We finally got round to bolting a hybrid turbo to our Citroen DS3 1.6HDI 90.
Starting out at 90bhp things quickly evolved to 138bhp. You can read that blog post here: http://www.ultimatetuning.co.uk/citroen-ds3/
We weren’t content with the power output though. When you know the injectors are good for 180bhp and the only limiting factors are the turbo and clutch, why not push for the maximum that is safely achievable?! So that’s what we have been doing.
The standard turbo that comes on the car is a Mitsubishi TD02. With a turbine size of 29mm and compressor size of 40mm it’s capable of 130bhp @22psi. After making a few enquiries with companies who specialise in hybriding turbo’s it was clear to sea that the next logical step was to hybrid the original TD02, thus creating a bolt on upgrade.
So 4 days after commissioning the OEM TD02 to be hybrid’ we received it, now with a turbine size of 35.1mm and compressor size of 44mm. With only a 4mm increase in size on the compressor side it means that there isn’t any noticeable increase in lag, whilst the 21% increase in turbine size provides plenty of extra power. The perks of it being a hybrid means its a fairly simple process to install, taking roughly 3 hour including a full service.
As it was a first time for us, installing a hybrid on a DS3, the research and development process for mapping the new turbo in was crucial.
The first issue we came across was underboost at low RPM. With our Stage 1 tune we increase the boost through out the range, in doing so the ECU expects a certain air flow and pressure. Now with the Hybrid turbo having larger internals it doesn’t match what the ECU expects to see. After a few calculations and adaptions we had it sorted.
With that out of the way it was time to start increasing the power. At WOT (wide open throttle) between 2000-4000rpm we set the boost target to 1.5 Bar (21 PSI) as that is what the hybrid turbo is rated to and set the fuelling to 16:1 AFR. In doing so we came across 2 issue, the first being a lot of smoke, the second, at around 3200rpm a fuel rail fault code (loss of pressure). From this it’s clear that the HPFP (High Pressure Fuel Pump) was struggling to keep up with the demand the injectors were putting on the fuel rail. As the smoke wasn’t a big issue we concentrated on the rail pressure. We increased the duty on the LPFP so that the HPFP was able to supply enough fuel under pressure to keep the injectors saturated.
After more testing the fault still appeared but further up the rev range at just under 4000rpm. The limit of the HPFP had been reached. With this in mind we reined in the fuelling to 18:1 AFR this meant fuelling was no longer an issue and could cope all the way to the red line. It also meant that that there was a lot less smoke!
As you can see we have put the car through it’s paces, testing at Stelvio Pass to see how the turbo and car react in thinner air at altitude, V-Max tested on the German Autobahns, tracked it doing copious hot laps of the Nurburgring and more importantly we’ve took it through many cities and have done thousands of miles of standard driving. The reason we find that most important is, whats the point in having a car that’s only good under hard driving conditions. You want a car you can take to the shops effortlessly and is a pleasure to drive which the DS3 is, but if you want to put your foot down you know you can any time!
The full retail price of our Stage 2 kit which includes:
Airtec front mount intercooler
Hybrid Mitsubishi TDO2
Stage 2 Software