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Premium diesel? Additives? Neither?

Neil P said:
Thanks, assuming that is the 250ml bottles that works out about £8-10 a litre of redex. I'll keep my eye out for offers.

What's the method for adding redex - add to a 1/4 tank than run car until fuel has nearly run out?
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Instructions on the bottle, just chuck it in when you fill up.
 
Ponty said:
Once in a while. It’s good for an engine to be opened up, almost mandatory in a diesel IMHO.
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It is indeed. I've been advised that if the engine light comes on, as it does from time to time, it's the egr valve and the fix is to drive on the motorway in a lower gear, at say 3000 rpm, for half an hour or an hour. It may not clear immediately but it helps. I'm fortunate, I don't spend all my time in town so on my hour long commute I get the thing to motorway speed for a while.
 
Neil P said:
I've always wondered about the optimum speed for fuel economy - I imagine it needs to be calculated for every make/model, rather than one size fits all.
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Give or take it’ll be the lowest speed your car can manage in top gear without labouring.

Back in the day that would have been around 35mph in 4th. Though with modern 7 speed autos it may be the above, but in 5th or 6th. I’d suggest at a speed under 40mph is likely in any event, due the the square law of resistance through air etc.
 
Just got a few bottles of Rednecks for £2. For that price I don't mind if it doesn't work. A lot cheaper than hifi cables
 
A 'coast road tune up' it was known locally to me!

Get up to 70 in top, then drop it to third and floor the fast pedal!

This was when top gear was 4th, and 5th was rare, and 99% of cars had a carb.

If you blew the engine the local scrap yard usually had them for around £25 (I did this twice!!)


Andy
 
stevec67 said:
It is indeed. I've been advised that if the engine light comes on, as it does from time to time, it's the egr valve and the fix is to drive on the motorway in a lower gear, at say 3000 rpm, for half an hour or an hour. It may not clear immediately but it helps.
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Been there, done that, with a Volvo diesel. It does work.
 
RJohan said:
Ten years ago I was talking to a lorry driver who delivered fuel to petrol stations. It all comes from the same large storage tank, irrespective of the brand of petrol station it's delivered to. If there is some kind of brand specific additive it's added automatically when the lorry is filled up.

The cars manual should say what fuel to use. It's a bit like having a car designed for 95 octane (talking petrol now) and thinking it will be faster on 98...
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thats interesting , i can tell immediately if i put 95 or 99 octane in. The 99 makes a very big difference
 
Haven’t noticed any difference with premium diesel in my 535D or my previous diesel Octavia VRS. Both remapped.

I also put the odd bottle of Redex through mine.
 
mine asks for 99, which is mostly what I feed it on. I have to I don't really notice any performance difference if I have to feed it on 95 occasionally.
 
RJohan said:
Ten years ago I was talking to a lorry driver who delivered fuel to petrol stations. It all comes from the same large storage tank, irrespective of the brand of petrol station it's delivered to. If there is some kind of brand specific additive it's added automatically when the lorry is filled up.

The cars manual should say what fuel to use. It's a bit like having a car designed for 95 octane (talking petrol now) and thinking it will be faster on 98...
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No.

Additives can go into the tank at the filling station.

And there are differences in fuels. A few times I’ve been desperate and put Tesco unleaded in, ran rough, even failed emissions test once. I’ve NEVER had trouble with fuel from the likes of Shell, BP, Texaco etc.

Back to the diesel in the OP.
When I was doing over 35k miles per year, BP Ultimate diesel somehow appeared to give better MPG. It wasn’t worth it financially. I didn’t feel like there was any extra power, and I don’t recall BP claiming it did.

More important for a diesel, if you intend keeping it into its old age is regular oil, oil filter, fuel filter, and air filter changes. They love a good clean diet.

And use the bloody thing! At least once a week, a good 25+ mile drive, with a bit of welly every now and then.
 
Martyn Miles said:
I use normal petrol and never think of additives of any sort.
When driving, I go for maximum economy.

Accelerating slowly, reading the road to anticipate and keeping my maximum speed to 55 mph
on single carriageways and 65 mph on motorways.

My little Skoda can do 60+ mpg easily.
I don’t think Audi drivers like me, though.
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I think driving to the speed limit on motorways might be safer for both yourself and the HGVs you are presumably forcing to overtake you
 
JezmondTutu said:
Haven’t noticed any difference with premium diesel in my 535D or my previous diesel Octavia VRS. Both remapped.

I also put the odd bottle of Redex through mine.
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You won't. The diesel is the same, it's only cleaning additives that are different in the premium ( I run the same car as you). A tankful of premium every 1000 miles or so is enough to keep the engine clean assuming the car is well maintained. I change the oil & filter every 3-5k at the most and also the air filter- I have done all the servicing and most of repairs on my cars for the last 30 odd years and run some cars to very high mileages. I work on site and some years have averaged over 50k. At each change I pour bottles of Forte Fuel System Cleaner and Turbo Cleaner into the fuel tank. Car is on 130k and runs perfectly. No major bills so far, fingers crossed.
 
Ali T said:
You won't. The diesel is the same, it's only cleaning additives that are different in the premium ( I run the same car as you). A tankful of premium every 1000 miles or so is enough to keep the engine clean assuming the car is well maintained. I change the oil & filter every 3-5k at the most and also the air filter- I have done all the servicing and most of repairs on my cars for the last 30 odd years and run some cars to very high mileages. I work on site and some years have averaged over 50k. At each change I pour bottles of Forte Fuel System Cleaner and Turbo Cleaner into the fuel tank. Car is on 130k and runs perfectly. No major bills so far, fingers crossed.
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Which model?

Mines an E61 MSport Touring LCI, 146k miles. Had it carbon cleaned as part of a load of preventative measures including gearbox service and swirl flap delete when I bought it. Have to say, I don’t change oil that frequently, it’s every 10,000 miles, definitely not more than that. It’s without question the best daily driver I’ve ever owned even though 14 years old.
 
Yes, best car I've had by a long way also. Saw a review on YouTube where the 5 Series was called all the car you'll ever need and I think there's a lot of truth in that. Family car, Executive mile munching motorway express, B-road hooligan- does them all well. Mine's an F10 MSport. Best compromise between performance and economy I found when I was looking. 313PS and 650NM, yet 50+ mpg is possible. Great machine.

Just get rid of the awful run flats..
 
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