Reading a dyno chart??

[.::F[L]Y::.]

hi guys,

In light of my for sale thread i have been advised by member 'String' that my claims are incorrect. I have posted up a dyno chart for those to see and that im not hiding anything. Not sure if im missing anything but clearly the chart shows max output of power and torque??

can someone shed some light on this.

http://server3.uploadit.org/files/tekman-NA088dyno.jpg

[aaronng]

The torque figure is at the wheels after going through your gearbox. Plus, the dyno is against road speed. So you can claim for power at the wheels, but you can't claim the torque. Could you ask for your dyno operator to plug in your gear ratio so that you can get a proper torque figure?

[Mr_will]

this is the same thing i was trying to point out to you.

i was a genuinely interested party before you fobbed me off, just because i wanted to question your claims.

do you see NM anywhere on that chart? i was asking you about TORQUE not power, which is why i wanted to see a dyno sheet with TORQUE on it.

[sivic]

yeah the ratios are put in you cant claim specific torque figures. obviously you can use the readout to examine the shape of the torque curve etc etc..
basically what a readout should be used for anyway

[fatboyz39]

You need torque to make power. Enuff said.

[aaronng]

You need torque to make power. Enuff said.
Yeah. If Fly can provide us with RPM numbers for the chart, we can just convert the power number to torque.

[.::F[L]Y::.]

You need torque to make power. Enuff said.

elaborate on that fatboy

[aaronng]

Y::.']elaborate on that fatboy
Power (hp) = RPM x Torque (lb.ft)/5252

[STOCK]

Dyno print out looks normal to me for a built motor.
Maybe those questioning the graph should spend 25cents and ring up Adrian and ask about the figures, thats if they are genuinly interested.

[CUL8R]

the right hand axis only shows a figure in newtons, this is a force not a torque
a torque is a force x lever arm giving newton meters.

so the right hang axis isnt giving a torque reading.

and yes the horizontal axis would be good to have rpm readouts.

was this run on a hub dyno or roller dyno?

[destrukshn]

more likely a roller.

[CUL8R]

i just read his FS thread and yeah didnt realise the mods extent...doesnt look like too bad a figure

[ProECU]

Dyno print out looks normal to me for a built motor.
Maybe those questioning the graph should spend 25cents and ring up Adrian and ask about the figures, thats if they are genuinly interested.

Fly should be giving us the contact details of the engine builder so that interested parties can research the motor.

Adrian just tuned the thing, its not his responsibility to defend/justify any torque claims.

[string]

He is running 205/45/16 tyres, so to keep things simple, we'll assume a tyre radius of 295.45mm. (Allthough tyre deformation will occur, it certainly won't throw the results off enough to make a difference). Also, we'll assume that you have a stock 4.4 final drive and that you were indeed dynoing in 4th gear which is a 1.034 ratio.

We'll do this two ways. Firstly, using the equation for power, deriving from RPM and Torque.

Your graph stops at 182kph, which is 7434rpm using radius above. At peak torque at 146kph, you are at 5963rpm. At this point, your graph indicates you producing 120kW.



Power (watts) = RPM (rad/s) * Torque (Nm)

5963 (revolutions / min) = 5963 / 60 * 2pi (rad/s)

Torque = Power / RPM
= 120,000 / (5963 / 60 * 2 * pi)
= 192Nm

Therefore it can be shown that at your peak torque, you are producing 192Nm, as derived from your power curve.

The second method is to actually use the other graph to derive torque. Your graph does NOT show any torque readings. It shows tractive effort on the rollers. This is a FORCE, produced by the wheel's torque as it acts on the edge of the roller.

We'll take your peak force on the rollers as 3000N, as it's pointless trying to estimate a closer number based on the resultion of the graph supplied. This is still at 5963rpm.



Torque = Force * Distance
= 3000N * 0.29545m
= 886.35Nm
(Now we need to take into account gearing as a torque multiplier)
Engine Torque = 886.35 / 4.4 / 1.034
= 194Nm


OP: You are welcome to correct any of my assumptions (such as final drives, or non-standard gear ratios etc...) and i'll happily re-calculate.

The minor difference in results is obviously caused by human errors in attempting to read the graph, and clearly not a form of argument against my case before you try.

193~Nm != 300Nm

[aaronng]

^^ what string said and has calculated is correct. :thumbsup:

[STOCK]

Fly should be giving us the contact details of the engine builder so that interested parties can research the motor.

Adrian just tuned the thing, its not his responsibility to defend/justify any torque claims.

Im not refering to the build of the motor, as this is not what the thread is about.

Im refering to the torque/power reading that apparently came from Toda Racings dyno print out.

YOu must still be attacking FLYS other thread in the for sale section :thumbdwn:

[ProECU]

Not attacking mate, but as an interested party, and all other interested parties, (obviously of which you are not) I would like to ensure my $7k and anyone elses in not being spent on a lemon (not that I think this is the case).

For that kind of outlay, one should ensure they know all details about what they are potentially purchasing. There are many horror stories on the internet, and for what its worth, I and most others here dont know FLY from a bar of soap... how much trust should one place on comments on face value?

see the dilemma.... he hasn't exactly detailed everything about the motor, so get back in your box.

[.::F[L]Y::.]

Not attacking mate, but as an interested party, and all other interested parties, (obviously of which you are not) I would like to ensure my $7k and anyone elses in not being spent on a lemon (not that I think this is the case).

For that kind of outlay, one should ensure they know all details about what they are potentially purchasing. There are many horror stories on the internet, and for what its worth, I and most others here dont know FLY from a bar of soap... how much trust should one place on comments on face value?

see the dilemma.... he hasn't exactly detailed everything about the motor, so get back in your box.

theres nothing to hide. As i mentioned i bought the engine already built from jap connections. This would be the same case as if you were to buy an imported engine. Like i have mentioned in my other thread if your genuinely interested then your more than welcome to come and inspect the motor/setup as its still in my car. You can also do compression checks and all other checks that you want.

thanks for the reply fellas

[fatboyz39]

more likely a roller.

:thumbsup::thumbsup: