Afternoon everyone,

I have a Citroen Xsara Picasso with the 2.0HDI motor. From what i have read etc i am led to believe that this is the same engine as used in various peugeots etc including the 406 which i have seen some VERY impressive results from on this forum! I am not looking for major power increases or miracles from this car as its a daily driver and familymobile however i think the standard flat, lazy sluggish 90bhp motor could definately do with a tweak or two to help improve everything including and most importantly the economy.
I cannot see a DPF and i think these are only included on the 1.6 110bhp HDI so i dont have that to worry about and i also think that the boost pressure is mechanically controlled by the actuator and not ECU controlled (Please correct me if i am wrong) meaning that i should only have to find and alter the smoke & torque limiter maps and the fuel pressure, duration and drivers wish maps.
I will also be trying to turn off the EGR valve and blank it off and remove the CAT too.

Is there anything on these motors that i should really be aware of before beginning to mess with the maps etc. I.e is there anything really fragile that must remain standard? and can anyone point me in the right direction for the best starting point for an economy tune.

Thanks

I may as well add what i have managed to find out so far....

The recommended max boost to run on these motors with the std turbo is 1.35bar although that is generally not recommended without an intercooler.
The boost is mechanically controlled by the actuator and the base engine is used on a HUGE range of different cars from the Peugeot 206 through to the Mondeo TDCI.
The 2.0HDI as fitted to my 2000 Xsara Picasso does not have a DPF or FAP, and the CAT can be removed without issue which will result in reduced EGT and lower back pressure.

Yep, 1.35bar/20psi is ok, but the odd spike to 21/22 psi is ok for the turbo. But ANY boost increase ideally needs an intercooler!

I tuned my 306 HDi 90 to 22psi on a GT15 and that has run with an intercooler for 4 yrs/40,000 miles+ without issues from what the subsequent owners have said...

My brother ran a HDi k03s on a modified manifold on his 1.9 Td 306 at 24psi and that ran for years like that, driven very hard too haha...


EGR can often be unplugged at the solenoid on this engine, but some may log a visible fault code, while others just leave one for diagnostic equipment to see when you read the faults.

There are switches which you can find to do the same job.



The HDi90 has wastegate control for the turbo from compressor feed only. The HDi110 has ECU boost control via solenoid signal.

I'm not sure if some Xsara had the HDi110 or not?!



You are right, there are not many maps to tweak for a 'basic' remap on this engine to the levels that are safe without an intercooler.

Obviously you can tweak more maps to improve details, but the general calibrations to 120-130bhp are all well made, it's just opening up the limiters mostly. Smoke limiter and torque limiter shape give the character and delivery. You don't really need to touch rail pressure or SOI for 120-130bhp.

There may be some steady-state economy improvements to be found balancing rail pressure and SOI tweaks at cruise speed rpm's, but it's not quite as easy as people make out. I've bought and tested many so called 'techniques' or +20% economy remaps and seen nothing of the sort.
Usually the best economy gains come from transient benefits, ie, the driveability enhancement of more torque makes the driving style more economical.



120bhp/205lbft is clean and safe, 130bhp/210lbft is also clean and safe with exhaust mods on a really good well serviced engine.

With an intercooler and pushing the boost hard, and with a good exhaust, then I've seen 295lbft and 162bhp peak figures, though the k03 tend to make less torque, and the gt15 less power... maybe 10lbft/10bhp... when you really push fuelling hard at higher rpm it's the super small exhaust turbine restriction that costs you.
I've seen a remap on a car make about 153bhp, and then with a hybrid turbo swap only suddenly make 173bhp... and I'm certain most of that gain is from the reduced back pressure, as much as it is from slightly cooler charge air temps.

I think k03 is exclusive to HDi110, wheras HDi90 may have GT15 or k03.



Assuming your engine is in good order/looked after then bar the clutch, exhaust and intercooler, there is nothing to stop you getting 150bhp/275lbft easily... but obviously adding the clutch/exhaust/intercooler and then doing the more in-depth mapping is less easy :D

Dave

Also, you can do 21psi and be careful on the temp. IQ limiters. Power will go down as the engine heats up... a failsafe if you don't have intercooler.