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To some people, modifying the engine could be a difficult option. There are the warranty and the reliability issues. The law in each country could also be an important factor. Since I did the first mod in the engine, I would never believe that my car would reach the stage that it is now. As I'm responsible for a tuning web site, I like to test the mods and show people what could be the pros and cons of each one. The dyno runs also prove if that mod is worth or not. Most of the dyno runs I did were on the same Maha dyno. Every group of mods was divided in stages. That will also show, in my point of view, what could be a correct road map to reach the power numbers similar to what my car has today. Before you make a serious investment in some mod to drastically increase
performance beyond stock, check all maintenance items to ensure that your car is
in good mechanical condition. There is little point in modifying an engine
which is suffering from problems. Using Vag.com can help identifying problems, plus it's a good tool to help you understand better the TDI engine. Also reading everything you can from books or websites is very important. You can see some other resources on the Tdi info section of this site.
The first engine modification I did was a chip. For some time I was thinking between choosing a box and a chip and I think I did the right choice going to the chip. A chip is a better option than tuning box.
A chip affects more engine controls than a tuning box. A tuning box changes the amount of fuel delivered. A chip changes fuel, boost and timing and some more parameters.
The chip was made by Fernandes Motorsport, a very well known motorsport company with a lot of experience with chiptuning back on 2000. Driving the car that day was an incredible experience. I never thought the feeling would be so different than stock. the throttle response was very impressive. The next mod was a Simota air intake. This intake was designed to fit on a Honda, but with some changes, it was installed on my car. You can read some details about this intake here in this page. Most of the mods I did was tested at F3Sport in a Maha dyno. It is nice to test all the mods in the same dyno, to prove the upgrade. With this setup the power was 135hp and torque 296Nm. Back on these days I did some tests with vag.com and different air filters and MAFs. I was very happy with the chip and never thought I would increase the engine power or achieve this type of modifications a few years later.
When the development of stage 2 began, some more engine modifications were done. First I tried to change the OEM intercooler by the one used on Golf 150PD. This intercooler is front mounted and is very eficient. But there where problems instaling it and I quit the idea. I changed only the pipes for stainless steel ones. The turbo was sent to Turbocenter to modify. The VDO boost and oil temp gauges were mounted. With all this stuff, and without changing the chip, another dyno run revealed less 3hp in maximum power. Then for some days, the car went throught a series of dyno runs to reach better results. This hybrid turbocharger was capable of doing higher boost pressures, so the point was to achieve the better results possible. For some days and nights, the car did several dyno runs to adjust the chip to the mechanical modifications. It became clear that there was fuel missing, the stock injectors didn't provide the fuel needed to rise the power more than 144hp. Several levels of boost were tested, combined with the tuning of other parameters like injection timing. The car was now very pleasent to drive, with very good throttle response. You can see by the graphs that power was still available at 5000rpms and didn't drop as in the stage 1 chip. The turbo was doing 1.45 bar stabilized boost pressure and something near 1.6 bar in overboost. The dyno measure 144hp. At some ranges of revs, the dyno showed 13hp more than before with the stock turbo and the standard chip. Some time later I changed the exhaust system. All system was replace by a straight 60mm pipe. The catalytic converter was also removed. Read the exhaust section for more details. This exhaut mod was also tested on the dyno and revealed 4.5hp more. The sound was realy cool and acceptable without any myffler, if you weren't seated on the back seats for a long trip. Some months later I decided to put a small muffler at the back.
Then one night Miguel ask me if I could borrow my car to test some improvents on the chip, and the next day he came with two more dyno graphs that showed some excelent results. You can see the last to dynos with 148 and 151hp (pics 3 and 4). In the next pictures you can see some graphs from stage 2 tuning. The first shows the results of the first version. Pic 2 shows the difference after changing the exhaust. Pic 5 shows the boost gauge when driving on overboost and the needle passes the 1.5 scale. Pic 6 and 7 were taken at a dyno day. Last pict was intended to compare Stage 1 with stage 2.
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Stage 3 was mainly about the change of the injectors and consequently the chip customization. By this time I had already the 12mm VW Motorsport fuel pump, but possible premature timing belt wear was espected with the stock nozzles, I didn't want to install it this time. Plus some more hardware was needed to the correct upgrade, like new turbo and bigger intercooler. So I wanted to try the transporter injectores and see the differences in performance. Changing only the injectores didn't do much about maximum power. I had the VW Transporter Injectors with nozzles. The smoke increased and the engine response was not the same. So the Fuel pump had to be modified. Have you heard of hammer mod? the hammer mod was done and more chiptuning to achieve a power increase of some hp. I lost most of the dyno runs made in this stage. The only I have on digital format shows 163hp.
While I do not have the time to explain what was done, you can check the 3 dynos. The first is with a stock ECU, and all the hardware installed. The second one is the version for the road chip. The boost in this case is 1.6bar. The last dyno is another evolution now, with 1.8bar boost. The last one is the 1.6bar chip now with the new camshaft and air intake mounted.
Next will can see a picture of some stages of the evolution of the engine until now. Two things are missing. the first is a stock dyno run on the picture. The other thing is a stage 3 plot.
Here are some of my favourite books. I use them as a reference for maintenance and to know more about mechanics and engine tuning, but I do not touche the engine my self, I let that job for other people with experience.
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I think one of the first mods was installing a replacement air filter from BMC. I also made some improvements to the original airbox and air path to the box. Then I dicided to upgrade. I had this Simota Air Intake system for 100000km I think. It was originally an intake system design to a Honda Civic. After some changes in the pipes, it fitted my Golf's engine. The system is made of an Big aluminum tube, an air filter with an heat-shield and and High flow cold air intake.
A larger air chamber of the inlet big aluminum tube ensures improved throttle response over conventional intake systems resulting in smoother, faster shifts. Highly polished aluminum tube is ok for the looks too.
The Simota high flow cold air extension kit comprises adapters to fit the existing heat shield filter, inlet screen & a specially formulated flexible, high pressure, internal wire supported hose that will not collapse. The hose can be bent to pick up fresh air from the front bumper. Cooler, cleaner air means more oxygen for combustion & hence better performance. The heat-shild is a very important piece so that the engine does not breath hot air. There were some gains in throttle response and some improvement in power. As I didn't have a good dyno run both before and after the kit was installed I'm not sure of what it actually performs. Recently with stage 4 modifications there were some more changes to the intake system. Some components changed place on the engine. The strees bar had to be removed so the intake pipe could fit on the site of the intake manifold. So I had to change the intake on more time. This time I choose the BCM CDA, or Carbon Dynamic Airbox. This intake is known to be one of the best on the market. CDA filtering system is composed of a cylindrical carbon air box containing a washable filtering element. The carbon air box ensures that hot air doen't enter the engine. Cold air is directly channelled through an internal airflow deflector to the
filter and drawn into the engine with a very small pressure drop. The air enters the intake from the front bumper, a place where the pressure created by speed is high. The pipes that goes to the turbo were custom made because of inlet manifold and stress bar positioning.
Custom made exhaust system |
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The Exhaust system plays a very important role in engine tuning. On TDI engines you can choose a very bright stainless steel exhaust and pay lots of money, or you can ask an expert to take everything off and replace with a 6 cm diameter pipe with or without a muffler. I ride the car for some months without muffler and no cat and it's very nice, when you want fun, nice spool noise at idle and through gear changes. When your driving with the family at constant speed, it's not so nice. The cat was removed not because of power, but to lower the EGT's. This modification in the exhaust increase power in 4 or 5 hp. This was tested on the rolling road. Then, I decided to put an end muffler because of the noise. More recently, with the change on the turbo (see stage 4), the downpipe was also changed so the complete exhaust is now custom made from the turbo. The engine noise, even with the end muffler was now more loud and I felt like I should do something about it. My family asked for less noise. The noise was bad riding on the highway at constant speed. Now I have a ressonator with small diameter on the place of the cat. Not you can here a good sound without being very bad for highway driving.
Hybrid turbocharger VNT15 |
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This was the first turbocharger. The stock turbo was modified at Turbo Center. A new compressor wheel was mounted. This turbo was mounted from the day I bought the car until 140000km, 30000 of witch, the turbo was hybrid. Only with the change of the turbo, a slower response was noticed and was expected too. After doing some tuning on the ECU program, better driveability and peak power was achieved. This turbo was used on stage 2, with different injectors.
Bigger Hybrid Turbocharger |
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With stage 4 a new hybrid turbo was adopted.
Allard front mounting Intercooler and pipes |
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The intercooler is a very important part in highly modified turbo engines. They provide de capacity to decrease the air temperature after the turbocharger heats it. Choosing the right intercoler is a very important. Cooler air going into the engine means that other modifications that increase
fuel delivery can be done, or if the exhaust is smoky at full load, the denser
air will help turn some of that smoke into power. My first approach was to install the 150PD OEM intercooler. I had the some of the parts needed but it was not possible to install it. So, my next try was with the Allard FMIC. This intercooler is incredible. A very high quality and highly effective intercooler system, designed and manufactured by Allard, incorporating welded mounting bosses top and bottom, very light weight (motorsport use recommended). The Allard conversion has the Intercooler, aluminum pipes, silicone hoses and clips and brackets. This conversion can not only be fitted in standard manifolds and turbocharger systems, but with specific Allard parts. This conversion requires no cutting of the bumper to fit, also de crash bar is not modified or weakened in any way. The intercooler is a single pass system, which should be the most efficient design. The inlet and outlet pipes of intercooler are 60mm O/D, also the size of the pipes. The size of the core is 500x32x60. the core provides excellent dissipation of heat and significant advance in power and torque, providing much improved driveability and reliability to the engine. The upper pipe was provided to fit an inlet manifold facing the other way. So this way the distance is shorter to the inlet manifold. The first 3 pictures shown here are from a standard Allard Install. All the otheres are form my car. The pipes were custom made at Vilauto Competições. Each pipe is only one piece mandrel bent. On this rolling road and this intercooler the intake air temperature was 43º C maximum.
Allard Inlet Manifold without EGR valve |
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Manifold design is a very low priority in a boosted engine, especially if there is going to be a $$$ increase in production. The SDI engine has tuned runners because without a turbo, it needs every extra advantage it can get from the intake. On a turbo engine, it's cheaper for the manufacturer to just make the cheapest possible intake manifold and crank up the boost a wee bit to compensate for its deficiencies! VW didn't pay much attention to this item in earlier TDIs. On some recent TDI like the 130PD the intake manifold has a better design. The Passat Manifold is the same design but the inlet pipe is facing other side. This Allard intake manifold is basically a Passat PD manifold with the Allard pipe attached to remove the EGR system. This intake allows for more flexible intercooler mounting/routing options, plus, pipes are shorter, therefore lag is reduced.
The EGR system reduces emissions by directing a small quantity of exhaust gases back into the intake manifold to dilute the air/fuel mixture efectively. An EGR cooler reduces the exhaust gas temperature by as much as 50º C. This reduces the amount of oxides of nitrogen (NOx). The funcion of the EGR is managed by the ECU via the EGR vacuum regulator solenoid valve. The remove of the EGR valve also removes the Intake manifold change-over valve. This is a flap valve that closes for aproximately 3 seconds when the engine stops, blocking the air to the engine. This reduces the suddenness of the diesel engine shut-down. The valve re-opens when once the engine has stopped. With the EGR removed there is a much lower air restriction. No more manifold clogging! Soot can no longer accumulate inside intake manifold and the EGR Valve. It's interesting to look at the next 2 pictures. Plus the Allard pipe has a much better looks and it should improve the revving and some marginal power gains at high rpms.
Injectors and .262 nozzles |
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The 1.9L TDI engine uses a two-spring injector that enables the fuel to be injected in two stages for "softer" combustion. In addition, the injectors are a 5-hole design that spray fuel from 5 ports in a more lateral direction rather than in a single conical pattern. Injector opening pressures are aproximately 190 bar. All 4 injectors are functionally the same. However, injector for cilinder #3 carries the needle lift sensor (G80). You can see the difference in one of the next pictures.
Custom made Chiptuning |
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One of my first power upgrades was a chip. I bought a chip and ride the car for some time. I would say that a good chip is the right performance upgrade for any Turbo Diesel engine. Then when was the time to upgrade the power to other levels, standard chiptuning is not enough. So I had a big help in this project from Miguel Patrocinio testing and improving the ECU to every new stage. We spend some nights on the dyno, fighting for every single horse-power.
Racimex Oil cooler kit |
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An oil cooler is an important device if you go to this kind of upgrades. If you can prevent the oil temperature to rise a lot , then you will have more reliability and prolonged use. With this kind of oil cooler 20 to 30ºC temperature reduction is possible. I bought a Racimex oil cooler kit (16 row radiator) and a racimex thermostat. An oil cooler construction utilizes a variable number of pressed plates forming oilways. These oilways contain turbulators to break down boundary layer effects in the oil flow, allowing for maximum heat dissipation without undue pressure buildup. Oilways are interspaced with corrugations providing airways between the plates and are also louvered to optimize heat transfer. An oil cooler kit like the Racimex I choosed, includes all the components you need to install. the oil filter adapter had to be threaded to fit the filter. Thermostats are designed to prevent engine oil from flowing through the oil
cooler until the desired temperature is reached. Prolonged use of engines in
conditions that oil cannot reach optimum working temperatures will cause sludge
formation and crankcase oil dilution, leading to excessive wear especially in
the cylinder bores. Thermostats combat this by regulating oil flow to accelerate
warm up. This in turn reduces drag, helping to yield optimum engine efficiency
and performance. Revving the engine without a load will not put much heat into the oil.
The Racimex oil cooler thermostat is a useful addition, particularly since if the
vehicle is driven in the normal operation and also in the winter. With
opened plug valve the oil presses at the same time over both inlets to the
radiator. Pressure and counter-pressure waive themselves, and it comes to the
pressure balance in the radiator system. The oil flows back thus by the
thermostats to the engine. Starting from approx. 75 degrees Celsius closes the
plug valve and the oil must circulate now by the radiator. With approx. 80
degrees full flow is approved to the radiator. It is therefore desirable to control of the oil flow through the cooler by a thermostat, set to divert oil to the cooler at 80ºC. This is the minimum temperature required to evaporate and dispel contaminating substances. the radiator was mounted in front of the right front wheel on the same place that was used by the stock intercooler. Correct air flow is achieved by the opening on the front bumper.
VW Motorsport 12mm fuel pump |
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The diesel fuel injection pump is controlled by the ECU and performs three primary functions: it takes the fuel from the tank and pressurizes it; itprecisely times the delivery of fuel to the injectors; it accuratelly meters the quantity of fuel delivery to the injectors. The pump is driven by the same tootheddrivebelt that drives thecamshaft at 1/2 crankshaft speed. Internal parts are lubricated and cooled by the diesel fuel. Because turbo direct injection system is fully electronic, the ECU can detect and store most fauls associated with the injection pump. Diesel Injection pump timing must be set using Volkswagen scan tool VAG 1551, VAG 1552 or equivalent like vag-com in a mode known as basic setting. Injection pump timing is correlated to several factors, including fuel temperature. Failure to properly set injection pump timing will result in hard starting, poor performance, excessive noise, smoking and increased emissions.
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