of hard to explain but I`ve taken some photo`s and will post them when they are developed.(no digicam).
I`m also convinced that the baffle in the outlet creates a wave that stops scavenging and holds just the right amount of back-pressure.
Blind luck in my case!
It works for me and it`s the end of development for the M2.
I`m not going for bigger CC`s or worked heads as parts in the UK are bloody hard to find and performance parts are impossible unless you want Genuine Buell and a three month wait!
Regards.
Pete. |
Aaron
| | Posted on Wednesday, August 28, 2002 - 07:13 pm: |
|
Bill, the Dynojet's inertia dyno has more or less set the standard, and the variation from one to the other of that kind of machine is pretty small. MCN actually did a test awhile back where they visited several local shops with Dynojets with the same bike on the same day and they only saw like 1-2% difference. And it makes sense when you think about it, there's really almost nothing to go wrong with the things. The mass of the drum doesn't change, and the thing just has a sensor to tell the computer every time a revolution has occurred. I guess if the pillow block bearings were worn it'd show up.
Really, the error is in the correction process, and even that error has been greatly mitigated by the automatic weather station that all Dynojets come with now. I wouldn't call that the correction process a "fudge factor", either, I'm sure there was a lot of work put into the correction formulas by SAE and the other bodies involved. No, it ain't perfect, and Dynojet's implementation of it is incomplete, but in the real world, it works pretty good.
Also, I wouldn't call an inertia test a "kludge". In the real world, extra rotating mass diverts some of the engine's power into storage, leaving less available to accelerate the bike. So in a way, measuring with an inerta dyno, as opposed to a brake dyno, is more real world. No, it's not as accurate of a measurement of the engine's real hp as you get with a brake dyno, but it's a more accurate representation of how much power you actually end up with. |
Blake
| | Posted on Wednesday, August 28, 2002 - 11:31 pm: |
|
Bill,
I'm with Aaron. 
The science of fluid mechanics plainly defines the factors to compensate for varying temperatures and pressures. Thermodynamics and chemistry allow us to understand how to factor for humidity. That's it. There really isn't a lot of guesswork involved. An error of 15% would be unforgivable.
Consider that For a land speed bike, BHP is what is most relevant. When approaching terminal velocity, the bike is crawling slowing towards peak speed. Engine/flywheel inertia at that point is therefore not a factor.
For a drag bike, the inertial dyno more closely replicates the real world. Accelerating WOT in 2nd gear, the engine in my M2 spins up much faster than it would in 5th gear on the dyno. So in 2nd gear, I actually have less RWHP than what my 5th gear dyno plot indicates.
A road racing bike is somewhere in between.
You are correct though when it comes to accelerating in higher gears. On the track, the engine does not spin up as fast as on the dyno, so my M2 would actually be putting down more RWHP than indicated on my 5th gear dyno plot.
It is of no consequence. The dyno tells me the engine is optimally tuned and how strong it is relative to other similarly tested engines. That's what I really want to know. |
Blake
| | Posted on Wednesday, August 28, 2002 - 11:39 pm: |
|
Petel,
Thanks for explaining that. Sounds like removing the crankcase breather from the intake and opening up the airbox really did the trick. Interesting to see a BHP dyno test result. I wonder if anyone has compared BHP results to inertial dyno results for a Buell.
One more question... Did they run the test in 5th gear or 4th?
You should be VERY happy with those results. Outstanding engine you have there. One of the best stock engine dynos I've seen.
You're hesitant to reveal your VIN and plate #?  You ever park you bike in public?  |
Gcpoland
| | Posted on Thursday, August 29, 2002 - 01:01 am: |
|
Dynojet has a huge kludge factor. Even they change it from one version of software to the next. If you get hung up just looking at the numbers, you are looking at the wrong thing. If you look at the shape of the curves, this is where you gain your usable information. Looking at peak numbers is only for those who want bragging rights or shops who want to prove to the customer how well they have tuned their bike.
Remember that Dynojet markets their machines to dealers, to encourage and promote parts sales. Nothing wrong with that, just something you should keep in mind, when trying to compare. Chassis dynos have their place, but they are not the precise machines that some would like you to believe they are.
Everybody wants to show their buddies, (on Paper), how fast their bike (or car) is. Dynojet plays to this audience and sells the hell out of their machines on this basis. Just remember that it is a tool, not the final determination of anything. |
Blake
| | Posted on Thursday, August 29, 2002 - 02:14 am: |
|
GCPoland,
Maybe you'd like to share the details of Dynojet's "huge kluge" factor? You see, as I understand the scenario, it wasn't dynojet that invented the SAE or STD correction formulas. Those were generated by professional standards institutes and societies who very much know what they are doing.
The fact that Dynojet might change/improve the rigor of their correction algorithms is certainly not convincing evidence that they are deficient or lacking integrity. In fact, I propose it is evidence of just the opposite, that Dynojet invests much effort into further developing the integrity of their correction algorithms.
I believe the inertial dyno to be far more precise than the engine output it is measuring and in many cases more precise than the operator who is running the test.
I await you answer. |
Steveshakeshaft
| | Posted on Thursday, August 29, 2002 - 04:49 am: |
|
Blake, bikes DO get stolen over here. It is by no means unheard of for Buells to get "stolen to order" by undesirable folk. I think Petel is right to not identify his bike on the net. |
Reepicheep
| | Posted on Thursday, August 29, 2002 - 10:09 am: |
|
Ultimately, Aaron answered the question. If they can get 1% to 2% repeatability between different installations, then Kudo's to them! Thats an impressive achievement.
I still wonder about transient versus steady state response, but after posting yesterday I went to the teamelves site and watched the Dyno run, and it looks like the inertia of the drum is pretty well chosen to match what the bike would actually do in at least some gears.
But I guess the transient response is what really matters in terms of how a bike feels... and that is what they are measuring. Steady state would only come into play when going for something strange, like, I don't know, a landspeed record or something
And frankly, what they are measuring really IS steady state. Because of my background, when I think of transients I think of a change from 90,000 pounds of thrust to -30,000 pounds in about 23 milliseconds... (a reading I had to recover manually because said transient ripped the acquisition parts of the data systems off the teststand and ingested many of them through said engine). Talk about a big bang...
But I digress. The 2% repeatability between locations and operators means that the Dynojets really are a useful tool for global comparisons... though I would still want a level of trust of the operator / shop to not be purposely fudging things (like a shady performance shop who gets numbers for their mods that nobody else can repeat). But thats just a truthfullness issue, not a hardware problem...
Thanks for the clarifications Blake and Aaron.. |
Aaron
| | Posted on Thursday, August 29, 2002 - 10:58 am: |
|
"I believe the inertial dyno to be far more precise than the engine output it is measuring and in many cases more precise than the operator who is running the test."
Ding ding ding! We have a winner!
Damn motor is varying all over the place with temp. And it's not a static temp thing either, it has to do with different parts of it being different temps. The heat soak thing is huge. The key to tuning a bike is making sure your procedures are conducive to getting a repeatable result. Otherwise you're not getting anywhere.
I'm still not sure I agree with him on the hp vs. gearing thing. Hp is just torque times rpm. Gearing moves torque & rpm opposite directions in equal amounts, hp should stay the same. I more or less accept the notion that with less gear reduction, the rotating mass on the engine side of the gearing has less influence, because essentially the drum has more mechanical advantage on it. That's how I rationalize that I generally see a slightly higher hp result in 5th than 4th.
Funny thing though, although many bikes show a higher result in 5th than 4th, some don't. My Blast for example shows pretty much the same number. Dale's LSR Sporty actually showed consistently lower numbers in 5th.
I couldn't do any 5th or 6th gear pulls on the LSR bike because the dyno croaks if you run it over 200mph. |
Gcpoland
| | Posted on Thursday, August 29, 2002 - 11:18 am: |
|
Blake
Ask someone who has a 150 Dyno to do 3 runs for you using the version 3.x software. Then reboot the pc and do 3 runs using the 4.x software.
We just did my M2. Ver 3.x =79.3 peak hp Ver 4.x =73.4 peak hp
Correction factors maybe standard formulas but the implementation in software can and does vary. What Dynojet gives you is consistency not accuracy. That is a big differance, but only important to those who wish to crow about big numbers. I know 2 operators in my area that will not use the 4.x software, because it gives lower numbers, and customers that have been on the dyno before get mad when they get lower numbers.
Why did Dynojet do it. You would have to ask them, but my guess is that are trying to fine tune the system. What good is corrected HP anyway? It tries to make up for weather and pressure factors, an educated guess at best. I have formulas for correcting jetting for air density, but they only get you close. People who believe that math can build motors, haven't built many motors.
Tune the shape of your curves, not peak numbers. You could play the same numbers and correction game by running at the drag strip and converting your time, speed and weight to HP. This is as accurate as any number you will get on the dyno. But you won't have a printout and that is what most people want.
If you believe that the Dynojet chassis dyno is the the bible on HP, that is your call, but you should talk to a variety of engine guys and get their feelings on them. Most will tell you that they are a good advertising tool and that is all.
What Dynojet gives you is their best estimate of corrected HP. If you read their manuals and take their courses, they make no bones about it. They try to give the best estimate they can, given the varying conditions. I didn't say it was a poor fudge factor, but you have to have a fudge factor to give this estimate because that is what people want. People (customers) become offended if the estimate isn't high enough.
If you really want to see the fudge factor at work, take your raw HP numbers and use your correction formulas with the atmospheric data printed at the top of the sheet. Does your corrected HP number match what the Dynojet software calculated? (ver 3.x does not equal ver 4.x)
It isn't really that important anyway. The factors are consistant enough so you can compare your bike in the middle of winter and the middle of summer and get usable data. The problem comes in when you treat the numbers as gospel. The shape of the curves will never change but the numbers will go up and down, depending how you apply correction factors. |
Aaron
| | Posted on Thursday, August 29, 2002 - 11:42 am: |
|
"People who believe that math can build motors, haven't built many motors."
There's a very famous motor guy I know who works out all his engine combinations in advance with formulas. Over the years he's figured out which formulas work and which ones don't.
If you send him your heads, and let him do the porting and select the cams and the pistons to match (often he'll get custom pistons and/or cams made), he can nail it right out of the box. It's amazing.
As an example, using these formulas he came up with a package that predicted 115hp for a certain M2. It made 115.5.
Your points on the dyno are well taken, though ... I certainly don't view the Dynojet's result as an accurate number, nor do I think that's particularly important. What's important is that it's more or less the standard because it outnumbers all other types of dynos put together, the correction process works well enough for reasonable comparisons, and the consistency between the dynos is good because there's so little to go wrong with them. In fact, like Blake said, other things besides the dyno are introducing more inconsistency into the measurement than the dyno itself.
I don't have any experience with that software revision you're referring to, but my guess is that's two versions of PEP (not WinPEP), so it would be very old. I know the 150 is discontinued. I believe it can be upgraded to the latest electronics with the integrated weather station and use WinPEP, though. |
Gcpoland
| | Posted on Thursday, August 29, 2002 - 12:25 pm: |
|
Sorry I have made an error. I got the version numbers backwards. Ver 4 gives the higher reading and 3 gives the lower.
Building motors with math. Exactly my point only made better than I did. Experience is the key. Experience gives you the frame of referance to use the math. I once designed the best set of 2 stroke pipes for one of my race motors (on paper). The problem was that in the dyno room, they couldn't make enough power to get out of their own way. I didn't have the experience to use the formulas.
Sometimes I sound like I dislike Dynojet dynos. That could not be further from the truth. They are a great time saving tool, but what I try to tell people is you can do the same tunning without it. It will take longer, but for the average street guy the result will be the same, minus the neat printout to show your pals.
Only my opinion, but just because they outnumber all other chassis set ups doesn't make their correction factors gospel to me. Dynojets big advantage is that they have convinced the general public that it is the only way to tune a motorcycle, snowmobile or cart. Their advertising has been the most sucessful part of their program. You can't run a shop now without buying one. Average customers have been so brainwashed by magazine articles and advertising that they insist that their bike must be tuned on the dyno. It has forced some small shops to buy or die. A great shame because some of these guys are really talanted and the last thing they need is a dyno taking up valuable space. A good running street bike runs good whether tuned on a dyno or by a guy reading plugs and piston tops. The winner is still the first one from point 'a' to point 'b'.
Sorry for the rant. I won't rant about the Dynojet further. A tool is only a tool. |
Sarodude
| | Posted on Thursday, August 29, 2002 - 01:28 pm: |
|
Besides the standard correction stuff, does DynoJet publicize what if not how they're fudge-factoring?
I read somewhere on BadWeB that they actually had a correction in there to get an inertia reading to be closer to a brake reading. Don't know if there's even a shred of truth there, but I'd really like to know stuff like that.
-Saro |
Aaron
| | Posted on Thursday, August 29, 2002 - 02:08 pm: |
|
Gary, I thought your comments were excellent, and I didn't read into them that you dislike the Dynojet at all.
Saro, I've heard from pretty reliable sources that what you just said is true. But I have no way of proving it.
My main point in all this is that it doesn't matter. All that matters is that the vast majority of the people showing dyno sheets use this same instrument and they're pretty good for comparing to each other. No, technically maybe it ain't the "right" answer and certainly other dynos will give a different answer and even an old version of this one might give a different answer, but in the real world, who cares. |
Blake
| | Posted on Friday, August 30, 2002 - 01:06 am: |
|
Gary,
Don't the top professional race teams in the world, formula 1, Superbike, Moto GP, all use a dyno to optimize the state of tune of their engines? Don't some moto race classes use a dyno to verify contestants' bikes are within class RWHP limits? Whether a brake dyno running straight off the crank or a rear wheel inertial dyno. It doens't matter. The result is the same. Tuning is optimized and in very short order. And no matter what you may believe, the environmental correction factors are indeed scientifically derived. They are not in any way "fudge" factors. Are they 100% infalibly perfect? No, but they aren't guestimated fudge factors either.
Say I gave you and Aaron each a Nallinized Blast with undisclosed performance components and a random state of tune (carb and ignition); by the time you returned from your first plug and piston-top reading ride, Aaron with his dynamometer and A/F sensor would likely already have the jetting and timing optimized.
You'll spend a lot of time dialing in the engine having to tune it the old fashioned way. And I'm sorry, the experienced dyno tuner will do a better (more optimum) job too. Bring programmable EFI into the mix and a tuner without a dyno and A/F meter will be pretty much left standing there scratching his head.
Uh, GC, You first stated that DJ changed their correction factors in their new version 4 software resulting in lower reported results so your friend still used the old version 3. But then you say it's actually the new version that gives higher results? I guess he's not still using version 3 then is he?
I have a hard time believing that a change in the correction factor algorithm would result in an 8% improvement. There was likely something else involved. Something relating directly to the dyno itself, not the environmental correction factor. Have him process/report the results uncorrected for each software version; I suspect the results will be similar (8% improvement with version 4) thus the difference would have nothing to do with correction algorithms.
Anyway, it's fun to argue about eh?
I guess you didn't know... I LIKE to argue. ![:]](http://www.badweatherbikers.com/buell/clipart/proud.gif)
No shame in a friendly discussion! |
Pammy
| | Posted on Friday, August 30, 2002 - 10:06 pm: |
|
A dyno taking up valuable space...I beg to differ with that statement. Being in business for over 20 years, tuning bikes with and without...I will waste my valuable space. Besides, It comes in handy as a lift and for cleaning the rear wheel(as it rolls). |
Blake
| | Posted on Friday, August 30, 2002 - 10:40 pm: |
|
GC,
Never mind. I reread your post. I must have had too much coffee after dinner yesterday. What an a-hole I can be. Sorry for the undeserved rant.
Blake (theadmin/azzholeextrordinaire) |
|