Not one, but two...

[I-S]

I take it your V6 is an auto from those rpm numbers?

The point about gearing is this... changing gear can waste fuel, and trying to accelerate at low RPM in a high gear is very inefficient (big throttle application, lots of fuel, little action). An example of that in a manual would be at 30mph in 4th... speed drops to 25mph, you're falling off the bottom of the torque curve and give it a big prod of the right foot to get back up to 30. In third, it doesn't require this, and doesn't sit at uncomfortably high revs either, and runs as efficiently overall. The advantage of this is that it's easier to pull back up to 30 when the speed drops and also you're more aware of the speed of the car and it doesn't run away up to 35-36mph and FLASH! Speeding ticket.

In the auto you'll find it doesn't shift into 4th until 35mph anyway.

[I-S]

In the time between me starting and finishing my post WODJNO has come up with a good analogy. In cycling you ideally want to keep your cadence (rpm of the cranks) at about 60-90. Pushing a harder gear might result in less turns, but you have to mash it hard and that tires you out quicker. More easier turns can be more efficient.

[Johnny_Cashed]

Sorry, I should have said, my V6 is a manual.

[I-S]

Second bit of fuel economy info: filled up at 430 miles - 300 miles round trip on motorways to parent's, and a week of commuting to/from work (for those that don't know, that's 13 miles, climbing over the pennines, down and up and down again, about 1400 ft climb/descend, 7 miles NSL, rest in 30 limit) for the last 130 miles. Came out at 38.2mpg. Proper calculation on the last bit of data gave 40.3 rather than 40.6, average so far is 39.2. Wonder if it will improve on the new tyres...

[Kieran]

You complete and utter barsteward. Nigh-on 40MPG in a Galant. My Poxy Rover 25 diesel only managed an average of 43mpg!

Anyone want a shagged Golf?!

[psbarham]

Second bit of fuel economy info: filled up at 430 miles - 300 miles round trip on motorways to parent's, and a week of commuting to/from work (for those that don't know, that's 13 miles, climbing over the pennines, down and up and down again, about 1400 ft climb/descend, 7 miles NSL, rest in 30 limit) for the last 130 miles. Came out at 38.2mpg. Proper calculation on the last bit of data gave 40.3 rather than 40.6, average so far is 39.2. Wonder if it will improve on the new tyres...

all together now , fingers in ears and , 'la la la we can't hear you '

[I-S]

I think it will drop to 36-38 when just commuting. In the GLS the furthest I ever managed was 411 miles with the light on - this was still above E at 430 miles.

Ade - I reckon your 500 miles is in danger. :-P

[I-S]

PSB - The cost is that you have to do that for the engine noise. Melodius it is not.

[Kieran]

PSB - The cost is that you have to do that for the engine noise. Melodius it is not.

Oh dear - not a howly V6 or a buttery 2.0 then?

[I-S]

Not as sweet as the 2.0, but the 4G63 was a league ahead of any other petrol 4 pot I've driven (including A4, Primera, Avensis, Zafira). The 4G64G doesn't stand out from those, while the 4G63 did.

[I-S]

Johnny - to add on the gear thing:

The GDI has a light on the dash which comes on when you're in lean-burn mode. Coming up one hill on my way home in NSL, I can climb the hill in 3rd, 4th or 5th at 55-60mph. In 5th it's not possible to get the GDI light on because it requires too much throttle to hold the speed (despite being right in the 1500-4000 rpm region where the GDI has more torque than the V6). It uses less fuel to use lighter throttle pressure in 4th to hold the speed up the hill.

[ritch_w]

how are you driving it Isaac? are you driving it purely for economy to squeeze as much mpg as poss, or just getting from A to B swiftly with only a few full throttle moments?

If a GDi can do over 400 miles to a tank with mixed driving (i.e. not driving purely for economy) it could be the answer to my prayers to ditch the diseasel!

[I-S]

I'm not driving madly economically, but my driving style tends to give good economy (eg leaving gaps in traffic and keep rolling rather than stop/start, coming down hills off throttle in gear, etc). I've also been doing a bit of italian de-coking because the GDIs do have coking issues.

Here's a typical drive home from work: 1 mile stop/start in 30 limit. Join 50mph dual carriageway up bad slip road, up to 50 in 3rd maybe pulling out around someone dawdling up the sliproad. 1 mile along dual carriageway back into stop/start 30mph for 1 mile, then 2 miles (up about 600ft height change up a hill) in 30 limit, then down hill in NSL into 40 then 30 limit in a village, out of 30 into NSL up the next hill and hoof it up the hill (30-60 in 3rd, climb in 4th), then keeping 60 to the twisties, down to 35 for the tightest one then hoof it out of that back up to 60 up to the top of the hill (about 800ft higher than where the 30 limit ended). Then little throttle just to keep 50-60 3 miles down the other side of the hill, then a few hundred yards in 30 limit to my house. The GLS auto would get 28-30mpg on a tank where I just did that journey to/from work. I'm still not sure what the GDI will get only doing that, but I expect 36 or so.

The GDI needs time to warm up (it won't go into lean-burn mode until it's warm), and in stop/start city traffic it's similar to the other galant engines in economy. It's just out on the open road or motorways where it will go up into the 40s and pull the average up.

[Johnny_Cashed]

Since you seem to be filling the role of mpg expert well, I wonder if you could answer some more of my questions. After getting pwned by the female MOT tester after I complained about how thirsty the V6 is ("Yes, I've got a mitsubishi with a 3L V6") I was wondering, I've seen other cars with a 2.5L V6 that give better MPG in a similar size car, is the galant quite inefficient?

The route I normally drive is fairly flat, with a few slight hills. The way I drive is: get the car up to 30ish and switch it to fifth, where I can keep the speed fairly constant with only very light application of the accelerator. Change to third for the engine braking when going down hills, keeps me around 30mph. Is this a correct assumption to make? IE when on a flat, go for the highest gear possible?

The other thing is what made you think my car was an automatic from the RPMs?

Cheers.

[I-S]

1) The galant is perfectly good for a 160bhp V6. The manual gets an EU combined 31mpg. Compares fine with the 170bhp mondeo 2.5 (30mpg) and 170bhp 320i (2.2 straight 6) at 31mpg). What have you seen around that power that is more efficient?

2) No. At 30mph 5th is a no-no for various reasons quite apart from economy. In terms of economy, you will need a bit more throttle in 5th than in 4th or 3rd, and even though it doesn't seem much, on the GDI it's the difference between GDI light on and GDI light off.

Do not assume that low rpm = good economy. Remember that when you cruise on the motorway, which as I'm sure you are aware is one of the most efficient modes of operation, you're sitting at 3000rpm in 5th. You're closer to the torque peak, which means you don't need such hefty throttle movements for response (eg if you put your foot to the floor at 30mph in 5th not a lot happens, despite depositing vast amounts of fuel in there with your right foot). In a 30 limit I rarely go above 3rd and never higher than 4th. In 3rd it's still just under 2000rpm (GDI's 3rd and 4th are slightly longer than the V6's, 1,2 and 5 are the same between the two), which gives good torque and response and is a perfectly efficient engine speed. Lighter throttle apps mean that less fuel is required per turn of the engine. More turns x less fuel might result in about the same economy, but the driving style you can adopt by staying in 3rd (controlling car with throttle, having engine braking on hand, etc) will generally give you a smoother and more efficient drive overall. Not to mention significantly safer.

3) You said "but in a higher gear like fourth or fifth it drops to around 1000-1250RPM". I should have seen from having a fifth that it was a manual, but I noted the 4th and "1000-1250", which suggested it was that low in 4th (which the autos would be, except my GLS never shifted into 4th until above 35mph. However, I believe that with the Tip boxes you can force it) and the way the rev range you mentioned wasn't a specific figure (the autos will vary revs in a given gear and speed depending on throttle position).

You mentioned 1750rpm as a target - 5th certainly isn't going to give you that (5th will be about 1200 at 30). I'd say that 1750 is a little low, and generally would aim for 2000-2250. What it gives you is the instant ability to let the car slow to 20mph and speed up again, which 5th won't and 4th will still struggle a bit. If it's a long, straight road with no traffic then 4th is ok. If there's a possibility of kids about, traffic, close parked cars, etc, 3rd will give you much better control.

[bradc]

Yeah anything below 2000rpm it dropping away from the efficiency range, and below 1750rpm is falling off the power and torque cliffs!

[Paul Beazer]

Italian de-coking?? Eeeehhhh?

[I-S]

It involves lower gears and the right foot.

[Paul Beazer]

It involves lower gears and the right foot.

You mean caning it?

[g6acb]

I think it will drop to 36-38 when just commuting. In the GLS the furthest I ever managed was 411 miles with the light on - this was still above E at 430 miles.

Ade - I reckon your 500 miles is in danger. :-P

I'll raise you one then......





Not really sure how as 1st 300+ miles was a round trip to the Lake District loaded up with camping gear on A roads rather than Motorways...., the rest going to work and stuff

60.34 litres to fill up gives 37.7 mpg


And I have to say it was very very dull not booting it down the M62 as usual