[x3oiler]

I have seen a lot of posts on this across different forums and a recent post on this forum that touched on this and rather than hijack that thread thought would relate my experiences.

The tuning boxes work on the premise that a diesel is quite simple. More fuel = more power and torque. What fuel is not burnt is exhausted. So injecting more fuel that the ECU thinks it is injecting = more power and torque.
I believe tuning boxes were first developed for heavy engined trucks and have a well earned place in this market. The problems I believe come with higher performance vehicles.
Hard to explain but here goes - you will have your stability control wonder wtf as it tries to control the vehicle by applying what is thinks is correct engine and brake management but then the tuning box steps in with up to xxx more power and torque and screws it all up.
That is the best description I can come up at this stage.
So for the heavy hauler - not an issue. One would assume that stability control - if it exists - is not going to be hit with a huge percentage increase in power/torque. For the smaller diesel engined vehicle that is certain to have stability control the same end effect - this time the increase will not over power the vehicle.
In both cases a benefit in power and torque will not have any bad side effects.
So what happens with a high performance vehicle.
The tuning box is open loop. It is not part of the closed loop "stability control system knowing what the vehicle is doing and knows what to do about it" control system.
Now I have a 3.0d circa 2006 - the 160kw/500NM beastie. Quite fast in it's own right and top heavy ie stability control can be triggered in stock form quite easily.
I ran a tuning box - one of the more reputable units - for 20,000km. Great to drive with - fun even. Side effects such as the distance to empty and km per liter etc being screwed up aside the driving was fun.
But then I started to notice things - scarey things. Normal driving no issue but as an example: try a full power hard 90 degree turn aka fast right turn from the lights. With the tuning box you have better be ready for it - the poor beast was going crazy as the stability control effectively "lost it" as the tuning box cut in.
This is why I removed the tuning box I was running and replaced it with an ECU re-map. The above experience scared the heck out of me and left me thinking what would happen if I really needed the stability control to cut in during an emergency.
With an ECU remap since installed there is no such issue on the "right turn test" - much faster (faster than the tuning box in fact) but all in control.
But that said, buy and fit a tuning box if you can source it at a reasonable price and get to like the extra oomp - and you will like it - the feeling of all four tyres squirming for traction as you hit it hard - but please start to look for other "closed loop" options aka an ECU remap.

[ozzielad]

Hi

What can you tell me about the ECU remap ? what difference in power and economy did it make ? where did you get it done at and how much was it .. Sorry to ask so many questions. Oh and does a ecu remap come up when its plugged into a dealers computer ?




Cheers

[deafwish]

Hey x3oiler,

Certainly not doubting your driving skill, but if you're worried about jepordising Traction Control by 'saving' you through a turn - you probably shouldn't be increasing your car's power/ torque levels!
Our X3's have a reasonable amount of torque, stiff suspension and rubbish 'open' front & rear differentials.
My stock X3 3.0d will do the same if I leave the TC fully enabled.
On wet roads with the TC off, I can quite comfortably get a bit of a controlled drift happening around corners.
From experience on different manufacturer's TC systems, the TC is solely reliant on your ABS/ wheel speed sensors & has nothing to do with how many Nm or KW your vehicle makes.
On petrol vehicles, it generally will retard ignition timing to limit wheel spin and pulse the brake caliper/s on the spinning wheel/s.
In diesels there's obviosly no ignition, so I assume it would implement some form of fuel cut to the fuel rail and pulse the caliper/s on the spinning wheel/s.
The more power your car has would potentially just mean your wheels would spin faster - which wouldn't be too dissimilar to driving on gravel/ snow/ mud.

Back to the original topic (sorry!), an ECU reflash is simply changing some parameters in your factory computer and drivability is generally much more linear than a Piggyback ECU.
The Piggyback Computer (Chip) is as old as Noah with minimal development over the past 5+ years.

[whatnxt]

As stated, a TB will only add fuel. This can be an issue, as over fueling can cause boost creep and higher than wanted ECG temps. Both bad over the long term. An ECU tune can control fuel, timing, and boost. Just more control.