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I agree I am confused too, as surely when the temperature of the compressed intake air varies so wildly (even once intercooled) the ECU cannot adjust effectively enough to not pop the engine.

thats what has me confused. it might be the same mass but its a compressed mass at reduced volume, hence the rise in temp. Boyles law has a pretty good rundown of this : http://en.wikipedia.org/wiki/Boyle%27s_Law for those willing to try n get their heads around it

-D

Edit - BTW whos going to see AC/DC tonite?

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turns out this is the way im going to be positioning my AFM

its easier to clamp and re-position the afm on the cool side, rather than chop up my stainless intake pipe to fit.

decs has done it before, and will do it again...

had a look at it today whilst dropping more goodies off, not long noe :) just waiting on a new welder to make the stainless

cooler piping, a touch up on wiring and its skid time!!! wooohoooooo

Ok here goes;

The Nissan style MAF/ AFM (hot wire) works by a wire being cooled by flowing air, which i'm sure most of you know.

<snip>

This is a simplistic view of tuning and what is going on, but you should get what i mean.

That explains it all.... thanks for the write up there dude

-D

Ok here goes;

The Nissan style MAF/ AFM (hot wire) works by a wire being cooled by flowing air, which i'm sure most of you know. Now what cools the wire is the actual atoms that make up "air", now as the temp of the air increases the density of the air decreases which means that then there are less atoms per volume and the cooling affect of the air is therefore less per volume.

This also means that there is less oxygen per volume which is why we run intercoolers to try and regain some extra density from the intake charge before it enters the plenum/combustion chamber.

So this mean that a MAF is less sensitive to temp changes that other forms of systems because what it is actually measuring changes as the temps are increased.

Now the reason that i said that the after turbo AFM mod's needs to be tuned is more to do with the VQ table that the ECU uses than temp correction. This table says that for a set voltage there is a set mass air flow. This air flow is calibrated to the size of the AFM body amongst other things, so if you change the body size you change the amount of air that passes for the voltage put out.

These calibrations (and the tune in your ECU) are worked out with the AFM being in a vacuum and the air being drawn through the AFM, once you put it on the pressure side for the set voltage you will be getting more airflow as it's now a pressurised system and the flow is therefore increased.

The AFM being out of calibration doesn't really matter though as you can tune around it, it just means that you can't just swap it to the other side and drive away. It would drive fine once the mod has been done while you are driving around under vacuum, as it is the same as it being before the turbo in terms of calibration but once it hits boost it'll stuff up your mixtures.

When i say you can tune around it is because the ECU doesn't care about air, infact it doesn't even know what air is. The ECU takes the voltage reading from the AFM and says well i have this voltage so i need this amount of fuel (using the fuel tables set in the ECU). When you tune an ECU you are adjusting the amount of fuel for the amount of voltage the ECU is seeing from the AFM. You adjust it using a wideband O2 sensor as reference and you are adjusting it to achieve the desired Air Fuel Ratio that you want to run.

This is a simplistic view of tuning and what is going on, but you should get what i mean.

Brilliant... perfect explaination

just had a meeting with a guy whos doing the job that im currently studying. found out what money ill be ruffly getting and doesnt sound to bad :)

casual = $3500k a month (working only 14-15 days a month)

full time after 5-6 months = $5500 a month (working only 14-15 days a month)

senoir roll full time after 2 years = $10000 a month (working 14-15 days a month)

thats 6 months a year of acutal work and have everything paid for while at work and cant spend any of it till i get back to adelaide from 14 days straight.

fingers crossed everything pans out!

just had a meeting with a guy whos doing the job that im currently studying. found out what money ill be ruffly getting and doesnt sound to bad :)

casual = $3500k a month (working only 14-15 days a month)

full time after 5-6 months = $5500 a month (working only 14-15 days a month)

senoir roll full time after 2 years = $10000 a month (working 14-15 days a month)

thats 6 months a year of acutal work and have everything paid for while at work and cant spend any of it till i get back to adelaide from 14 days straight.

fingers crossed everything pans out!

Thats pretty good coin. I always wanted to be a male prostitute too but I was told early on that I just didnt have the looks for it. Best of luck tho mate ;D

-D

cool, got another fine from dtei today.

a fine for having my feet on the seat on a train.

but before you flame me for that, i had my feet on my satchel.

but id be happy to wear the fine...

... if it werent for $140.

no, youre not misreading that, one f**king hundred and forty dollars.

since when are our trains made of solid gold.

was gonna go to melbourne for my birthday with that money.

but before you flame me for that, i had my feet on my satchel.

Nuff said. Call the authority and explain that to them. Explain to them that if they are uncooperative in reaching a reasonable settlement privately, that you'll invoke legal aid and sue them via the civil court. Tell them that you will elect to have a civil trial in front of a magistrate, and that means they would have to prove the offence - if they have video evidence then it'll show your feet on your own property and exonerate you etc

legal tactic 1 : factotum

legal tactic 2 : innocent until proven otherwise

at least thats where I'd start... its a huge, stupid run around the authorities. it takes time and effort which is why some people say 'stuff it' and just pay the fine, where they SHOULD be contesting the nonsense.

-D

just wondering if anyone can tell me if this is good?? not familiar with stuff this technical

Inlet:

Lift 100 200 300 400 500 600 700 800

Flowscale 150 298 298 298 447 0 0 0 0

% of flow 71% 66% 80% 88% 69%

CFM 106.5 196.68 238.4 262.24 308.43 0 0 0 0

Airspeed

Exhaust:

Lift 100 200 300 400 500 600 700 800

Flowscale 152 152 320 320 320 0 0 0 0

% of flow 60% 90% 66% 72% 75%

CFM 91.2 136.8 211.2 230.4 240 0 0 0 0

Airspeed

In Ex %: Potential Hp:

@ 500 lift @ 500 lift

77.81% 476.497 Hp

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