I was wondering if someone could give me the algorithm for how horsepower and torque is calculated in BE/EA. Thanks?

My results do not meet real world facts. 1.5cfm = 1hp I would like to analyze the algorithm to see if it matches or my tune has some unseen flaw.

_________________
94 Cobra:
10.27:1 327sbf, Edelbrock Vic. Jr heads, Victor 5.0 EFI, XE276HR w/1.6RR, 80lb/hr Siemens injectors, HPX slot MAF, 65mm fox body TB conversion, 1 and 5/8" BBK shorty headers, Xpipe with stock mufflers, T5 trans, aluminum drive shaft, 3.73 gear, and no smog, AC or EGR.

Running a Vortech V1 SQ-trim head unit with a 2.95" pulley, but without a belt while I tune for N/A.

CBAZA- J4J1

91LX Hatch: Build put on hold until I finish school.

The most likely location for error is going to be with the Brake Specific Fuel Consumption (BSFC) value BE/EA is using to convert fuel demand to HP. I don't know the formula BE and EA use, but I do recall when talking to Clint that the BSFC must be entered accurately or the numbers won't be close. Unfortunately that's not an easy number to get ahold of if you don't have a dyno run of your vehicle. Add to that, BSFC value of your engine changes as RPM/Load/RPM/AFRs/Gears/Wind resistance changes. Thus the BSFC at idle and cruise when the engine is running relatively close to stoic is not going to be the same as it is at WOT. And the richer WOT is, the higher the BSFC will be hence why supercharged engines often have a BSFC value in the mid .6s and N/A engines are in the upper .4s. So because BSFC is a best-guess to start with, HP and Tq in BE/EA are ballpark estimates, not values to be taken as what you should expect to see on a dyno. More likely you should finagle the BSFC until BE/EA give you close to what a dyno run shows.

_________________
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

Member V8-Ranger.com

I was hoping that was done in BE/EA based off of CID/Inj. size/PW and MAF.

So no one on here knows the Alg.?

_________________
94 Cobra:
10.27:1 327sbf, Edelbrock Vic. Jr heads, Victor 5.0 EFI, XE276HR w/1.6RR, 80lb/hr Siemens injectors, HPX slot MAF, 65mm fox body TB conversion, 1 and 5/8" BBK shorty headers, Xpipe with stock mufflers, T5 trans, aluminum drive shaft, 3.73 gear, and no smog, AC or EGR.

Running a Vortech V1 SQ-trim head unit with a 2.95" pulley, but without a belt while I tune for N/A.

CBAZA- J4J1

91LX Hatch: Build put on hold until I finish school.

There may be others that do. Obviously Clint does. If he doesn't respond to this thread, drop him an email. I'm sure he'd give you the formula used.

_________________
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

Member V8-Ranger.com

Here is the formula if you are not using an Accelerometer.

avgSTFT = (1 - ((STFT1 + STFT2) / 2 / 100)) * Stoichiometric
avgLTFT = 1 - ((LTFT1 + LTFT2) / 2 / 100)

If blnPounds_Per_Min Then
CurrentHP = Current MAF * 60 / BSFC / avgSTFT * avgLTFT
Else
Current HP = sngCurrentMAF * 2.2046226 / BSFC / avgSTFT * avgLTFT
End If

CurrentTQ = Current HP * 5252 / RPM

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EEC Analyzer & Binary Editor
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I know I'm reviving a relatively old thread, but I've always wondered why you'd want to calculate HP this way. At best you have the user likely incorrectly guessing at an average BSFC, which changes dramatically based on where the engine is operating from idle to max rpm, so say nothing of changes from cams, heads, etc.

This is especially true when you have a device capable of very accurately measuring time, vehicle speed, and engine speed. The only other variable needed to calculate horsepower is vehicle weight (mass) -- which a user could get very easily and accurately. Basic physics really.

You can get significantly more sophisticated pretty quickly if you want by determining power loss due to drag, rolling resistance, etc...but that's pretty close to splitting hairs.

I will grant that this approach assumes no wheelspin, but there are ways of dealing with that as well.

I've got an old excel model somewhere that makes some pretty neat dyno curves this way...if someone's interested I'm happy to share...

_________________
1966 Mustang
5.0 EFI Swap
Ported GT-40 Heads
1.6 Roller Rockers
Edelbrock RPM Intake
E-cam
76mm C&L MAF (blue tube)
70mm Edelbrock TB
24 lb injectors
Tri-Y Headers
T-5
3.55 Gears

A3M, QH, BE/EA
No Emissions Equipment

I wouldn't be surprised if Clint came out with a version of EA that interfaces with accelerometers in people's smart phones or with accelerometers that are now inside people's computers. If that's not technically possible, then I'm sure Craig could put an accelerometer chip on the Quarterhorse somewhere and add that to the datalog stream of things BE receives.

Besides, the intent of the HP/Tq isn't so much to give you an accurate value. It's to give you an arbitrary value to compare against. Although as you said, any changes might also affect the BSFC, not just actual output. And as BSFC changes along with HP output, you really don't know what kind of change that'll do to the logs if the change between the two is not in proportion.

_________________
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

Member V8-Ranger.com

Chris,

Perhaps my post was confusing, my point is that you have a device (the EEC) that can measure vehicle speed, time, and engine speed very accurately, and you have a device/software that allows you to log those parameters - so the point is that you have every thing you need (except vehicle mass) to calculate horsepower. An accelerometer is not needed nor are estimates of bsfc.

The physics is simple: measure speed (velocity) and time. Plot these on a graph (or not) and fit an equation to the graph. Calculate the first derivative of the equation at each point...now you have acceleration. From acceleration you can easily calculate force and then power.

Really the only difficult part is getting the units correct at each step if using English units.

_________________
1966 Mustang
5.0 EFI Swap
Ported GT-40 Heads
1.6 Roller Rockers
Edelbrock RPM Intake
E-cam
76mm C&L MAF (blue tube)
70mm Edelbrock TB
24 lb injectors
Tri-Y Headers
T-5
3.55 Gears

A3M, QH, BE/EA
No Emissions Equipment

I never considered that. Although I do enjoy having this method of analysis too just for anecdotal purposes. But I agree, that would be probably a better way to come up with Hp/Tq...using vehicle mass. One thing I did enjoy about the existing method is that you can see about how many HPs it takes to just idle the engine. Again, it's not highly accurate, but even if it was +/- 2HP, for anecdotal purposes, that's interesting to see although not useful for much.

_________________
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

Member V8-Ranger.com

Send me the excel worksheet and i will take a look. I never considered using mass. The whole reason for the HP/TQ was to see the change in number to make better decisions on weather the change you made to a tune was beneficial or not. I agree that the BSFC is constantly changing and is not that accurate unless you could measure bsfc.

BE can take and accell parameter and calculate HP/TQ. You can use a PLX accelerometer.

I will take a look at what you have and if i can get it to fit in BE and EA i will do so.

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EEC Analyzer & Binary Editor
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Clint,

It's been two years, a crashed computer, a wedding and a house since I fooled with it, but I may have a copy on my work computer. If not I can recreate it pretty easily.

At the end of the day, I don't know how close you could come to a dyno...but it was fun to fool with.

Sam

_________________
1966 Mustang
5.0 EFI Swap
Ported GT-40 Heads
1.6 Roller Rockers
Edelbrock RPM Intake
E-cam
76mm C&L MAF (blue tube)
70mm Edelbrock TB
24 lb injectors
Tri-Y Headers
T-5
3.55 Gears

A3M, QH, BE/EA
No Emissions Equipment

Sounds good to me. I will see what it takes to implement in BE and EA

_________________
Car Info
EEC Analyzer & Binary Editor
Other Photos

phutch - if you are able to find or re-create the file I would also love to get a copy of it as well!

Thanks
Cody

Clint - Email sent, email me if you have questions.

Twisted - Happy to, but just a warning that it's not very user friendly.. PM me your e-mail.

Sam

_________________
1966 Mustang
5.0 EFI Swap
Ported GT-40 Heads
1.6 Roller Rockers
Edelbrock RPM Intake
E-cam
76mm C&L MAF (blue tube)
70mm Edelbrock TB
24 lb injectors
Tri-Y Headers
T-5
3.55 Gears

A3M, QH, BE/EA
No Emissions Equipment

thanks i will take a look

_________________
Car Info
EEC Analyzer & Binary Editor
Other Photos

I'd like to add that the data logs can tell if the car is spinning or not. I haven't tried to burn rubber in a while, but I think I remember the data log showing a mph increase and held steady along with all of the other parameters for a brief period of time before dropping back down slightly and then increasing again. I'll have to go do some testing again after I get my timing sorted out, damn CBAZA.

_________________
94 Cobra:
10.27:1 327sbf, Edelbrock Vic. Jr heads, Victor 5.0 EFI, XE276HR w/1.6RR, 80lb/hr Siemens injectors, HPX slot MAF, 65mm fox body TB conversion, 1 and 5/8" BBK shorty headers, Xpipe with stock mufflers, T5 trans, aluminum drive shaft, 3.73 gear, and no smog, AC or EGR.

Running a Vortech V1 SQ-trim head unit with a 2.95" pulley, but without a belt while I tune for N/A.

CBAZA- J4J1

91LX Hatch: Build put on hold until I finish school.

Also, I've noticed in my recent logs that my horsepower is reading ~380hp in the HP column, but when using the HP calculator in EA, it only shows a peak of ~240hp. Any thoughts of why the log shows a different number than the calculator?

_________________
94 Cobra:
10.27:1 327sbf, Edelbrock Vic. Jr heads, Victor 5.0 EFI, XE276HR w/1.6RR, 80lb/hr Siemens injectors, HPX slot MAF, 65mm fox body TB conversion, 1 and 5/8" BBK shorty headers, Xpipe with stock mufflers, T5 trans, aluminum drive shaft, 3.73 gear, and no smog, AC or EGR.

Running a Vortech V1 SQ-trim head unit with a 2.95" pulley, but without a belt while I tune for N/A.

CBAZA- J4J1

91LX Hatch: Build put on hold until I finish school.

look at the BSFC in both EA and BE. They should match

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EEC Analyzer & Binary Editor
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They did not, EA was still setup from when I was running the car with boost.

_________________
94 Cobra:
10.27:1 327sbf, Edelbrock Vic. Jr heads, Victor 5.0 EFI, XE276HR w/1.6RR, 80lb/hr Siemens injectors, HPX slot MAF, 65mm fox body TB conversion, 1 and 5/8" BBK shorty headers, Xpipe with stock mufflers, T5 trans, aluminum drive shaft, 3.73 gear, and no smog, AC or EGR.

Running a Vortech V1 SQ-trim head unit with a 2.95" pulley, but without a belt while I tune for N/A.

CBAZA- J4J1

91LX Hatch: Build put on hold until I finish school.