Free DCI power increase

[edde]

Ok here goes Im not 100% sure of the power improvment but I think there is some and some MPG improvment (about .5/1mpg according to my calculations) but the theory behind it sounds good to me.

Ok so take of the cover on the DCI engine (you mave have to pull it very hard) it comes straight off three rubber mounts (make sure it back on properly when you finish).

Now look at near the back of the engine there is a large intake pipe with a sensor on it the picture should give you an idea what to do the sensor is help on by a piece of metal use a screwdriver to pull the thing up and then pull the sensor of the pipe then put the metal contecto back over the oose sensor as not to loose it.

http://erc.qmuc.ac.uk/cliosport/gallery/full/1072752240__DSCN0077.jpg

The theory behind it is that the sensor works out the air temp and uses this in the measuring of fuel to the injectors.
When its hot the intake temp will be higher and more fuel will have to be injected for the same hp (diesel has less hp per liter when its hot as it expands).

When the sensor is disconnected the computer thinks its a failure (nothing shows ont he dash though) and resorts to a predetermned value for an adverage temp since this adverage temp is higher than what the value would be at the moment with the cold weather the computer injects more fuel.

Hey presto more power. When I go back to work I will get some testing on the value the sensor gives in the cold weather and when the weather gets better what the value is in the hot weather and then I can tell you all what value resister to put in the sensor to make the ECU think its very hot all the time and inject as much fuel as possible within the set maps.

Some people charge £50 for a box which does the same job as the above resister trick. When I find out the value I may try and make a more advanced resister trick

Its so simple to do that if any problems occure you can easily remove any evidence of it but I cannot see any problems at all

EDD

 

[1.6 16v]

how much is ".5/1mpg " and how does increased fuelling mean more mpg. Not got a diesel just interested

 

[Slugger]

0.5-1mpg better I think???

 

[Clart]

are people really going to bother for a .5mpg increasE?

 

[edde]

Its about half to one MPG increase but Im not 100% sure of its accuracy they may infact do nothing but Im of the opinion that it does.

The trick is similar to the ebay boxes you see for sale every now and agian claiming more hp for almot nothing as they put a resister in the sensor loacation. However doing the mod on a diesel is much less risky as there is no A/F mix which needs to be run on a diesel.

Increased MPG may be released by two reasons

1 Higher compustion temps which make for a cleaner and more efficient burn

2 As the mod may give you more power and more torque as long as acceraration is the same you dont need to rev it as hard so less fuel is used as the torque is used more. Also the extra torque means you can jump two gears going up on the box.

If it did give you half an MPG imporvment its worth about £42 every 60k so or a free mod thats good value in my opinion

If it gives 1mpg improvemnt its worth about £84 after 60k

Sure its only tiny but for free who can complian.

If I can find out the resistance for max fueling the resister is about 20p and some people pay £50 for boxes which do the same thing.

EDD

 

[JAY172]

the sensor you have unplugged is 1 of two temp sensors that the computer uses to work out airflow.i sensor just after the air filter and one just after the turbo.this allows the computer to calculate airflow/mass after it has been through the turbocharger.the information is used to calculate correct fuel pressure,boost pressure and injection duration.by unplugging it all you are doing is causing the computer to use a defect stratagy and ignore the sensors.

 

[BRUN]

id have thought you will probably lose power by disconnecting it, as JAY said it will be used to calculate quite a lot of things and the car will think its faulty and probably resort to get you home mode, which is far from best performance

 

[edde]

Quote: Originally posted by JAY172 on 30 December 2003

the sensor you have unplugged is 1 of two temp sensors that the computer uses to work out airflow.i sensor just after the air filter and one just after the turbo.this allows the computer to calculate airflow/mass after it has been through the turbocharger.the information is used to calculate correct fuel pressure,boost pressure and injection duration.by unplugging it all you are doing is causing the computer to use a defect stratagy and ignore the sensors.




Are these the only two temp sensors then? If so then these could be fooled into thinking the weather was better so injecting more fuel.

Being that is below freezing where I live could the default settings be higher than the setting the sensors would give out?

I was under the impression that fuel injection pressure was kept at 1400 all the time under the common rail system.

What is the mass airflow figured used for?

The turbo maps setting? (I would have thourght that the turbo would have another sensor for boost pressure) .The injectors timing, injection and duration? As less fuel is flowed per cycle when there isnt enough air, as to much fuel injected with insuficcient air leads to poor emisions and smoke trails.

If you or anyone out there could tell me some more about the Dci engine (diagrams, pats or anybting etc) I would be much abliged. Ive got a useless memory for names so Id forget you name or address after you give us any details.

Thanks

EDD

 

[JAY172]

probably why there has been a slight improvement in fuel consumption due to you wont be able to get maximum throttle when the computers in defect stratagy(boost and injection pressures will be restricted)

 

[edde]

What would happen if you could change the resitance of the sensor yet still use the senors ie add resisters in series or parrellel.

Ive reconnected the sensor today anyway as after a quick drive to the shops I noticed smoke or something comming from under the bonent. When I opened the bonnet the smoke or steam had gone and the top of the dipstick was missing. Are these two things related I may have hit a few puddles on the country roads but it I guess that some water on the radiator or engine would do that. Anyway its booked back to get a new dipstick and get looked as soon and apparently I can use any dealership (handy as my original one is 50 miles away from the new house)

EDD

 

[king.stromba]

Try this for 10 mpg decrease in fuel consumption. At junctions short shift. Accelerate really slowly. Try to maintain a constant speed of 56 mph. Brake as little as possible to maintain speed. Rip out the spare tire.

Above will also increase the lifespan of your car and reduce component wear

And its free

Now thats amazin........mate

 

[edde]

Quote: Originally posted by king.stromba on 30 December 2003


Try this for 10 mpg decrease in fuel consumption. At junctions short shift. Accelerate really slowly. Try to maintain a constant speed of 56 mph. Brake as little as possible to maintain speed. Rip out the spare tire.

Above will also increase the lifespan of your car and reduce component wear

And its free

Now thats amazin........mate






You only get a 10mpg improveent thats poor I got over 80 mpg doing this. (about 20mpg improvemt)

It would seem though that my modification would achually decrease power.

56 isnt the best speed I think its about 30mph in top I got well over 100mpg when testing a courtesy car like this. My guess I was geting about 120 like this.

At the peak of the torque as when the car should be driven for max economy normally but since the dci does about 52mph at these revs there is loads of air resistance so a slow speed therefore less drag is better even if the engine isnt at peak economy the energy used to pull the ca along is less.

The 56mph max economy speed is what everyone claims it achually comes from the old merc (I think its the 300 series) which had a load of performance charts which showed that 56mph was the best speed it sould be driven at. The Clio is a different shape so has different drag coefficent numbers and so is unlikly to be most economical at 56mph.

The Lupo, 3L VW prototype and Yaris cars used in MPG challenges drive at an adverage of something like 25mph and cruise on the motorway at 45 or so. It shows that 56 isnt the best figure everyone always quotes.

Also strip the car of some more weight back seats and passenger seat, engine cover, passenger wing mirror, headrests, wtaer and fluids levels 3rd barke light and get on the atkins diet

Regards _KDF comments below the diesel engine doesnt run lean its a different system than petrol there is no 14.7 A/F ratio like petrols have.

I thought it may work as this is the trick that VAG PD engine owners use (they use a resister) to trick the car to make more power and it works (apparently). Renault dont make production of power as easy as easy as fooling sensors but the engine is tunned to make the same amount of power over loads of situations and fooling ECU that its hotter it will injector for longer although emmisons would be higher which is somehting Renault didnt want when they wanted the dci to be economical and very environmentally friendly.

Look at the 172 engine why dont Renault decat it for more power. Its because they need the emisions to be lower.

EDD

 

[KDF]

Why on earth would people think disconnecting a sensor would be better for your engine, do you really think renault would put something in that will make it use more fuel, or less power ? fraid all you will do is make your engine run lean or rich. http://erc.qmuc.ac.uk/rolleyes.gif

 

[king.stromba]

Stripping out eddes last post alone decreases fuel consumption by 100 mpg.

 

[word_easy]

120 miles per gallon???what?!

 

[edde]

Quote: Originally posted by word_easy on 30 December 2003

120 miles per gallon???what?!

Yep Thats what I guessed to to be about.

It may have been less than possibly as low as 25 though and the engine didnt respond well to the treatment. I did cruise along like this for some time so its not a one of down a hill mpg reading it was going up from 100mpg at some rate.

My idea of the trick etc comes form the VAG PD engien and although _KDF seems to think Im stupid or mad (not quite sure which)

The VAG resister trick info can be found here

http://www.uk-mkivs.net/forum/topic.asp?TOPIC_ID=11160http://www.uk-mkivs.net/forum/topic.asp?TOPIC_ID=11160

If you look downt he page and follow some of the links you can see the result of dyno testing there mod here

http://members.rogers.com/wong5102/dyno.htmhttp://members.rogers.com/wong5102/dyno.htm

Here is the info I was using thinking the mod would work

TD5 motor used in Discoveries:

"The fuel temp sensor is in direct contact with the fuel and measures its temperature continuously between a range of -40°C to 140°C (-40°F to 285°F). If the signal from the fuel temperature sensor is interrupted or corrupted at any time then the ECM will implement a predetermined default value of 60°C (140°F)."


I was assuming (or hoping) the same would be true for the DCI that the default value used is higher than the value the sensor would give in this cold weather.

This resister trick is sold on Ebay (someone tried selling one today on the site although the thread was removed) for 172 and other cars all the time alhtough it messes up the A/F ratio. A higher amount of fuel in a diesel doesnt make problems like the trick does in petrols as here is no 14.7 A/F misture rature problems.

EDD

 

[JAY172]

Quote: Originally posted by edde on 30 December 2003

Quote: Originally posted by JAY172 on 30 December 2003

the sensor you have unplugged is 1 of two temp sensors that the computer uses to work out airflow.i sensor just after the air filter and one just after the turbo.this allows the computer to calculate airflow/mass after it has been through the turbocharger.the information is used to calculate correct fuel pressure,boost pressure and injection duration.by unplugging it all you are doing is causing the computer to use a defect stratagy and ignore the sensors.




Are these the only two temp sensors then? If so then these could be fooled into thinking the weather was better so injecting more fuel.

Being that is below freezing where I live could the default settings be higher than the setting the sensors would give out?

I was under the impression that fuel injection pressure was kept at 1400 all the time under the common rail system.

What is the mass airflow figured used for?

The turbo maps setting? (I would have thourght that the turbo would have another sensor for boost pressure) .The injectors timing, injection and duration? As less fuel is flowed per cycle when there isnt enough air, as to much fuel injected with insuficcient air leads to poor emisions and smoke trails.

If you or anyone out there could tell me some more about the Dci engine (diagrams, pats or anybting etc) I would be much abliged. Ive got a useless memory for names so Id forget you name or address after you give us any details.

Thanks

EDD

the sensor set up is different to the conventional air temp sensor so you cant try and fool it by using resistors.the 1st sensor meassures the air temp at the air filter,the second temp sensor meassures the air after the turbo.the computer compares the two readings and calculates airflow from which it decides an injection stratagy(boost pressure,injection pressure,injection duration etc).there is a boost pressure sensor but that is only there so the computer can check the turbo is producing the boost the computer is requesting.the computer controls the boost via a vacuam solenoid that operates either the wastegate or internal vanes(on the latest variable vane type turbochargers).the dci engine directly injects deisal into a combustion chamber in the piston crown under high pressure(old desials used a separate combustion chamber and a lot lower fuel pressure).the high fuel pressure means injection can be more precise and the fuel mixes with the air better so giving a better burn.the fuel pressure also has to be increased due to the higher compression ratio of the dti engine.there is a high pressure pump(with a fuel flow control solenoid) and a injection rail.each injector is opened via a solenoid controlled by the computer(same set up as a conventional petrol injection system).the fuel pressure at idle is 300bars at full throttle it can be up to 1600bars.the pressure varies between these two values depending on throttle position.extreme care must be made when working on the fuel system due to the dangerously high fuel pressures and the fact that even the smallest particle of dirt in the fuel could damage the high pressure pump.

 

[edde]

Renault dont make it easy do they for cheap moding ideas do they.

The higher pressure efficiency is linked with the mutiple nozzles to make the highy efficient spray.

I cannot see why you need higher injection pressure due to higher compression ratios, you will need them for more efficent spray distribution but old modded tdis run 30+lb boost on only slight higher injector pressure.

Im still confused as to why you cannot add say 10% to the resistance of the sensors to make the car think there is different temps before and after the turbo so make the car think its hotter.

How does the car know how hot it is therefore how much fuel to be injected as the hot weather more fuel needs to be injected due to the lower potency (not the right word I know) of fuel in the heat. Or does the

Thanks for telling us about the oil dipstick problem. Im hoping playing the idiot (Im good at that) will mean I can get away with not paying. I hope no one at the dealership Im going to reads this forum.

How about tricking the common rail system as to what pressure its at ie run a rail 5% above the normal pressures so more fuel injected per cycle.

Renault claim the new 100dci is ruuning at 200bar higher pressure that the 80 and 65 and it now runs at 1600bar. So how come the 65 and 80 run at 1600 is that a peak pressure and not what the engine normally runs at (ie 1400bar normally max)? If so the new 100 engine could hit 1800bar which is almost PD pressure. The common rail tested limit is 2200bar so 1800 on a prodcution car is excellent.

The engine works out injection pressure timing and duration from its maps the pre and post turbo sensors, the RPM and throttle position then?

Soory for alll the questions Im just interested and dont get out enough

EDD

 

[KDF]

Quote: Originally posted by edde on 30 December 2003

although _KDF seems to think Im stupid or mad (not quite sure which)

Im leaning towards "mad"

 

[JAY172]

Quote: Originally posted by edde on 31 December 2003


Renault dont make it easy do they for cheap moding ideas do they.

The higher pressure efficiency is linked with the mutiple nozzles to make the highy efficient spray.

I cannot see why you need higher injection pressure due to higher compression ratios, you will need them for more efficent spray distribution but old modded tdis run 30+lb boost on only slight higher injector pressure.

Im still confused as to why you cannot add say 10% to the resistance of the sensors to make the car think there is different temps before and after the turbo so make the car think its hotter.

How does the car know how hot it is therefore how much fuel to be injected as the hot weather more fuel needs to be injected due to the lower potency (not the right word I know) of fuel in the heat. Or does the

Thanks for telling us about the oil dipstick problem. Im hoping playing the idiot (Im good at that) will mean I can get away with not paying. I hope no one at the dealership Im going to reads this forum.

How about tricking the common rail system as to what pressure its at ie run a rail 5% above the normal pressures so more fuel injected per cycle.

Renault claim the new 100dci is ruuning at 200bar higher pressure that the 80 and 65 and it now runs at 1600bar. So how come the 65 and 80 run at 1600 is that a peak pressure and not what the engine normally runs at (ie 1400bar normally max)? If so the new 100 engine could hit 1800bar which is almost PD pressure. The common rail tested limit is 2200bar so 1800 on a prodcution car is excellent.

The engine works out injection pressure timing and duration from its maps the pre and post turbo sensors, the RPM and throttle position then?

Soory for alll the questions Im just interested and dont get out enough

EDD

if you put a fixed resistor in the sensors then the computer would read a fixed amount of airflow.the computer would then highlight a fault in its memory and run in defect mode.65/80 max fuel pressure 1400bar,100 max fuel pressure 1600bar sorry about that i was just giving a general figure in my last explanation.the rail is tested to 2200barbut if the computer see a excessivly high fuel pressure compared to the engine conditions it will cut the engine out.any pressure over the max rated fuel pressure will mean the computer will cut out the engine.the rails are rated a lot higher than max rated pressure so to give a large safety margin(rail no where near max tested pressure so not under a lot of strain).if you mess with the rail pressure sensor to try and confuse the computer into thinking there is more pressure it would only adjust the pressure regulator to bring back down the pressure.if youve put a fixed resistor in it so no matter what the computer does the pressure reads the same then the computer would eventually cut out the engine because it would think there is a fault.the computer regulates rail pressure depending on the engine conditions.the system also has coolant and fuel tempurature senors.the fuel is passed through a cooler to keep a constant fuel tempurature.the airflow is one of the more important figures the engine needs to calculate fuel,boost pressure etc.it also looks at throttle position,engine speed,engine coolant temp,fuel temp,vehicle speed and ambient air pressure(normally around 1 bar)