Gearshift Indicators On Dash

[Andy Kay]

These are a novelty to me, but they frequently go against my intuition. They seem to tell me to change gear when I would also intuitively change gear as long as I'm on a level road, but not when I'm going uphill or downhill. Would I be correct in assuming that they make use of the engine speed and the road speed alone to give that indication, and not of the demand on the engine?

[bobkneale]

I see these gear change green arrows as a basic indicator of reccomended gear changes, it does not seem to be perfectly programmed to indicate gear changes to maximise economy in all situations, (going up a hill is an example) however as a general guide it is better than nothing in my view.

I attempt to keep revs quite low and throttle pressure light, and coast in gear as often as possible, basic hypermilling practice is perhaps better than just relying on the green light indicators provided.

[Andy Kay]

Yes, that was the impression I was getting Bob.

Thanks for the confirmation.

[FROSTYBALLS]

There is an EU requirement that all cars which required new Type Approval after !st November 2012 and for all new cars from 1st November 2014, be fitted with gear shift indicators to save fuel and CO2. The majority of these gear shift indicators use engine speed as the trigger. More sophisticated systems are also used which monitor changes in various engine parameters to take into account the driving situation and driver demand (eg BMW Efficient Dynamics).

Most manufacturers introduced gear shift indicators well before the required deadline

[Soeley]

I tend to ignore these (well not tend to, I do) as if you followed them you would be changing gear twice as often as you would just driving normally. I wonder if that is why some people complain at having to change gear too often, because they follow the lights?

[tarquin]

Don't look into the light ( A Bugs Life)

David

[Andy Kay]

Thanks for the info Frostyballs. Soeley, I too have gotten used to ignoring them. It just occurred to me that they might be a bit more sophisticated than I was giving them credit for... when I'm coasting downhill in sixth gear and they tell me to change down, I thought maybe it could be a "being in full control of the vehicle" issue. But definitely when going uphill and they tell me to move into a gear that makes the engine labour, they seem to be wrong.

[Hairy Nugget]

Mine wants me to put fifth gear at 55-60km/h, which I have seen decrease fuel efficiency compared to fourth..

Following the indicated shifts also leads to a lot more vibration from the engine, and it makes the driving experience totally gutless under 80km/h (at which point using fifth is acceptable)

Thinking of making a sticker to cover the light, maybe some wise words like "All work and no play makes jack a dull boy".

I average 4.5L/100km on mixed driving with the shift light being on 50% of the time..

[Andy Kay]

Thinking of making a sticker to cover the light, maybe some wise words like "All work and no play makes Jack a dull boy".

I average 4.5L/100km on mixed driving with the shift light being on 50% of the time..

I know what you mean. My 1.3 litre engine is very free-revving and I like to make use of that. Once I missed a gear pulling away from lights and the engine went very quickly and smoothly right up into the red. It's a fabulous little power unit.

With ECO mode off, and doing mainly town driving, initial measurements show I'm getting 7 litres per 100 miles (crazy mixture of units... reminds me of wheel measurements mixing mm tread width and inches for the diameter). Converting to km, that's pretty much on par with your fuel consumption.

[korat102]

They were quite useful for me in the Verso. First diesel I've ever owned - the car kept telling me to change up while my brain, still wired for petrol, told me to change down. As I got more used to driving the thing, I started ignoring the indicator and hardly notice it (or studiously ignore it) now.

[Andy Kay]

They were quite useful for me in the Verso. First diesel I've ever owned - the car kept telling me to change up while my brain, still wired for petrol, told me to change down. As I got more used to driving the thing, I started ignoring the indicator and hardly notice it (or studiously ignore it) now.

I have to admit that they were useful at first to me too, not being used to a six speed gearbox they provided a gentle reminder that had still had another gear to move into.

[scimberk]

Bobkneale, I try to keep the revs low, but it makes me smile way to much to drive it like an old Mini, so the revs stay fairly high, as does the MPG a win/win situation.

[tarquin]

I have noticed recently, that in the cooler morning the car "fly's" but later not so. Its either air pressure or hot air under the bonnet.

Strangely, its on coldish overcastish mornings that its at its peak

David

[korat102]

Cool air has a greater density than warm air and your internal combustion engine likes it cool :)

[tarquin]

Hi Korat

Its ok i do the about the temperature its just often so pronounced

David

[bobkneale]

If petrol combustion engines like "cool" air better than warm due to density, if there any merit in ducting a more direct (better) in to get the air from outside the car, If i remember correctly someone had cut a round hole in the front that took air to a free flow K & N filter mounted just behind and had fitted a shield to prevent engine heat rising towards it all in an effort to get better (free flowing) Cool air into the engine.

All comments welcomed !

Perhaps I should have found that post or started another ?

Or perhaps I should just keep quiet !

[korat102]

Yep, absolutely. Ducting cool air from outside instead of heated air from the engine bay has always been one of those 'performance tweaks' that are high on everyone's list of options. It'll make a noticeable though not huge difference to an otherwise completely standard system but if you're intending to carry out any other mods, better airflow is a must.

There are drawbacks though, aren't there always?

If you're in a cold climate, your engine will take longer to warm up when you're ducting cold air from outside.

If your duct is too low it might draw water in with potentially disastrous results.

[tarquin]

I did go along the ducted K&N filter and added a blower. And although i increased the top speed the bottom end was poor on acceleration. Just couldn't get enough cool air without modifying the body So have abandoned it.

David

[Soeley]

Bobkneale, I try to keep the revs low, but it makes me smile way to much to drive it like an old Mini, so the revs stay fairly high, as does the MPG a win/win situation.

My sentiments exactly :)

[Hairy Nugget]

Sorry to be "that guy", but..

Any of you K&N guys had engine oil analysis done on stock filter and compared?

[tarquin]

No just an experiment really.

David

[Soeley]

Sorry to be "that guy", but..

Any of you K&N guys had engine oil analysis done on stock filter and compared?

How/Why?

Please explain more?

[korat102]

I would assume he's talking about the 'studies' showing that K&N filters don't filter as efficiently as paper filters.

Proponents of oiled filters talk about less restrictive airflow (probably mostly to do with removing the airbox) and the ability to clean the filters; the particles of dirt stick to the oil and are simply washed away. Those who prefer paper filters point out that while paper filters can't be cleaned, they are cheap enough to throw away and replace regularly.

Personally, I think I'd prefer a paper filter for a road going vehicle, those K&N's are just too messy (have you ever cleaned and oiled one?) and as long as a paper filter is changed regularly, it should provide adequate flow with good filtering.

Of course, doing away with the restrictive airbox is going to have a dramatic change on the intake sound and, for some people, that sort of thing is important...

[craggle]

I did a half way thing and kept the original airbox but fitted a Blitz motorsport cotton air filter into it.

The original airbox is actually quite well designed and the intake is positioned at the front of the car so it gets cool air.

Blitz do claim a free flow design but as said above, the only way to get more flow from a filter is increase it's size or increase the size of the holes in it. Bigger holes through the filtering medium will flow more air but allow bigger particles to pass through.

I can't say I noticed a huge performance increase between the standard paper and cotton filters though.

Craig.

[Soeley]

Sorry to be "that guy", but..

Any of you K&N guys had engine oil analysis done on stock filter and compared?

So come on HG will you elaborate?

Are you trying to say that using a K&N type filter has an effect on the engine oil?

If so how?