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Discussion Starter · #1 ·
whilst many people seem to be reporting small improvements (typically 2-3mpg for a 320d) in combined driving, does that still apply if the car is driven at a steady speed with only small changes in throttle openings (e.g. cruise control).
 

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1999 E46 320d Dyno tuned

Hi,
my car has the old fuel system (not common rail)
so it comes with 136bhp standard.:mad
i've had this rolling road tuned to 163bhp which is what my car can handle safely on my original turbo (remap done at 160k, now at 182k).:jaw-dropping

As to your question, the economy increase is quite negledgable,
especially after you factor in some stress busting enthusiastic driving each tank.

The real benifit to this Modification is that it makes your car more pleasurable to drive. Not only at the limit, but all day everyday, right turns, joining a dual carriageway/roundabout, overtaking, getting that amber light etc.
in many of the above situations, the extra power actually makes the manouvre safer, Because you get to choose whether to brake or accelerate, to avoid that pratt in the merc when you're joining a carriageway.

This is my 2nd rolling road tuned turbo-diesel (1st was golf mk4 -150bhp)
and i have to say, the best thing about them is that the peak of what the car can do is available at normal revs.
You dont have to down shift & tell the world that you're thrashing your car
to fly forwards and leave people in your dust.

what kind of mileage do you get per tank ?:confused
i get abt 400-420miles,
but once i've got 250-300 (around the 1/2 mark)then my driving changes a bit.:lol
 

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dyno-tuned turbo diesel

Also note, that improved economy is more about the torque then the peak BHP. (so it will make more difference when your car is loaded)
Torque is relates to the ability to carry load whereas BHP refers to the acceleration or speed.
Think of a skinny fast guy and a strong slow guy,
the fast guy can run with a cement on his shoulder but only one, but the strong guy will carry 2-3 bags in one go.

So more torque means that quite often you will be able to just
accelerate in 3rd, 4th or 5th without having to change down.
also makes for an easier drive.

Its worth shopping around for your tuner, a good one will talor the power to suit your demands ie lots of power low down, or more top end, and try and iron out the flat spot that comes due to mechanical reasons @ a little over 3000rpm.
 

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Also note, that improved economy is more about the torque then the peak BHP. (so it will make more difference when your car is loaded)
Torque is relates to the ability to carry load whereas BHP refers to the acceleration or speed.
Think of a skinny fast guy and a strong slow guy,
the fast guy can run with a cement on his shoulder but only one, but the strong guy will carry 2-3 bags in one go.

So more torque means that quite often you will be able to just
accelerate in 3rd, 4th or 5th without having to change down.
also makes for an easier drive.

Its worth shopping around for your tuner, a good one will talor the power to suit your demands ie lots of power low down, or more top end, and try and iron out the flat spot that comes due to mechanical reasons @ a little over 3000rpm.

Well said !
:thumbsup
 

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I've tuned both my BMW's....a 320 d se and a 330 cd both automatics and 2004. The reason I tuned the 330 was because the already tuned 320 was driving better than it! I used a Superchip tuning for each. The mpg went up by 10% each car....I monitored both really scrupulously. The drive from each (150bhp became 190 bhp and the 204bhp became 250 bhp) made each really much smoother at low speeds.....at overtaking they (esp the 330) are simply astonishing....and one can't help smirk when its a moron in an Audi up your backside one min and dust in your mirror the next couple of seconds. However tend not to drive like an idiot in either.....but it really is nice when you are sandwiched on the motorway and need to get out of trouble. In the fast lane you really have no shame being there knowing you can out accelerate practically anything on the road......that feeling is really satisfying!
 

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Discussion Starter · #6 ·
Sounds all very promising. As 75% of my driving is on the M40 and I tend to stay below 80mph, I'm getting 600 miles + from each tank atm.

...I know I'm not straining the car very much as following its last service the predicted following service was indicatated at almost 19,000 miles!!!
 
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