having had a quick read through there are a few questions to ask

where are these temprature sensors supposed to be mounted to take readings from in the first place?

and what's the difference between it being in a cup of tea and above the exhaust? they will both be hot right so how will they make a difference to the pwoer reading?

cheers

 

my perspective on the cup of tea is it will be at about 90d, rather than just hot unmeasured temperature on an exhaust.

it will show how much is gained from ambient temp say 25d upto 90d.

 

90 deg.C? that's a fucking hot cup of tea! i'd like to see you drink that.

 

But HOW does it affect the power graph readings?

If you have 25c and it makes 150 brake, why will it make more/less power @ 90c?

Won't the ecu already compensate for it being too hot/cold?

 

Every 'corrected' dyno figure is what the car made, then adjusted to suit a certain set of atmospheric conditions. In reality a car making 150bhp at 25oC might make only 100bhp at 90oC (depends on the car) so the corrected figure adjust's the power back up to the what the calculation say's it would've made. And that's the big problem, it's based on what the calculation dictates.

The ECU will compensate but only to protect the engine, for example if you tried to dyno my car in 90oC heat it would be pulling ~5-6 degree's of ignition whereas a N/A engine may only be pulling 1-2 degrees or even none at all.

 

and this is where the confusion comes in because people aren't making the distinction between measured power and corrected power and the potential power that would have been measured at the corrected for temperature (which is unknown). i tried to make that point earlier in the thread before it got "tidied up" but never mind.

 

but i still don't understand why you would make your air temp hotter to give the graph more power

surely if it's hotter it would make LESS power? like has been explained a few posts further up?

 

lol its a very simple scenario.

take your actual measured power.

this is then corrected to an industry standard the main factor being temperature, the hotter it is the more the dyno adds, the colder it is the dyno takes some away.

take the temperature sensor and make it read a ridiculous high temperature to fool the dyno into adding far to much power and without any figures looking fudged as its just corrected to the industry standard.

its very simple tbh I don't get why its so hard to grasp lol

its not about actual power measurement were mainly talking about how easy it is to make a dyno read more power without adding a silly tcf.

simple concept if its extremely hot your car will make less power so the dyno will correct the power upwards to compensate for the temperature so fooling the sensor into thinking its really hot when it isn't will give a high dyno plot that no doubt goes on quite a lot.

 

I have added the temperatures for each run in an earlier post, I got the data from the dyno operator I knew it would be around 50d - 60d anyways but as you were so persistant I thought id get the exact data.
I don't know why anythings been cleaned up I didn't ask them to ?
my temp readings were 23d newest run and 58d old run and theres 50 hp difference IN THE CORRECTIONS, its very simple to grasp tbh.

and another 65 hp is available corrected just by changing to sae aswell.

 

its not making any more power in reality we are just looking at the dyno readout at industry standard.
the hotter the dyno thinks the temperature is the more power it will add to the plot to compensate for the heat, thus making it so a dyno plot can easily be manipulated to show a lot more power without showing and tcf.

 

that makes much more sense now

 

you don't have to explain it to me but it's not until you spell it out or use the correct terminology that special people like dojj can understand it

so hopefully we've all learnt something from this thread. you've learnt that you need to spell it out, dojj has learnt the relevance of the temperature sensor, and i've learnt that not everyone is as clever as me

 

lol no one is as clever as you lol

 

Data collected - video created and new topic coming up.

 

I understand.In simple terms your just fooling the dyno .

 

Topic with video here.
https://passionford.com/forum/genera...n-read-on.html

 

no you're not. the dyno itself cannot be fooled as that is the bit that does the measurement. it measures what it measures (unless there's something wrong with it). you can manipulate the data that the software outputs, but i'm sure Stu goes on to explain that in his topic which i am now about to read.

 

from what i can understand glenn, it's not the dyno you are fooling, it's the calibrated settings that you are fooling into giving you a different corrected figure

for example, if you have a school where they give you extra points for kids who don't have english as their first language and those kids get better scores than the national average, the school "looks" to be doing better than it actually is

if you were to level the playing field and say that every school would publich the resluts that their kdis actually achived, then that school would be below the national average

the national average being the industry calibration for the dyno depending on how hot/cold it is and the school scores being the power figures

 

it's nothing to do with calibration of the dyno dojj the calibration of the dyno means how accurately it measures - this is all just how the measured figure gets manipulated. i really can't understand how anyone can fail to understand it, it really is simple.

 

Which is exactly what I've said, I think lol

The dyno reads whatever routes it reads and then the person putting in the data adds an extra degree to the temp say and the corrected figures is what gets put out

It's like statistics proving whatever you want them to show based on which questions you ask to the interviewee

You've just manipulated the information to your advantage, so that works for everything

 

no it's not what you've said at all.

i've been trying to think of an analogy that your addled brain can understand, it's been difficult but i'll give it a go.

you have a man who is wearing a pair of pants and a shirt and you want to know what he weighs (what his mass is technically, but we don't need to get involved in that). the real mass of him in his pants and shirt, as measured on a calibrated balance is 100kg exactly. this is equivalent to an engine making a quoted power at the standard test conditions, say 100bhp at 25 degC and 1013 mbar.

if he goes on another set of scales somewhere else, provided they are calibrated, those scales will also tell you that he weighs 100kg, as will any set of scales in the world if correctly calibrated (there will be some tolerance, but not much, say for arguments sake it will be within 1/2kg so between 99.5 and 100.5kg).

he gets on some cheap scales (or ones made for gullible women who don't want to believe that they really are that fat) that say he weighs 90kg. he doesn't, he still weighs 100kg, but the scales are not properly calibrated and have a measurement error. another set of cheap scales might say he weighs 110kg. that is just because they are not calibrated - there is no correction of results at this point (although you can always calibrate such scales provided the error is repeatable - if you know that when you put a 100kg weight on them and they read 90kg, you can effectively redraw the scale so that it reads 100kg). this situation should not really happen on a dyno, but it could if the load sensor is not kept in calibration or it, or its signal, are interfered with on purpose to give false readings.

now he puts on some thick trousers, a heavy wool jumper and a big overcoat. he gets on some calibrated scales and they say that he weighs 110kg. we know that in his pants and shirt he was 100kg, so the other clothes have added 10kg so we need a correction factor to get back to the unclothed weight. that is like an engine being run with a hotter inlet air temperature than at standard conditions - it will make less power because of the less dense air (and therefore less power would be measured on the dyno) so we need a correction factor to normalise it back to what you would get if you were at standard conditions. provided that the correct air temperature is measured, the correction factor applied by the software to the dyno measurement should be accurate and the corrected power calculation is applicable. so for example if the dyno measures 90bhp and it is 45degC and the correction factor is 10bhp, then the corrected power comes back to 100bhp which is what it would make at 25degC.

now if we lie and say that our man had a concrete crash helmet on when he was on the scales at 110kg and therefore we need to take off another 10kg as well as the 10kg for the cold weather clothes, we would over correct and say that it would be equivalent to him weighing 90kg in his pants which would flatter him somewhat. that is the same as putting the temperature sensor somewhere hotter than the air the engine is taking in and therefore over correcting and flattering the corrected power output. so at the same 45 degC temperature as before, the measured power will still be 90bhp, but if the temperature sensor is put in a bowl of ready brek at 65 degC, the correction factor applied by the software might be 20bhp and therefore the corrected power calculation would be 110bhp which is falsely flattering.

the corrected power figure can be useful if you know that the measurements have been done correctly (and if everything is calibrated, including the temperature probe of course, which is another area where a fiddle could happen), but the dyno in an uncontrolled climate is most useful for back to back measured power comparisons at the same conditions. for example, you add 5psi more boost and want to know what difference it made. that would be like the man using the same set of scales and getting on with a pair of wellies on in addition to his pants and shirt and finding out that he now weighs 102kg and therefore his wellies made 2kg difference.

i hope that makes some kind of sense to somebody and helps explain it a little.

 

After that short explanation, your version of events is better than mine

 

I get it now thanks for that explanation.