rwhp is good and correct. Torque is not correct, as it is based on wrong rpm. It is also shown as estimated torque at engine, not measured torque at wheels.

On an inertial dyno, rwhp can be assumed equal to the hp dumped in the drum, which is directly measured. So the rwhp curve ( 2nd from top, and does not include the hp "loss" curve at the bottom of the chart) you have is correct, except for the rpm. But, engine rpm is then used to get the torque curve. In your case, a flywheel torque curve is used, based on flywheel hp and the false rpms.

To get a rear wheel peak torque that can be loosely compared with most other dyno output, you can estimate it from the rwhp at the torque peak, using a corrected rpm:

T=5252xhp/rpm

CV=hp=280 at torque peak shown
rpm=6000x(7500/6850)=6570 rpm (corrected)

T=5252x280/6570 = 224 ft-lbs rwtq

 

That doesn't make sense to me, since both products are being sold in every state. Pettit doesn't limit its sales to Florida, and we don't have people in CA blowing engines on the Pettit ecu because of low octane.

 

I'd have to agree for the most part, because otherwise I would have popped a motor long ago . However, I have heard from various people that Pettit uses a slightly more aggressive tune than M2's setup, but I cannot confirm that.

 

I know people in CA with good condition, low mileage FD's blowing their engines with the pettit ecu running on 91 octane.

Considering both products are advertised for "off road use" it would still make sense to sell them in other states as most racetracks have high octane gas available anyways.

 

Why don't you call Pettit, and ask them? That would confirm your "rumor".

 

Well, you can count my FD as one of the "good condition, low (well, fairly low ) mileage FD's" that have run 91 octane using the Pettit ECU for years with no issues. And that's with a lot of bolt-on components. I also know of another FD owner running a Pettit in CA who hasn't notified me of his popping an engine yet.

 

Here in the KC area, 91 is about the max we see (there are a few 92's around, but they are like gold).

While I did pop my motor, it wasn't run running 91 on the Pettit ECU. There are at least 4 others around me on the same ECU and have been for years without issues.

 

If you take a better look at the graph, torque drawn is tq at the wheels.
Basically, tq and hp are the same at 5250RPM, yes ?
Ok... now scale the RPM axis 7500/6850*5250 =~ 5750RPM.
There you see that tq =~ 350Nm, which you can convert to lb-ft here: http://www.boltscience.com/pages/convert.htm

It gives you around 260lb-ft of tq.

So now we only need to check which hp curve corresponds to about 260 at 5750RPM. Its the rwhp curve


Come to think of it, could it be that my HP readings should be actually higher due to lower RPM scaling ?

Anyway, when I get my HKS TP installed, I'm heading back for a run @13psi

 

About Pettit vs. M2. I saw almost no difference and dyno shows it.

I was kind of hoping Pettit wouldnt get ignition breakup (leaner AFRs up top), and it did.

I would maybe need to run them at @13psi again once ignition is sorted, where I'd expect to see some difference in favour of Pettit ECU. Until then, they're basically the same.

Why many owners of Pettit ECU make more power is the fact M2 advises use of midpipe with ther ECU. I have no problem with it. Track proven

 

You mean "advises against use of a midpipe with their ECU."

 

and if I wanted to determine the real torque at 7000 rpm, instead of 5250, I would use which data point off the torque curve?. This method has no basis, assuming, as you said, the range of rpms on the x axis was fudged, and really reflects runs up to 7500 rpm. That is, the last point on all curves was taken at about 7500 rpm.

The cross over on all the existing curves agrees with the 5252 rule, assuming torque curve is at the flywheel.

It is a flywheel torque curve. I had verified it on the dimsport website. I don't speak Italian, but this web site has a sample (a4?) curve set about 1/2 way down, with a partial data table below it. Based on labels and values, the torque curve location label is the same as that of the engine hp curve at the top.

http://www.dimsport.com/download/MANUALE_(Italiano).pdf

 

Yes sir