Bobupndown
What could possibly go wrong?
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Its not but mine is equally tidy.
- Thread starter Ubique
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Ubique
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Short term, it'll mask issues, as it's a friction modifier, it just makes the transmission more bearable until nearly all the friction material is shed from the clutch plates....
Useful if you're selling the car, un-useful if you plan on keeping it as it could cost you a set of fluid solenoids as well as the clutch plates if you have your own unit refurbed.
Ubique
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There's no way I'd be asking a 2007 to suddenly cope with more BHP...
Yes, you're correct, they reduce the reported fuel pressure, which increases the actual rail pressure, thereby putting more fuel in per injection sequence (actually four 'shots' per cycle), that causes the fuel trims to reduce the amount injected under normal driving, thereby giving a better mpg. Of course, once someone has more BHP, they tend to want to use it, negating the mpg increase possible....
Guineafowl
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I didn’t know that. My guess was, because the ECU has a false rail pressure reading, it’s injecting more fuel than it thinks, so this artificially increases the displayed mpg.
Ubique
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The fuel trims monitor the cylinder contribution to the rpm, mostly below 1100rpm for Lion diesels and similar Siemens equipped engines, Bosch equipped engines can monitor this at higher engine speeds but only within a specific power band. The outcome is that the fuel is trimmed downward if the cylinder is too effective at contributing to engine output, the supervisor function for this doesn't care if all cyl's are trimmed downward, there is naturally some variance in injector performance (which is why fuel trim is there in the first place) and all trim values will be slightly different. On some 3.0TDV6 engines you can hear the injectors briefly shut off on deceleration as part of the calibration process.
There are two things to watch out for - diesel knock and DTC's set for 'fuel trim limit exceeded', presumably the DIP switch settings are to set the fuel pressure value offset in a range where these events won't be triggered.
Improvement in mpg is measurable - provided the driving style and journeys remain the same.
There are two things to watch out for - diesel knock and DTC's set for 'fuel trim limit exceeded', presumably the DIP switch settings are to set the fuel pressure value offset in a range where these events won't be triggered.
Improvement in mpg is measurable - provided the driving style and journeys remain the same.
Trevorleach
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It got me another 6/7 years out of my well worn torque convertor on the 06 disco, in the end I had the t/c rebuilt, and it was the best it had ever driven and still does, but knowing what I now know I would have had the t/c rebuilt sooner or shifted the car on!
RWD3M
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This!
I read your earlier response to a similar post, but surely the Ecu reduces the length of duration of injector pulse so records less fuel used, but the engine still needs the same mount of power/torque to move the car, so actual Mpg is the same at cruise.
Every time one calls for more torque more fuel is injected as the Ecu increases the injector pulse time.
The manufacturers of such maps/boxes simply rely on drivers only using the trip computer figures, never actually performing brim to brim calcs.
Ubique
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Because the fuel is pushed in at higher pressure, it is atomised more efficiently (this is how it was done moving the Lion engines from EU3 to EU4, although with changed injectors and 'proper' calibrations) so there is less unburnt fuel (unless you boot it, which is why mapped vehicles always black smoke when pushed) and the peak torque is increased, some maps also move the peak downwards a couple of hundred rpm, which also helps with fuel efficiency.
Yes, in most cases, the mpg is calculated from the fuel used by pressure x injector open time = xx μl of fuel so the boosted fuel pressure will falsely give a better indicated mpg, so although the indication is still 'off', there can be a real improvement if the vehicle is driven in the same manner due to the improvement in combustion efficiency.
That said.... the tuning boxes are pretty simplistic and won't give as much mpg improvement as a (quality) software remap, but I wouldn't recommend any vehicle that is more than a couple of years old with very low mileage be remapped as it can accelerate internal wear on already worn-in engines.
Ubique
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Nothing really of note in the last couple of days - although I did get a reasonably rare Discovery5 Si6 (V6 3.0l Supercharged) to road test today for a braking issue, turned out the brakes were fine, the Chinese ditchfinder tyres were not....
Maybe on something with a 1.0l engine that pootles to the post office and shops twice a week, but on two tons of fast, high CofG metal? I just don't get it.
It certainly drives nicer than the 3.0l TDV6 and the Di6, as you'd expect, but it doesn't sound 'right' like the 5.0l V8 supercharged does, which is hardly surprising as it's the same engine with two cylinders blanked off!
If I absolutely had to have a Discovery 5 - for the extra space, then that engine would be my choice, this one has the black, with extra black, with 'ugly kid' glass - too depressing for me, I'd need something with a bit of light trim in it, makes it feel less enclosed too.
Maybe on something with a 1.0l engine that pootles to the post office and shops twice a week, but on two tons of fast, high CofG metal? I just don't get it.
It certainly drives nicer than the 3.0l TDV6 and the Di6, as you'd expect, but it doesn't sound 'right' like the 5.0l V8 supercharged does, which is hardly surprising as it's the same engine with two cylinders blanked off!
If I absolutely had to have a Discovery 5 - for the extra space, then that engine would be my choice, this one has the black, with extra black, with 'ugly kid' glass - too depressing for me, I'd need something with a bit of light trim in it, makes it feel less enclosed too.
Guineafowl
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Stealing that one…
…and that one. Thank you
Just to bottom out the diesel tuning box thing, the classic question: if higher rail pressures give better performance by improving combustion efficiency, why don’t they make them like that from the factory? There must be some sort of compromise.
..and if Volvo can do a 'Polestar' software upgrade adding 20bhp and 'improving economy' - why don't they do it from new instead of charging £700+....Stealing that one…
…and that one. Thank you
Just to bottom out the diesel tuning box thing, the classic question: if higher rail pressures give better performance by improving combustion efficiency, why don’t they make them like that from the factory? There must be some sort of compromise.
I think you've answered your own question there ....
RWD3M
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Emissions?Stealing that one…
…and that one. Thank you
Just to bottom out the diesel tuning box thing, the classic question: if higher rail pressures give better performance by improving combustion efficiency, why don’t they make them like that from the factory? There must be some sort of compromise.
Ubique
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VWG were early adopters of that business model...
Ubique
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Emission controls - and mechanical stress.Emissions?
To greatly simplify the process, engines are tested to a known-safe point, then de-rated to give the accountants their safety margin allowing for manufacturing tolerances of the engine and ancillaries. sometimes, this is de-rated further to allow for future upgrades of addition of further emission controls.
A remap has none of this testing, calibration or inbuilt likelihood of longevity. A diesel remap is often paired with a 'DPF delete' as the DPF would not be able to cope with the amount of soot generated by constant enthusiastic driving.
Most people don't realise (or care) that a remap, tuning box or deletion of emission controls makes their vehicle no longer type-approved and therefore in breach of insurance rules (unless specifically insured as non type-approved). Not so many years ago, you'd take a chance, now everyone knows how to check for DPF deletion - look at the exhaust pipe! no need for clever diagnostics.
Guineafowl
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I deleted the centre silencer, cat and EGR on my Td5 Defender 16 years ago - the MoT man in Devon spotted it and asked where I got the kit
Still going strong to this day.I think the only way I’d buy a modern diesel is if I could delete the EGR, DPF and adblue. And run it on the next oil grade up.
