OffCenter,

It's my beleif that a high RPM motor geared with a small pinion will acclerate just as fast as a Low RPM motor with a big pinion. I personaly don't beleive the mechnics, or elecrical propertys of either of these motors gives it any advantage if the proper gear is choosen for each motor. The torque whould be the same with proper gearing.

Fantom low, medium, and high power factor numbers remain a mystery to me. I have a vague idea of how they are calculated, and given the fact that Fantom dyno users always use the same flywheel, I beleive that these numbers are basicly meaningless. It's all related to the fact that a single flywheel can not possibly correctly represent the actual load seen by a variety of cars and gearing situations. I'm not really doubting the power numbers a flywheel dyno gives, however spinup time on a flywheel dyno in my opion is worthless. My understanding of Fantom Low, Medium, and High power factor numbers, is that it's directly related to spin up time, so I find those numbers to be nearly worthless. (this is just my opion, but I have good reasons for having this opion)

I'm not trying to say the Fantom itself is worthless... just the low, medium, and High power numbers...

By the way Tfram... I accept your idea about the lack of support for the wire as also being a explination for why there seem to be more smokers from the ranks of the high RPM motors... not to mention the fact that the higher RPM would tend to cause the wire to have more force throwing it towards the outside...


FYI... Mike Golden gave me this link a week or so ago... There is some really good basic information here about motors and gearing...

http://www.geocities.com/budb3/arts/gear/gfun.html

For those who don't know this, it is Illegal for Stock Motors to have their windings epoxied, and they cannot be epoxy balenced. Because their windings are not epoxied, they fly outward under high RPM. This can cause the windings to get caught or cut on the magnets, which will smoke the motor. I've personally wound modified motors myself, and it only took me one try to find out that this happens. Of course it is more pronounced on mod motors, but the same principal still applies.

Actualy... are you sure it's illegal to have epoxy on the stock motor? It's my understanding that it's only illegal to ballance the arm using epoxy, and that having epoxy to hold the wires in place is not nessasarly against the rules. I think this recently came up, somewhere else around here...

I personaly don't really know for sure which is the correct answer... I guess I should go read the ROAR rule book again.

The rule book basicly states... 'no epoxy balancing of armatures' this is for re-buildable stock motors. I think that technicaly this does not preclude the use of epoxy for other purposes.

For instance... the tag in the motors are epoxied in...

Then again, at some point how would you know if epoxy was there for balancing or for securing wires, etc...?

I'm not sure adding epoxy would be a great idea anyway... it would likly impeed air flow to the wires, and tend to reduce the cooling effect that may be taking place on these motors. You may gain stablity in the physical posistion of the wires, but would likely loose in cooling ability.

Assumming we dicount the low/med/high #'S I also have these available from the dyno. This is a rev of the monster example:
Max power 60.91 @ 13933RPM
Max Rpm 22366 @5.2sec
Max torque 909gm/cm
Max Eff. 49%@ 14942 Rpm

Which of these numbers changing would show the most improvement that any tuning, truing or changing of springs/brushes make.

Do I only want to see more RPM's?
Does an increase of power mean more than an increase in RPM would
Would increase in efficiency or more torque be a more important # to be looking at.

I am using the dyno to try see what changes best suit a particular motor and gaining RPM the point of losing some other factor might not be an improvement, I need help understanding what role the power and efficiency play in determining if a change I made was really for the better.

By knowing which #s are most beneficial I think it would also help me determine which of 2 or 3 motors tested would be a better one.

In my humble opion Max Power is what you want to increase. From what I have seen of other's Fantom data, 60 watts is pretty low for a stock motor. But, it's not really a good idea to compare dyno numbers... Too many variables between one dyno and another.

If you take your data, and put it into a spreadsheet, or Golden's DynoViewer, you will see that Max Power, pretty much uniformly translates into more power everywhere in the RPM range.


POWER is most important... next would be efficiency. Well... lower track times would be most important... then POWER, then efficiency...


If you have the Facts II software, I would highly recomend viewing it on Golden's DynoViewer... I know of no way to get the DOS Facts data into a format that would allow you to transfer it to the DynoViewer without the use of the Facts II software.

RPM is needed only for selecting gearing. The same is basicly true of torque.

Thank you. Having the machine and not really knowing what it does was like watching TV with the sound off. You see stuff going on but really don't have an idea of what your seeing. Now at least with any changes I make I can track progress. My only other avenue for info is at the track and there really isn't time between races for lessons. Your help will be appreciated:wave:

Actually if I had no way to get the data into something like the DynoViewer... I would use Max Power, and the RPM where it occurs to do all my gearing.


Say you have motor X, that has max power of 60 @ 22,366 RPM, and motor Y, that has max power of 62 @ 20,000 RPM. First I'd say Motor Y is the better motor, and then I'd set out to try and figure out how to gear it.

Using lap times to select the best gearing is the best way... lets say you get the best gearing for motor X, and then want to switch to Motor Y...

Lets say you have a ratio of 5.0 for Motor X...

( 5 / 22,366 ) * 20,000 = 4.47

I would use a 4.47 gear ratio with Motor Y.

This is based on my newest gearing theroy that says using the point of peak power for gearing is the easiest way... I am pretty confident that if the data is correct, the gearing calculation should work out. If you showed me actual Facts II data, I could illustrate why I have come to this conclusion... I could show you with Robitronic data too, but you might not be as eager to beleive me if your a Fantom user...

I'm not saying this is the absolute best way, but it is easy, and I think 90% of the time or better, it should work.

Have been away for several days, so missed some of the discussion. A couple of points:
1. The max power will always be at 50% of max rpm. The is because power is a parabolic curve derived from the torque and rpm curves, which, at constant voltage, are straight lines. So Dyno is correct, it is alway at 50% max RPM.
2. A flywheel is not a constant load for a dyno. Its moment of inertia gives a maximum load at startup and goes to zero load at maximum rpms. (If it wasn't zero load, it won't be maximum speed, and if it wasn't a heavy load at startup, acceleration to top speed would be "instantaneous."))
3. I think there are some people that are confusing power curves and useful power. If you think about oval racing, when a car goes into a turn, it slows down to some degree. That represents the "lowest" motor speed. At the end of the straightaway, it represents the maximum motor speed. For the car to work well, the motor has to provide the necessary power to get between those 2 speeds, i.e., thru the turn, accelerate down the straight, and maintain top speed. The "size" of the power band needed therefore depends on the track characteristics. The argument can be extended to on-road which is a series of curves connected by straights.
4. I think (3) explains why more people are liking "rpm" motors. If you have a sweeping course, then the motor doesn't change speed much and either a torque or rpm motor will work (with a torque motor being easier to find the right gear). But if you need larger changes in motor rpms, then you need an rpm motor. In either case, you need a motor that makes the necessary power in a "useful" range. This "useful range" appears to correspond to 15-30 amps for stock. You can load the motor up more, but i2r losses due to the increased current usually makes the motor hotter at the end of the race and "soft."

Well based on my dyno data, and Golden's DynoViewer, there is no differance in this 'useable' power area when you compare a motor with equal power, but differnt RPM. Near as I can tell, the only real way to increase the range of useable power, is to increase power overall.

When you compare two motors with differnt power levels, then it's easy to see how and where the advantage could be.

I think there is some possiblity that some motors just happen to hit on the best possible 'rollout' for a perticular motor. Even with 64 pitch gears, there are a finite number of ratios that can be obtained. Now you could play with tire size, and swaping both Pinion and Spur gear, but most people don't go to these lenghths.

Anyway... I still think if there are differances in the RPM and Torque motors, it's related to something other then 'powerband'.

Just bringing this to the front page...

And giving a BIG thanks to Mike Golden for the DynoViewer. I spent a few hours this weekend inputting data front some motor testing. What a great tool the viewer is for us CE guys that don't have a PC link like the others do.

Also - Glenn did you save any dyno numbers from when you had the CE? I was hoping to use some of your better #'s as a baseline for mine.

Thanks, Denney

No, I didn't really save any of my TD data... well I did, but I didn't do it in any orginzed fashion.

Basicly I was going by much of Big Jim's recomendations. at 7 volts, 20 amps, 100 watts... etc...

Actualy though I did dyno some motors this weekend on my Robitronic and a TD that was at the track... using 5 volt setting (we're all running 4 cell oval).... 84 watts at 30 amps was about the best motor... 64 at 20 amps. I saw a whole bunch of other peoples motors that were barely getting 74 at 30 amps...

These stock motors that were putting out 84 watts, at 30 amps, 5 volts were a GM3, a Paradox, a Monster, and a P2K... (actualy the P2K was the only one to hit 84, but all these types of motors were able to put out at least 81 watts at 30 amps.

I let a local fast guy use my Monster, used the DynoViewer to figure how to gear it in relation tho his really good GM3.... He TQed with the Monster, but basicly his GM3 ran just as good, he ran his GM3 in the main and had a lap on the feild. He would have had more laps, but second place kept him from getting by him, by roughing him up a bit... it was all in good fun really, but he was blazingly fast.... and the guys he was competing against were also very fast... but my personal feeling is that he was beating them with motor mostly. I saw dyno data from the second place guys motor... it was like a 70 watt at 30 amps, 5 volts... I tried to loan my motor to the second place guy... but he apparently wanted to run his own... I gave him a hard time afterwords about getting beat so badly...

On the Robitronic, my Monster was like 61, and the winner had a 61.7 watt GM3.... He didn't want to try my 63 watt P2K...

I ran 19 turn... I have a 90 watt Chameleon II... up from 87 watts previously. It was flying down the straights, but I just can't get through the corners...

I got me a tire truer now, and I'm going to be concentrating on getting my setup much better for the rest of the season.

I have question. I just got a Robitronic dyno. What would cause a bad curve? I made my first pull on a Trinity Monster stock and it looked good. But on the second pull with the same motor some time later it did not look good. The graph was a little jagged at the end. I'm still new at reading dyno reads so any help would be appreciated. Thanks.

It's a mystery Tskelton...

People from Robitronic have claimed it has something to do with bushings, presuably the bushings causing little voltage spikes or something. However I have seen the same behavior on motors with bearings, so I don't beleive this explination.

My best guess is that it has something to do with 'commutation'... or in other words, I think it has to do with how well the motor is transfering the electrical power to the windings of the motor, via the brushes and commutator.

However, I see no direct correlation between how well a motor runs and how much it has these 'glitches'.

I do know that these glitches occur more on some motors then they do on ohter motors. It seems that on some motors, you can hardly ever get a clean dyno run, other motors rarely have those glitches.

I personaly often try to get runs without any glitches, mostly because I often try to display some of my data and findings. This often causes alot of extra effort on my part. If I'm dynoing for my own personal use at the track or something where time is more important then perfection... I ignore the glitches for the most part. If the glitche effected parts of the curve I am most interested in, then I will make anohter dyno run as well.

Denny
I have a TD and punch all my data into a spread sheet. I could send some of my better numbers if you like. Realize that no 2 dyno's will read the same.

300M - Thanks, I would appreciate that very much. I'm not so much trying to compare exact numbers, but relationships between rpm/eff/tq/watts. I have spent a bunch of time inputting data into excel & trying to graph them, but the Dynoviewer is way easier - You could send dynoviewer files if you have them too. I have attached the results of a P2K I've been working on, it's still a work in progress, but looks hopeful.

Denney

DynoMoHum will you be making it to snowbirds?

No, I won't be making it to the snowbirds... I have a hard enough time getting my wife to let me go to race on a Friday night where I won't return home till after midnight...

Besides... I'd be like dead last, due to my poor driving and car setup skills.

A few locals will be going... the Ulbriks I'm sure... Big John Zubak... Ted and Bobby Flack, Walter Henderson, and a local guy that's helped me alot over the last couple years... Keith Racknor. I just try to stay out of these guys way when they're all at the local track... If you see Keith there... tell him 'Mr RC' said hi...

FYI on golden's DynoViewer...

There's a minnor bug I see with regard to CE TurboDyno Data... If you leave a line empty, it seems to have problems with it... Putting in a empty data point, rather then just ignoring it...

Also... You can enter data into a text file, with a format like the Robitronic data uses, and then you can read it by using the 'Load Robi Data' menu item. You may find entering your CE data easier just by editing a text file with the Robi format...


The format is pretty straight forward... feilds are seperated by a ; and a 'tab'... The order is...

RPM; Power; Eff; Torque; Volt; Amp;

You can enter as many or as few data points as you like in this type of file.

Denny: I will post my stuff later tonight as the file is at home :)
I will see what I have on dyno files from golden's viewer.

I recently had someone ask me how I determin gearing using the DynoViewer. In this perticular case, the person was using a TurboDyno... they eventualy gave me a couple TD files to look at.

I found it very hard to explain why I do what I do with my gearing choices... Perticularly when one motor is not really as good as another. I started to go into a long explination of what has lead me to some of my conclusions...

One of the things it forced me to look at was some TurboDyno data again... ( I sold mine to Denney )

I would like to attempt to answer the question more througly... however I'm still trying to figure out how...


One thing that has complicated my thoughts is in trying to explain how to gear when given TurboDyno data... It turns out, that I find it much more difficult, and it forces me to basicly point out some things that I see as problematic with trying to use a TurboDyno to accurately evaluate motors.

More later...

A hint of what I have in mind...

I'm begining to think that TurboDyno users should normaly use the 5 volt setting, even when they race 6 cell. The reason I say this, is because it is more likely to show you the true nature of a motor when you view data at 30 amps or less. Mainly this is because at 7 volts, 30 amps has not really started to reach the point of peak power. At 30 amps 5 volts, the peak should be pretty close to this... To me, I can tell more about a motor from it's peak power, then nearly anything else... with typical 7 volt TurboDyno tests, I can only guess what is happening at peak power.

Even at 5 volts with steps of 30, 28, 26, 24, 22, and 20... (which is personaly what I would recomend) it's very hard to get a really good idea of a motor's overall charactoristics. But I think I could learn more from these steps, then the 7 volt steps normaly used by many TurboDyno users.

Denny
I was tied up last night and worked late. Will be Friday AM on the data.

Dyno: I do not have trouble gearing mine and I use a TD. You might be reading to much into the equation on this.... Time is my enemy right now so I cannot elorabate right now. Boss is pushing me to do 140% of my capicity :p

I understand that it is not all that hard to gear a motor using TurboDyno data... However I also still beleive that there are some issues that need to be understood to do it well. Mostly it can be somewhat difficult at times to see which motor is really best, primarly because you see things from a very small window of the motor's total operating range.

Dynohohum, In your opinion when viewing 2 or 3 stock motors what determines which is a good motor. Assuming you use the same dyno for testing each your numbers should be relative to each other. I see power, rpm, torque and efficiency. Now if all three show similar power and torque do you go for the most rpms? I know that some lesser rpm motors stomp higher ones on the track. I realize they could be geared differently and spool up times come into play, but off the dyno numbers how do you determine which is good vs. bad? How does the graph work better than just reading the numbers?

To some degree it depends on the Dyno in use.

In general I think Peak power is a very good indicator of orverall useable power. I base this on looking at tons of dyno data, and trying to understand it.

Next is effciencey and to be honest, I haven't found a good way to determin how much is enough, or how much is too little... Too much is never a problem... basicly with effciency, the more the merrier.... but it does help if it's located in a really good spot. I haven't came to any real conclusions on where it should be either... Basicly I rarely see efficincy as a problem with most motors.

Lastly I look at RPM. Recent observations by me, and others have lead me to beleive that there may be some value in RPM stictly as possibly allowing a little more cooling of the motor, due to more air whirling around inside the can...

Ok... I lied... results on the track are the most important... but we all know that...


As for TurboDyno Data... in absense of knowing the actual point of Peak POWER... I'm thinking that by looking at the slope of the power curve is a good indicator of what the peak power is likely to be... To do this properly, you have to adjust the data to take into account the gearing that is likely to be used... Without gearing, the slopes are fairly meaningless in two motors with greatly differnt RPM. This is what I'm working on now, trying to explain this idea.

Graphs vs. Numbers... Either works fine... but i'm 100% convinced that if you don't apply gearing to the data, the numbers can easily fool you. You don't have to graph it, but you do have to change the numbers based on gear ratios...

Viewing things with a graph tends to make it all easier for me, but it's mainly just a personal choice.

Well, as a turbodyno user, I think I need to chime in on a few things.

First, you should always tune your motors based on what your "best guess" is of "on track voltage" Yes, the normally accepted 7.0v for 6 cell and 5.0v for 4 cell are ok. You can use the standard loads for 4 cell because the motor hits peak power at or before 30 amps.

If you only have a 30 amp dyno, you're pretty much hozed for 6 cell racing. The best compromise is to put trendlines in an excel spreadsheet and extrapolate what the peak power is. I've checked this out on my dyno and it's normally pretty close as long as the comm is in good shape.

As for gearing, oval is pretty easy, I take split times on the track and use the length of that section to see what the motor is running (back the average RPM for that section out using the rollout). I normally gear to go just below peak power at the slowest part of the track (slightly higher current than peak power). Then fine tune with lap times.

On the roadcourses, I split the straight in half and use that as a starting point for gearing. It's easier with the datalogger because I get the peak current at each corner but that's another story.

Basically, you have to run the same voltage as "on track" because that's the only way to figure out what load the motor is pulling. If you use 5 volt numbers you will get fooled because the amp draw will be way off.

The best way to view turbo data for 6 cell is to have the dyno updated and test up to 45 amps.

What I look at on the turbodyno is:

1) Peak power
2) The slope of the torque curve. (You want more everywhere and still have good power)
3) Efficiency. (more is better because there's less heat)

RPM means nothing once you compensate with gearing.

When I was talking about gearing... I was talking about something slightly differnt then Fred is... Basicly, I've never made any attempt to do what Fred is doing.

The only thing I use the dyno for in terms of gearing, is if I already have one motor that I feel is geared correctly... based on track times... Once I have this referance motor... I use the dyno to gear a new motor in relation to the other motor's gearing.

Reading what Fred has described, fits in really closely with what some of my own personal theorys are with regards to gearing... Basicly I think normal operating range should be between peak power and peak effciency. Sometimes your forced out of that range, but I think that is where things should be centered... From what I can see of what Fred is doing, it makes perfect sense to me.

The reason I was suggesting 5 volt testing might be best, is because it's not as hard on the test motor...


Typicaly what is the current input when a stock motor peaks at the 7 volt setting on a turbodyno? 40 amps? maybe higher? What about 5 volts? 30 amps?

One thing I see as slightly problematic with all dynos, except maybe for something like the CS dyno... The voltage at the motor is not the same as will be seen in the car under heavy load... With the CE Turbodyno it's too high, and with the Robitronic and Fantom, it's too low... AMP numbers are inaccurate as a result as well. So... I think it would be very hard to make a one to one comparsion of dyno numbers and real car numbers... It's probably fairly easy to get close enough with either of the dynos... but it's not exact.

Fred... I'm also currious... what kind of settings/steps do you use on the TurboDyno? Can you give me an example of some data you use?

Actualy, I'd like to see other peoples TurboDyno data as well...

Oh... and Denney... I think that P2K you gave data for a few items back, looks like a pretty good motor...

Peak current at 5 volts is at around 28 amps sometimes 30. I can only guess at peak current at 7 volts but it's around 40 amps.

Both types of dyno's have trade off's.

The TD does not do a very good job of simulating on track voltage and it builds excess heat during the end of the pull. The motor doesn't see these steady state conditions on the track. The voltage thing is less of an issue with the 3300's because there is less voltage drop at high loads. Heat is a big issue at 5 volts though. I'm going to look at that a little when I get back from Vegas.

The flywheel dyno's have their own set of problems. I'll limit this to the Robi because I haven't seen some of the Fantom results that it would take to lump both together. Judging by the Robi data that Dyno has provided, the Robi has lower voltage under heavy loads (high amps). It's a bit more than what I've seen on the track with the new batteries but it's a start. Flywheel dyno's in general are less accurate due to the short time they spend at each datapoint. I think the Robi samples at a higher rate and is better but that's another story. Typically inertia dyno's are fooled by the weight of the armature. A lighter armature will often show more power than a heavier one because the software doesn't take into account the "flywheel" effect of the arm. This is not a big issue as long as all of the arms are about the same weight.

Posts like this normally start a big argument over what type of dyno is better. Let's try to cut this one short by saying that neither one is better, they are just different. There's nothing wrong with either type as long as they make you faster on the track. In the end they're just a tool and you have to use them properly.

Here's a few more I've run lately. The Mvp I'm basically done with, the GM3 belongs to a friend & I'm still sorting it put, the 19T is a Cham 2 I've had a while & haven't done anything to yet...

I've been tuning for 12th lately:

5 volts

18-20-22-25-28-30 amps

Not much data here at work... but peak power for a blue endbell is 70-75 watts at 28 amps

I think the peak is actually at 30 amps but the brushes get too hot by then. I'm going to try running the motor at 30 amps first to check it out.

here's the MVP data

Denney... that's only one motor you just posted... you indicated there were more... what happened to the others?

I don't have any idea what a good 19 turn looks like... although I did see some hitting 115 or so at 5 volts 30 amps recently... that's about the only numbers I remember from the 19 turn motors...

...and the GM3 (guess I can only have one attachment per...)

I guess I just have to wait a few minutes for you to post the others... :)

I'm currious about something else... Big Jim continuely maintains that MVPs will work as good or better on the track then EPIC motors, even though they are down on power by several watts... I personaly have not been able to back that up at all with my testing... basicly I've never had a MVP run quite as good as a good EPIC on the track... And basicly they are always down on power a bit on the dyno... Big Jim will clearly back up the lower dyno numbers... but has anyone ever really seen that the dyno numbers lie about this issue?

I've always found it hard to understand how this issue could be... For one thing... if it's really true, it would seem to give evidence that the dyno itself is of very little value...

My personal experiance is the MVP is not as good on the dyno or the track... but I'm very currious if others see this. I mean I know they can be close... and quite frankly 2 or 3 watts at 7 volt testing is a very small differance. Typicly less then 3%... You really have to work hard to notice 3% differance in a motor on the track.

Glenn, As I've told you before, in touring, the MVP is an absolute rocket! I have found that narrowing the brushes makes the car feel little better on the track, but it doesn't show up on the Dyno. The MVP I run in my TC3 is 55 watts on the Fantom. Most people wouldn't run it, and going strictly by dyno numbers neither would. On the track (and lap time prove this) I don't have an Epic that will touch it..... Oval is another bag of tricks though.....

BJ tells people that the MVP doens't look good on the dyno, just gear the crap out of it and smoke your competition. I guess it "fools" the dyno? LoL :) For offroad it is a toss up for me to run either a P2K or an MVP, touring car its the MVP hands down!

Ok let me try to ak this way. Stock motor (PK2, GM3, ROV)
What would a good motor be in terms of Power 60. 65. 68?
What about torque for the same motors High .9'2 or do you go over 1.
and last efficiency? What is the scale.? I realize the higher the better but how low of a # is still a decent motor.
Note: my testing will be based on Fantom #s

The idea that a motor that makes less power will be as fast on the track is wrong. I seem to remember from my MVP days that it outperforms the EPICS under heavy loads. I had to gear the poo out of it and hope it didn't let the smoke out. The ice cube trick is a must.

I remember pulling Dave Johnson off the corners and all the way down the straights for the first 2 minutes and then they were about the same once the motor got hot. You couldn't compare those motors based on current draw because the MVP needed to pull more current to run well.

The MVP was also the motor that I used to find out what brushes performed well once they got hot. Peak power cold is one thing and peak power hot is another. I'd rather give up 1 or 2 watts up front for 10 at the end.

Denney... I'd say your motors are all looking pretty good. To me, the GM3 you posted is the best, but not by a very much. Second place, I'd give to the P2K... Third is the MVP...

Maybe you could get Jake to buy the MVP from you... :)

I'll try to go find some of my TurboDyno Data... but based on what I remember, your getting as good or better then I ever got from motors... However, back then I was viewing things a whole lot differnt, and I rarely paid any attention to 28 amps numbers, and now, that'd be the first place I looked... Oh... actualy... I know where I have some data... it's on a web page...

I found one set of TurboDyno data for what I think was likely a P2K... it was just over 100 watts at 20 amps, and about 125 at 28 amps... (7 volts)

Basicly, I think your motors look quite good Denney. If your not keeping up with most guys at the track, it's very likely it is due to something other then your motors.

OffCenter,

If you get a 68 watt motor on the fantom not using the production version of the software AND your fantom is working correctly, put that motor in a SAFE plase and only bring it out for special occasions.

55 watts isn't even a good practice motor because it's too slow.
If I have a choice I won't run a motor under 60 on the fantom. I often don't have a choice.
63 is a really good motor. Anything above that is treated special.

I've seen some Monster motors 65+. I'm beginning to think a bad monster is about 60.

I'll find out tonight how well I keep up. Most of these motors I was running when they were 6-8 watts lower & they seemed fairly fast then. I have been thinking about the MVP vs Epics a bit lately though...& was thinking about dynoing just before I race & immediately after - while the motors are still hot. Maybe this will show that a narrowed MVP may appear weaker when cool, but could close the gap when at racing temp. Anyone out there done such a test??

Denney

Offcenter... I've seen quite a large variation in Fantom numbers, depending on the dyno...

Having said that...

I beleive anything in the neighborhood of 65 watts is good for peak power. I've heard people say somethig about 70 watts for peak on some motors. My motors rarely saw 60 on the Fantom I had access to.

Effciency seems to be much lower then with other dynos, I think better then 50% is accpetable from a Fantom.

Torque... I've never seen one go over 98... in fact at one point I questioned if the torque number is some how realtive... realtive to a max of 100 or something... I've never seen one hit 100, and never really seen them lower then 80 or so... The really strange thing with torque is that often the lower RPM motors have lower Torque numbers as well... this is just the oposit of what is seen on other dynos I've worked with.

The MVP's didn't run well at 5 volts for me, you needed the extra voltage on the dyno to make them look good. I'm thinking that they're more efficient at higher voltage.

Dyno,

I've seen torque numbers over 1 but not with a stock motor.

What do you run Denney?

My best guess is that you might notice a couple tenths of a second at the most with a 6 or 8 watt increase in power... asuming you get the gearing right...

I've given people motors to use that are 10% better, and their lap times don't improve at all... Alot depends on driving... If a persons driving isn't up to speed, the extra power seems to do nothing...

Even good drivers sometimes see very little differance in a motor that is less then 5% differnt... at least that's my experiance with motors.

I'd have to agree with you on that one Dyno. Where I race some of the fastest guys on the track are using batteries and motors no better than I am and some times even worse than mine. they're still one hell of a lot faster than I am though.