All I can say is with the tunning box on my av. mpg is around 65mpg looking at the MFA but working it out is is nearer 55mpg. If I unplug the box it goes back to normal.
Quite simply, the tuning box is injecting fuel that the ecu doesn't know about, so as far as the ecu is concerned the car is doing x number of miles for y litres of fuel used and calculates accordingly. But as it doesn't know about the tuning box dumping a little bit extra in the calculation is meaningless. So your car shows a mpg figure that would be correct for normal running but is actually overly optimistic due to incorrect parameters.
javorb
Guest
Quite simply, the tuning box is injecting fuel that the ecu doesn't know about, so as far as the ecu is concerned the car is doing x number of miles for y litres of fuel used and calculates accordingly. But as it doesn't know about the tuning box dumping a little bit extra in the calculation is meaningless. So your car shows a mpg figure that would be correct for normal running but is actually overly optimistic due to incorrect parameters.[/QUOTE
a tuning unit asks the ecu for more fuel and gets it ,that is why it accelarates better ,so how can the ecu read the signal and give the tuning unit more fuel but cant work it out through the mpg ?as it knows more fuel is being used lower down ,a tuning unit then asks for less higher up the rev range as there is so much unburned fuel that goes through the system,as i have had a unit on previous and present cars i work out my mpg by the litres used not by the computer as this gives you an exact mpg
javorb
Guest
tuning unit facts
The TD PowerBox works by modifying the electronic signals that control fuel pressure produced by the VP pump in order to optimize engine performance. The TD PowerBox increases fuel pressure at the pump to compensate for lost pressure as fuel is distributed to each injector. The increased pressure enables injectors to respond faster during acceleration. While actual injection pressure is not increased, the pressure required to activate injectors is readily maintained.
The TD PowerBox includes the complete installation material you need. The TD PowerBox is easily installed at the the Electronic Control Unit (ECU). With the instructions provided, an inexperienced driver can complete the installation in 15 minutes. The TD PowerBox will not override the safe operating parameters of your engine and does not change or interfere with ECU functioning.
The TD PowerBox works by modifying the electronic signals that control fuel pressure produced by the VP pump in order to optimize engine performance. The TD PowerBox increases fuel pressure at the pump to compensate for lost pressure as fuel is distributed to each injector. The increased pressure enables injectors to respond faster during acceleration. While actual injection pressure is not increased, the pressure required to activate injectors is readily maintained.
The TD PowerBox includes the complete installation material you need. The TD PowerBox is easily installed at the the Electronic Control Unit (ECU). With the instructions provided, an inexperienced driver can complete the installation in 15 minutes. The TD PowerBox will not override the safe operating parameters of your engine and does not change or interfere with ECU functioning.
As far as I understand, tuning boxes can work in a couple of ways:
1) The cheapy ones modify the output of a sensor, such as the fuel temp sender, causing the ECU to think the fuel is less dense than it is, and injects more to compensate. The ECU is then basing it's MPG calculations on incorrect information. In the early days of my Ibiza ownership I experimented with my own "resistor" mod across the fuel temp sender, and the MPG figures given by the ECU went stupidly optimistic - far, far higher than reality. Where I might have been getting 50mpg before, with the mod, the trip computer often used to claim 60-70mpg or more.
or
2) They intercept the output from the ECU that controls the injectors and vary the injector timing/duration, (presumably some dearer boxes will have their own internal map that applies varying amounts of correction at differing points through the rev range). In this case, the ECU is completely unaware that anything is going on, except the car seems to be covering more distance with the same amount of effort/fuel as before and is therefore seemingly more efficient.
The ECU doesn't measure the amount of fuel running through the fuel lines, it just works it out from it's internal maps. So anything that modifies inputs or outputs to/from the ECU will reduce the accuracy of it's MPG calcs.
Remaps and/or tuning boxes can improve MPG, assuming you retain a similar driving style - but not by much, certainly nowhere near as much as the optimistic figures you'll get from some tuning boxes.
They use the fuel temperature sender, not pressure. The temp of the fuel supply affects the fuel density and therefore the amount of energy available in a set volume, for which the ECU has maps to compensate - the amount of fuel injected varies depending on fuel temp. Fuel temps can get pretty hot, on the PD TDIs at least, some of the fuel runs & returns through channels in the cylinder head, which is why they have fuel coolers to cool the excess fuel before it returns to the tank. If the ECU sees the fuel temp going over a certain threshold though, it will start cutting back - so the resistance values of these boxes have to be chosen carefully in order to avoid a fault being flagged (with geeky hindsight I think it was 150 ohms for a PD 130
)javorb
Guest
VP pumps - doesn't apply to PD TDIs then
sorry i posted the wrong info
With the PD (Pumpe Duese) or direct unit injection system, the diesel fuel is heated to a very high temperature due to its thermal properties. The direct injection system has a temperature sensor that communicates with the Electronic Control Unit (ECU). When diesel fuel is heated to substantially higher temperatures, its density decreases. When this occurs, the fuel temperature sensor communicates the change, and the ECU compensates by injecting more fuel for combustion.
This is where the PowerBox intervenes. Integrated electronics communicates a higher temperature to the ECU, causing more fuel to be injected. The additional fuel is burned along with the excess air, which leads to a proportionate increase in output. The increased fueling will not override the safe operating parameters of your engine and does not change or interfere with ECU functioning.
sorry i posted the wrong info
With the PD (Pumpe Duese) or direct unit injection system, the diesel fuel is heated to a very high temperature due to its thermal properties. The direct injection system has a temperature sensor that communicates with the Electronic Control Unit (ECU). When diesel fuel is heated to substantially higher temperatures, its density decreases. When this occurs, the fuel temperature sensor communicates the change, and the ECU compensates by injecting more fuel for combustion.
This is where the PowerBox intervenes. Integrated electronics communicates a higher temperature to the ECU, causing more fuel to be injected. The additional fuel is burned along with the excess air, which leads to a proportionate increase in output. The increased fueling will not override the safe operating parameters of your engine and does not change or interfere with ECU functioning.
So it just modifies/replaces the output of the fuel temp sensor then. In other words - it's a resistor, or maybe a variable resistor - with some OE looking connectors on. This will make your MPG reading very optimistic.
javorb
Guest
resistor?
this is not a resistor it is an analogue chipped unit ,yes it is very crude as to the way it works but i can assure you in 6 years i sold them i did not get a single complaint,your comments are typical of people stereo typing tuning units without ever using one or buying one of the £20 ebay ones and judging eveyry unit as the same,which they are not
this is not a resistor it is an analogue chipped unit ,yes it is very crude as to the way it works but i can assure you in 6 years i sold them i did not get a single complaint,your comments are typical of people stereo typing tuning units without ever using one or buying one of the £20 ebay ones and judging eveyry unit as the same,which they are not
Lots of money or £20 from Ebay, if they interrupt the fuel temperature sensor reading, modify it, and report the modified figure to the ECU then the end result is the same. The ECU is injecting more fuel than it thinks it is and its calculations are incorrect. The only variable in the situation is how much money Joe Public pays for his resistor.
This statement intrigues me though.
What is this "excess air" you speak of, and where does it come from?
I have to say, selling tuning boxes for 6 years doesn't seem to have made you an authority on their function. It seems to have made you a little blinkered as to their function, which is hardly surprising given that you made a good bit of money out of them for a wile (no doubt). My brother in law workd for Coca Cola for over 20 years selling the stuff by the wagon load. He has no idea what goes into it though.
This statement intrigues me though.
What is this "excess air" you speak of, and where does it come from?
I have to say, selling tuning boxes for 6 years doesn't seem to have made you an authority on their function. It seems to have made you a little blinkered as to their function, which is hardly surprising given that you made a good bit of money out of them for a wile (no doubt). My brother in law workd for Coca Cola for over 20 years selling the stuff by the wagon load. He has no idea what goes into it though.
Given that the ECU just measures the resistance across 2 pins of the fuel temp sender to work out the fuel temp, how else can the box function, other than by altering the resistance value presented to the ECU?
That couldn't be further from the truth - I've probably got more intimately involved with fuel-temp based devices than most on here, as ages back I spent quite some time researching and making my own for my PD130 - there's even a post somewhere on here where I list the part numbers of the OE connectors from VW that are used to connect to the temp sender, plus my findings with testing various resistance values - both with bypassing the sender completely, and leaving it connected in parallel with a second resistor to try and reduce the actual vs. reported fuel temp differences to reduce smoking when the engine/fuel is started from cold.
In the end I got rid of it, as it made for a lumpy idle and too much soot.
For the record, I'm not against tuning boxes at all - I think the more sophisticated programmable tuning boxes (which have some intelligence and modify injector timing/duration signals based on various inputs) are pretty good, as they don't just indiscriminately dump more fuel in. For the cost of them, personally I'd still have a remap any day, but I do appreciate the ability to unplug/remove them can be an advantage to some.
I've quite often defended the more sophisticated boxes on here when others have just lumped all types of tuning box into the "resistor in a box" category.
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Diesels always run on a very "lean" or air rich mixture. So not all of it is used during normal combusution but add a bit more fuel and you can get some more power to a point, but add too much and you get lots of smoke as theres no longer an air rich mixture to ensure all the diesel burns. But yes i agree the cheap tuning box on the fuel temp sender most probably works just as well. A more expensive one will most probably have some sort of timer to delay it's switch on to allow the engine to see normal fuel temps during cold start ups and similar. The VP tuning boxes actually work on the fact that the vp pump has stroke sensors in it so it works out how much fuel is injected that way. The tuning box works as a resistor across these sensors (but with a timer circuit to stop fault codes during start up) which makes the ecu think the pump is not pumping quite as much as it's requesting so it makes the pump pump further.
Yes, I know that. But by design there is excess air provided during combustion, and using this excess air to burn more fuel moves the operating parameters for clean combustion closer together and you end up burning fuel incompletely, and produce excess soot.
But our friends statement "The increased fueling will not override the safe operating parameters of your engine and does not change or interfere with ECU functioning.", while factually correct, is meaningless in regard to excess sooting and problems related to that. A bit like saying "Fitting lowered springs to your car will not affect the rolling circumference of your tyres, and will not alter the speedometer calibration.". Factually that is also correct, but is a pointless statement because it's irrelevant.
Adding a tuning box does not interfere with the ecu functioning, merely forces the ecu to use values that are incorrect while still being within it's operational control. Additionally, adding a tuning box will not override the safe operating parameters as it does nothing to impact on turbo rotational speed, does nothing to alter any parameters which are controlled by the ecu such as engine speed, injection timing, boost levels, oil temperature, coolant temperature, radio station reception, climate control operation, and any number of unrelated features.
javorb
Guest
to be honest the text is from the supplier i had in germany ,it is the manufacturers claims not mine ,at the end of the day the poor guy who started this thread has had it hijacked to such an extent he is tottally confused ,obviously you like a good argument or work for a remapping company ,please remember forums are about individual opinions !!!
No, I don't work for a remapping company. And I admit I like a good argument (or debate) but the main gist of my point here is that so much misinformation (or misleading information) is being used to big up a product which basically just dumps extra fuel into the engine. So I doubt that the OP is confused, more likely he now has a more reasoned opinion and answer as to the question he asked.
And while forums are about individual opinions, that's really all they are. Opinions. Unless they're backed up by facts to validate them, of course.
And while forums are about individual opinions, that's really all they are. Opinions. Unless they're backed up by facts to validate them, of course.
javorb
Guest
hillbilly
Guest
tuning boxes just trick the ecu to throw more fuel in, or just boost the total fuel pressure, which is great if u wantt to break things, get a remap done everytime, youll only waste your money on a box then more money fixing the things it breaks! i do maps at £250 all in with lifetime garantee
Ha, i noticed a few threads from this guy which all funnily enough included the same info in red (as above). Nice to see he's been banned
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