I keep reading about AFR everywhere specially with tuning turbos and have no idea what you all on about, so far i have learnt its not actually Angry Fucking Rage when things go wrong, corrected its Air Fuel Ratio?

So what is good AFR? does it apply to all engines and how does it affect power and all that other stuff when tuning?

 

Correct

Steve.

 

good afr differs from turbo to none turbo

http://www.zeitronix.com/

 

At a basic level, an AFR of 12.5 is optimum for making peak power from an engine, but the amount of heat generated at this level can be too much in turbo engines (or even when totally flat out for an N/A engine) so people tend to run a richer mixture (lower number) to help control the heat.

Turbo motors typically will be mid 11s when flat out, but in some cases where the engine is badly designed in terms of manifolds or similar (Focus RS being a good example Stu mentioned) you may have to dip into the 10s to keep exhaust gas temperatures at a reliable level.

 

rightyo so lower the AFR number the richer the mixture is, higher number leaner it is.

does the same figures apply to say a V12, V8, Straight 6, V6 all the way down to bikes? if not how the hell you know what it ment to be?

 

The same figure for peak power applies to all cars using petrol, although i would imagine it varies very slightly based on octane rating etc.

HOWEVER, thats only the thoeretical peak, and with regards to the temperature side of things, the way you know what it should be is by being a talented tuner with 20 years experience

 

true experience counts for everything, just trying to understand a bit more the hows and whys behind things

 

Thats what we are all here for mate, welcome to the site

 

Thanks Chip-3door!

This stuff really facinates me, have so many questions on things i do not get. Only so much my limited brain can absorb through books, often leaving me more baffled than i started off with

 

LOL, yeah it can be a bit like that.

Im in london most weeks, if you fancy discussing it over a pint one evening then let me know cause ive usually got feck all to do of an evening anyway while im working away!

 

and there it is,....

a truly classic "hit"

start with being friendly, (in some cases a shoulder to cry on) then when the "victim" is not expecting it,....BAM,....

lets go out for a drink.....

before they know it, the innocent party is bent over a sofa in room No 30 of the nearest travel lodge.....





however, chip seems to know a thing or 2 so being butt raped for free info isnt that bad....

 

just incase youre not sure

air to fuel ration of 15:1 means 15 "parts" of air to 1 "part" of fuel

i know 99% of people might already realise that, but not everyone will unless it's said...

 

lol

 

Im sorry but thats THE funniest thing ive read in ages

 

PMSL

only if she isnt old enough to drive

 

poo the bed

 

thought it was one way or the other

 

yes jim, but that 'part' is a mass, not a volume