You need to remember, you are presenting information that long standing members have never heard of or seen.

[QUOTE=RedMY01Owen;725093]In some cases the customer might ask for a dyno plot representing a low rpm launch.[/QUOTE]

I've never seen a dyno graph of someone wanting a low rpm launch. Can you provide any information where someone has received this?

[QUOTE=RedMY01Owen;725093]Bear in mind that some people do use the accelerator before they engage the clutch and this will result in more than idle torque at takeoff. [/QUOTE]

I would be very concerned about a power run where the clutch is released at 2500rpm to generate maximum torque.

I would advise learning more of how a hubpack dyno works. With the ramp rate, the car will be in 4th gear and idling along under 2000rpm before the operator presses the accelerator. Clutch and starting a graph at 2500rpm just doesn't come into it.

A dyno plot should always start out low, build up to maximum and then taper off. Any graph that doesn't show these items must be questioned.

The shape and time to achieve maximum torque is the most valued part of the dyno graph. Not receiving this means you have very little information on what your car is doing.

Whilst you have said there is some information to show mid range and top end power, without the starting point it is meaningless.

LOL at launching on the dyno in 4th gear!

[QUOTE=RUSSGT;725113]LOL at launching on the dyno in 4th gear![/QUOTE]

If you read my post I never said anything about launching a car on a dyno. A dyno is a very useful tool, far more useful than just for WOT power runs from 2500rpm. A dyno can easily simulate a launch.

[QUOTE=Kato;725111]
I would be very concerned about a power run where the clutch is released at 2500rpm to generate maximum torque.

I would advise learning more of how a hubpack dyno works. With the ramp rate, the car will be in 4th gear and idling along under 2000rpm before the operator presses the accelerator. Clutch and starting a graph at 2500rpm just doesn't come into it.

A dyno plot should always start out low, build up to maximum and then taper off. Any graph that doesn't show these items must be questioned.

The shape and time to achieve maximum torque is the most valued part of the dyno graph. Not receiving this means you have very little information on what your car is doing.

Whilst you have said there is some information to show mid range and top end power, without the starting point it is meaningless.[/QUOTE]

Obviously you wouldn't use the clutch to launch a car on a dyno, the sentence of mine that you quoted was referring to real world conditions. People are usually much more interested in how a car performs in the real world as opposed to a WOT power run from 2500rpm. As you say, the dyno will start at a given rpm, and ramp up at a certain rate, both of these parameters can be set by the operator to show many different scenarios.

I completely agree that a standard dyno plot will "start out low, build up to maximum and then taper off" but this isn't the only way that a dyno can be operated.

I would argue that "The shape and time to achieve maximum torque is the most valued part of the dyno graph" is slightly misleading and the dyno only really shows this for a single, abitrary ramp-rate. I really don't care what my car performs like when subjected to WOT from 2500rpm because I don't drive my car this way. I would be much more interested in how the car performs in the normally used rev range and how it spools up from say 4000rpm at WOT (simulating a down shift). Dynos are great, but people put far too much emphasis on the pretty picture they print out from a WOT run.

I'm not trying to attack anyone here, least of all you. I was originally just trying to help out the OP to extract some useful information from the dyno print-out. the dyno plot should be questioned, but not completely disregarded.

This is complicating. Both of you guys are actually right.

Just worried that the rest get confused.

[QUOTE=RedMY01Owen;725122]Obviously you wouldn't use the clutch to launch a car on a dyno, the sentence of mine that you quoted was referring to real world conditions. People are usually much more interested in how a car performs in the real world as opposed to a WOT power run from 2500rpm. As you say, the dyno will start at a given rpm, and ramp up at a certain rate, both of these parameters can be set by the operator to show many different scenarios.

I completely agree that a standard dyno plot will "start out low, build up to maximum and then taper off" but this isn't the only way that a dyno can be operated.

I would argue that "The shape and time to achieve maximum torque is the most valued part of the dyno graph" is slightly misleading and the dyno only really shows this for a single, abitrary ramp-rate. I really don't care what my car performs like when subjected to WOT from 2500rpm because I don't drive my car this way. I would be much more interested in how the car performs in the normally used rev range and how it spools up from say 4000rpm at WOT (simulating a down shift). Dynos are great, but people put far too much emphasis on the pretty picture they print out from a WOT run.

I'm not trying to attack anyone here, least of all you. I was originally just trying to help out the OP to extract some useful information from the dyno print-out. the dyno plot should be questioned, but not completely disregarded.[/QUOTE]

Ok, because we are talking about being on a dyno, I and others have assumed you are referring to launching and clutch stuff on a dyno.

The way the torque curve comes on and tapers off will determine the drive ability of the car. Regardless of dyno conditions, ramp rates blah blah, the way the torque curve behaves tells you instantly how that car will drive on the road in any rpm, gear, flux capacitor etc. The shape of that curve shows you more than any peak figure can tell you. And we are back to area under the curve...

Anyhoo, interesting discussion. It will be good to see the full graphs of this run to actually see what is going on.

Kato,

Most people assume WOT to be max power. This is not true as rpm is only one derivative of actual torque.

There can be area above the graph as well.

WOT = wide open throttle

side note: Never Ass-u-me because it will make an ass of you and me

Also, I would like to take this chance to say a WOT is just a guide.

A lot of guys talk about lag and torque especially on a WOT graph. A WOT graph tells you less than 10 percent about how a vehicle will perform.

My answer:
The manual transmission is there for me to shift down.

A true power run = driver + tune to suit driver

In my world, we have this saying: The driver must be fiercer than the car. The driver is all that matters with a tune to suit his driving ability.

[QUOTE=mao;725456] A true power run = driver + tune to suit driver

In my world, we have this saying: The driver must be fiercer than the car. The driver is all that matters with a tune to suit his driving ability.[/QUOTE]

So theoretically speaking would a tuner, make a car run lean at the top of the rev range to suit his driving style ?