More Air.

[grahamw48]

I was thinking about putting in a K&N filter.
Not understanding Fuel Inj', will I need to adjust anything else, or does the system sort itself out?

[wedg1e]

Hmmm. In theory you're not getting more air into the engine, you're just helping it to get in there a bit quicker. In which case the fuel metering unit should simply see the faster-flowing air and add more fuel quicker...
You really need a CO meter to see whether the fuelling is anything like correct to start with.... plenty on Ebay for anywhere between buttons and as-new cost.

Speaking of which, why the hell do people pay some of the prices they do?
I was looking at welding gear and found the same 90A SIP that I started with, list price then was £120.
Secondhand on Ebay: currently at £155. Wtf?!

[redcar]

wedg1e said:

Hmmm. In theory you're not getting more air into the engine, you're just helping it to get in there a bit quicker. In which case the fuel metering unit should simply see the faster-flowing air and add more fuel quicker... You really need a CO meter to see whether the fuelling is anything like correct to start with.... plenty on Ebay for anywhere between buttons and as-new cost. Speaking of which, why the hell do people pay some of the prices they do? I was looking at welding gear and found the same 90A SIP that I started with, list price then was £120. Secondhand on Ebay: currently at £155. Wtf?!

Top business man the ebay seller.:

[grahamw48]

Ok, thanks Ian.

When I had the tuning man round a couple of weeks ago (contrary to what I was expecting) he gave the CO readings a clean bill of health, 1.5 I think, both banks, and reckoned she was working pretty efficiently.
I think my next door neighbour has a CO meter, so I could set it up round there. (I do pay him )

Ebay can be quite amusing, can't it.
My natural tight-fistedness protects me most of the time though.

[chunder]

Whilst Ian's spot on in that a free flow air filter will allow an acceleration in the speed at which any required increase in volume of air (i.e. opening of the throttle) is met (and therefore increased responsiveness and possible top end power improvement), and that the AFM will sense this and increase injector pulse width, fuel enrichment is also controlled by the TPS and you may find a slight leaning out under some conditions - mainly heavy throttle application.

It's unlikely to be major unless the ECU has been remapped with a particularly poor air filter in use but this won't show up with a CO meter in a static test - only when the engine is under load.

[jchase]

Erm, the 280i doesn't have a TPS. or an ECU for that matter.
Basic fuelling is set by the PRESSURE going to the mechanical injectors, which are contunously on. Engine load compensation is done by the warm-up regulator, which tries to maintain a differential pressure between manifold and basic fuel pressure to the metering head. You can adjust the response by shimming the WUR so the compensation is non-linear, but I wouldn;t go there...

-Jim

[grady]

Graham, I think the plus for us is almost infinitely longer life (albeit with occasional cleaning and re-oiling), smaller particle trapping and a bit more air though compared to a thick, pleated paper kind.

Not sure it makes a real difference but it is a must have. Grady

[grahamw48]

I think I'll give it a go, as long as it doesn't weaken the mixture up too much.

At least they're harder to break than thermostat housings.

[chunder]

jchase said:

Erm, the 280i doesn't have a TPS. or an ECU for that matter.

Bob, I think you've got the wrong vehicle there - I know Graham didn't mention it but he has a V6.


quote chunder
No worries - please ignore my comments.