c5 2.2hdi inlet throttle butterfly question

[antonioneves]

The Turbo is a variable geometry device in that the amount of exhaust gas passing through the turbine is modulated by a sliding difuser driven by a vacuum driven servo, now if this sleeve was to seize then it could well be that the turbo will never deliver maximum boost. I am told that this is not an uncommon scenario on VAG diesels.
It would seem to me from such drawings I have that carbon build up could also limit the amount of movement even if not seized
This brings me to another thought, the Eolys injection results in a softer carbon which burns off at lower temperatures than in a non eolys injected system, this carbon passes through the turbo, I do wonder if cars that have had the DPF removed and as a result are creating harder carbon deposits which do not burn may be more susceptible to seizing or carbon build up on the variable geometry diffuser.

cachaciero

thanks for your reply. but correct me if I am wrong: if that was the case, then with vacuum disconnected it wouldnt produce more than with vacuum connected. and it does overboost fine, so...
i'm guessing something more "electronic". with lexia on, the Requested Boost is 1.2. so its not that the turbo cant do more, its just doing what's asked of it. swapping the EVs didnt made a difference.
short of new MAF... i'm running out of ideas.

[taffy]

so when dou get overboost?
is it intermitant?

[cachaciero]

You need to bear in mind that the Turbo characteristics / performance are mapped in the ECU if the actual Turbo pressure is above the mapped values then you will get an overboost warning, even theoretically at idle if the turbo was cable of producing significant boost at idle gas flow rates which it isn't.
Now with the vacuum disconnected and the Turbo not under control it is quite probably, almost certain, that the Turbo will be able to produce enough pressure in the intermediate rev range to trigger an overboost condition even if the variable geometry diffuser is stuck in a position that is not the maximum boost position i.e fully in.
So in simple terms it is I believe possible to get an overboost at intermediate revs while still having inadequate boost at higher revs due to a sticking variable geometry diffuser.

You said that the maximum pressure you are reading with the Lexia is 1.2 yet the mapping is calling for 1.5 ergo the problem is in the Turbo. or possibly the Electro Valve.
It would be a good idea to check the calibration of the inlet pressure sensor with an external pressure gauge just to make sure the ECU / Lexia is getting a correct
value.

Might also be worth taping into the vacuum line and check that there is no vacuum on the servo under those conditions when you expect maximum boost.


cachaciero

[taffy]

also maybe what about a leak in the pipe to map sensor (if it has one like xantia)

[antonioneves]

You need to bear in mind that the Turbo characteristics / performance are mapped in the ECU if the actual Turbo pressure is above the mapped values then you will get an overboost warning, even theoretically at idle if the turbo was cable of producing significant boost at idle gas flow rates which it isn't.
Now with the vacuum disconnected and the Turbo not under control it is quite probably, almost certain, that the Turbo will be able to produce enough pressure in the intermediate rev range to trigger an overboost condition even if the variable geometry diffuser is stuck in a position that is not the maximum boost position i.e fully in.
So in simple terms it is I believe possible to get an overboost at intermediate revs while still having inadequate boost at higher revs due to a sticking variable geometry diffuser.

You said that the maximum pressure you are reading with the Lexia is 1.2 yet the mapping is calling for 1.5 ergo the problem is in the Turbo. or possibly the Electro Valve.
It would be a good idea to check the calibration of the inlet pressure sensor with an external pressure gauge just to make sure the ECU / Lexia is getting a correct
value.

Might also be worth taping into the vacuum line and check that there is no vacuum on the servo under those conditions when you expect maximum boost.


cachaciero

thanks for the input and sorry for the late reply.

"maximum pressure you are reading with the Lexia is 1.2 yet the mapping is calling for 1.5 ergo the problem is in the Turbo. or possibly the Electro Valve."

Lexia shows 2 values, Requested pressure and measured pressure. both stay at 1.2... its not like it reads 1.4 and delivers 1.2. no: it only sees 1.2 as max requested pressure at all times.
so even thou I'm asking 1.4 in the remap, it only translates to 1.2 requested. theres a 1.2 limitation it appears on the ECU. need to find time to go to the mechanic again and remove that.
hopefully that will be it. turbo was checked by a turbo repair house, they said its fine, seals could be better but its not letting that much oil by so, no need to repair they said. the actuator works fine with a manual pressure pump and gauge. we can see the wategate moving freely...

When you say geometry diffuser are you refering to the wastegate actuator right? I can buy a repaired turbo, but these are not common turbos and its a bit more expensive. and would like a bit more clarification thats the issue before spending 600 euros...

The EV was swapped by the egr as they are identical. no difference.
no vacum leaks, that I am sure as we measured it manually with a pressure gauge by tapping into the inlet pressure sensor sensor plug.

i will put it on a dyno soon and see what numbers this gets me.
i tested 80-120 kmh with 4th and 5th gear and got me 8 and 10 seconds.
OEm specs are 8,8 and 11.7 so its definately better than stock.

one thing it bothers me thou: the stock map I had on the car made it feel like s**t. i never tested anything with it, but it was soooo much slower. it was probably doing less than 1 bar max pressure. and I guess this is the key to it. why? probably not a bad idea to put the stock map and check values. but i need time for that.

I need to take lexia out in a long stretch of highway and see the values for turbo pressure above 3900 as this is where it looses punch significantly. ok top speed of 200kmh roughly with close to 4100 Rpms seems ok. I dont expect a diesel engine to produce any power above 4000rpms, certainly not this generation of turbo diesel PSA engines... and read somewhere the 2.2 head doesnt flow well for more than 160hp anyway, regardless of what size turbo you put on it.

dont get me wrong, I'd just like to get to the bottom of this. but no data to compare and these are not common here in Portugal and certainly not for remaps.
but drives fine pulls well after 1500rpms, before that is dead but normal from what i read.
and i'm getting 7.5 litres average per 100km with normal driving, no special care with fuel savings and both short trips inside the city and highway at 140kmh+ so it seems very good for a 2.2.
a mate with a brand new 508 with the 1.6 e-hdi lump is getting 7.2...

thanks for all the help so far!

[taffy]

im pretty sure the turbo is alot less effective after 4000rpm as standard its mainly for 1500-4000rpm

[antonioneves]

i think we can call it a day:

did a dyno and another remap and got 169bhp and 385NM which is 284 ft lb of torque. fair enough for me. happy as a clam
was doing 150bhp and 367Nm before but now the torque is much smoother through the rev range and doesnt drop abruptly so pulls much stronger. before anyone asks, it now keeps going past 200kmh but I didnt get more open road and I am interested in that anymore. car is ok as fair as i am concerned. I was just curious to see the potential.

not sure how long the turbo and clutch will last, but not worried as I am carefull with the right foot anyway and never press down before 2000rpms. no need for it, plenty of torque with just a slight press.

will post the dyno plot soon: before vs after. no comparation with stock sadly.

[antonioneves]

[taffy]

i bet that feels nice!!!

[waynedance]

I have been offered a remap on mine for free (chap at work) but not sure what to do.

Not bothered about speed, he said could map for better mpg and a little speed. Do not want to mess up the car.

Your thoughts please!!

Sent from my GT-I9505 using Tapatalk

[antonioneves]

I have been offered a remap on mine for free (chap at work) but not sure what to do.

Not bothered about speed, he said could map for better mpg and a little speed. Do not want to mess up the car.

Your thoughts please!!

Sent from my GT-I9505 using Tapatalk

i'd choose very carefull who will be doing any changes to the ECU. cheap = problems.

before you do anything make sure your turbo, clutch, flywheel and injectors are ok. and bear in mind the clutch and dual mass flywheel are the first ones to go if the remap pulls strong from below 2000rpms. they're not cheap to replace nor is the turbo. and you have to remove the FAP before doing a remap or is just a matter of time to get into problems and you wont be able to take the full benefits of it.

MPG gets better, mine's doing 7.5l per 100km and before with the same utilization (city traffic) was 9...

[waynedance]

Car runs sweet at the moment the clutch and duel mass were renewed approx 10k ago. Think I will leave well alone and leave factory standard.

Sent from my GT-I9505 using Tapatalk

[antonioneves]

dont get me wrong, I had all my cars over the years remmaped, and the only time I had an issue was with a dual mass flywheel on a Leon mkII Tdi. but in all fairness i abused it over and over...

well done and with proper care, it affects little any car normal components lifetime.

[KP]

IIRC you have blanked the EGR.


Therefore you can reduce lag by tidying up the inlet tract.

If it were me i'd decide if i want to keep the chargecooler or the the intercooler and ditch the other one and block off the pipes for it

The chargecooler has the advantage in cold weather of providing warmth to the inlet air to help speed up engine warming but can also take a lot of heat out of the inlet air when needed and dump it into the system. This is generally considered as being a cheap CC system as it should have its own radiator and pump to dump the heat from.

The intercooler in the 2.2 C5 isn't a massive size so could struggle on hotter days but if there was good airflow provided to it i cant see why it couldn't do the required job 99% of the time.

The other option for more power and less lag is Aquamist. But then you'd need to look at soe customer silicone to run the pipework over the top of the engine and then you may even get spool up at 1200rpm!

[antonioneves]

IIRC you have blanked the EGR.


Therefore you can reduce lag by tidying up the inlet tract.

If it were me i'd decide if i want to keep the chargecooler or the the intercooler and ditch the other one and block off the pipes for it

The chargecooler has the advantage in cold weather of providing warmth to the inlet air to help speed up engine warming but can also take a lot of heat out of the inlet air when needed and dump it into the system. This is generally considered as being a cheap CC system as it should have its own radiator and pump to dump the heat from.

The intercooler in the 2.2 C5 isn't a massive size so could struggle on hotter days but if there was good airflow provided to it i cant see why it couldn't do the required job 99% of the time.

The other option for more power and less lag is Aquamist. But then you'd need to look at soe customer silicone to run the pipework over the top of the engine and then you may even get spool up at 1200rpm!

in my country we never get below 0 temperatures, lowest is around 10-8 and thats cold around here so the chargecooler doesnt make that much difference. agree it takes a little longer to get up to normal temperature now, but we are talking 5-7 minutes so i dont see a massive difference.

ditching the pipework is not an option because of the work it will require and the fact someday I'll sell the car and I'm sure that would complicate things

as for the size of the IC, not sure if warmer weather countries like mine dont have a bigger one than in other colder countries. never monitored intake temperatures to be honest but the remap was conservative to lower boost with higher intake temperatures. that much i do know.

aquamist is not an option for the cost and hassle.

been thinking about something it may help, let me try to explain:
when I removed the inside of the FAP/Cat housing it created a huge "air chamber" in the exhaust pipe. the diameter coming from the engine side is small then opens for the FAP/Cat and then gets reduced again. I got a very weird whistle sound coming from the backbox at idle since I removed the FAP guts.
someone told this creates a storm/swirl effect and the exhaust gases will not flow as fast as they need to look for the exit, so putting a straigth-through pipe inside the FAP housing connecting the cat and the other side of the FAP would help with spool up. only problem with that is that I have to exhaust temp/pressure probes in the engine side of the FAP/CAT housing that will not get any Reading if i put the pipework inside. which i think its ok because those probes are used for FAP regen and thats not there (removed from ECU) anymore... that and I need to destroy the cat ceramic guts.

thoughts?

http://www.citroenet.org.uk/passenger-c ... tech3.html" onclick="window.open(this.href);return false;
pic of the fap/cat housing at the bottom of the page, items 6 and 7.