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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » BHP/Torque Figs

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Author Topic: BHP/Torque Figs
Blazebro
Member
Posts: 4
Post BHP/Torque Figs
on: August 30, 2011 (GMT)

Just started using this app and have to say I’m really impressed. However I’m somewhat perplexed by the figures it’s giving me for BHP/Torque.

I drive a Ford Focus ST which is fairly heavily modified. From previous dyno’s I’m getting around 280bhp. With this software I’m getting on average 188bhp, about 100bhp shy of what I expect. It’s not like the car isn’t quick, I’m getting sub 6secs to 60.

I’m putting it down to the way I’ve set the app up, so wander if anyone has any ideas of what I can do to correct this?

Cheers.

piemmm
Administrator
Posts: 6071
Post Re: BHP/Torque Figs
on: August 31, 2011 (GMT)

Hi!

The most important figures for the test is to correctly setup the vehicle weight in the vehicle profile, and make sure you’re using that profile

The vehicle weight *includes* fuel, driver, and any extra equipment you have installed (subs, etc). If you have used the vehicle weight from the manufacturers site then that will not include things like fuel, fluids, driver, etc.

Also, when doing the test, do it on a level straight road starting from a slow rolling start.

If you have entered the correct weight(the most important aspect for that benchmark), then you will get very accurate figures :-)

Blazebro
Member
Posts: 4
Post Re: BHP/Torque Figs
on: August 31, 2011 (GMT)

Thanks for the help. I thought that might be the case. Yep I was just using the manufacturers figs.

Other than that I’m really impressed with the app. The amount of things it’s checks is amazing. I love the way it seta everything out too, very clear.

I’m using one of the cheapo chinese 347 things. No problems to report atm

Blazebro
Member
Posts: 4
Post Re: BHP/Torque Figs
on: August 31, 2011 (GMT)

I think I’ve got this sussed now, just one last question:

The Figs it produces are they for power at the wheels, with no correction made to give a fig for power at the cam?

I assume as it’s using GPS and any figure it produces is related to distance, the fig is therefore a wheel power fig.

piemmm
Administrator
Posts: 6071
Post Re: BHP/Torque Figs
on: September 1, 2011 (GMT)

Hi!

It uses GPS to validate and OBD to get the accuracy, the figure is at the wheels (useful bhp) as there is no way to know the losses involved between the engine output and wheels

Blazebro
Member
Posts: 4
Post Re: BHP/Torque Figs
on: September 3, 2011 (GMT)

Thanks for the info, much appreciated. Getting some quite usefull results.

stupink
Member
Posts: 40
Post Re: BHP/Torque Figs
on: September 3, 2011 (GMT)

have a read on any accelerometer based hp meter, it will give some good hints and tips on how to get good accurate (read consistent) readings, and also how to interpret the hp figures. as they are not only at the wheel figures, but even lower again as they are at the wheel minus wind resistance and any gradient or rolling resistance of road surface or under inflated tyres etc..
in short, great for tuning, to get a relative figure after doing mods etc and to monitor the shape of the graph etc, not great for pub talk “my car is X hp”.

you have to avoid wheelspin, so may need to do it in second gear, im not sure how torque deals with that as I use a Gtech pro.

Joao
Member
Posts: 6
Post Re: BHP/Torque Figs
on: January 23, 2012 (GMT)

Congratulations for this amazing program!

I have tested the HP and Torque but in my case they seem very inconsistent. Specially with speed.

Based on a simple deceleration test it is possible to automatically compute the rolling and drag coefficient that would permit to accurately estimate the HP and Torque.

I would like to suggest to the developer to compute the HP and Torque based on physical data calibrated automatically by the program and the actual physical equations of motion.

I used a similar procedure to estimate the HP of a car based on a sound recording and it worked quite nicely! (If interested I can provide the paper. It is in Portuguese, though!)

Please get back in touch if interested in developing this, or other, issues.

piemmm
Administrator
Posts: 6071
Post Re: BHP/Torque Figs
on: January 24, 2012 (GMT)

Hi!

Accelerometers are not used in the HP/Torque calculations, it is done by various sensors from the engine and the GPS (if present) to increase the accuracy / provide validation

The tests at the moment do not take drag co-efficients into account which is why you must start them from a slow rolling start and will be very accurate up to 55mph on a flat road. The fact you cannot do the test uphill or downhill makes also implementing drag coefficients of little value

The vehicle weight is very important for these calculations. If you have put the stock vehicle weight in, then you will get an incorrect reading. The weight must be total weight including driver and fuel (and any extra kit in the vehicle).

If you have done all of this, then the calculations will be very accurate!

HERC
Member
Posts: 19
Post Re: BHP/Torque Figs
on: January 24, 2012 (GMT)

Quote from admin on January 24, 2012
The vehicle weight is very important for these calculations. If you have put the stock vehicle weight in, then you will get an incorrect reading. The weight must be total weight including driver and fuel (and any extra kit in the vehicle).

If you have done all of this, then the calculations will be very accurate!

Goes off to fix my vehicle weight to account for my fat ass

Torque_Kid
Member
Posts: 38
Post Re: BHP/Torque Figs
on: January 25, 2012 (GMT)

unless the calculation can account for % rotational mass (the wheels) then the rwhp calculation will be off somewhat.

2 cars of equal weight and motor hp, A & B, but A has lighter wheels it will be A that can accelerate faster. hence, using change in gps coords/time and weight will give different results, yet the rwhp of each car is identical.

Joao
Member
Posts: 6
Post Re: BHP/Torque Figs
on: January 25, 2012 (GMT)

I did not mention accelerometers in my post.

You are correct weight is important. What I said is that there is a way to automatically calibrate all those coefficients (including weight).

If there is no interest in this issue, I will not post again on this thread.

piemmm
Administrator
Posts: 6071
Post Re: BHP/Torque Figs
on: January 26, 2012 (GMT)

There isn’t a database as such in the app (or an easy way to find this information out programmatically, as every vehicle is slightly different), though a couple of people have suggested it so may get included into the profile editor (with a ‘send to server’ option so people can help populate the database)

Joao
Member
Posts: 6
Post Re: BHP/Torque Figs
on: January 26, 2012 (GMT)

It is true there isn’t a database, though I have read about some people proposing it in this forum.

What I am proposing is a programmatically way to compute all those coefficients.

If you which I can send you a pdf with the method.

Ruderegime
Member
Posts: 3
Post Re: BHP/Torque Figs
on: March 7, 2018 (GMT)

How would you add the weight for fuel? Fuel levels obviously fluctuate

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