You can trust Stu at MSD! (I Did, through Chip, that map was the best map I have ever had )

But I know what you mean, one day I dropped my car off at my local garage for an MOT as usual except I had been to the fuel station the night before, so I had a full tank and 550 miles on the DIS.

When I picked it up it had done 500 miles more on the odometer and said I had 10 miles of fuel left.

I contested it but obviously they claimed they didnt know what I was talking about, so now I don't trust them and have to make sure if I have to go there that I do so with an empty tank!

 

Ok so where is he and can he map a porsche ?

 

interesting video stu, interesting to see how much the correction can affect the result
thanks for taking the time out to make the vid, and explaining it so clearly

top man

 

We can map pretty much anything.

Www.evolutionchips.co.uk

We have done my porka

 

you got a gt3 james? very nice pal!

 

It's a Carrera 4 with the factory aero kit, I've just never taken the badge off that the previous owner put on

She is pretty though, a bit more work and i may even be happy lol

 

So where would the probe go on the most universally used dyno.

The arse dyno.....

 

Where the sun dont shine!!!!!!!!!!!

 

Can you do my Lexus??

 

Nics porky james you have come a long way since owning old fords.

 

Stu must be paying you to much money.

 

Strangely it owes me less than half of the 40k I put into my cossie!

What a waste lol

 

You put 40k into a cossie???Are you mad lol.

 

Now, forgive me for sounding dumb - it's a genuine question, cos I actually don't know - but how does an air temp sensor (which I presume it nothing to do with the car's ECU) have any effect on brake horse power, depending on whether it's reading higher or lower?

I thought that a dyno tested horsepower mechanically, reading it from the wheels (vs resistance), and to get flywheel bhp it measure the run down and converts the transmission loss?

I don't get why a thermometer position would affect horse power?

Answers in as plain English as possible please

 

the temperature to rate hp is I think 25d, so if its above that the software will add a percentage to bring the figure in line with a run on a 25d day, and if its below 25d it will take some hp away as its cool and the engine will make more power.

its to make the figures comparable otherwise cars run at night in freezing cold conditions would make a lot more power than they do on a hot summers day. the figures must be corrected for temperature otherwise they aren't comparable at all even on the same dyno its just something an operator can manipulate and give an unsuspecting customer a massive dyno plot that means f all.

 

any news on the cuppa tea plot at sae correction stu, id much appreciate it if you could do it mate

 

all dyno's take a reading from the ambient temp and then convert it to an industry standard of say 25 degrees, so if its only 10 degrees then it will calculate the differance as if its 25 degrees and show that, same with its 70 degrees it'll calculate and show what it would be at the 25 degrees,its so you can test the car in any country/climate at any temp and it will still give an accurate reading anywhere, cause as we all know
turbo'd cars pull harder and seem to be faster when its colder as the air is densor
so if you dyno'd it in alaska and in dubaii the dyno correction SHOULD always make it consistant

i knew somebody would post while i was trying to type this out

 

maybe my post to Dojj in the other thread might make sense?

https://passionford.com/forum/6288619-post61.html

again, there is confusion here because people don't distinguish properly between measured data and corrected data

this has nothing to do with flywheel figures either, just purely measured power vs corrected power 'at the wheels'

 

Hot certainly differ,s from cold ! as altitude does!


My best, T.

 

I see (I think). So the computer is compensating for BHP loss due to temperature? IE, on a hot day a turbo car generally makes less BHP than on a cold day, down to temperature (and also the oxygen content of colder, denser, air)

No?

 

yes, but not just relevant to a turbo engine

 

In a word, Yes the denser the air the more bang for your buck. thence intercoolers. At sea level = 1 atmosphere the air is thicker (ie-denser) than @ 2 Atmosphere! (1 Atmos=33feet) therefore achieviable bang for buck is less as altitude increases. (Not enough oxyegen for burn regardless of how much fuel is injected.


Cheers, T

 

So with that, it's still not a "true" BHP reading, but possibly a more accurate one? (ie, a bit of clever computing, algorithms, etc, figuring out a more accurate bhp figure)

 

Interesting thread.

We recently had to dyno a car on a DD and the power runs were done with no corrections to the power so whp only.

The figures were 244.4hp ATW so is that figure actually lower than what it should be ?

 

depends what the ambient temp was
it could be higher, lower or exactly the same
without knowing what the ambient temp was on the day and the correction factor then its impossible to know

 

"should be" in what way? it was what it was

 

I agree Nick, this is why we didn't use any sort of calculations but in fairness we were not there to get anymore than the car mapped, the fact it made good power was just an added bonus.

the pic below is quite crap but I see the air temp was 15.2 degrees which seems about realistic from how I remember the day.

 

are you sure it wasn't corrected though mate ?
its not the same as flywheel projections its a correction to industry standards, either way if it was or wasn't if the temp sensor was just hung in the room itl make very little difference, at 23d room temp my car recorded 563.3 hub power and the industry standard din correction corrected that to 561.9 hub power, even at 30d the corrections are gonna be so small there irrelevant its only when the temps get silly high where the corrections get big.

 

at 15d the correction would of taken away approx 10 hp. it seems as a rough guide it takes away 1 hp for 1d below 25d, and adds 1hp for every 1d above 25d.

 

99% sure mate, I wasn't running the dyno but I was told that there were no corrections, it just showed the whp only, I could well be wrong.

The car did ironically make less power than the old engine but smashed its previous pb so that is why I was curious if the dyno could of actually been under reading

 

that the best place to test it anyways ay mate, the tarmac doesn't lie
she sure looks a screamer from the height of that plot

 

What car was it? Revs high! Bit of an odd looking graph low down

Our dyno certainly corrects atw figures, all the figures in the video are atw,

 

It was a Vauxhall nova running quite a serious C20xe engine, it ran a 10.6@130mph the following day !

 

130 mph with 300 odd hp fair play
us lard arses can only dream lol
what a cracking result

do you know what it weighs ?

 

They backed it up on the sunday with 5 more 10.6 passes as well ! best trap was 128mph on the sunday though. Its all motor, no nitrous or anything.

I did put up a thread about the car and the manic week we had with it.

You can probably now see why I am questioning if the hp was reasonably accurate as that is a seriously impressive time for something with only 244 whp

 

Great video Stu, I found that really interesting although I would of expected the cup of tea to of been in a more traditional PassionFord mug surrounded by hob nobs

Great thread

 

it is very impressive, what does the nova weigh all in on the line ?

 

550kg without a driver afaik

 

please stop using the symbol d to mean degree Celsius, it offends my engineering sensibilities

http://en.wikipedia.org/wiki/Celsius

 

550kg thats nowt is it.