But again, and I mean this with the utmost respect, are you just churning out the usual internet chatter?
No. I am basing it on experience.
This is from mechanically making alterations for tuning. Rather than a magic box.
Firstly, can you categorically say that a remap does not increase the fuelling in any way shape or form? (I know other parameters are changed too, but thats not the question). Its either yes or no.
A remap alters other parameters.
I've not read anything to state the detrimental effects of overfuelling. How much extra fuel are we talking here? nobody seems to know - either percentage wise or by volume. What is under extra stress by overfuelling ....but what is its tolerance anyway for extra stress? If the overfuelling was 1% more than standard, would that seem negligible, if it was 15% more, how is it a problem?
Erm how about Bore wash for starters... The amount of diesel NOx that gets chucked into atmosphere. By over fuelling you are increasing some boost pressure given that the ECU compensates for it.
Percentage terms it really depends on what power you can push through. IE how much Air and Fuel you can mix. You can run rich for extra power but too rich you get black smoke. Or unburnt fuel.
You turn the settings up too much on those boxes you get black smoke. Too far outside the ecu parameters you get an engine management light.
Is it actually better to just use the overfuelling technique, rather than increasing boost and whatever other things are increased too?
Its better to adjust all parameters when tuning. This way you get the best results.
Overfuelling most ECU's will increase boost or air to try and compensate for the rich mixture. Thus allowing more power to a certain extent. But there are limits in the ECU's tables.
Its better to have those parameters tweaked before the ECU tries to adjust its standard tables.
There are lots of really car-knowledgeable people here, but on this subject, lots seem to turn into sheep and just go with what everyone else says. I have actually had a cheap tuning box fitted for 3 years now (I just checked), with absolutely no issues relating to it. Its nearly 8 years old, 110k miles, original clutch, and runs sweet. How can my experience be dismissed so quickly by so many, when they probably have never had one!
No one is dismissing your findings at all.
I have like you used a cheap "tuning" box with equally good results. No issues more power and would you have guessed it more mpg. This was on an older 8v JTD but effectively the same block etc. It cost me £50 and it was amazing. It was a TMC box.
Value terms they can be amazing bits of kit.
But don't fool yourself into thinking they are the next best thing since sliced bread.
Also as long as you are willing to accept that pushing through more power from an engine WILL reduce life then its fine.
If you push and drive a car to its limits all the time then the increase of 30% power lets say will wear parts.
The thing is although you have that extra power it doesn't mean you use it 100% of the time. If you did there's a good chance you'll end up in a hedge or without a license.
So even though you have that extra power doesn't mean you are using it.
All I am saying is that for the best solution a tailored remap that adjusts several parameters is the best option.
Best value solution. Probably the tuning box.