/ Diesel Chip Knowledge

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marky - on 20 Nov 2012
Chipped my Audi A3 140bhp with Chip Express DIY fit chip. Initially performance and economy noticably increased but this seems to have dropped off recently. Anybody any ideas - unplug and reconnect?
In reply to marky: control-alt-delete?
butteredfrog - on 20 Nov 2012
In reply to marky:

Assuming car is in good condition, oil and levels ok.

Unplug chip, scan car to make sure no engine management faults present. While the scanner/laptop is plugged in go through the other systems and check for faults.

Audi's have around 27 control modules onboard all conected via CAN/bus. Faults in anyone of these modules can affect other systems. (I have had window motor faults showing as engine management before now)

If everything checks out, plug the chip back in and see what happens. If nothing suspect duff chip.

Cheers Adam

Got a job rob - on 20 Nov 2012
In reply to butteredfrog: ok, to highjack this thread a bit. would this type of thing be any good for my skoda? Its a normally aspirated 1.9 diesel, with 64bhp, i dont really care about more power just more economy. I can currently get 72MPG on the way to work but would love more. What do people think.
Swig - on 20 Nov 2012
In reply to marky:

We might be onto "winter diesel" by now which doesn't normally do quite so well for mpg.

The people on seatcupra.net are knowledgeable about this sort of thing. Tuning boxes don't have a great reputation though (some just con the ECU into overfueling) and you'll get people telling you that you should have had a remap instead of installing something.

DANNYdjb on 20 Nov 2012
In reply to marky:
suspect duff chip!
butteredfrog - on 20 Nov 2012
In reply to Got a job rob:

Probably not, most chips just trick the ECU by modifying the signal from the airflow meter. Tricking the ECU into thinking the engine is someware else in its power curve. Upping the boost and fueling and altering the EGR responses.

On a normally asperated (non Turbo) engine I can't imagine much power gain.

72 mpg is pretty good anyway. Maybe blanking the EGR valve off would give you a couple more MPG's


Marcus Tierney - on 20 Nov 2012
In reply to marky:
swig is probably right remap more reliable than chip
Got a job rob - on 21 Nov 2012
In reply to butteredfrog: thank you for the info!
George Fisher - on 21 Nov 2012
In reply to marky:

First place I'd look would be a MAF sensor. Common that you find a fault here after chipping as you are asking more of them. . Split or loose boost pipe is pretty common too but less likely on a 140.

Tuning boxes are perhaps not as good as a remap but diesels are pretty easy to tune, they mainly respond to having fuel dumped in. This can cause problems with soot though. Is the car dirtier after fitting the box?

I'd start with getting and fault codes read with a diagnostics unit. You can do this yourself with a program called vag-com but you need a obd2 lead.
owlart - on 21 Nov 2012
In reply to marky: Out of interest, does this sort of modification need to be declared to your insurance, and if so how does it affect it (I seem to remember reading that a remap must be declared as it's not 'factory standard')? I'm wondering if the premium hike is more or less than the mpg gain you achieve?
jkarran - on 21 Nov 2012
In reply to marky:

Have you possibly just got used to it?

Did you actually measure performance before and after? Operating conditions have changed quite a bit in the last few weeks: Air temperature, moisture, fuel. Wet roads sap power as do low pressure (due to cold?) tyres. If you didn't actually measure it, how accurate is the seat-of-the-pants dyno? Mine is rubbish!

jk
dunc56 - on 21 Nov 2012
In reply to owlart:
> (In reply to marky) Out of interest, does this sort of modification need to be declared to your insurance, and if so how does it affect it (I seem to remember reading that a remap must be declared as it's not 'factory standard')? I'm wondering if the premium hike is more or less than the mpg gain you achieve?

You are such a mummy's boy :)
thebrookster on 21 Nov 2012
In reply to owlart:
> (In reply to marky) Out of interest, does this sort of modification need to be declared to your insurance, and if so how does it affect it (I seem to remember reading that a remap must be declared as it's not 'factory standard')? I'm wondering if the premium hike is more or less than the mpg gain you achieve?

Yes. ANY deviation from factory spec has to be declared, including say alloy wheels. If you have a crash, your insurance company will happily declare you insurance null and void for this type of thing. The only possible way around something like that is if you bought the car in good faith like that (a friend of mine had an aftermarket air filter fitted to his Vectra that was written off, but didn't actually realise it was an aftermarket item!! Fortunately his insurance company accepted his innocence, though was helped by the fact his car was parked up, and someone else smashed into it, meaning his insurance really didn't care!).

If the ECU has been modded in any way shape or form, it must be declared. Common sense, this is quite a major alteration!
owlart - on 21 Nov 2012
In reply to dunc56: I'd rather not pay an arm and a leg for insurance ony for them to declare it null and void due to e technicality. If you can afford to self-insure, go ahead, I can't.
owlart - on 21 Nov 2012
In reply to thebrookster: That's what I thought, hence the question. The next question though is how much does it affect the premium? If it bumps it up by more than you're saving, then it's a false economy. Of course, if you don't declare it, and then make a claim which is turned down, it'll be even more of a false economy.
jkarran - on 21 Nov 2012
In reply to owlart:

How is anyone ever going to know? Pull one nondescript EEPROM out, remove the sticker and pop a new nondescript EEPROM in. I can't imagine even the most diligent of insurance assessors reverse engineering your ECU register by register on the off-chance it's non-standard.

jk
dunc56 - on 21 Nov 2012
In reply to owlart:
> (In reply to dunc56) I'd rather not pay an arm and a leg for insurance ony for them to declare it null and void due to e technicality. If you can afford to self-insure, go ahead, I can't.

Hannah will look after you :)
hydraulicwave - on 21 Nov 2012
In reply to marky: I took apart some of these chip box things. Some were full of potting compound, when I chipped away the potting compound I found a 70p Maplin resistor.
owlart - on 21 Nov 2012
In reply to jkarran:
> (In reply to owlart)
>
> How is anyone ever going to know? Pull one nondescript EEPROM out, remove the sticker and pop a new nondescript EEPROM in. I can't imagine even the most diligent of insurance assessors reverse engineering your ECU register by register on the off-chance it's non-standard.

Because your car as just been impounded as evidence, and/or you're laid up in a hospital bed?
jkarran - on 21 Nov 2012
In reply to owlart:

Why is anyone going to be poking around in the ecu whether it's impounded as evidence or not? Personally I don't see much point in these things, many are basically a scam or bodge anyway but unless you go slapping *MEGGACHIPPED* stickers all over the thing they're pretty discrete.

jk
Ciro - on 21 Nov 2012
In reply to jkarran:
> (In reply to owlart)
>
> How is anyone ever going to know? Pull one nondescript EEPROM out, remove the sticker and pop a new nondescript EEPROM in. I can't imagine even the most diligent of insurance assessors reverse engineering your ECU register by register on the off-chance it's non-standard.
>
> jk

If you've bumped into someone in a car park and caused a couple of grands worth of damage, they wont find out.

If you've caused a pile up on the motorway which has left several people in wheelchairs and is going to cost them millions, they're going to be pretty diligent about finding a way out of paying up. And you're f*cked if they manage to find one.
GrahamD - on 21 Nov 2012
In reply to marky:

Can someone explain the downside of chipping ? presumably there is a reason why Audi don't programme their cars for better performance AND better efficiency for a reason ?
Epic Ebdon - on 21 Nov 2012
In reply to owlart:

Would it invalidate your 3rd party insurance too, or just the "fully comp" part? Just wondering, as they could probably then invalidate your insurance for any minor offence/fault, and we'd all be essentially driving around uninsured.

Just wondering....

Tim
Ciro - on 21 Nov 2012
In reply to GrahamD:

You lose about 5 to 10 % off the life expectancy of the engine.

Since a modern turbo diesel is probably designed to last 300k under UK conditions, you're still probably going to scrap the car for other wear and tear before the engine dies.
marky - on 21 Nov 2012
In reply to owlart: Yep informed Admiral and stumped up an extra 75 but including the cost of the chip will still be quids in over the 3 years with the improved economy.
thebrookster on 21 Nov 2012
In reply to GrahamD:

There is a marked difference between performance and economy! It is measured with something called "AFR", or Air Fuel Ratio. The bigger the number the less fuel it puts in compared to air, the smaller the number the more fuel used.

Power (and therefore performance) is directly related to the amount of fuel burned. Most performance mods, like K&N air filters, port flowing, bigger pistons etc are all about increasing the amount of air sucked in, and therefore the more fuel can be burned. Engines like a certain amount of fuel, roughly between 12 and 13 AFR for max power.

Economy, however, is all about the least amount of fuel you can get away with. The less fuel you use, the hotter the engine will run, which increases pre-detonation (the mixture explodes before it should, which forces the piston downwards when it is supposed to be going up). This causes a lot of damage. It may be possible to run quite high AFR ratio's, I know of people running 16-17 happily.

Your manufacturer however, will simply balance the two, to get the best of both worlds. So really, Audi etc HAVE made the car for best performance and efficiency, but improving one detracts from the other.
fraserbarrett - on 21 Nov 2012
In reply to GrahamD:
> (In reply to marky)
>
> Can someone explain the downside of chipping ? presumably there is a reason why Audi don't programme their cars for better performance AND better efficiency for a reason ?

As has been hinted at there's lot of reason's; engine life and or durability are just two.

More importantly these days is the emissions legislation which dictates a level of NOx, CO2 and soot which a diesel can produce. This means a careful balance between cylinder temperatures, fuel pressure, injection timing, shape of the injection curve and quantity injected; not mentioning pilot or post injections. This in short means that the optimum fuel economy/power are not possible to achieve.
Your chip is one of two things, it is either clever and changes the signal going to a particular pin on the ecu with a mapped variable; or and this is much more likely its a resistor that drops the voltage, meaning you move to another part of the ECU map and get a richer fuel mix. This can cause more soot and in turn clog up the DPF (diesel particulate filter), or clog the EGR(exhaust gas recirculation) valve. This will cause the drop in power you are seeing.
Alternatively the OBD system on the ECU may have recognized the 'chip' and compensated, I don't know if Bosch (who make this ECU) do this; but I know for a fact that their biggest competitor in Diesel engines do (as I work for them, doing FIE (fuel injection equipement) development and engine calibration).
I personally would avoid a chip, but defiantly have every faith that a good remap would give you considerably more power and fuel economy with the 'only' negative being increased particulates (cause cancer) and NOx.

P.S. And of cause the other reason that the engine isn't as good as it could be is that the manufacturer needs to be able to design one engine and gradually increase it's power and fuel efficiency with each face lift model; and the cheap way of doing this is just to increase the power from the same engine with a remap as you get confidence in the durability with more engine having done more miles...
thebrookster on 21 Nov 2012
In reply to fraserbarrett:

You know, I completely forgot about the emissions side! Though to be fair, the entire of my experience with ECU's is converting classic cars, so we get to ignore emissions :P
GrahamD - on 22 Nov 2012
In reply to thebrookster:

Thats what I thought, which was why I was curious about the OP's statement:

"Initially performance AND economy noticably increased"

thebrookster on 22 Nov 2012
In reply to GrahamD:
> (In reply to thebrookster)
>
> Thats what I thought, which was why I was curious about the OP's statement:
>
> "Initially performance AND economy noticably increased"

Aah, there you start getting into the nitty gritty, and things become a bit more complex.

Whilst increasing the performance of an engine as a rule reduces economy, it also depends on factors such as the car itself. For example, you might have a Fiesta with a 1l engine, and another with a 1.4l engine. Most people would automatically assume the 1l is more economic, but this really depends on usage. Say you carry yourself, a passenger and some luggage, this would mean the 1l has to be pushed to reach an efficient cruising speed. The bigger engine, however, can reach the same cruising speed far faster with a lot more ease. Therefore the 1.4 can suddenly become more efficient.

You also have to factor in where fuel is needed. A fuel "map" is quite a complex item, as it has to take into account what the engine is doing. An accelerating engine will require far more fuel at 2500rpm than a engine cruising at 2500rpm, and deccelerating requires hardly any fuel at all. Adding this chip will affect all the sections without discretion, so it may well give better fueling for acceleration, yet move cruising fuel to a more efficient value.

Also, driving style has to be factored in. The OP possibly still drives exactly the same as he always did. Lets say for argument he uses each gear, and changes religiously at 4000rpm, until he reaches his criusing speed of 70mph in top gear. Chipping his car gives more power, meaning his engine revs to 4000rpm faster. This means he accelerates faster than before, so he reaches his cruising speed far faster, and spends longer at the efficient cruising speed as a result. This will also translate to a better economy.
Ciro - on 22 Nov 2012
In reply to thebrookster:

> Also, driving style has to be factored in. The OP possibly still drives exactly the same as he always did. Lets say for argument he uses each gear, and changes religiously at 4000rpm, until he reaches his criusing speed of 70mph in top gear. Chipping his car gives more power, meaning his engine revs to 4000rpm faster. This means he accelerates faster than before, so he reaches his cruising speed far faster, and spends longer at the efficient cruising speed as a result. This will also translate to a better economy.

So for maximum fuel efficiency I should always go foot to the floor to accelerate up to cruising speed? That sounds counter-intuative...
fraserbarrett - on 22 Nov 2012
In reply to Ciro: Not nessaserally foot to the floor but as close to the peak of the power curve as possible, so that engine is running efficiently. The extra power means that you pass throught the inefficent region of the power curve (i.e low revs, high torque demand) more quickly and therefore more efficiently.
Martin W on 22 Nov 2012
In reply to GrahamD:

> I was curious about the OP's statement:
>
> "Initially performance AND economy noticably increased"

I experimented with a RaceChip chip on my Yeti 140 (which has much the same engine as the OP's Audi) out of curiosity as much as anything else. Although the on-board computer indicated that fuel economy was much improved, calculating the mpg fill-to-fill suggested otherwise. I don't know what else the chip was fooling the ECU about, but it was certainly causing it to be about 9% optimistic in terms of fuel economy.

Although it definitely did alter the driving characteristics of the engine, I can't say whether it actually increased the maximum power.

I decided that it was largely junk and took it off.
thebrookster on 22 Nov 2012
In reply to Martin W:

> Although it definitely did alter the driving characteristics of the engine, I can't say whether it actually increased the maximum power.

Peak power is essentially a misnomer for a daily driver, and the majority of drivers will not notice a difference if it is changed. The difference in a few horsepower equates to fractions of a second on a racing track, for example. Racers dedicate large amounts of money and time to achieving that extra half a horsepower, which could be the difference between them and their rivals.

A lot of what we do on the road comes from racing however, and over the years people have seen racers striving for power, and then apply the same logic to their road cars (boy racers etc are a classic example of large groups of people making mods to their cars, believing to make them faster simply because "racers do it").

You can stick a chip into a car to alter the fueling, and maybe this gives you 10bhp more at 6100rpm, which is fine at the rpm, but what of the rest? You don't drive at 6100rpm all the time. Also, like economy, increasing in one area often adversely affects another. Look at a race engine, lots of power high up the rev range, but almost impossible to drive normally. I drove a friends road legal race car not that long back, to set off from traffic lights I had to rev the engine to 4000 rpm before I could even consider lifting the clutch else it would have stalled. This car made roughly 120-130bhp at over 7000rpm (classic car, which standard had 70bhp, so this was big power), and on paper looked wonderful.

The point I am trying to make (in a rather long-winded manner) is that we get overly hung up about power, and as you noticed most people simply do not notice it.



butteredfrog - on 22 Nov 2012
In reply to thebrookster:

Torque is much more important on the road.
Epic Ebdon - on 22 Nov 2012
In reply to thebrookster:

> Also, driving style has to be factored in. The OP possibly still drives exactly the same as he always did. Lets say for argument he uses each gear, and changes religiously at 4000rpm, until he reaches his criusing speed of 70mph in top gear. Chipping his car gives more power, meaning his engine revs to 4000rpm faster. This means he accelerates faster than before, so he reaches his cruising speed far faster, and spends longer at the efficient cruising speed as a result. This will also translate to a better economy.

Don't confuse maximum engine efficiency with best mpg. I for one would prefer maximum mpg to maximum engine efficiency. Think of it this way: I pull away from the lights next to some boy racer. I ease away relatively gently, with my car's engine not at maximum efficiency. The chav next to me gives it the berries, runs his engine at maximum efficiency, and shoots off in front of me. Now assuming same car, engine etc., your logic would suggest the boy racer gets better mpg than me. Not true! Consider the following figures as an example (I realise they are unrealistic).

I perform a manoeuvre (pulling away from the lights) which requires 100J. My engine runs at 66% efficiency, so I burn 150J worth of petrol.

Our friend the chav pulls off in such a way that the energy required to accelerate his car like that is in total 200J. However, he's cracking out the maximum efficiency from his engine - lets say 100% for the sake of argument. How much fuel has he used? 200J worth.

Of course engine efficiency and mpg have a lot to do with each other, but running the engine at the best point on it's power curve does not necessarily give you the best mpg.

Tim
thebrookster on 22 Nov 2012
In reply to Epic Ebdon:

You are confusing two issues here though, which is where you are going wrong. Your example is fine for two different styles of driving, however I stipulated that the style of driving in my example had not changed!!

My point was that chipping the car would make it more efficient, so if he drives exactly the same two times, but the second time has an engine that is more efficient, then he will use less energy than the previous run.
dunc56 - on 23 Nov 2012
In reply to Martin W:
> (In reply to GrahamD)
>
> [...]
>
> I experimented with a RaceChip chip on my Yeti 140 (which has much the same engine as the OP's Audi) out of curiosity as much as anything else. Although the on-board computer indicated that fuel economy was much improved, calculating the mpg fill-to-fill suggested otherwise. I don't know what else the chip was fooling the ECU about, but it was certainly causing it to be about 9% optimistic in terms of fuel economy.
>
> Although it definitely did alter the driving characteristics of the engine, I can't say whether it actually increased the maximum power.
>
> I decided that it was largely junk and took it off.

I did exactly the same . It said 50 and it was more like 42. And I was driving like suggested above - where you accelerate to a speed quick and back off. It felt fast though.

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