Here is the ultimate guide to preparing your 1.6 TDI CAY, all versions included.
No other guide available on the internet offers such a comprehensive level of detail.
All the modifications presented here are based on our own experience and achievements.
The values given are based on actual measurements taken on both our own vehicles and those of our customers.
Turbocharger
Several options are available to you, depending on your objectives and budget.
The power output achieved depends mainly on the condition of your injection system, an essential component that tends to lose efficiency over time and with mileage.
The values listed below are therefore indicative and may vary depending on the overall condition of your engine and its peripheral components.
| Turbo | Technology type / Shaft support | Advantages | Disadvantages | Max Power |
|---|---|---|---|---|
| Stock | Hydrodynamic bearing | Good spool at low RPM, responsive | Limited at high RPM, low airflow, smoke above 160 hp | 150–160 hp |
| Stock + MFS* | Hydrodynamic bearing, MFS wheel | Good spool, better airflow, simple installation | Lower pressures, higher EGT, rebalancing needed | 170–190 hp |
| 1549 (stock) | Hydrodynamic bearing | Reliable OEM part, higher pressures possible, easy replacement | Limited gains without other modifications | 180–210 hp |
| 1549 / 1556 MFS* | Hydrodynamic bearing, MFS wheel | Slightly faster spool, more airflow | Higher EGT, slightly lower pressures | 210–240 hp |
| 1752 | Ceramic bearings | Excellent spool, handles high EGT, perfect for daily/circuit use, replaceable CHRA | Higher cost | 240–260 hp |
| 1756 | Ceramic bearings | Ideal for high-RPM runs, good power potential | Slower spool at low RPM, less suited for daily use, expensive | 260–280 hp |
| 2060 | Hydrodynamic bearing | Very high theoretical potential | Very slow spool (<3200 RPM), many modifications needed, not practical for everyday use | 280–320 hp (theoretical) |
| 1749 / 1752 / 1856 | Older-generation turbos (1.9 TDI) | No gains compared to the above options (1549/1752/1756) | False good idea – these turbos aren’t designed for Common Rail engines and won’t perform optimally compared to the above options | Similar to 1549 / 1752 / 1756 |
*MFS = Machined From Solid = lighter alloy for overall lighter rotating assembly
Beyond the 2060 turbo, it is of course possible to consider more extreme setups - for example, with 2260 ball bearing turbos.
However, these turbos are oversized for a 1.6 TDI engine and require major modifications.
As the aim of this guide is to steer you towards reliable, proven, and reproducible setups that deliver concrete results without risking engine failure, we have excluded these marginal possibilities from our comparison.
Turbo damper delete
The plastic outlet on the original turbo restricts airflow, significantly reducing the turbo’s ability to spool early. This limits low-end torque and overall performance.
The use of our turbo damper delete allows for a 100-350 RPM lower spool curve of the turbo, depending on your turbo size and settings, allowing better response to the pedal and faster acceleration.
Intercooler / Heat exchanger
It is important to understand that reducing intake temperatures not only improves performance, but also the reliability of the setup.
By lowering the IAT (Intake Air Temperature - air temperatures in the intake, i.e., after the intercooler):
- The engine heats up less, and the coolant has less difficulty dissipating heat
- Parts wear out less, especially rubber seals, which tend to dry out and crack over time, especially at high temperatures.
- Combined with high turbo pressures (affecting the pressure in the oil pan and the entire engine), these conditions create a breeding ground for leaks, which can develop and spread very quickly.
Therefore, the intercooler must be a key consideration when tuning a diesel engine, and more generally for any engine tuning, in order to ensure performance and longevity.
Intercoolers are available in several sizes and volumes (the volume is calculated as Length × Width × Height of the “core,” i.e., the center of the intercooler).
Original intercoolers have a volume of 3.5 L on Polo/Ibiza/Fabia/A1 models, and 7 L on models in the higher segments (A3, Golf, Passat, Octavia, Leon, etc.), and the market offers options ranging from 5 L for the smallest to around 9 L for the largest intercoolers.
For a “light” setup of 180–200 hp, these may be sufficient to achieve these power levels, but they are not optimal for the reasons mentioned above.
We recommend at least an intercooler twice the size of the original, and we prefer 11.5 L intercoolers, which are about three times the size of the original (compared to the size of the smallest original intercooler), in order to perfectly control the IAT.
You can find our universal adaptable intercoolers here, either welded (see image) or coupled (silicone elbows) with other parts to fit perfectly with your current supercharging system.
Clutches
With the increase in torque, the original clutch in the 5-speed manual transmission becomes insufficient: the pressure plate is no longer able to handle the additional torque, and the disc begins to slip during rapid acceleration.
The original clutch kit can handle a maximum of ~300 Nm. Beyond that, premature wear occurs, even on a new and properly broken-in clutch.
For torques of 350–360 Nm, we have observed OEM clutches lasting less than 10,000 km, which is insufficient for proper use and results in more frequent replacement.
Several replacement options are available, each offering a different level of comfort and durability:
Original clutch kit
- Single-mass or dual-mass flywheel
- For simple reprogramming (stage 1), this kit is sufficient and offers a good compromise between comfort, price, and performance.
- Maximum torque 300-320 Nm
- this kit retains the original single-mass flywheel, or allows you to switch from dual-mass to single-mass, while maintaining acceptable pedal comfort
- option to purchase only the clutch kit without the single-mass flywheel (for those who already have one)
- Slightly more noise when idling, but identical sound when driving to the original kit (no noise)
- Maximum torque 380-440 Nm (depending on use, how it is used, and running-in)
Sachs Racing reinforced clutch kit
- Harder pressure plate and organic clutch disc or disc with pads
- Sharper engagement, may be unpleasant for everyday driving (traffic jams, frequent stops and starts, etc.)
- Quite expensive to replace
- Harder clutch pedal (due to pressure plate with hard springs)
- Maximum torque 530-550 Nm
Exhaust
The original exhaust system limits the engine's optimal performance.
With the DPF (diesel particulate filter), the temperatures and pressures in the exhaust manifold only allow for a performance of around 140-150 hp and 280-300 Nm.
To exceed this, the installation of a downpipe is essential. Several diameters are available: 50, 55, 57, 60, 63, 70, or 76 mm.
As the original line is between 47 and 55 mm, any larger diameter promotes better gas evacuation and helps to unleash the engine's potential.
Our downpipes are made of food-grade stainless steel (304L) with a diameter of 60 mm, allowing for better exhaust gas evacuation without losing turbo responsiveness.
These downpipes are suitable for preparations up to approximately 220-240 hp.
Two variants are available, due to the slightly different chassis design:
- Downpipe for Polo, Ibiza, Fabia, and A1 models
- Downpipe for Golf, Leon, Octavia, A3, and other models
Cylinder head bolts
In principle, the original cylinder head bolts are sufficient to withstand the power and pressure, even for advanced tuning.
However, it is not uncommon to see them stretch, especially in the case of high turbo pressures and extreme temperatures in the engine when it is pushed to its limits (220+hp).
To ensure maximum reliability and peace of mind, we offer a reinforced cylinder head bolt variant.
These bolts can withstand power and torque levels well beyond the engine's capabilities (450+ hp and 850+ Nm), while remaining plug-and-play, without requiring any modification or adjustment to the existing system.
Injection
The original injection system already offers good modification possibilities.
Admittedly, replacing the injectors with new ones is costly, but it guarantees reliable operation and, above all, precise fuel flow, thus avoiding overconsumption and optimizing engine performance.
OEM injection (nozzles and injectors)
- High cost if replaced, but once replaced, the injectors are reliable (a tutorial is available for replacing, coding, and adapting the injectors)
- Very reliable and durable high-pressure (HP) pump, provided it is regularly maintained (replacing the fuel filter is inexpensive compared to replacing the HP pump)
- Maximum power: 200–210 hp, depending on engine condition
- Maximum torque: 380–420 Nm, depending on engine condition
- Relatively low cost: OEM injectors can provide higher fuel flow with these nozzles, provided they are in good working order.
- The original high-pressure pump can handle these flow rates without loss of pressure in the rail (up to a certain level).
- Theoretical maximum power: 300–320 hp (actual 250-280 hp MAX)
- Theoretical maximum torque: 650–700 Nm, well above what the engine internals can handle (actual 520-550 Nm)
EGR delete kit
The EGR valve on the 1.6 TDI consists of two main components:
- The EGR valve itself, which controls the flow of exhaust gases to the intake.
- The EGR cooler, which cools these gases before they return to the engine.
Common problems:
EGR valve : the flap (butterfly) can jam or even break, allowing 100% of the exhaust gases to pass through; the EGR control solenoid valve can fail; the vacuum hoses can leak and prevent proper control/adjustment during operation, etc.
Cooler : tendency to leak, either internally (coolant consumption) or externally (coolant and/or exhaust gas leakage).
We offer a complete EGR delete kit (EGR valve + EGR cooler) for Polo, Ibiza, A1, and Fabia models.
For other models:
When choosing the Polo, Ibiza, A1, and Fabia option, the EGR valve ducts can be blocked, but removal of the cooler is not possible.
This operation requires a dedicated hose (option available at this link), due to the slightly different design of the EGR valve on other models such as A3, Leon, Golf, Octavia, etc. (see photos below):
EGR valve Polo/A1/Ibiza/Fabia:
EGR valve on other models (Golf, A3, Leon, etc.):
Camshafts
The camshafts in the 1.6 and 2.0 TDI engines are identical.
There is therefore no point in interchanging them, as this does not improve performance.
However, a set of performance camshafts allows you to:
- Keep the valves open longer
- Fill the cylinder with fresh air more efficiently
- Gain an additional 10–15 hp and 15–20 Nm at equivalent rpm, with all other parameters remaining the same
Caution during installation:
- The camshafts must be timed with extreme care to avoid breaking the timing gear or bending the valves.
- The opening angles and maximum opening height of the valves differ between Street and Race camshafts.
- The camshaft pulley screw can be reused (tighten to 100 Nm).
Reinforced valve springs
Valve springs determine the maximum permissible engine speed.
Above this speed, a phenomenon known as “valve float” can occur: the spring takes longer to close the valve than the piston takes to reach TDC (Top Dead Center), which can cause the piston and valve to collide, resulting in serious damage.
The use of reinforced valve springs makes it possible to:
- Increase the maximum RPM by a few hundred revolutions per minute,
- Gain power (Power = Nm × RPM).
Some springs on the market require modifications to other components of the moving assembly (support or retaining washers).
Our springs, on the other hand, offer plug-and-play installation without any modifications.
Braking
With the increase in power and torque, it is strongly recommended to upgrade the chassis, and in particular the brakes.
Going fast is one thing, but controlling a vehicle traveling at full speed is another.
During rapid acceleration or track use, or even in the event of runaway (engine runaway: the turbo allows oil to pass into the supercharger circuit while the engine is turned “off,” thus fueling the combustion cycle until the crankcase is empty), it is crucial to have a braking system capable of stopping the vehicle.
Recommendations:
- Front brakes: minimum 288 mm for Polo models and equivalents, and at least 310 mm for Golf models and equivalents (due to weight), from 170–180 hp and 340–350 Nm.
- Rear brakes: upgrade to ventilated discs recommended (tutorial for installing 256 mm ventilated discs)
A performance braking system is preferable, but for reliable results with less expensive parts, nothing beats a refurbished original system. We also offer this brake refurbishment service.
Final word
The parts mentioned in this guide constitute most of the components needed to achieve reliable tuning.
For all the parts we offer, we provide personalized support and advice to ensure correct and safe installation.
If you encounter any difficulties during installation, please contact us directly via our contact form or one of our social media accounts (at the bottom of the page).
Thank you for your support, and we wish you an excellent adventure with your 1.6 TDI!
4 comments
Bonjour , y a t il un différence en le moteur cayc et cayb ?
Y a t il 2 version de moteur CAYC par rapport à la grosse durite du caoorstat ??
Je vous remercie d’avance
Bonjour,
J’ai une Golf 7 rline 1.6 tdi J’aimerais la préparer avec une prépa fiable, qu’est-ce que vous proposerez ?
Je n’ai pas de budget.
Bonjour,
J’ai une Golf 7 rline 1.6 tdi J’aimerais la préparer avec une prépa fiable, qu’est-ce que vous proposerez ?
Je n’ai pas de budget.
Bonjour je me permet de t´ecrire car j’aime beaucoup t’es videos sur le 1.6 tdi . J’ai une golf 6 1.6 tdi est j’aimerais d’abord la fiabiliser avant de passer sur une augmentation de puissance.. je m’explique le vehicule est entierement d’origine est c’est la 4eme fois que la vise de bride d’injecteur casse sur autoroute à grande vitesse elle sont serrer à 8nm + 190 degre.
2eme probleme : j’ai un claquement de nez injecteur , je l’es est remplacer par d’autres acheter sur aliexpress mais ça claque toujours un peu trop c’est tres desagreable. À tu une recommandation sur des nez d’injecteur origine fiable en neuf ? Merci beaucoup