Calculate HP/Torque from ECU parameters

[turbodelta]

Hello to all,

did a little search and found no threads wich could give me a
clue to my question.

I got a ECU parameter reader of a Lancia Delta Integrale, wich
is able to give a read out of the following parameters:

- Absolute manifold pressure in mmHG
- Air temperature in °C
- Injector pulse width in ms¨
- RPM/Min
- Water temperature in °C

- Stock injectors are 381 cc/min
- Fuel pressure is 3 Bar
- 1995 ccm
- 90 mm Stroke
- 84 mm Bore
- 4 cyl

Is there any possibility to approximate a hp figure out of these
parameters? Or wich parameter do i need additionally to get some
attendable power figures?

Thank you very much in advance

 

[dgallup]

You need to know the brake specific fuel consumption as a function of speed and load. Once you have that you can calculate the fuel flow from the data you have and convert that to a power output.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[turbodelta]

Thank you for you answer.

Is the bsfc just an assumption (turbo engine) or do i need a lambda
factor to calculate it?

 

[Lou Scannon]

Even better parameters for inferring power in a typical automobile engine are BSAC and air flow. But they may not be as easy to come by as BSFC and fuel flow.

 

[patprimmer]

You can actually get apps for smart phones that use the GPS and g force sensors and some punched in data, like car weight to calculate horse power reasonably well, especially if you do a two way run.

If it's not that accurate, even chassis dynos vary a fair bit from brand to brand and installation to installation.

Regards
Pat
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[turbodelta]

Well i would like to see on base of the rpm range where a
modification has benefittet from a single modification, so
i guess this would be more precisely with such a calculation
as im able to make log files of each run.

I've already a g-tech accellerometer, it's a very precise tool
even compared with some rolling road dynos we've used even with
a good constancy of measuring.

How should the formula look like using the given parameters?

 

[patprimmer]

The accelerometer is not the source of most inaccuracies. The source of inaccuracies comes from estimation of things like vehicle weight during test, wind, tyre rolling resistance, air density variation, aero drag and change of gradient to list a few.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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[patprimmer]

Opps. To quick on the submit.

The smart phone app is still an excellent tool for evaluating changes if you always use the same section of road.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[turbodelta]

Tried also the iphone app, but wasnt happy at all with the results,
too much inconstancy troughout the runs and differences from 10-20%
compared to the RR and G-Tech measurements.

This is why i would like to give it a try with the log file calc
wich would give me the possibility to consider different correction
factors between the run.

 

[1gibson]

Most cars with automatic transmissions perform a torque calculation (feel bad using that term, I'll go with "estimate" instead) that is used to trigger abuse modes and/or traction control. I'm sure it is a very rough estimate.

Maybe start there and see if you can figure out what is considered.

 

[turbodelta]

Hi thanks for your help, but i dont have a auto tranny, like
mentioned i would like to use these paramenters, as im able to
read out in a log file the mentioned data, this would allow to
put these in a excel file to make a calculation, right now i
need help to make the equation out of these as im definately
better with the wrech as with math hihi ;-)

Here some pics of the build for those interessted:

http://www.flickr.com/photos/turbodelta/sets/72157625713256692/

http://www.flickr.com/photos/turbodelta/sets/72157626673969925/

 

[pwildfire]

If you can get an accurate dyno run, you can correlate this with the fueling rate to estimate the BSFC curve. You can then use this curve to calculate power based on fueling. The problem with this is that BSFC will change slightly as you make modifications to the engine. However, based on the variables which you are able to measure, this is as close as you can expect to get.

 

[pontiacjack]

A new-products column in a recent magazine (Circle Track?) showed a torque sensor that can be "inserted" into a vehicle driveline. This setup would result in a true "rolling dyno".

 

[GregLocock]

Modern EECs and other systems estimate engine torque from a map of throttle position or MAP vs RPM. That is enough for their purposes. I don't know what parameter you are thinking of changing, but given that most engines run open loop at WOT then it seems to me that all you'll be able to sense is inputs not outputs.

IF your engine runs closed loop at WOT then I suppose you could look at injector pulse width, that would tell you how much fuel you were using, and all other things being equal, would be proportional to power at a given rpm. That is one big IF, and a lot of assumptions.

Cheers

Greg Locock


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[vagman2]

Hi turbodelta,
I like your work very much!
Not exactly the answer you're looking for but could be accurate if inputs are accurate too.

http://www.motorgeek.com/?fullpage=true&page=flowcalc

 

[turbodelta]

@ Pontiacjack: Here in switzerland there's a manufacturer wich has
already a few years ago developed a dyno, wich uses a torque sensor
on the drive shaft axles, it's enough accurate to have torque power
figures that are comparable to high end RR:

http://www.alpin-tuningshop.de/inde...ry_id=64&Itemid=15&lang=de&vmcchk=1&Itemid=37

@ Greg: The idea would be to have peripheric modifications, such as
IC, intake and exhaust system etc. and see also smaller changes in
the VE i.e. power output, if this would be possible accurate enough
based on these figures, a WB lambda probe can be installed on this
type of ECU we use so where able to monitor this.

@ Vagman2: Thanks for the compliments and thanks for the link could
be helpful