C5 (X7) 1.6THP remapping

[The Ace]

From the very first moment that I drove my C5, I knew that this day would come. The rather hefty curb weight and the veeeeerrrrryyyyyy lazy drive-by-wire gas pedal, made me wonder if the car did indeed had 155 horsies under the bonnet. You see, I don't know how popular the THP is in the UK or France, but here in Greece it's probably the best selling engine for all the model it powers (PSA, Mini and BMW). And since it's a test-bed even for PSA/BMW -with all its versions and updates and mods- it's only logical that it would become one of the most favourable engines for various tuners.

So I finally took my C5 for a pimp-my-ride session (power-wise of course ) with probably the most knowledgable tuners when it comes to PSA and the THP in particular, the e-Tuners. Most of these guys have PSA and/or THP-powered cars, and they have been tinkering with these models and engines for many years now. They have various "Stages" remaps (from a basic Stage1 for 95RON, to custom turbo/intake/exhaust/internals Stage3), but since I have just a drop-in K&N and a freed-up precat, I opted for the Stage1+ (more aggresive timing and a bit more over- and constant- boost levels, since the car only ever sees 100RON in its tank ). It also removes or pushes back various cut-offs and thresholds, and -most importantly- makes the gas pedal a LOT more aggresive and responsive Of course, it's still a C5, and not a DS3R or a 308GTi, so the guys have prepared a "special" Stage1 with more appropriate settings for the heavier sedans/family cars.

We didn't have time for a proper dyno sessions, which will follow in the next couple of days, but some "before" and "after" Torque logs reveal how the critical figures have increased after the remap:

Before: Max boost: 0,77bar over, 0,5bar constant, 112WHP

After: Max boost: 1,18bar, 0,9bar constant, 135WHP

The car is now pretty nippy, it doesn't set the tarmac on fire, but it does get up and go more decisively, pushes with a more persuasive manner, and the torque/HP really feels like they either continue to rise or, at worst, stay on a higher plateau of performance. From various dynos performed on similar THP cars with the -more or less- similar Stage1+ remap, power output is expected to be around ~200HP and ~330-340NtM. Which of course remains to be verified on my car.

[Hell Razor5543]

Take a look through DHallworth posts. He had/has a car that needed some work, but one thing that made a huge difference (power wise) was getting it walnut blasted (walnut shells being softer than sand, so reduces the chance of damage), and this recovered 21BHP of the power (that had gone 'missing'). The company does need to have the right equipment and fittings, but other that that is is not difficult to get done.

EDIT; Found the thread;

http://www.frenchcarforum.co.uk/forum/v ... 7&start=45

[The Ace]

I know about the carbon deposits issue, I've had similar concerns for my previous car (CX7), so I have already performed a oxy-hydrogen clean-up, which didn't show any serious problems (exhaust remained fairly clean). However any cleaning or tune-up procedure only restores lost power, the remap is for gaining additional ponies

[Lighty]

I know about the carbon deposits issue, I've had similar concerns for my previous car (CX7), so I have already performed a oxy-hydrogen clean-up, which didn't show any serious problems (exhaust remained fairly clean). However any cleaning or tune-up procedure only restores lost power, the remap is for gaining additional ponies

In you 1st post, you suggested that the car should have 155 ponies, but even after a remap , you have nowhere near this.
I am sure this is why Hellrazor suggested the blasting.
In my experience most of these engines are "flat", so I am investigating some equipment to carry out the blasting myself.

[The Ace]

....but some "before" and "after" Torque logs reveal how the critical figures have increased after the remap:

Before: Max boost: 0,77bar over, 0,5bar constant, 112WHP

After: Max boost: 1,18bar, 0,9bar constant, 135WHP

As anyone who has performed similar logging sessions with Torque will testify, WHP measured with Torque is actually even lower than the WHP that you get from *any* dyno, since Torque measures the net horsepower that actually moves the vehicle, i.e. taking into account wind resistance, rolling resistance, road imperfections etc etc.

So actually it goes like this: Flywheel HP > Dyno WHP > Torque WHP

So the 112WHP that Torque measured while I was stock is actually pretty decent for the 156HP version of the THP, most of the guys that performed similar runs using Torque never measure above 110WHP

That's not to say that my engine is spotless, the oxyhydrogen I performed is far from 100% effective, but I'm *guessing* that my THP is rather clean....

[The Ace]

An update on this issue, since it combines both the remap, and intake valve carbon build-up cleaning, just so all you guys with DI engines know what's up with these engines.

So I've noticed that my C5 was particularly slow the last couple of months, and feared that something was wrong with the engine. So I decided to go for a dyno session to the tuners that had remapped my C5 last year, just to see what's going on. Apart from realizing that the dealer had installed the latest version of the stock maps (so I was back to the stock 156HP), we noticed terrible timing, reduced maximum HP and torque, and horrendous top-end losses. Since all the tell-tale signs of carbon build-up were there, I decided to do a decent soda blasting cleaning and then come back to re-dyno the car.



Just by cleaning the intake track and valves, and a new set of plugs (although the old ones didn't have any seriously obvious wear), maximum power jumped from 135 to 153HP, maximum torque from 22Kgm to 24,5Kgm, but its the top-end that seriously benefited from the cleaning, since the engine picked up almost 30HP at 6000rpm, and the increase of 2,5Kgm of torque is almost 4Kgm at the same rpm !!!!

So after taking care of the carbon build-up problem, we proceeded with the new remap (we had to take the ECU to the bench to decrypt the new stock maps), with the same goals as before. And after 3 reflashes and about 5 or 6 dyno runs, we ended up with 195HP and 30Kgm of torque. Car feels decently quick now, has more pull throughout the rpm range, continues to push hard even in the reds, and even has difficulty putting down all its power in 1st and 2nd!



So first conclusion: for those with THP engines, check your intake for build-up, you might be losing some horsies without even realising it. And second one: car should have been released like this, or at least have an "uprated" option from the dealer, since the THP engine has no trouble at these power levels.

The eTuners guys even produced a new article about intake valve cleaning, based on the results of my car
https://www.etuners.gr/citroen-c5-1-6-t ... ves-remap/

[The Ace]

And a proper dyno plot, with lines for before-after valve cleaning, and for the Stage1+ remap.

[DSNL]

What costs the soda blasting in the UK
I was quoted at my local Citroen dealer at nearly 1000 euros

[The Ace]

What costs the soda blasting in the UK
I was quoted at my local Citroen dealer at nearly 1000 euros

I'm in Greece, so don't really know what the blasting price is in the UK, however here its between 100 and 250€.

The amount quoted by the Citroen dealer probably refers to the "proper" cleaning of the intake and valves, which means opening up the intake manifold, removing everything, cleaning, reinstalling, and rebolting the manifold. For this process, at an authorised dealer, labor plus parts might indeed be around that figure, 900-1000€...