Survey: Tuning TDI engines? Experiences!

Hi. I was just thinking that with 811 registered users, there must be a lot of different tuning options and opinions represented.
What kind of tuning have you done (e.g., cold air intake, turbocharger, chip tuning, or other)?
What positive and negative experiences have you had?
What was the performance like? How about the durability?
I'd be interested in a brief report from anyone who has modified or customized something. It's definitely interesting to gather all of this information in one topic.


I used to have a Golf 3 1Z with 90 horsepower. The engine was chipped after 110,000 kilometers, and I estimate it produced around 120 horsepower. At 197,000 kilometers, the engine failed. There was a hole in the piston. I think the chip played a part in it.
I now have an AFN. Sure, here's the translation:

'Still original.'

I replaced the gears for the 5th gear in my Golf 4 (81kW TDI) with ones that have a longer ratio. I guess that kind of thing could also be considered tuning, *g*.
Performance is still original.
The speedometer now indicates a top speed of 210 km/h, which is the same as before, but now at 4100 RPM, whereas previously it was around 4500 RPM.
It no longer revs past 4500 RPM. However, subjectively, it feels better at speeds of 100-150 km/h. At 150 km/h, the engine speed is just over 3000 RPM. Consequently, it feels sluggish both before and after that speed. Furthermore, the engine noise is much less intrusive on the highway, and at a brisk pace, the fuel consumption is significantly more reasonable!
On March 13th, I'm getting a ******** chip implanted. Primarily because of the 2-year warranty you get, but of course also with the hope that it will have a better acceleration again in the 5th year .

kenny wrote:

I have the gears for the 5th speed in my Golf 4 with an 81kW TDI engine. Gang replaced with a longer translation.

Hey, that sounds interesting. How much did you pay for that?



I had my A3 TDI AGR with 66 kW tuned by Wetter@uer at 85,000 km. It's the third stage of tuning, which results in 125 horsepower. And yes, it really does have that power. It accelerates like a rocket. Currently driving with 135,000 km on the odometer and no problems.
"Recently had an exhaust gas recirculation (EGR) system installed - noticeably more responsive, especially when starting from a standstill at traffic lights ;o)"
Next up is a catback exhaust system from Supersprint, which I already have at home.
Experiences with it will be shared later.

Hi.

I have an (registered) car charger, which can be activated when in use.
After adjusting the settings according to the DZR (German tuning regulation), the power output is approximately 135 hp, although there is some initial "rubbing" or vibration between 1500 and 2000 rpm (possibly due to the dual-mass flywheel).

Otherwise, the engine doesn't exhibit any of the common problems associated with turbochargers (e.g., surging at low load), and is therefore, in my opinion, highly recommended.

However, due to material limitations, I almost always drive with the boost disabled.

The injection timing has been advanced by approximately 1 degree using VAGCOM.

Hi,

I have a switchable 10-cent tuning module with diodes, installed at approximately 50,000 km, and now I have 75,000 km on it. So far, I haven't experienced much negative. The increase in power is significant, but I think it's hard to accurately gauge. Unfortunately, my clutch is struggling a lot, and I definitely need a reinforced solution soon (I would be very interested in information about that). I deactivated the EGR system the day after I bought the car, because in my previous diesel, I saw firsthand what damage it can cause when the intake manifold is open at around 160,000 km. And the long 5th gear... I also installed a gangway, and I have to say it's very comfortable on the track.

@tagessuppe: 1. Gear 02A311158R for €98.00.
"Gear 02A311361M, priced at €62.80 each, plus shipping." VAT.
I did the conversion myself, but you'll need an impact wrench and a suitable three-arm puller for the synchronizer housing, and of course, some know-how.

Best regards, Frank.

I have a Passat Variant, model year 1999, with an AFN engine and 110 horsepower.

I started about 3 years ago with a tuning chip that boosted the power to around 130 horsepower - it wasn't bad, very 'practical for everyday use.'
In late 2002, I installed the larger injectors, and then it started to misfire because the tuning chip only increased the fuel injection amount.
So, I had a custom chip made to switch between standard mode (well, not quite standard, more like 125 horsepower?) and a 'stage 3' mode (1.3 - 1.44 bar).
The boost at the high boost pressure is immense up to 2500 RPM.
Unfortunately, the intake air gets very warm very quickly (the cooling system doesn't keep up), which means the fun doesn't last very long (it then becomes noticeably 'slower' ).
Next up is the 130 horsepower PD turbo, and possibly a larger intercooler and a larger intake manifold with an EGR bypass.

Best regards, Jens.

Not bad, what has already accumulated. But surely, this can't be all there is.
Does anyone have experience with other turbochargers or larger intercoolers?

@Red I
Not bad! What exactly is a custom chip? How does it differ from a regular chip? Did you drive the 1.44 bar with a standard turbocharger and the original engine? Is that the turbocharger doing that? What about a larger intercooler and the original turbocharger? It would actually make a difference.

There's a boost pressure control system in place. There's definitely a sensor somewhere that allows the EDC (Electronic Diesel Control) to know the current pressure. Accordingly, it then adjusts the pressure up or down to the target value. This means that even with a larger turbocharger, you might experience stronger pressure spikes because the turbocharger might respond faster or more aggressively, and the control system is intentionally designed to be slow. As stated in the technical article about the boost pressure control system, a larger turbocharger shouldn't actually produce higher boost pressure, because it's always regulated to the target value. Or am I wrong?
The same principle applies to a larger intercooler; it only makes sense if more air is flowing through it, which requires a higher boost pressure. So, if you're planning extreme tuning modifications, you'll need a larger turbocharger, a larger intercooler, and a chip tuning solution that allows for increased boost pressure.

However, the stability might increase if you, for example, use a 'standard' chip tuning and still use a larger turbocharger, but operate it within its specifications with the increased boost pressure (as might be the case with the standard turbocharger).

However, simply increasing the fuel pressure doesn't necessarily provide much benefit. It also requires more fuel, and the amount that can be injected is limited (only a certain amount of fuel can pass through the injectors per unit of time, and injection can only occur within a specific time window). So, there are also modifications to the fuel injection system.

So, if you install a larger turbocharger and intercooler without expecting much, for example, to be on the 'safe' side when chip tuning, that's definitely possible. But is it worth it?

But if you really want a lot more power, you might be better off selling your car and buying one with a more powerful engine. It probably won't be much more expensive.

correct me if I'm talking nonsense

Hello Kenny,

I'm not a 'specialist' either, and I can only relay what my tuner tells me, as well as what I've learned from various forums and personal experience.


I commented on your post.
There's a boost pressure control system in place. There's definitely a sensor somewhere that allows the EDC (Electronic Diesel Control) to know the current pressure. Accordingly, it then adjusts the pressure up or down to the target value. This means that even with a larger turbocharger, you might experience stronger pressure spikes because the turbocharger might respond faster or more aggressively, and the control system is intentionally designed to be slow. As stated in the technical article about the boost pressure control system, a larger turbocharger shouldn't actually produce higher boost pressure, because it's always regulated to the target value. Or am I wrong?

-> No, you're right - that's not what it's about.
The original charger is not designed for sustained pressure, and it cannot handle it for long. Furthermore, the turbo's regulator seals at 1.5 bar, which was observed during overboost. Therefore, a larger turbo is being installed, which draws in more air (due to differently shaped impeller blades), and the regulator will then engage at 1.7 bar. This turbocharger is actually used as standard equipment in the PD 150PS engine, running at a boost pressure of 1.5 bar.

The same principle applies to a larger intercooler; it only makes sense if more air is flowing through it, which requires a higher boost pressure. So, when you're implementing extreme tuning modifications, you'll need a larger turbocharger, a larger intercooler, and a chip tuning solution that allows for higher boost pressure.
-> No, I need a larger intercooler to cool the existing air more effectively, not to force more air in (which wouldn't work anyway, even with a larger intercooler).

However, the stability might increase if you, for example, use a 'normal' chip tuning and still use a larger turbocharger, which you don't operate outside of its specifications with the higher boost pressure (as might be the case with the standard turbocharger).
-> When it comes to durability, I don't think we need to discuss it when we're doing a tuning job like this, do we? I am aware of the high risk. A thicker cylinder head gasket would help, as it would reduce the compression ratio.
But that's why I have a switchable chip that allows me to temporarily increase the power to 150-160 horsepower.


However, simply increasing the fuel pressure doesn't necessarily provide much benefit. It also requires more fuel, and the amount that can be injected is limited (only a certain amount of fuel can pass through the injectors per unit of time, and injection can only occur within a specific time window). So, there are also modifications to the fuel injection system.

-> That's exactly what the custom chip does! The fuel injection pump and other components also handle those functions. You probably have to modify something to get around 180 horsepower.

So, if you install a larger turbocharger and intercooler without expecting much, for example, to be on the 'safe' side when chip tuning, that's definitely possible. But is it worth it?!
-> I'm not buying the parts from VW, and I'm having a workshop install them, so the costs are kept within reasonable limits.

But if you really want a lot more power, you might be better off selling your car and buying one with a more powerful engine. It probably won't be much more expensive...
--> probably not! it always depends on what you've already installed. the alternative would be a Passat with a 130 hp PD engine and a chip.

'@Golfmann, yes, I was running the original turbocharger at 1.44 bar.'

Best regards, Jens.

no, I need a larger intercooler to cool the existing air more effectively, not to force more air (which doesn't work, only with a larger intercooler.

You're getting more airflow, and your turbocharger is boosting to 1.44 bar, as you mentioned! What I meant to say was: When the amount of air increases significantly, the liquid cooler can no longer keep up with the cooling demand.

I'm driving an Aharan AFN with a 'custom chip,' larger injectors, 220 bar fuel injection pressure (190 bar stock), a modified VNT-17 turbocharger, a different intake manifold, an AGR bypass pipe, and a CDA airbox. The power is immense. I'm running a maximum boost pressure of 1.5 bar and a sustained boost pressure of 1.3 bar.
I've already outsmarted quite a few large gasoline engines with this. The standard 1.8T has no chance...

The topic is interesting. You usually only hear about everyday things in this forum. And often: 'The operating license will expire.' It's clear now.
I was planning to increase the power of my engine to around 150 horsepower. I've already read a lot in forums about this topic.
'Question: If I install a second Golf intercooler on the right side of an engine control unit (ECU) that has been tuned with a chip (and this intercooler is supposedly very efficient), shouldn't the ECU compensate for the pressure loss caused by the intercooler? Up to a certain point, this should work. What benefits would the second intercooler, in conjunction with the chip, provide?' Does an *** chip increase the turbocharger boost pressure?

@golfmann
It depends, but the intercooler cools down the airflow that has been compressed by the turbocharger. By increasing the boost pressure during tuning, a larger mass of air, with a higher temperature due to increased compression, is forced by the turbocharger towards the cylinders.

'Is the old intercooler oversized for the standard engine? Does it have enough capacity, meaning can it still effectively cool the increased and hotter air mass that results from the higher boost pressure after the tuning?'

In this case, a second (or higher) LLK (likely referring to a specific metric or value) can even be negative. The performance gain is either nonexistent or very minimal.
Since the 2nd... However, if the intercooler is located further away from the turbocharger, requiring a larger volume of air to be filled, the response time will be slower.
Installing a heat sink with the same volume (thus, no degradation in thermal response) but with a higher efficiency (better heat dissipation) is probably not worthwhile due to the unfavorable cost-benefit ratio.

If the existing liquid cooling system (LLK) was already operating at its limit, it may not be able to effectively cool the increased and hotter air mass. A second (larger or more efficient) LLK would be beneficial because its larger surface area can dissipate more energy, allowing it to cool a larger airflow to a lower temperature. This, in turn, allows for a greater volume of air in the cylinder, which leads to better combustion and room for further increasing the fuel injection, resulting in a power gain.

Regards,
Michael.

Thank you for the detailed description. So, the responsiveness suffers, which is actually what makes the TDI so great.

@rotes I:
Where can I get a custom chip? And what is the cost? It's not bad that you can turn it off; I had the same feature on my power box.

Hi!

Golfmann wrote:

Where can I get a custom chip? And what does it cost? It's not bad that you can turn it off; I had the same thing with my power box.

With a good tuner, you'll get the "custom" chip. There are many dealers who only sell chips, and of course, they can't offer something like that. Disabling the chip doesn't make sense. If you want to use less power, you can simply ease off the accelerator. That will have the same effect.

@Ulf
Why do you usually turn off your power box? Does it make a difference (with the car's computer/control unit) whether you give less gas with the control unit active compared to giving more gas with the control unit deactivated?

Best regards,
Uwe

Uwe wrote:

@Ulf Why do you usually turn off your power box? Does it make a difference (with the box) whether you give less gas with the box active compared to giving more gas with the box deactivated?

Hi Uwe,

If I'm driving in the boost range (boost pressure > approximately 0.3 bar), it makes a difference.

For example, the engine control unit (ECU) might calculate that 20 mg of fuel is being injected per cycle and adjust the injection timing to 8° before top dead center (BTDC).
However, 24 mg is actually injected, and the injection start time is set to 10° vOT (volumetric overlap timing) for optimal effectiveness and minimal consumption, as indicated in the characteristic curve.
So, I'm going to adjust the application timing by 2° based on the actual amount of product used.

However, if I administer 24 mg of gas without using a dosing box, the injection start time is also set to 10° (all values are arbitrarily chosen).

Okay

Furthermore, I only want to utilize the extra power or torque that increases wear and tear when it's actually needed.
But at least my accelerator pedal doesn't have a built-in speed limiter at 81 kW / 235 Nm (nominal).