Citroën Xantias are....

Kowalski · Post by **Kowalski** » 22 Mar 2005, 15:20

16 valves are better than 8. An 8 valve diesel needs more turbo boost to produce the same power as a 16 valve diesel. More boost is usually accomanied by higher inlet temperatures and means less thermal efficiency which means worse fuel economy. It also means worse emissions, since the engine doesn't scavenge as well, so higher cylinder pressures are needed to have the same amount of available oxygen to burn fuel.
I suppose you don't see the point of the turbo on a diesel either...

Post by **Thunderbird** » 22 Mar 2005, 15:32

Richard, your point is right, but Tom's point is even more right.
No matter the fancy technology under the skin if the final results are not relevant, and the 2.2 has poor output given it's a 2.2 liter.
The ecological performance comes from the use of the FAP.
The 16 valve technology on diesel engines has poor practical results.
Now, if you want a good example of technology serving the driver and the environment, that allows engines with less capacity to be more powerful, and provides the best power/ecological ratio, take the new twin-turbo technology most brands are starting to use on diesels.
One example, the new BMW 335d's 3.0 diesel engine (now on stores):
Config: 3.0 liter (2993cc), 6 cilinder in-line, Twin-turbo
Power: 272 BHP [}:)] 2.2HDi 133BHP 16 valve??!! [xx(]
Torque: 560 N/m [}:)][}:)]
0-62MPH: 6.8s [}:)][}:)][}:)]
Mqx speed: 155.3mph (electronically limited)
MPG: (Road, City+Road): 45, 35
Rostami, have done my at Upsolute. They connected a laptop to the car (near the fuse box inside the car) and extracted the original program. They sent it by email to Austria (main dealer) where they changed only the critical parameters, including the checksum. Signature and other data remains unchaged - Citroen can´t trace it. They sent an email back. Uploaded via the laptop (the laptot had a wireless connection), and voila! Clean, as it could be, and what a diifference the 293N/m torgue make! It's a new car.

Kowalski · Post by **Kowalski** » 22 Mar 2005, 19:43

I think the 2.2 HDI will be cleaner emissions wise than your chipped 2.0 HDI, granted it'll produce more CO2 but particulates and nitrous emissions will be lower, its a second gen common rail engine.
Twin turbo technolgies are used because small turbos are cheap and larger turbos aren't. Large car diesel engines are relatively low volume so small turbos are used because they are volume produced. The thing that is different about the BMW 535d (there is not currently a 335d available) is that it has asymetric twin turbocharging. This gives low lag at the bottom end and and high boost at the top end without killing the turbos. No other diesel engine in a car uses twin asymetric twin turbos (the Jaguar 2.7 is symetric).
Incidentally, the BMW 535d is not as economical as the 530d, they've sacrificed economy for performance, it is always a trade off. The 138bhp 2.0 HDI is less economical than the 110 bhp.

jeremy · Post by **jeremy** » 22 Mar 2005, 21:07

Isn't part of the arguement for using small twin turbos and 16 valves a question of driveability? If you want to drive a boat which runs at a constant speeds most of the time you can get the power up by winding up the boost and install a large turbo. However all this takes time to get going and while in a boat that doesn't matter it does in a car which needs to respond rapidly to small throttle movements.
So large turbo takes time to get spinning before it produces useful output. High manifold pressure takes time to achieve and so on. make it easier for air to get in and out of the cylinder means you can reduce the boost, so quicker response, same with a smaller lighter turbo.
V6's are of course a bit different and twin turbo's are probably essential for manifold considerations as well.
jeremy

Post by **Thunderbird** » 23 Mar 2005, 21:03

No, the Chiped DW10 (136/293) is much more economical than the original 110/250 version, except if pushed hard.
The average comsumption droped from 6.5 liter per Kilometer to 5.9 liter per kilometer. It's true that on sports driving the chiped version responds much better and also burns more diesel.
I believe the main reason for this is the turbo - on the chiped version it starts to work much sooner and with more intensity. The 90Hp version non-turbo also has a higher comsumption than the 110hp at stable road/high-way speeds.
I have obtained better results on economy than those expected by Upsolute (who has chiped the car). Their official figures for fuel comsum. are:
At 56mph - Original: 52mpg Upsolute chiped: 55mpg
At 75mph - Original: 43mph Upsolute chiped: 45mpg
City use - Original: 32mph Upsolute chiped: 34mpg
Top Speed - Original: 119mph Upsolute chiped: 126mph
The small increase in top speed (7mph) doesn't represent the car's real power. I can now climb a particular hard hill at 105mph where before chiping my best result was 85mph. Brutal!

Kowalski · Post by **Kowalski** » 23 Mar 2005, 22:14

How is the Upsolute more economical?
All the chipping will do is allow more boost and more fueling to give more power, so the constant 56mph and constant 75mph figures could not be different.
I understand that urban, extra urban and combined figures can improve since you can be a gear lower at times, but the constant figures can't. The engine hasn't changed and it has a given thermal efficiency and is producing a fixed output. The increased fuel economy claims of some tuning products are in the same category as the claims that they don't shorten engine life...

Post by **Thunderbird** » 23 Mar 2005, 23:22

Kowalsky,
I don't care about guessing theory - only real facts interest me.
I call it guessing theory because you don't know all the changes that are made in the ECU program. Some point for performance, other for economy. It's an intelligent upgrade. This is not one of those boxes that provide more power in a blind way.
Also don't care if it has 16 valve or if it is chiped, but only the final results.
Previously I ran about 920Kms and had 5 liters left on deposit.
Now I run about 1000Kms with the same 5 liters left.
Same roads, same speed.
Concerning engine life, the Upsolute dealer was very clear: It shortens engine life!!! Transmission, and other parts will suffer to.
In order to minimize that, he recommended me a series of preventive actions. A few examples:
- Use high quality full synthetic oil and change every 10000Kms/6Kmiles.
- To buy a better air-filter (don't remember the brand) and clean it every 6Kmiles too.
- Keep the cooling system fully operational (levels, change liquid, etc.).
- Drive below 2000RPM before the cooling liquid warms up.
- Etc. and a few others.
All my friends that have chiped (1 Peugeot, 1 Renault, 3 VW, 1 BMW, 1 Mercedes), also noticed a lower comsumption (except if using the new power).
The final (and important) results, in this matter are only five:
- Performance: (++) It's a new car. Unbelievable.
- Economy: (+) Improved. Much better than the 2.2HDi also.
- Engine life: (-) It is shorten, but that's not important to me as I expect to own the Xantia only up to 200.000KKms/125Kmiles.
- Price: (++) 520 Euros! The price of an extra when you're buying a new car, and you get a new engine!

ActivaV6uk · Post by **ActivaV6uk** » 23 Mar 2005, 23:37

At 56mph - Original: 52mpg Upsolute chiped: 55mpg
At 75mph - Original: 43mph Upsolute chiped: 45mpg
These can not be right, as Kowalski states. these will not change because of chip tuning they can only change because of less restriction/friction

Post by **Thunderbird** » 24 Mar 2005, 00:06

They are not right! I've achieved even better results!
Wake up mates! It's time to give a new soul to your lazy cars (and also make them more economical), by doing an upgrade of the ECU.
I've done mine at Upsolute but there might be better companies out there.
<blockquote id="quote">quote:<hr height="1" noshade id="quote">
Tasks of the ECU

1) Retarding and advancing ignition timing
For an economic and efficient fuel combustion, it is important, to, under all possible driving conditions, compute the correct ignition timing in dependence of engine-rpm, load and other relevant parameters for diesel engines the right injection timing (pump timing).

2) Dwell control
In dependence of the engine-rpm the time between ignition trigger signals varies. To ensure a constant ignition energy it requires a certain ,,Primary Current" to flow through the windings of the ignition coil. To sufficiently build up a magnetic field inside the coil, it requires time. The time delay from switching to interrupting the primary circuit has great influence on the voltage induction into the secondary circuit of the ignition coil the higher the engine-rpm, the shorter the delay from switching to interrupting the primary circuit, the less energy is inducted into the secondary circuit. This may lead to engine misfire at high rpm.

3) Detonation detection
On all modern automobile engines the compression ratio is rather high in order to achieve higher torque output and better fuel economy. Due to high compression ratios the risk of an uncontrolled inflammation of the air-fuel mixture is, especially under high loads running at high rpm, potential is higher. Detonation causes severe engine damages. Whenever detonation is detected, the ECU will retard the ignition timing for the particular cylinder.

4) Fuel injection
In accordance to the signals air-mass (air-flow), rpm, load and correctional factors such as ambient as well as coolant temperature etc., the ECU determines the momentarily needed fuel amount and injection timing. This increases fuel economy and reduces exhaust emissions and in the mean time is responsible for a higher specific engine output.

5) Lambda control
One of the previously mentioned correctional factors, is the lambda-signal. The lambda sensor located in the exhaust system, in front of the catalytic converter constantly measures the remaining oxygen in the exhaust gases. This signal is used by the ECU, too, under all driving conditions except ,, Full Load", adjust the air to fuel ratio to ,,Lambda 1" (14,8 kg of air to 1kg of fuel) and ensures the highest degree of effectiveness of the catalytic converter and at the same time lowest exhaust emissions. Under full load condition i.e. top end speed, the Lambda system, in order to gain higher engine output and prevent severe engine damage due to leanliness of the fuel-mixture, is deactivated.

6) Idle-speed control
In- and decreasing of internal friction related to varying engine temperatures and engine wear as well as operating conditions such as i.e. engagement of the air-conditioning compressor, will lead to a strongly fluctuating idle-speed. The engine rpm signal and current operating information, such as, idle contact, a/c engagement, gear detection(Park, Neutral- or Drive mode of the automatic transmission) etc., are used by the ECU to calculate the appropriate idle speed. Parameters for hot and cold start, in dependence of environmental conditions, are implemented i.e. High Idle during engine-warm-up.

7) Boost control
On cars with turbocharged engines the ECU calculates, in reference to the load indication, the pressure and the currently needed air charge- volume and adjusts, in dependence of the corresponding sensor signal, the appropriate boost.

8) EGR - Exhaust Gas Recirculation
In order to improve the " Exhaust Gas Quality" (reduction of NOx), exhaust gasses, by a certain volume, are inducted into the intake manifold under partial engine load.

9) Service, security and surveillance functions
- Monitoring of currently adjusted values, to avoid malfunction.
- Strict surveillance of "Drive by Wire" systems, meanwhile installed into all modern automobiles
as "E- Gas" (Electronic Gas Pedal).
- Recognition and memorization of system malfunctions.

10) Top end speed governor and rpm limitation
One very important function of the ECU is rpm limitation. Due to enormous mass and centrifugal forces, applied to all rotating and oscillating parts of the engine at high rpm, the maximum rpm range of a particular engine must be constructionally determined and programmed on to the EEProm. Excessively exceeding this max. value i.e. 6500rpm, will eventually result in severe engine damage. The rpm signal is constantly monitored and in case the programmed value of i.e. 6500 rpm is reached, the ECU, either by reduction or interruption of fuel supply or on modern E-gas systems, reduction of throttle position, or by ignition switch-off, prevents exceeding of the max. rpm value. The same parameters apply to the top end speed governor.
<hr height="1" noshade id="quote"></blockquote id="quote">

ActivaV6uk · Post by **ActivaV6uk** » 24 Mar 2005, 00:17

You obviously don’t understand the limitations of the engine. you can change the air and fuel mixture but to get a speed the engine has to be at a certain RPM and there for the energy being used to create that rpm has to be the same... the only way you can improve this is to make the engine run more efficiency through less friction different gearing etc. I believe that chip tuning is good and as a bit of a speed freak the second I can I will chip my 2.1 but the efficiency gain is there if you use it to get to speed not for constant speed and even then its slightly questionable.
Andy

FDV · Post by **FDV** » 24 Mar 2005, 00:21

Have to say the 2.2 is a far superior engine IMO, though not that economical.
C5 over later Xantia for me. Mk1 Activa or V6 over any C5 though!

Post by **Thunderbird** » 24 Mar 2005, 14:31

Like I said, I do not know how it happens, I just know it happens. I am not a liar. My Xantia is now more economical. No doubt about it.
Now, it is true that the radical improvement in torgue changed my driving style (not the driving speed, as I usualy drive at the limit of the legal speeds). I like to drive using high gear-speeds and before the new ECU the Xantia didn't like that.
Before ECU, if you changed to the next speed to soon, the engine would start to fail. For instance, when almost stoped if you changed to second, the engine would die. You just couldn't drive at very low RPM. At any speed, below 1500 RPM the engine would start to fail. Now I can change gear much sooner. In the city, where I traveled in 2nd I can now travel in 3rd at the same speed, and so on for the other speeds - except on the highway I'm always one speed up, and drive below 1500rpm most times, what was impossible before. The extra torgue makes it much more pleasant to drive.
It feels stronger than the C5 2.2 and is much more economical too. Now, I recognise there's a catch - the C5 2.2 engine will last much longer and will always be more ecological due to the FAP.
For those who expect to do high mileage I wouldn't recommend an ECU upgrade. Otherwise, if you can undertake the extra-precautions, I think it's a mistake not to do it. Not only for the economy but especially for the driving pleasure it provides, even when driving at low speeds in the city, and the safety on maneuvers where the extra stamina is welcome.

Post by **RichardW** » 24 Mar 2005, 14:43

Chipping invovles increasing the boost pressure. When you do this the thermal efficiency of the engine increases, and hence the lower consumption figures. For once this is not snake oil! Of course, if you drive on the power peak all the time, then consumption will suffer, but possible not as much as the un-chipper version. Take a look at the figures for the Xantia HDi - the 110 is more economical than the 90 over the official cycles - although I suspect this is due to the intercooler as much as higher boost pressures.
No point in buying a 90 HDi then - it's slower and uses more fuel. Insurance probably a bit cheaper though!

Kowalski · Post by **Kowalski** » 24 Mar 2005, 15:17

Increasing boost pressure decreases thermal efficiency at the same power output. Increased boost means more energy is expendended compressing the charge, giving higher top end temperatures and pressures which means more conducted heat loss out of the engine. There is no way for collecting this boost when it is scavanged out of the engine, so exhaust temperatures would be higher too, this what happens if you increase boost even without matching it with greater fueling, greater fueling would increase temperatures even more but because its internal combustion you are able to recoup this energy.
The HDI 110 is more efficient because the intercooler decreases charge temperature, it allows greater charge density without needing greater charge temperature, so more air can be taken in without losing efficiency. Greater boost is possible because of the intercooler, but its not the higher boost that increases efficiency.

ActivaV6uk · Post by **ActivaV6uk** » 24 Mar 2005, 18:57

There is only a certain amount you can change the air to fuel mixture to get a better burn not enough to see these kind of figures... unless when fitting the chip they fitted a larger or more efficient intercooler or modified the engine the constant running efficiency will be unchanged. i do know that with more torque you get to your constant running speed faster and more efficiency but this would not effect the constant speed figures around town it may make a difference (I’m hoping as this is what I’m telling my wife so i can chip mine later).
If you want more economy from the engine your still looking at dry sumps, knife edged cranks better lightening and balancing or massive intercoolers or in dead a charge cooler.
Andy