Poor mans dyno, SB Hotrod roll on remote compare

[jacksonracingcomau]

To not derail the 3 SB hotrod threads and maybe useful to all
Looking at the free GPS software I've put on my tablet

It has acceleration recorder, exactly all a rolling road dyno like a dynojet really is.
Mine only tells you current and max but must be easy to record acceleration and time and then graph them.
Then 60mph roll on in top could be shared between the Aero, the 4 valve neuvo and the hot Lario
Here's mine today, quick blat from 60mph in top


Only 90 cos it's wet, bumpy roads, cops etc
Have no idea why it's in metres per second per second when it's supposed to be in imperial but think Chuck probably works in G's anyway so that should be unit to use

For reference between 60-90 I hit 2.0496 G's today in top gear (conversion from net, NFI if true)

Wasn't trying for number but normal braking in wet at -13.16 m/s 2 is still -1.3419 G's !!!

For nothing we can test acceleration & braking & compare, wind or gradient use considered cheating.
For tuning, why pay for a dynorun ?

Think I hold the record for now, king for a minute ?

[Chuck in Indiana]

So, what's the name of this free GPS software? What operating system? It's highly unlikely that the four of us will ever be in the same place for a proper roll on.. ;D Yep, you're king for a day, and probably the contest.

[charlie b]

Put in exact weight of bike and rider, record rpm at each point.  Get torque and HP.

[Rough Edge racing]

 Looks like a useful tool that's for sure... I use chassis dynamometers frequently for my race bike and the often mentioned Dynojet is a inertia dyno...The rear wheel spins a weighted roller and the dyno measures power from the time it takes to accelerate the roller. They work for tuning but give exaggerated  power readings.. and that's why they are popular..and the fact although expensive are the less expensive dyno... Eddy current or brake dynos apply a load to the engine and actually stall the engine ...
 Watch and hear this 830 Hp V8 struggle to overcome the dyno brake...

     https://www.youtube.com/watch?v=TsNKGQozXvQ
 


   

[Triple Jim]

For reference between 60-90 I hit 2.0496 G's today in top gear (conversion from net, NFI if true)

Very nice.  I've heard about apps like that.  I have a Veypor vehicle computer that does this sort of thing, automatic 1/4 mile timing, etc., but an app is a lot cheaper.

Recording more than a 2g acceleration in any gear probably means you need to throw that run away and record another one.  The Veypor actually has an accelerometer in it, probably to avoid glitches in position that cause odd accelerations like that.  And why does it say your average speed was zero?

[charlie b]

The 2g part is probably when the clutch is let out at gear change.  The sensitivity of the gyro would record that little 'jerk' and that becomes the peak.

[Triple Jim]

The 2g part is probably when the clutch is let out at gear change. 

You're certainly correct that an abrupt gear change would cause a spike in acceleration, but any sudden torque that would cause a 2g acceleration would cause rear wheel spin if it were real, and the bike wouldn't actually accelerate that much.

[Chuck in Indiana]

The 2g part is probably when the clutch is let out at gear change.  The sensitivity of the gyro would record that little 'jerk' and that becomes the peak.

I've been researching apps for my tablet this morning, and that seems to be one of the problems reported.

[sign216]

A great idea.  I imagine one could smooth out the false peaks and graph the results like a regular dyno.

[kevdog3019]

To not derail the 3 SB hotrod threads and maybe useful to all
Looking at the free GPS software I've put on my tablet

It has acceleration recorder, exactly all a rolling road dyno like a dynojet really is.
Mine only tells you current and max but must be easy to record acceleration and time and then graph them.
Then 60mph roll on in top could be shared between the Aero, the 4 valve neuvo and the hot Lario
Here's mine today, quick blat from 60mph in top


Only 90 cos it's wet, bumpy roads, cops etc
Have no idea why it's in metres per second per second when it's supposed to be in imperial but think Chuck probably works in G's anyway so that should be unit to use

For reference between 60-90 I hit 2.0496 G's today in top gear (conversion from net, NFI if true)

Wasn't trying for number but normal braking in wet at -13.16 m/s 2 is still -1.3419 G's !!!

For nothing we can test acceleration & braking & compare, wind or gradient use considered cheating.
For tuning, why pay for a dynorun ?

Think I hold the record for now, king for a minute ?

This is a foreign language to me.  I'm not seeing data I understand there.  GB stand for Gigabyte and m/s2 almost sounds like Microsoft software to me.  Lets say you on how it reads??  ;)

[Triple Jim]

m/sē is meters per second squared, or meters per second per second.  It's the acceleration, given in how many meters per second the vehicle is changing speed per second.  Gravity (1g) is about 32.2 ft/sē or 9.81 m/sē.  More than that is more than 1g and about impossible for street tires.

[jacksonracingcomau]

App is OZI explorer free trial but doesn't record acceleration only shows current and max
Was in tank bag during run, 50 odd mile shopping trip yesterday with one chance for 60mph roll on, no drag start,  high rpm gearchange etc, was wet road most of trip, pretty certain max acceleration was in top when I tried hard, never related m/s 2  or g to bikes before, entirely new to me, number could be bollox, others need to try.
Av speed 0 cos it had sat still for a couple of hours before posting, guess it resets to 0 after x time still ?


Somewhere there must be another app that records acell against clock while keeping record of speed too, I'm sure there are better geeks on here than me, in theory any gps can do it, anyone here write software ? Vid of tablet itself would work but convoluted way to do it, noting time / speed / acceleration and graphing every second

As for 1g being more than tyres can take, odd that braking normally in wet beats that, certainly didn't brake harder than I accelerated.
Will try again this week in dry trying to stay in top for several runs and braking as hard as I can but software is limited by "peak" as said, all recorded would be ideal

[Triple Jim]

As for 1g being more than tyres can take, odd that braking normally in wet beats that, certainly didn't brake harder than I accelerated.

I didn't quite say 1g is more than tires can take.  In any case street tires might get above 1g by a little, but certainly nowhere near even 1.5g.

[jacksonracingcomau]

Looks like a useful tool that's for sure... I use chassis dynamometers frequently for my race bike and the often mentioned Dynojet is a inertia dyno...The rear wheel spins a weighted roller and the dyno measures power from the time it takes to accelerate the roller. They work for tuning but give exaggerated  power readings.. and that's why they are popular..and the fact although expensive are the less expensive dyno... Eddy current or brake dynos apply a load to the engine and actually stall the engine ...
 Watch and hear this 830 Hp V8 struggle to overcome the dyno brake...

   

I'm a water brake kinda guy too

Best thing about the old days was BSFC, only just being reintroduced, as far as I'm concerned is the only true way to tune, no lambda just the amount of power you get from every pint of fuel.

But tablet / phone on your bike on road or track recording all is seriously easy to use, datalogging for everyone,

[mwrenn]

Ah, very interesting app.  Need to research and find the best one for comparison.  A simple log measuring 60 to 100 time would tell the tale...

[Morizzi]

I'll go back to Martin's original suggestion of rolling on with the bikes side to side.

GPS is a wonderful thing but it has its limitations. HDOP (Horizontal dilution of precision) would have an effect on a comparison of this nature unless the bikes were together and the satellites were in the same orientation.

GPS has a lag time too for it to calculate.

I have big blocks and small blocks. I like them both. If I want to go for a blat for a coffee or such then I reach for the Monza. If I want to ride to Melbourne on a 4000km tour then I reach for the LM III.

Rod in Oz.

[Triple Jim]

GPS is a wonderful thing but it has its limitations. HDOP (Horizontal dilution of precision) would have an effect on a comparison of this nature unless the bikes were together and the satellites were in the same orientation.

Yes, it may be that the GPS receiver thought the motorcycle jumped in location because of the HDOP, creating a false momentary acceleration.

[PeteS]

Put in exact weight of bike and rider, record rpm at each point.  Get torque and HP.

Seems to me the varibles you can't control are wind speed and direction along with drag coefficient.

Pete

[Triple Jim]

Seems to me the varibles you can't control are wind speed and direction along with drag coefficient.

Pete

I talked to a tech support guy at Veypor about that, and what you said is true for that system as well.  If you use a gear that lets the run stay under about 60 mph or so, wind isn't a big deal.  Since I use the feature of recording dyno curves only for comparing one run to another similar one, wind isn't a problem.  Comparing to a calibrated dynamometer wouldn't work so well.