Is it possible to tell with 100% certainty if a dyno run was done on an M6 or A4 just by looking at the graph?

Those of you familiar with my recent travails might be able to figure out why I am asking. Here is the link to the graph:


http://www.svt-enthusiast.com/albums/album05/mp.jpg

 

Looks like an auto to me, can't be 100% certain though without a description on the printout.

Reason, because the torque spikes hard like a converter slipping and multiplying the torque, then the torques drops down, levels off, and drops gently as rpms increase.

how did you come accross that dyno, what is it supposed to be of? Why do you ask ect. I'm not familiar with your recent tribulations.

-brent

 

Thanks Brent. Read this thread. It might give you an idea about why I am suspicious:

Mark

http://web.camaross.com/forums/showt...hreadid=180913

 

OH, that thread.

So you weren't there to actually witness the pulls or what?

There is some good suggestions in there already and i didn't reread it all. I dunno what to say about it now. But if it was a decently tuned motor in good order, i would say it looks like an auto because of the tq spike. With all that you've been through, i don't know what to say. Like Bret said, it's not the cam because i've got a dyno sheet from a 383 lt4 m6 here and it has none of that abnormal shape. You've already had a lot of brainpower looking at that and i'm sorry to say i have no buisiness making any other suggestions for you, sorry.

good luck,
Brent

 

You don't believe me?

It's either an automatic, or a 6-speed with the clutch replaced by a torque converter.

 

Looks like a Auto dyno pull to me too.

Your spring pressures look soft too, I would like to see at the minum 130lbs on the seat and some light retainers too.

Bret

 

Here's a thought, if it was manual/clutch...wouldn't the sampling
start a little sooner? IE: 2000 RPM?

It seems the dyno operator may have started the sampling once
the torque converter was closer to the stall rating (assuming that
t-con was rated for 2500-3000 stall)?

Just a thought.

What are the rest of you basing your assumptions on? The output
power peaks?

Is this a stock motor? I didn't read the entire post, or the link...it's just too long for me

 

While a stick shift car with no drivetrain slippage will show 'nice' hp and torque curves, with peak torque 'around' 4,500 range, an automatic car with an unlocked converter will show peak torque at whatever the dyno run is started (converter flashes at WOT).

From there, the drum is playing catch-up with the engine due to the slipping converter. That is why you instantly see peak torque.

Another indication is an unusually high peak HP rpm. An engine in the 350rwhp range would 'usually' peak in the 6,000 rpm range. Dynojets do not accurately measure rpm with an unlocked converter, and will show higher than actual rpm. (notice the HP hasn't even peaked by 6,600 in the graph posted).


That graph, was positively made by an automatic car with an unlocked torque converter.

Here is an example of a stick shift dyno sheet-

http://www.ls1speed.com/z06.cfm