Big powered build guide 1.6 TDI CAYA/CAYB/CAYC etc..

Here is the complete guide to a big power build on your 1.6 TDI CAY, regardless of the version (4th letter after the CAY engine type). There are no other guides available on the internet that are as complete as ours, and we have decided to share it with our followers.

We draw these modifications from our own experience and our own setups. The figures announced are real data, which we have collected on our vehicles as well as on the vehicles of our customers.

Turbo

Several choices are possible, depending on the power levels you are looking for, and of course your budget. The achievable powers depend almost entirely on the condition of your injection system (in particular) because it tends to lose efficiency over the lifespan of the car.

Original turbo (hydrodynamic bearing)

- good spool at low RPMs

- limited power in high RPMs

- not much air volume

- reliable maximum power 150-160hp, significant smoke beyond

Original turbo MFS wheel version (hydrodynamic bearing)

- good spool thanks to the turbine identical to the original

- lower pressures due to MFS shell and wheel machining because everything on the exhaust side is original

- Higher EGT because more air flow but identical passage of gases in the hot shell

- CHRA replacement requires rebalancing with MFS

- maximum power 170-190hp

Turbo 1549 original version (hydrodynamic bearing)

- original part

- reliable and easy to replace in the event of breakage (unlike MFS wheels)

- higher pressures possible because wider collector therefore larger gas passage

- EGT +/- as original

- maximum power 180-210hp

Turbo 1549 MFS compressor wheel version (1549 or 1556) (hydrodynamic bearing)

- spool like the 1549, loads a little faster because it is lighter (1549), and more air volume (1556)

- disadvantages equivalent to the original mfs turbo (EGT, pressures, CHRA remplacements)

- maximum power 210-240hp

Turbo 1752 (ceramic bearings)

- the best suited turbo for 1.6 TDI engines used every day or for a track car

- spool much like original thanks to ceramic bearings

- holds more EGTs

- better responsiveness thanks to the fast spool, not limited in high RPM's like the original thanks to its size

- more expensive than hydrodynamic bearing turbos

- Original CHRA therefore easily replaceable in the event of breakage

- maximum power 240-260hp

Turbo 1756 (ceramic bearings)

- turbo adapted to runs (to optimize operation at high revs and to generate some additional horsepower)

- spool a little slower at low revs so not suitable for daily driving

- more expensive than hydrodynamic bearing turbos

- CHRA needs rebalancing with MFS wheel

- maximum power 260-280hp

Turbo 2060 (hydrodynamic bearing)

- huge turbo, to be used only with very very big builds

- extremely slow spool due to its size, before 3200 rpm you shouldn't expect much boost

- to make this turbo work efficiently, very heavy modifications are necessary

- maximum power 280-320hp (not fully achievable with this engine)

Beyond that, the sizes of the turbos do not allow them to be used by a 1.6 TDI engine, because they are too large and therefore not enough air pumping by the engine to make them turn. Some will tell you that it is possible, but the turbos charge from 3700 rpm to be full boost at 4500 rpm, therefore not really usable, also with a lot of smoke.

Intercooler

Regarding the intercoolers, a range of sizes and different volumes (Length x Width x Height of the “core” = of the center of the exchanger) are available to you. The original exchangers are 3.5L, 5L options are available on the market. For a small preparation of 180-200hp, they will be sufficient, however not optimal.

We recommend a size at least 2x larger than the original size, and we prefer to fit 11.5L intercoolers ourselves, or approximately 3x the size of the original IC, to be sure to control the IAT (Intake Air Temperature = Air temperatures in the intake manifold = after IC).

You can find our adaptable universal ICs here, to be welded or coupled with other parts to adapt perfectly to your current turbo charge circuit.

Clutches

With additional Nm, the original clutch of the 5-speed manual gearbox will no longer be sufficient: in fact, the pressure plate cannot overcome the additional torque even for some stage 1 remaps. OEM, the maximum torque supported by the clutch pack is around 300Nm, beyond which premature wear of the clutch occurs, even when new and properly broken in.

With torques of 350-360Nm, we have seen new original clutches last less than 10,000kms, which is rather poor in terms of performance and requires replacement once again.

Once again, several options are available to you, each having a different “level” of comfort.

Original clutch kit

- single-mass or dual-mass flywheel

- for a simple remap(stage 1), this set is sufficient and allows you to maintain a good compromise between comfort, price and performance

- maximum torque 300-320Nm, depending on remap parameters

Single reinforced clutch kit

- this kit retains the original single-mass flywheel, or allows you to switch from dual-mass to single-mass, while maintaining correct pedal comfort

- possibility of purchasing only the clutch kit without single-mass flywheel (for those who already have one)

- slightly more noise when stopping at idle

- maximum torque 420-440Nm

Sachs Racing reinforced clutch kit

- harder pressure plate and clutch disc with pads

- sharper grip, can be unpleasant to ride every day (traffic jams, lots of frequent stops and starts, etc.)

- quite expensive to replace, harder pedal (because of the hard pressure plate)

- maximum torque 530-550Nm

Exhaust

The original exhaust system does not allow optimal operation of the engine.

With the DPF (Diesel Particle Filter), the temperatures and pressures in the intake manifold only allow a performance of around 140hp and 280-300Nm.

Installing a downpipe is essential to go further. Several diameters are possible: 57, 60, 63, 70, 76 mm. The original line is 47mm, so any larger diameter will allow better gas evacuation.

Cylinder head bolts

Logically, the original cylinder head bolts make it possible to hold the power and pressures of even the most advanced builds. However, it is not uncommon to see them stretch, especially under turbo pressures and extreme temperatures in the engine.

For this reason (and a peaceful sleep), we also offer for sale a variant of reinforced cylinder head bolts, making it possible to hold powers and torques well beyond what this engine can produce (450+hp and 850+Nm) . These bolts are made to be a plug and play solution, therefore they require no modification or adjustment to your block or head.

Downpipes

We offer 2 types of downpipes:

- 60mm stainless steel downpipe for Polo, Ibiza, Fabia, A1 models (due to chassis dimensions)

- 76mm stainless steel downpipe for Golf, Léon, Octavia, A3, etc. models

The 60mm downpipe allows powers up to 200-210hp, and is therefore sufficient to go with a large turbo available here. The 76mm downpipe allows you to go up to 300+hp, only thanks to its greater diameter, but this does not mean you can reach this power levels on an engine with original internals.

Injection

The original injection system is already pretty good in terms of modification possibilities. Of course, new injectors are quite expensive, but once replaced, they ensure good operation and above all a precise flow of diesel, thus avoiding overconsumption.

Original injection

- quite expensive but once changed, it is reliable (replacement tutorial, coding and adaptation of injectors)

- very reliable and very durable HPFP (High Pressure Fuel Pump), if well maintained (fuel filter which costs anear to nothing to replace, compared to the HPFP)

- maximum power 200-210hp depending on the overall condition

- maximum torque 380-420Nm depending on the overall condition

Injector nozzles 50%

- for a relatively low cost, your original injectors can deliver more fuel

- original HPFP is capable of handling such flow rates without dropping the pressure in the rail

- maximum power 300-320hp (theoretical, based on flow charts)

- maximum torque 650-700Nm (much more than the internals can handle)

EGR deletion

We offer a complete EGR removal (valve + cooler) for Polo, Ibiza, A1 and Fabia models. For other models, by purchasing the option for the previously mentioned models, the ducts can be blocked, but the removal of the cooler cannot be done. This removal can only be done with a dedicated pipe (therefore necessarily more expensive), due to the slightly different design of this EGR valve (see below):

Polo/A1/Ibiza/Fabia EGR valve:

EGR valve on other models (Golf, A3, Leon, ...):

Camshafts

The 1.6 and 2.0 TDI camshafts are identical. There is therefore no point in changing one for the other model, this will provide absolutely no additional performance. However, a set of performance camshafts makes it possible to keep the valves open longer, and therefore to fill the cylinder with fresh air for longer, thus allowing, while keeping all other parameters at the same level, to gain 10- 15hp and 15-20Nm more at the same speed.

The assembly requires extreme vigilance when timing the camshafts to avoid timing belt snapping/bending of the valves, because the opening angles and the maximum opening depth in mm of the valves change with the Street and Race camshafts , therefore damage may occur if assembly is not done correctly. The camshaft pulley bolt can be reused (not a stretch bolt).

Reinforced valve springs

The valve springs determine the maximum RPMs admissible by the engine, beyond which a phenomenon called valve float occurs (the time it takes for the spring to raise the valve is greater than the time it takes for the piston to rise to the TDC - top dead center - at this precise moment, piston-valve contact is made, and serious damage can be caused).

The use of reinforced valve springs makes it possible to push back the maximum RPMs by a few hundred, thus making it possible to gain power (Power = Nm x RPM). Some springs require modifications to other elements of the whole valve assembly (such as spring washer in head or retaining washers), our springs allow plug and play assembly without any modifications.

Braking

With additional power and torque, it is highly recommended to upgrade your chassis, especially in terms of braking. Going fast is one thing, but controlling a speeding vehicle is another. Likewise, during a runaway (engine runaway = turbo which lets oil pass and sends it into the sural circuit despite the engine being off, thus feeding the combustion cycle until the crankcase is empty) , it is better to have something to slow down an engine, now freed from all means of “braking” it.

We recommend braking of at least 288mm at the front for Polo models and equivalent size, and at least 310mm at the front for Golf models and equivalent, from 170-180hp and 340-350Nm.

A performance braking installation is also possible, and to install new parts, nothing better than a refreshed original system. We offer this service ( brake caliper refreshing ).

In addition, we recommend switching to ventilated rear disc brake disc. You will find the assembly tutorial for the 256mm ventilated rear axle brake as well as the parts themselves in a video that we will post later.

Assembly is quite simple for DIY enthusiasts, requiring only a few basic tools. The only parts that can cause problems are the rear insert holder screws, which are often rusty (with allen marks). To facilitate their removal, you must dismantle everything around and heat the screws with a blowtorch or heat gun.

Final words

The parts mentioned above are for the most part all you need to make a reliable build. For the parts we sell, we guarantee follow-up with advice (if necessary) to ensure proper assembly. If you encounter any difficulties during assembly, please contact us directly via the contact form or via one of our social networks.

We thank you for your support and wish you a wonderful adventure with your 1.6 TDI!