Preferably the graph of his escort which has never been posted on here would be nice

 

Stage 3 cossie would be my first choice of graph if I get a choice, as thats a "typical car" where as martin's isnt.

 

Yes but I don't have time to print them off, I do know that the difference between the two air temps stays pretty consistant but without the fan on and with the engine idling after a run the IT does rise but quickly comes back down when the fan is back on. I'm doing a load of work on the Escort next week so will let you know how that gets on.

 

My thoughts would be that the IT probe should be as close to the Airfilter as poss and if the IT probe was massively higher than the AT then the airflow/fan to the rolling road is inadequate

 

Not sure how many stage 3 cossies require long mapping sessions really. Although that does depend on what you determine long mapping session. Bet martins escort has had a few longish mapping sessions with plenty of data available

 

In my opinion the IT probe should not be above the engine bay.

I'm sure Chip mentioned it only takes one reading prior to a run.

The air temp that passes over an air filter during a run will be totally different temp to the air convecting off a warm engine prior to the run.

 

ok, got that, understood the mechanics behind it, now for a different question

where does the car manegement take it's reading from?

assuming it would be at the same place due to it wanting to know how hot the air was etc if that's one of the paramiters invovled in engine fueling

and

i'm sure i've read on some tests for i/c etc, the air going into the engien is virtually as cold, if not colder, than the ambient before/after

or

is this for rolling road runs for pure power figures as opposed to rolling road runs for mapping etc?

 

Depends if the readings are taken with the fan running for a few mins first or not ?

 

True.

I would have thou DD would have issued some sort of method statement for performing a run that should clarify everythingn and lead to consistent practice between DD RR owners.

 

you'll be asking for TUV approval next

 

Good to see we have so many people on here excercising 'theory' and clearly knowing more than those that have actually used dyno's.

Using our method, Gary's Evo made within 5bhp at 640bhp on 2 runs that were WEEKS, if not MONTHS apart.

I bet there are only a handful of Dyno's in the country used by people that are more interested in giving what the operators feel are fair and honest (even if sometimes disappointing) figures, but a hundreds used by people that either can't accept a new way of doing things or who operate their dyno to make them look good.

 

but there in lies the heart of the problem

you cannot make the same resluts on 2 different days of the week as something will change, so you can only test it in the same way with the differences pointed out in temps etc of the probes and sensors that are still mounting in the same places for the original run

 

So what you are saying is that you have achieved 0.8 % variance between those TWO runs.

Can this be acheived with all your runs.

No one has said that they "know more than you" but no one with a DD RR has been able to come up with a definative answer.

Look at it this way, would you accept data as proof from 5 different labs that had done the same type of experiment but each made up their own test procedure?

 

The temperature in the cell doesn't vary by enough to make a significant difference. If we were running the cars on a dyno outside, then I would expect to see more variation.

 

Air/Baro temperature correction is there to make sure the car makes the same power every time you run it (if you don't use it then it becomes almost impossible to see if you have actually made or lost power between different days)

the rules state the air temp probe should be at the air filter, measuring the temp of the air that the engine is breathing

however - if the Dyno cell / engine bay is not efficient then the temp you see may not be realistic - the dyno has to compensate for the temp that it measures

the beauty here is that if the operator has tried to fudge the graph - then its there as plain as day for all to see and can not be covered up ! plenty of dyno's hide this information

I'm not suggesting that this dyno operator has tried to interfere with this graph at all - what we can see however is that there was a higher intake temp than expected. It would be worth investigating why that was

 

it's also 'good to see' that some people actually using dynos seem to have little idea of the physics and engineering principles behind how they work

that would be some acheivement - a 100% or greater efficient intercooler

 

Where do the manufactures say to place the IT probe?

 

Chip I undertstand why dynos do it but the DD rollers SOMETIMES seem to be so innacurate that its almost pointless.

 

i had one of them little widgets that mike r used to sell for measuring inlet temps and, on a cold day, i could see it going below what the outside tempsratures were so there may be something in it

 

Seems the saying "Dyno's only as good as it's operator" is very true

 

Hmmm i suppose pressure drop as it goes through the intlet track could cause a slight temp drop???

 

no, there can't be something in it one or both gauges were inaccurate or you were driving marty mcfly's delorean

 

he just did mate Mike Gurney is head of Dyno Dynamics in uk.

 

Oh, cheers lol

 

i don't think mikes gauges would under read by as much as 6 or 7 degrees mate

i'm sure you wuill find this isn't as uncommon as it may seem