Horsepower calculator?

[AnotherUser]

Is the delivered torque accurate? I have been doing some thinking, and using either the delivered torque, or other methods, could a horsepower calculator be added into the VCM Suite?

Another method I was thinking is, since you can log RPM, timestamps, and vehicle speed, using those inputs I wouldn't think it would be too hard to estimate horsepower as accurate, or more accurate than the stand-alone horsepower calculating devices on the market. This feature would make the VCM suite excellent for determining if changes made to the tune made a difference. All of the information needed to make the calculation just seems to be there...maybe even enough to build a whole dyno chart?

Sorry to ramble, but the idea got me pretty excited.

[Magic_Chicken]

For answers to this check out this thread.

[jimmyblue]

Delivered torque I guess is considered "reasonably
accurate" (now that scaling is fixed) but it is only a
prediction from "upstream" sensors and a computer
code model, not any measured output quantity. So
while it will respond to changes (like I can see my
cutout open Delivered Torque is greater than my
cutout closed, even though the PCM doesn't know
about this directly) I'm a bit suspicious about how
"qualified" the thing is to predict torque, when you
stray off the beaten path with big mods or non-
standard sensors, etc.

But as the only tool in hand, it's definitely the best
(until we get the stuff needed to make a delivered-
energy-to-vehicle-mass inertial dyno work in Excel,
or as a native "widget&quot.

[AnotherUser]

Yeah, but with the proper numbers from the cars computer (and the right equation), plus maybe a couple of extra bits like vehicle weight (with an included standard curb weight for the vehicle of course), I would think that a real horsepower calculator would not be too far from reality. I mean, based on weight and gearing, isn't it going to take X amount of time to move the vehicle from rpm x to rpm y for a given horsepower? Maybe? Then you could just make a run in third gear, with no wheelspin, and generate a dyno chart. Heck...somebody might even be able to make it in excel.

P.S. I read that info about "how accurate is delivered torque"...I just wanted to double check while I was on this subject.

[arthansen]

I developed a spreedsheet (originally for ODB II Scanner but now for HP Tuners) that looks at Vehicle weigh, frontal area, drag coificient, Air Temp, Air presure, and Tire presure. It then uses the time stamp, and speed to come up with a HP reading. It calculates HP to overcome air drag, HP to overcome rolling friction, and HP based on Acceleration. I add these numbers and it gives me a RWHP number. I have to do some averaging since the time is very accurate but the speed is rounded to the nearest MPH. I can send the spreedsheet to anyone. It has a page that shows all the formulas I used. If anyone is interested, let me know.

[jimmyblue]

I'd like to see this - especially if you have some of the
necessary inputs like F-body Cd , frontal area and
rolling resistances.

[arthansen]

Jimmyblue, check your e-mail. Hope it works for you. Let me know.