406oc.co.uk

After nearly 2 years of owning it I have finally applied the 180bhp map file. I, like many others here, work in IT and quite happily update, jailbreak and unlock all sorts of phones and devices without a second thought, however when it came to my car I was more than a little nervous about flashing a new map.

However having just paid out for the cam belt damage I thought I would finally give the 180 map ago to rejuvenate the car.

Up until the cam belt snapped I had been driving round with a diesel tuning box on the car. Now I know they are about as sophisticated as a brick, and many dont like the idea of them, I don't want to start another of those threads here but it did make a difference to the MPG I was getting and made towing a lot easier while being 'safe' on my ECU.

For the past few weeks I have been using it without the tuning box to avoid stressing anything after the rebuild, but boy was I missing the extra oomph. So today I plucked up the courage to remap it (Slightly less risky now I know I have a spare car in my Twingo, should it have decided to stop working!).

It went without a hitch of course, and I have been for a little bomb up the local B road to try it out. First impressions are that it feels very similar to how it was with the tuning box on it. I'm sure it is more sensitive to the engine, and more subtle then the brick tuning method, but It does show that the tuning box achieves good results for a very little outlay (mine came with the car so £0 outlay)

Just thought I would share my thoughts, will let you know how it does towing in comparison on my next outing.

That's interesting Ben. When you said the tuning box helped with mpg, was that as displayed on the trip computer, or real world brim to brim measurement?

Trip computer and perceived movement of the fuel gauge.

Before the snap, with the tuning box (one of these http://www.dieselexpress.co.uk/ but I'm sure they are all identical) over a 100 mile run of the A30 from Exeter to home I would get an average of 42 Mpg on the computer running at 10 above on cruise.

After the snap and without the box I get a reading of 37/38Mpg doing the same run (same on 4 separate trips).

Driving like a vicar on a 20 mile Journey from Falmouth to home I have managed to top 52Mpg in the past, the other day I couldn't break 45.

Anecdotal I would say the box gave me a 10% boost on computer indicated MPG

I have no idea what the tuning boxes do but I would stay well away from them, despite the obvious advantages.

I, myself, have had a generic remap on the ECU for my 2.0 110 and the car is much more lively and usable. It does make my car smoke quite a bit on acceleration and I get occasional vibrations when accelerating very hard due to clutch/DMF friction. I had the generic file analysed and was told that the timing was completely out and maps were badly made. So I opted to have a custom remap done, which I am hoping will make the car drivable AND safe!

That said, I've driven with the generic remap for nearly 3 years and it hasn't completely killed the car!

Bear in mind because the car is now being tricked and isn't being given a true reading of the fuel pressure so it has no idea of how much fuel it's using. For that reason with a tuning box the trip computer will read higher because it thinks less fuel is being used than it actually is.

Captain Jack wrote:I have no idea what the tuning boxes do but I would stay well away from them, despite the obvious advantages.

I, myself, have had a generic remap on the ECU for my 2.0 110 and the car is much more lively and usable. It does make my car smoke quite a bit on acceleration and I get occasional vibrations when accelerating very hard due to clutch/DMF friction. I had the generic file analysed and was told that the timing was completely out and maps were badly made. So I opted to have a custom remap done, which I am hoping will make the car drivable AND safe!

That said, I've driven with the generic remap for nearly 3 years and it hasn't completely killed the car!

Your fuel pump has a fuel pressure sensor in it. It does what it says on the tin, it tells the ECU what pressure the fuel rail is at.

A 'tuning box' is basically a resistor in a box which distorts and reduces the signal so the ECU thinks the rail pressure is lower than it is.
As a result the rail pressure gets increased and so does the fuel injected.

Bailes1992 wrote: Your fuel pump has a fuel pressure sensor in it. It does what it says on the tin, it tells the ECU what pressure the fuel rail is at.

A 'tuning box' is basically a resistor in a box which distorts and reduces the signal so the ECU thinks the rail pressure is lower than it is.
As a result the rail pressure gets increased and so does the fuel injected.

Does that go for ALL tuning boxes including those from large reputable companies? I was under the impression that the resistor thing was the case for the Ebay cheapy ones. TDi Tuning actually do 2 types of tuning boxes for many cars & the expensive CRTD2 ones are advertised as being much more than that.

http://www.tdi-tuning.co.uk/product.htm ... 000000891/

Their website states:

Our diesel tuning boxes connect securely to your cars fuel injection system and work in harmony with your vehicle's Engine Control Unit (ECU). The device effectively modifies and streamlines the engine's fuel injection parameters, including the timing, pressure and quantity of fuel added, to improve its overall performance quite significantly both in terms of power and fuel economy.

Surely a resistor fooling the fuel pressure couldn't do all that?

Bailes1992 wrote:Bear in mind because the car is now being tricked and isn't being given a true reading of the fuel pressure so it has no idea of how much fuel it's using. For that reason with a tuning box the trip computer will read higher because it thinks less fuel is being used than it actually is.

Potentially, but my MPG readings are backed up by the amount the fuel gauge moved over the 100 mile trips.

Bailes1992 wrote:A 'tuning box' is basically a resistor in a box which distorts and reduces the signal so the ECU thinks the rail pressure is lower than it is.
As a result the rail pressure gets increased and so does the fuel injected.

I would like to think they are a little more technical than that, potentially having a pressure distortion curve rather than telling the ecu it is low all the time. So that if you a tootling about it is at standard or even reduced pressure, and when you put your foot down and the pressure is increased it reduces the reading to increase it further.

But I have no proof either way and as Fifth Gear recently proved, they will sell you a green LED for £30 if they can get away with it...

Captain Jack wrote:I have no idea what the tuning boxes do but I would stay well away from them, despite the obvious advantages.
<snip>
That said, I've driven with the generic remap for nearly 3 years and it hasn't completely killed the car!

A bad map and a tuning box are both probably about as bad as each other! In the same way you can say you drove without damage for 2 years on a bad map, I can say the same for my tuning box

I did say "I don't want to start another of those threads here"

How can it be anything more than a resistor in a box if all it plugs into is the FPS?

Where would it get data about engine revs, throttle position, load, engine tempreture, timing etc etc etc if all it's plugged into is the fuel pressure sensor?

It's just like the 'tuning boxes' you could get for petrols that plugged into the MAF. All they used to do was trick the engine into thinking it was getting more air than it actually was.

When people say they've had a remap it dosen't just mean they've opened the MAP and gone "Oh we'll add some more fuel by here".
An ECU has lots of different Maps in it. Every one gets altered to get better performance and smooth power delivery from the engine.

Bailes1992 wrote:How can it be anything more than a resistor in a box if all it plugs into is the FPS?

Where would it get data about engine revs, throttle position, load, engine tempreture, timing etc etc etc if all it's plugged into is the fuel pressure sensor?

It's just like the 'tuning boxes' you could get for petrols that plugged into the MAF. All they used to do was trick the engine into thinking it was getting more air than it actually was.

I remember those. Didn't they just fool the car into thinking it was permanently on cold start? Interesting point with where it gets the info from if only plugged into the fuel pressure sensor though. Reckon it might be worth a phone call to see if they can better explain how it works.

Unless somebody has an old one that they're brave enough to dissect in the interests of science?

There was somebody who disected a tuning box on another forum.
It needed a switched 12v supply and plugged into the fuel pressure regulator.
It had a fancy blue LED on it and looked like a cracking bit of kit.

He took it apart and all the 12v feed did was light up the LED
Then there was a circuit board with a few wires and a resistor in it

I had my 406 (HDi90) remapped, it cost me £300 but it took the power from 86bhp to 128bhp. It took the economy (Brim to Brim test) from 45mpg to 55-65mpg. It paid for itself in a few months!
Also with 128bhp on tap with the short ratio'd HDi90 gearbox it went like stink!
If I kept it longer then I would have fitted a HDi 110 intercooler and gearbox.
The power was effortless and totally relentless. It would pull from idle right through to 4750rpm.
I didn't regret spending the £300 one bit!

There is more to it than a resistor it would appear.

Photos are not very clear, but I didn't have the time to chisel all the hot melt off. but there are clearly two chips on the board.

Can you get the board out?
Even if the chip is wired up I can't see what else it would do other than retard the fuel pressure signal.

I will attack the glue tomorrow and post a better pic.