Air : Fuel Ratio.

[DIDZ]

Hi Guys,

Was just wondering what the stock A:F ratio is in Veedubs, in particular stock Golf GTIs.

Any help ?

[h100vw]

It's what VW or your chip programmer decides mate. As weak as they can get away with to make the grade for emissions.

You can't go too rich or the cat will take a beating.

The lambda probe monitors what's going on.

Have you got a reason for asking the question?

Gavin

[Golf Loon]

112km atw from a 250kw chip. Someone stuffed up.

[gpk_gti]

your after the stock ratios right? maybe william knows???

[syncro]

Wouldn't it be the same for any car?

[DubSteve]

Wouldn't it be the same for any car?

Wouldn't it be different for a vr6 and GTI 1.8T

[syncro]

Wouldn't it be different for a vr6 and GTI 1.8T

Why would it be different. It's a ratio?

[DubSteve]

Why would it be different. It's a ratio?

Its a smaller engine, turbo?

[syncro]

Less fuel, less air. Still the same ratio.

[DIDZ]

112km atw from a 250kw chip. Someone stuffed up.

It's a sarcastic comment, everyone takes a signature for granted. That's why I put it there.

I'm interested in the stock air : fuel ratio.

I've been looking at various different dyno charts here and there and I'm seeing ratios that are all over the place throughout the rev range (APR, Revo, MTM and standalone management etc included). Hence wondering what the stock A:F is.

Does anybody have an answer ?

[Bora Sport]

From what little I know it is basically the same for all internal combustion engines except maybe the stratified charge style that Honda was playing with.

I believe it is referred to as the stoiometric ratio and it is variable depending upon load, engine speed, temperature etc.

Generally a cold engine on initial start up will run rich say as low as 12-13 to 1 air to fuel. An engine at operating temperature and cruise (light throttle opening) is around 14 - 14.5 to 1 and under full load and acceleration like on a dyno run for instance it is best to be a little but not too rich.

I have a recent dyno run for my Beeza Cupra 2.0 16V and it is 13.1 at 2190 rpm and stays betwwen 12.9 and 13.3 all the way to 6278 rpm where it starts to lean out a bit before it hits the limiter. Between 6350 and 7000 rpm (rev limiter) it is 13.4 - 13.6.

The guy who did the dyno run is big into turbos and big horsepower applications. He told me that for a totally factory setup he felt that VW couldn't have gotten it any better.

I hope this helps.