Driving the 4.2 efficiently while still having fun

[AndrewRS4Avant]

First of all my excuse for discussing economy on this forum is that my previous car was an A3 1.9 TDI 110 where everything was about economy. Plus I’m not exactly swimming in money like some folks are.

For those times when you just want to take it easy e.g. to enjoy the views, or when you have people in the car that moan about going too fast, or you’re just wedged in a row of traffic, or your missus is banging on about an aching neck, I’d like to share what I have figured out which reduces fuel usage. I regularly average close to 30MPG while still having regular bursts of fun up to the red line. Having your cake and eating it appeals to me.

My rule #1 is simply adjust your driving so you do not use the brakes. Think about what is happening ahead e.g. in normal town driving conditions don’t tare up to red lights and junctions. Obvious stuff but so many people do just that! Judging speed and distance stop is a game to me. Every time you touch the brake pedal it costs you money. Keep a good distance between you and the car in front so when people slow to turn off at junctions you just lift off the accelerator and do not need to use the brakes.

Second is if you do need to use the brakes, use the engine as a preference by downshifting a few gears. Downshift again when the revs drop to ~1500RPM. I notice my car lurch slightly when in a low gear with my foot off the gas and the revs drop to 1500. I presume the ECU begins injecting fuel at this point as the revs are dropping towards idle. During a down shift I have perfected the sequence of blipping the accelerator while the clutch is down, selecting a lower gear and catching the revs as they fall by lifting the clutch when the engine speed matches the speed of the gearbox in the lower gear. With the right technique you can drop from 6th to 3rd with no noticeable lurch of the car (however in synchrony with a barrier of V8 wine which occurs). Also good technique to drop 4 cogs for a lively overtake.

When accelerating gently i.e. cars in front, change up a gear around 1500RPM. Get into 6th at 30. Think of the pistons as 8 cans of baked beans. If you hold a baked bean can and shake it up and down slowly it’s not very tiring. Shake it up and down as fast as you can and it soon makes your arm ache. The same physics are going on in the engine so the slower it turns then the less power is required to turn it.

Next is that I found it makes the MPG rocket when I use neutral when going downhill or any other conditions when you don’t need to accelerate. If my foot’s just on the accelerator enough to keep the engine from slowing the car down, I select neutral. Yes fuel will be used to keep the engine turning at idle speed, but much less than to keep the engine turning at ~ 3000RPM e.g. when travelling down a relatively steep gradient without any need for engine power. I haven’t found any problems with stability of the car when coasting in neutral. Just be ready on the clutch and gear stick to engage quickly should you need power to manoeuvre. This works on motorways as well.

When I wind it up I generally make sure I don’t have to subsequently slap the brakes on.

Using all of the above I recently did a 160 mile trip through the middle of Wales and averaged 32MPG thanks to all of the downhill coasting opportunities.

Then there’s times when all of the above goes out of the window and low 20 MPG results with a big grin!

Just a few ideas for when you feel like driving efficiently. That is all.

[S4Player]

Posted in the wrong thread

[adsgreen]

There are some good points - not using the brakes via anticipation is an excellent skill. Not just for saving fuel but it will make you a better and safer driver. You find yourself looking ahead and planning things.

I'd really not recommend sustained 1500 rev usage. To me that's too low and you are putting a lot of strain on things.
A good example is trying to ride a mountain bike uphill in 21st gear. It hurts - the same principles are going on inside the engine and transmission. Also worth googling carbon buildup in fsi engines...
(and I bet you don't have a non resonated miltek exhaust )

As an advanced driver selecting neutral is a big no no imo.There's a number of reasons but one big one as an example is that engineers design the brakes balance assuming the car is in gear. Abs also works a lot better with engine power - much easier to lock up coasting. Anyway, with zero throttle the ecu should cut back on fuelling - it should in theory above a certain rev be using no fuel.

My biggest contribution to mpg driving - just avoid the cruise control. It does everything the wrong way with regards to conserving fuel. When you are going downhill, accelerate. One way of thinking about it is that for the duration of slope you have a lighter car so make the most of it. Any fuel you use will go further. Then when you go up hill trade speed for distance. So the idea is to use what you gain going downhill to get ou over the next one. In fact you can gain mpg by holding your foot at a constant throttle

Oh - don't believe the ecu mpg reading... It lies!

[adsgreen]

Second is if you do need to use the brakes, use the engine as a preference by downshifting a few gears. Downshift again when the revs drop to ~1500RPM. I notice my car lurch slightly when in a low gear with my foot off the gas and the revs drop to 1500. I presume the ECU begins injecting fuel at this point as the revs are dropping towards idle. During a down shift I have perfected the sequence of blipping the accelerator while the clutch is down, selecting a lower gear and catching the revs as they fall by lifting the clutch when the engine speed matches the speed of the gearbox in the lower gear. With the right technique you can drop from 6th to 3rd with no noticeable lurch of the car (however in synchrony with a barrier of V8 wine which occurs). Also good technique to drop 4 cogs for a lively l.

I can honestly say I've never heard 'heel n toe' technique used in the same topic as conserving fuel.

I heel n toe because it's better balance for the car under hard braking. Oh, and cause with the right exhaust it sounds epic
My preference is to walk through the gears as less of potential for screw ups (misshifts etc) and the blip is smaller and usually more accurate. That being said I've argued long and hard about that with professional race drivers so it's down to preference. Although on a road car it'll wear the synchros faster skipping gears.

Does sometime fck me off tht you can't heel n toe and left foot brake in the RS as it kills the power under braking. Still I guess with the Quattro there's less room for adjusting attitude mid corner.

[PeteS4]

I am sorry, but if you have the slightest worry or concern about MPG, then you have the wrong car.

Foot to the floor, as they say.

[Rick_RS4]

I am sorry, but if you have the slightest worry or concern about MPG, then you have the wrong car.

Foot to the floor, as they say.

+1 x infinity

[Brooner]

I am sorry, but if you have the slightest worry or concern about MPG, then you have the wrong car.

Foot to the floor, as they say.

+1 x infinity

+2

death before deceleration

[yorkie]

Lol, the "coasting downhill" bit reminds me of a guy I used to sometimes get a lift with in the early 80's he had a Reliant Robin and it used to take us a bloody long time to get anywhere. He said it saved fuel too but since he had to rev the nuts off the thing going uphill again I'm not so sure!

[DazN]

"There are some good points - not using the brakes".

I'm happy to enjoy driving mine in my own style and fill her up every 230 miles

[ShaneyB]

Wow - just WOW! Sounds a bundle of laughs!

I though coasting was boarderline ellegal also?

I reckon you should sell it and buy a Metro 1.0HL.

[Ian_C]

Nah I agree with opening poster Andrew in all aspects bar neutral coasting. There are times you just want to cruise along, when you've got passengers (namely girls!) and I absolutely LOVE the ability to cruise along using the V8 torque, especially when you want to be lazy and just leave it in sixth. It will indeed pull top at 25-30 mph, and I don't imagine for a moment 1000 rpm in sixth is over stressing the 4.2. I certainly do the whole lifting off the gas and letting the car gradually slow in sixth approaching roundabouts, dual carriageways, Milton Keynes, avoid the braking harshly, saves bucket loads of fuel. As mentioned above, its good driving to read the road ahead and use the brakes less in anticipation, and actually makes you more relaxed

[rs4blacked]

Nah I agree with opening poster Andrew in all aspects bar neutral coasting. There are times you just want to cruise along, when you've got passengers (namely girls!) and I absolutely LOVE the ability to cruise along using the V8 torque, especially when you want to be lazy and just leave it in sixth. It will indeed pull top at 25-30 mph, and I don't imagine for a moment 1000 rpm in sixth is over stressing the 4.2. I certainly do the whole lifting off the gas and letting the car gradually slow in sixth approaching roundabouts, dual carriageways, Milton Keynes, avoid the braking harshly, saves bucket loads of fuel. As mentioned above, its good driving to read the road ahead and use the brakes less in anticipation, and actually makes you more relaxed

+1

[sonny]

Coasting downhill would put massive amounts of wear on the brakes causing them to wear more quickly and need replacing, so where you would make up in fuel savings you would lose in wear and tear. Also if you had to make a collision avoidance you would have no control, so very dangerous imo

...but I know where you are coming from

I remember when I worked in the middle east locals would drive around with no lights on at night to save on fuel, Iv actually seen that in some parts of London too.

[AndrewRS4Avant]

You guys are probably right about it being the wrong car for me, buy hey, I've totally admired the whole RS4 thing since the first models came out over 10 years ago and have always wanted one ever since. So after buyuing a house I saved for a few years and finally got one in 2010. I love the understated sophisticated looks, its blistering performance and practicality just to name a few.

Just that when driving I like to think about what I am doing and do a good job of it. I expect that everyone on this forum takes great pride in their driving style. If you didn't, you'd have that Metro 1.0HL which someone mentioned above, or a Micra. They are the most mennacing people on the road because a car is a means to an end for them. They hate driving and pootle along on the phone or singing to some <beep> music rather than notice that they are drifting out of a lane on a bend or pulling out infront of a car moving at speed that weights twice as much as theirs etc. (DRL significantly reduces this in my experience).

I am glad that at least 2 people can see where I am coming from. It's just a shame that my old diesel driving habbits die hard. Maybe a lottery win would stop me thinking about it.

The thing that pisses me of the most is the flawed road tax g/KM system. I cycle to work so the car is more of a weekend thing for me. My girlfriend and I spend roughtly the same on petrol each month because she needs her car every day and drives a Yaris which costs £30 to tax. How does that work, we burn up the same amount of petrol but I get stung with £460 for a healthy and environmental cycle commute. Oh <beep>, I mentioned the environment word on this forum. Que another bashing

[klauster]

I can completely understand people wanting to save money on fuel, the prices these days are daft, but there isn't much we can do about it... Driving an RS4 if not for the faint hearted when it comes to visits the the pumps, its not for everyone... my guess is that its probably not that right car for you if you are trying to get the best economy from it, I'm pretty sure that is not what the car was designed for