A Really Good Read - Dyno's - Much for u to learn from

[xoom]

this is an article which was sent to me by a fellow car enthusiast and it eloquently details everything ive ever said in every discussion ive ever had ..... from now on i will be using this link when ever a debate about this stuff comes up.

http://www.dmhmotorsports.net/DynoRacing.html

http://www.gbmini.net/wp/2005/08/the_probl...f_dyno_testing/

the best sentence

So next time you read dyno claims, consider how useful they really are - if gains of 20+ are claimed, that is significant, but a gain of 5-10 hp is easily swallowed in real world variations …

as i also saw today exactly what a difference of 20 degrees on the intake does to those power figures ;) ;) ;) ;) and i also saw another way to jig the results and there will be NO WAY to prove that the results were jigged ..... good old roller ratio's ;) ;) ;)

[SILVABULLIT]

BINGO!!!! Some have critisied me about my thoughts on this matter and how happy I am using the old mechanical dyno at CES for most of these reasons. The only thing that changes the results on their dyno is the conditions of the day.(temp,humidity etc) No other variant can be altered to give a different reading. Good old "ol school" readings that have proven to be accurate within 1-3kw of other dyno shops in the area with the latest dyno dynamics dyno's.

Everyone can have a whinge at dyno readings but at the end of the day the "operator" can and will determine your results on all computer controlled dyno's.

[xoom]

BINGO!!!! Some have critisied me about my thoughts on this matter and how happy I am using the old mechanical dyno at CES for most of these reasons. The only thing that changes the results on their dyno is the conditions of the day.(temp,humidity etc) No other variant can be altered to give a different reading. Good old "ol school" readings that have proven to be accurate within 1-3kw of other dyno shops in the area with the latest dyno dynamics dyno's.

Everyone can have a whinge at dyno readings but at the end of the day the "operator" can and will determine your results on all computer controlled dyno's.

to be completely honest though SB as stated ANY dyno can be fiddled with ..... even the mechanical ones i.e. the bearings in the rollers ...... fair enough u couldnt do it between runs without people seeing it happen but it is also a means to alter the output.

[Suprathai]

meh, any device that is used to perform a measurement usually needs to be calibrated to ensure an accurate reading.

Results can only be comparable if testing conditions are exactly the same and the procedure that was used, or if there are variations they are within the error that is expected.

I still laugh at those pod filter test though.

" And the <INSERT BRAND HERE> is the best performing filter beating the average by 1kw "

Quite a good read as well

Thanks for sharing

[beaves]

you would be highly suprised by how much humidity and temp have an effect on performance on piston engines. In my line of work fixing piston engine aircraft we use static barometric pressure of the day as a guide when running the a/c. before starting the engines, a reading is taken in the flight deck of the pressure felt just before the supercharger whilst the engine is not running, once up and running, the pressure felt is negative but as the throttles are advanced to get the pressure up to the "static" pressure of the day (which is usually around 29.9 inches of mercury), the RPM is annotated on a reference card and left inside the plane. It's basically a way of monitoring the condition of the engine, if you get spark plugs that are on the way out, or even air leaks from say a cracked cylinder this 'static" RPM will decay, so it is a good guide of letting you know how the donk is going (this is on R2000 engines mind you). Major component changes always result in a new static card with the new rpm annotated and left inside the plane. Doing this sort of ground run in say PNG as opposed to doing it in say a Sydney winter, the "static" RPM can have a increased difference of say 200-300 RPM(which is about 10-15% difference) because of that nice cool air and relatively nice low humidity in Sydney.Wind can play a factor in the RPM as the prop is really just a big brake but there are formulas that can adjust for the wind. Humidity and temp play massive roles in engine performance, and i think it becomes over looked when people are trying to get performance out of a car engine. I am no car buff in anyway, I fixed gas turbine based engines before my current job, but I am keen to learn all the time, but I would hope that when cars are being placed on dynos, all possible variables are made to be consistent whilst doing the runs. Tweaking results here and there after mods have been done to try and show to joe public that their POD filter has made massive increases is purely unprofessional on behalf of the operator.

Edited January 2, 2008 by beaves

[xoom]

Tweaking results here and there after mods have been done to try and show to joe public that their POD filter has made massive increases is purely unprofessional on behalf of the operator.

this is exactly the point i was trying to make ..... the process is not proofed 100% from being totally unmanipulatable ....... my car right now is in the process of being tuned .... and the boys at the workshop were kind enough to show me what a lot of the variables are that they can play with and how these variable will at the end of the day affect what is coming out on paper ..... NOT how the performance is actually working .....

i posted this because not all people are honest and because it was sent to me by a fellow mod from another forum where i was linked and finished reading another forum flare up about "how accurate" the reading is that was produced and "how there is no way" it could be incorrect ...... just thought i would enlighten people to hopefully not get that same sort of ignorance .....

As stated by superthai u can create all sorts of results by shifting the environment the key is consistence of all variables to the best of ur ability.

At the end of the day to be honest the piece of machinery that is built is useless IF the operator is unable to use it ..... so personally i couldnt give 2 hoots if a car made 400kw at the wheels and only weight 1000kg's..... if its taking over 14 seconds to get down the 1/4 or cant get around wakefield below a minute & 15 sec (im taking a guess that this is a reasonable time ;) ) then to me i'd either be asking questions of the machinery or looking straight @ the driver who cant handle what they have just built not even bothering with the dyno sheet .... because that means nothing.

[Suprathai]

Thats why researchers must study ethics, :( .

Don't want to get caught in a scandel where your results are fudged....

[Keisari]

this is exactly the point i was trying to make ..... the process is not proofed 100% from being totally unmanipulatable ....... my car right now is in the process of being tuned .... and the boys at the workshop were kind enough to show me what a lot of the variables are that they can play with and how these variable will at the end of the day affect what is coming out on paper ..... NOT how the performance is actually working .....

i posted this because not all people are honest and because it was sent to me by a fellow mod from another forum where i was linked and finished reading another forum flare up about "how accurate" the reading is that was produced and "how there is no way" it could be incorrect ...... just thought i would enlighten people to hopefully not get that same sort of ignorance .....

As stated by superthai u can create all sorts of results by shifting the environment the key is consistence of all variables to the best of ur ability.

Amen. Dynamometers are not black boxes, nor is any other equipment worth mentioning. Anything that claims to have anything as small as a 1kw gain must be scrutinized using statistical methods, to see if that gain really is 'real'. That's assuming all of the environmental variables have been adequately controlled (absolutely necessary when measuring such small quantities). But by that stage the entire exercise becomes superfluous and the shrewd motorist decides that there's really nothing wrong with their stock filter on an otherwise stock setup :P

Thats why researchers must study ethics, :(

What's wrong with ethics? :P