Do you really switch to 5th gear at speed 30mph?

[Tuner]

Very often the green arrow prompting switch to 5th gear when your speed is only 30mph (50kmh). Is it not harmful for the engine? I used to switch to 5th at 45mph with my previous Jazz MK1... 1.2l DSI engine.

[culzean]

Very often the green arrow prompting switch to 5th gear when your speed is only 30mph (50kmh). Is it not harmful for the engine? I used to switch to 5th at 45mph with my previous Jazz MK1... 1.2l DSI engine.

The 'change up' light is monitoring the load on engine ( probably inlet manifold vacuum which is a good indication of how hard engine is working ) - You could change to 5th with the earlier MK1 DSi engine,  but I would not be happy to do that in the 'gutless at lower revs' i-VTec in MK2  -  where to go below 2,500 / 3000 revs means no acceleration available ( except downhill ).

[peteo48]

Must admit I would change to 5th in my Mk2 at 30 mph. I didn't feel the engine was labouring at all. If I was getting a shift on, however, I might change at 45 ish.

[Jocko]

I used to switch to 5th at 45mph with my previous Jazz MK1... 1.2l DSI engine.

I have a 1.2 DSI and I select 5th from anywhere from 20 mph up, depending on gradient (or lack of it).
In fact, most times I miss out 4th altogether, both going up and down.

[nowster]

Must admit I would change to 5th in my Mk2 at 30 mph. I didn't feel the engine was labouring at all. If I was getting a shift on, however, I might change at 45 ish.

Same here, but only on the flat or downhill. In latter years of ownership I'd avoid doing that, as I felt it was labouring the engine a bit and the old fellah no longer tolerated it.

[Koubra]

I do, sometimes I even skip some gears and go higher (2nd to 4th or 3rd to 5th).
The engine is set up more towards fuel saving and that helps.
The only time I was prompted to shift down by the green light is when I was on 5th at 35mph and pushed the accelerator over 50%.

It’s 1.4 btw

[Tuner]

Same topic was discussed in our forum here https://clubjazz.org/forum/index.php?topic=786.0

[MartinJG]

Very often the green arrow prompting switch to 5th gear when your speed is only 30mph (50kmh). Is it not harmful for the engine? I used to switch to 5th at 45mph with my previous Jazz MK1... 1.2l DSI engine.

The 'change up' light is monitoring the load on engine ( probably inlet manifold vacuum which is a good indication of how hard engine is working ) - You could change to 5th with the earlier MK1 DSi engine,  but I would not be happy to do that in the 'gutless at lower revs' i-VTec in MK2  -  where to go below 2,500 / 3000 revs means no acceleration available ( except downhill ).

What is more, it seems to work because the green light rarely comes on when I am in fourth gear on our local hill .

[TnTkr]

Mine is Mk3 and I use 6th gear (same ratio as Mk2 5th) even when cruising through flattish residential areas at 40 km/h (25 mph). It goes smoothly, but of course there is no power available without switching two or three gears down. When I'm leaving home and joining the highway I often accelerate flat out at 2nd gear close to the redline and then switch directly to 6th.

Gear change indicators were interesting to follow for first weeks but now I find them just annoying. I have been considering a sticker to hide them. Same thing with fuel consumption indicator. It is too coarse to be of any interest. I've been considering a Scangauge to get more precise information of instantaneous fuel consumption.

[Jocko]

I can strongly recommend the ScanGauge. You can slowly accelerate in top at 35 mpg but if you change down that jumps to 28 and down again to 21.

[TnTkr]

Have you tested how much air-conditioning increases fuel consumption? My estimate is around 7-10 %.

[Jocko]

If my wife winds a window down I give her a row and tell her to wind it back up again so I have no authoritative data. Air con is for the puny 

[peteo48]

Have you tested how much air-conditioning increases fuel consumption? My estimate is around 7-10 %.

Is that based on actual tests? If you google it or look at various articles, turning off the air con is seen as a fuel saving measure and I've seen the 10% figure quoted frequently.

I've also heard that modern systems take less power than older ones. I've also wondered if the 10% figure is based on manual air con which will leave the system on permanently (until turned off of course) whereas a modern Climate Control system will use the air con intermittently (at least that's how I understand it).

I haven't done any testing myself I must admit but I have the Climate Control on most of the time.

[TnTkr]

That 10 % is based on my measured long distance highway fuel consumption values last summer using manual air-conditioning and similar trips without air-conditioning. With my GK5 Jazz of course. Because of traffic and other variable conditions it is just estimate. With scangauge you could see immediate effect on fuel consumption when switching it on and off. That's why I asked Jocko.

[Jocko]

But Jocko doesn't have Air con.