Advantages to a 04L 906 054 Rail Pressure Sensor over stock

[Ron A]

Hi, I have a 2014 Golf TDI with the 2.0L CJAA engine. Installed is a Stage 2 Tunezilla tune.
The tune has an optional 04L906 054 2200 bar option, which I didn't choose because I don't know exactly what it does.

Searching through the threads using "04L906054" as the search, there was some mention of it in conjunction with another mod, but no specifics.
I did ask Tunezulla, but received an answer I didn't understand.

I've priced them out, and they are probably one of the cheapest parts on the vehicle.
But what exactly does it do in conjunction with the Stage 2 tune with that option checked?
Will it produce a HP or 2, or are the gains more significant like improved drivability.
Also, what car was this used in as it appears to be an OEM PN?

TIA, Ron

 

[oilhammer]

The CJAA is already running a very high rail pressure. Asking for more seems like a recipe to shorten the life of the already fragile HPFP.

 

[KERMA]

sounds like a question for the customer service folks at that company.

 

[Ron A]

sounds like a question for the customer service folks at that company.

Tunezilla has been extremely helpful in the past.
I queried them long after I purchased and installed their product; and they responded that the pressure sensor needs to match the tune.

I find that product focused forums are the best place to ask more detailed questions, so I posted it here - TDI Forum - Power Enhancements.

There are a lot of extremely knowledgeable people in this Club who know exactly what the difference between a Stock 03L906054 and a 04L906054 is, and why changing to the 04L906054 (with additional tuning) would be desirable. - I just couldn't find the answer by searching for it -

Oilhammer responded that the HPFP (High Pressure Fuel Pump?) might be adversely affected, so can I assume changing this sensor allows the fuel pressure going to the injectors to increase, which would allow more fuel to be delivered to the cylinders at WOT and result in an increase of power?

 

[arazvan2002]

04L906054 it's a rail pressure sensor. If you want to see spikes or use pressure bigger than the limit of the original sensor, you need the bigger sensor installed and calibrated acordingly in the software. It's the same thing with boost sensor, when you install bigger one to use more boost.

 

[Ron A]

Maybe I wrote the original question wrong as I am looking for detailed info not generalities or references back to my Tune company ::|

I have a 2014 Golf with a Tunezilla Stage 2 Tune and aside from the ECU tune, the sensors are all stock.
What is the difference in BAR between the Stock 03L... sensor and the 04L.. sensor, and what vehicle does a 04L... sensor come stock in?
Is there a chart?
Assuming the software adjustments are made to take advantage of the 04L Sensor, what kind of gain am I looking at?

azazvan... you mentioned a boost sensor. Any specifics?

 

[P2B]

There are a lot of extremely knowledgeable people in this Club who know exactly what the difference between a Stock 03L906054 and a 04L906054 is, and why changing to the 04L906054 (with additional tuning) would be desirable. - I just couldn't find the answer by searching for it -

According to this Pierburg data sheet, and assuming the VW to Pierburg part number cross references I found are correct, the stock 03L906054 pressure sensor is capable of measuring 0-2000 bar while the 04L906054 can measure 0-2200 bar.

The transfer function (pressure to voltage formula) differs between the two sensors, so the ECU software would need to know which one was installed in order to accurately measure fuel rail pressure.

In theory the ECU software could command rail pressures in excess of 2000 bar, and still be able to measure them, if the 04L906054 sensor were installed - but whether it would do so, and what effect that would have on performance, is something only the tuner could answer.

 

[Ron A]

According to this Pierburg data sheet, and assuming the VW to Pierburg part number cross references I found are correct, the stock 03L906054 pressure sensor is capable of measuring 0-2000 bar while the 04L906054 can measure 0-2200 bar.

The transfer function (pressure to voltage formula) differs between the two sensors, so the ECU software would need to know which one was installed in order to accurately measure fuel rail pressure.

In theory the ECU software could command rail pressures in excess of 2000 bar, and still be able to measure them, if the 04L906054 sensor were installed - but whether it would do so, and what effect that would have on performance, is something only the tuner could answer.

TU!
So the difference between the stock 03L sensor and the 04L sensor is 200 BAR.
a 10% difference in upper readings if fairly significant, and my Tuner will support that.

I see your point about the performance figures. I use a 1/4mile dyno, but they don't open till April.
I can bring the LT try it one way, then the other and see what transpires.

 

[lemoncurd]

never ask malone why they dont opt for the 2700bar sensor
(they cant figure out how to actually tune for it, so they rather just pin the pressure to above the max read of the sensor)

 

[Ron A]

never ask malone why they dont opt for the 2700bar sensor
(they cant figure out how to actually tune for it, so they rather just pin the pressure to above the max read of the sensor)

Hopefully I won't get too involved in the high dollar/high HP mods as I am on fixed income

So far I haven't gotten too crazy. Muffler delete (18lbs), and the Stage 2 tune. If this sensor helps me pick up power I may have left on the table, I'll be happy.

Sort of OT, but has anyone put cooling fans on the intercooler?

 

[oilhammer]

Sort of OT, but has anyone put cooling fans on the intercooler?

Yep, the folks that built your car did.

 

[Ron A]

Yep, the folks that built your car did.

Where?
All I see are the 2 stock cooling fans that cool the IC/AC Condenser/Radiator and are turned on based on AC or Cooling demand (engine temp).

I know of no independent fan for the IC.

 

[p.e.fletcher]

Where?
All I see are the 2 stock cooling fans that cool the IC/AC Condenser/Radiator and are turned on based on AC or Cooling demand (engine temp).

I know of no independent fan for the IC.

So you’re obviously aware the IC is sandwiched between the AC condenser and radiator with the 2 stock fans covering the back side of the radiator. Where are you going to add more fans and why would you even want to go to the trouble? If heat soak is an issue for you, you’d be better off just getting a bigger IC.

 

[Ron A]

So you’re obviously aware the IC is sandwiched between the AC condenser and radiator with the 2 stock fans covering the back side of the radiator. Where are you going to add more fans and why would you even want to go to the trouble? If heat soak is an issue for you, you’d be better off just getting a bigger IC.

No, sorry, I was blissfully unaware VW did that.

As to why:
The Golf is my AutoX car.
Often, I will start the Golf and let it come up to temp before a run; if I don't I will get inconsistent engine performance.
There are also the hot days where you get back from a run, let it run a bit to stabilize the temps and then shut it down between runs. On those days I worry about heat soak as the fans are off and no air is moving past the IC. It seemed to me that adding a fan would help. But if it's impractical, maybe manually overriding the stock fan would be a solution.

I don't think your solution, though it makes sense, will work for my situation because of how points are assessed by modification.
An IC upgrade costs 3 points, and IC add is 4 points. A fan would have cost zero points.

I suppose another possibility is to install a spray system to cool the condenser/IC/Radiator. Though I would worry about leaving puddles.

 

[oilhammer]

If the intercooler isn't doing it's job, the ECU will know, and it'll flag a DTC for "intercooler efficiency", which I've never, ever, EVER, seen or heard of happening on any BRM, CBEA, or CJAA, even on ones that have been modded and are running far more boost and taxing the heat exchange abilities of these beyond the stock level.

Conversely, in stock form, they're actually more likely to work TOO well, which is why so many CBEAs and CJAAs suffer from intercooler icing and excess condensation which can cause hard starts, no starts, and even hydrolocking and in extreme cases bent rods.

 

[p.e.fletcher]

No, sorry, I was blissfully unaware VW did that.

As to why:
The Golf is my AutoX car.
Often, I will start the Golf and let it come up to temp before a run; if I don't I will get inconsistent engine performance.
There are also the hot days where you get back from a run, let it run a bit to stabilize the temps and then shut it down between runs. On those days I worry about heat soak as the fans are off and no air is moving past the IC. It seemed to me that adding a fan would help. But if it's impractical, maybe manually overriding the stock fan would be a solution.

I don't think your solution, though it makes sense, will work for my situation because of how points are assessed by modification.
An IC upgrade costs 3 points, and IC add is 4 points. A fan would have cost zero points.

I suppose another possibility is to install a spray system to cool the condenser/IC/Radiator. Though I would worry about leaving puddles.

Gotcha, so are you allowed to simply have an external fan setup on the ground in front between runs without being penalized? That could help and would be pretty easy.

 

[oilhammer]

The dry ice jammed into places was always a trick, LOL.

 

[lemoncurd]

which I've never, ever, EVER, seen or heard of happening on any BRM, CBEA, or CJAA, even on ones that have been modded and are running far more boost and taxing the heat exchange abilities of these beyond the stock level

uhm, hello! checking in here

ive had this DTC pop before lol. "stage 4" GTB2266 turbo with stock IC. happened down in the armpit of florida, >100f outside with the car fully loaded. i could try to find the VCDS print out somewhere. i saved it because the reported temp was incredibly high!

 

[oilhammer]

OK, now I've heard of one time... on a modded car... in Death's Waiting Room.

Thanks for sharing, though, because it does prove the ECU's logic works, and the stock intercooler on a stock car (which is what it was designed for) is pretty darn efficient.

 

[KERMA]

This is going to sound crazy, but when I was running bracket races with my 2001 Golf, between runs I would keep the engine idling with the A/C on. This keeps the fans activated and the engine temperature stays very stable, even on triple digit days. I would even do passes with the A/C on lol. You can open the hood while running the engine with A/C on, if you want to be extra sure about heat soak, which wasn't such a big deal in an ALH anyway. But CJAA is a whole different animal. There's some derate stuff that triggers in a CJAA with heat. Especially if you are already flirting with EGT issues.

 

[TurboABA]

For AutoX you'd benefit from W2A setup... or a custom icebox setup with sufficient volume to sustain a typical run.

 

[Ron A]

This is going to sound crazy, ... I would keep the engine idling with the A/C on. This keeps the fans activated and the engine temperature stays very stable, even on triple digit days. ...But CJAA is a whole different animal. There's some derate stuff that triggers in a CJAA with heat. Especially if you are already flirting with EGT issues.

Not crazy really. I have noticed that keeps the engines performance consistent, and on those 100+ days I have AC
I honestly couldn't speak on EGTs I'm sure the ECU measures it ; I could see if Racer Renderer is able to able to monitor and output that figure.

When I've tried bracket racing with a manual, I have never managed to be consistent at the line; so I stuck with an automatic - so great job!

Gotcha, so are you allowed to simply have an external fan setup on the ground in front between runs without being penalized? That could help and would be pretty easy.

Yes, no points are assessed for external fan in the pits/grid.
I'll give it some thought; I've also seen folks use garden sprayer bottles between runs.

For AutoX you'd benefit from W2A setup... or a custom icebox setup with sufficient volume to sustain a typical run.

Interesting thought!
I'm almost certain a W2A setup would cost me the same points as an additional IC (4 points) in conjunction to adding to the sprung weight of the vehicle up front. Perhaps when I've given up on the premise of this being a low cost hobby

 

[Matt-98AHU]

The 2200 BAR sensor is really only for more extreme tunes.

If you're not planning on going past your current stage 2 tune (which would require at a minimum, a bigger turbo) you don't have a need for the higher reading rail pressure sensor.

Also, using the higher reading sensor means you *need* to re-tune it simply for the ECU to be correctly calibrated for the signal that sensor puts out (much like how you would for a higher reading MAP sensor than stock...).

So, basic idea, if you aren't planning on upgrading the car to the point where you would need to have those higher rail pressures for a more extreme hardware and tune setup, I would just keep the stock sensor...