Best Mods for the 1.9 TDi ALH PD engines.

"So what are the best tuning Mods and Upgrades for the 1.9 ALH?"

As one of the greatest VAG diesel engines we are often asked about tuning mods and upgrades for it.

It can be tuned significantly, and will still offer decent fuel economy. It has a lot of potential for improvement when it comes to performance gains after tuning mods are fitted. In stock form it offers a respectable 109hp it is possible to wring out quite a bit of extra power from it with the right mods and take this to the next level.

The 1.9 ALH engines have 109 bhp at 4150 RPM and 173 lbft at 1,900 RPM but with the right mods this can be lifted easily to around 160hp and you'll still get very good fuel economy.

Despite the fact that it was an older engine, it was produced for a longer period of time than the 2.0 TDi. Many enthusiasts believe it to be a more dependable engine than the 2.0 that succeeded it and the ALH still has many fans around.

These are getting on ow, but I've seen many of these reaching 250,000 miles and still providing to be as reliable as ever.

From the VAG group, the 1.9 TDI was utilized in a broad range of vehicles, with varied power outputs.

Newer versions are always revised & improved but I would avoid new innovations until they have had a chance to settle any problems in subsequent revisions.

All of the cars used Bosch injectors and Bosch ECUs, which are both very durable and engine-protecting making it hard to wreck an engine through poorly chosen mods and upgrades. The typical worst case scenario is going into limp home mode.

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The 6 Best 1.9 TDI ALH Mods

  • Differentials A better diff on a front-wheel-drive automobile powered by a 1.9TDi engine is essential for reducing power loss.
  • Mapping, remapping, aftermarket ECUs, and piggyback ECUs are all viable options for saving money.
  • Intake & Exhaust Aside from reducing limitation, intake and exhaust modifications DO NOT ADD POWER on their own, although they CAN aid boost power once other changes have been applied.
  • Forced induction and hybrid turbo improvements are the most efficient ways to boost air supply, enabling you to burn more gasoline and produce more power. However, it's one of the more expensive improvements, but it's worth it.
  • Fuel mods Adding more power will need upgrading the fuel pump and injectors.
  • Intercooler An FMIC that flows better and resists heat soak for longer may be used in place of the factory intercoolers, which are restricting while using maps.

Avoid using this engine with an engine flywheel that is too light. The vibrations will make you insane, and the gearbox's lifespan will be diminished.

Upgrades and Mods for the ALH in Stages

  • Stage 1 upgrades often include remapping, lighter flywheels (stay with dual mass, SMFs aren't excellent on the 1.9), sports exhaust, and panel air filters. stage 1 mods
  • Head work on the 1.9 ALH - Porting and polishing the head, installing an upgraded fuel pump and injector, and installing a Power/Sport clutch are all common Stage 2 modifications. stage 2 mods
  • Engine balance, internal engine enhancements (pistons, heads, and valves), a competition cam, and the addition or improvement of forced induction (turbo/supercharger) are common Stage 3 modifications. stage 3 mods

If you're new to tuning diesels, check out our new video instructional for a quick overview on your options.

1.9 ALH TDi Problems:

Most of the flaws had been ironed out in the second generation PD engines, making them more bulletproof than the later 2.0 TDI engines.

Many people consider the 1.9 TDi to be the greatest diesel engine ever offered by the VAG company.

Cracked injector looms were a problem in the early engines and these caused misfires and poor running. But problems and issues are few and far between.

  • Other Codes for a 1.9 TDi engine which shares a similar block and head design to the ALH.
    C1Z, AHU, AGR and ALE are the pre-PD engines - 1Z and 2Z are the pre-PD engines. BSU, BRU, BXF, ANU, ATD, BXR, BEW, BMT and AVQ are the pre-PD engines. BSU, BRU, BXF, ANU, ATD, BXR, BEW, BMT and AVB are the pre-PD engines. BXE, BPZ, AJM and ATJ are the pre-PD engines.
    The 1.9 R4 TDI is a pre-PD version.

Inline four-cylinder design and displacement. TDI turbodiesel with direct injection and a 19.5:1 compression ratio.

Al-alloy cylinder head and valvetrain, with two valves each, for a total of eight valves, with bucket tappets VP37 Verteiler Pumpe electronic distributor injection pump operated by timing belt for SOHC fuel system and engine management. The fuel pump works from the timing belt, but some regions had more power than the US versions, such as the Europe models.

This arrangement was simple, but very effective and is a long way down the development cycle of the 1.9 TDi engine.

The 1.9 TDi ALH engines have 109 bhp at 4150RPM and 173 lbft at 1,900 RPM.

PD version of 1.9 R4 TDI came later, and presented a number of new problems and issues, despite offering better power and economy.

For the PD Pumpe Düse injectors, the cylinder head of the redesigned engine has been reworked. So if you plan to follow the VAG group and go with PD fuel delivery you'll need to do a head swap, and ECU swap.

Cast aluminium intake manifold, Garrett, KKK, or Borg Warner variable turbine geometry turbocharger VGT, water-cooled exhaust gas radiator, and aspiration hot-wire mass air flow MAF sensor

You can swap in the PD150 short block on these for more strength but the crankshaft sensor will need swapping over as well.

ALH Engine and fuel management Upgrades?

A direct injection pump for the Düse PD. A low-pressure fuel lift pump operated by the engine, and four camshaft-actuated via roller rocker arms high-pressure fuel lift pumps The Bosch 27,850 psi Unit.

A Bosch EDC16 or EDC17 ECU with a solenoid valve injection nozzle in the injectors. This can be retrofitted and an ECU/sensor swap & head swap is required. But in my opinion it would be easier to just do an engine swap in the first place.

Engine codes and their corresponding horsepower ratings

When it comes to horsepower and torque, it's hard to go wrong with and ALH 1.9TDi.

Remaps are a great way to get a lot of power for a little price. The OBD port may be used to tune/remap most engines built after 2000, however pre-2000 models need a bench flash.

After a tune/remap and no further modifications, these are the approximate power figures.
Peak power ratings are just a minor portion of the equation; the whole torque spectrum is enhanced.

P90 = 120ps; P100 = 130ps; P100 = 135ps; and P105 = 135 P90:
There are two TDi models: TDi110 (143ps) and TDi115 (124ps).

The larger powered PD140 is referred to in Germany as the 175 ps, whereas PD150 is a 182ps version.

These figures seem reasonable targets in your ALH tuning project.

In general, PD engines provide more power gains from mods than these older TDi engines. Increasing the turbos on the stock block might provide further benefits over and above that offered by a remap

Upgrades and Mods for the ALH in Stages

  • Stage 1 upgrades often include remapping, lighter flywheels (stay with dual mass, SMFs aren't excellent on the 1.9), sports exhaust, and panel air filters.
  • Head work on the 1.9 ALH - Porting and polishing the head, installing an upgraded fuel pump and injector, and installing a Power/Sport clutch are all common Stage 2 modifications.
  • Engine balance, internal engine enhancements (pistons, heads, and valves), a competition cam, and the addition or improvement of forced induction (turbo/supercharger) are common Stage 3 modifications.

Solving traction issues on a tuned ALH engine

Keep in mind that at 250bhp you will have a lot of traction troubles, so don't try to move when your wheels are spinning!

The Torsen differential is the greatest option for a vehicle that will be driven in a variety of weather situations.

To describe Torsen, as a game changer, ("Torque Sensing,") would be an understatement. Slowly but surely, it provides traction, pulling the car out of the tightest corners, even in wet conditions.

LSDs aren't as obvious as Torsen diffs, but the difference is still apparent. It all comes down to the car's setup and the diff manufacturer. So you should choose a differential to suit your requirements as a driver.

Many production automobiles have Torsen differentials. Cars that have a lot of power or are expensive are more likely to have LSD diffs installed. Torsen diffs may be classified as one of three ways: A, B, or C. Some are more suited for occasional usage than others, and each has its own unique set of benefits and drawbacks.

A Quaife LSD was one of the diffs that some of our members suggested. ATB diffs are also produced by Quaife.

It is necessary to tune/remap the 1.9TDi

Yes, this is a highly recommended ALH engine Mod, consider the following. How are VW's factory maps set? Each nation has different objectives and targets to meet for CO2, hydrocarbon, and nitrogen oxide emissions. As a result, the lowest common denominator and settings must be used to save costs and R&D.

Also if consumers are inconvenienced by mechanical problems or poor fuel efficiency, they will switch brands. So manufacturers have built in a broad tolerance to ensure that they are not inconvenienced and are aiming at reliability here.

The output of each engine may vary by up to 20bhp depending on how well the components are machined and installed. In instead of creating a specific timing map for each vehicle, they employ a generic technique which saves time and money.

In order to cut insurance premiums and improve fuel efficiency, manufacturers use software to generate different power variants of the 1.9 TDI engine. So often there are few mechanical differences between the higher powered 1.9TDi and economy versions.

As a result, a 1.9Tdi tune/remap offers a lot of potential for increasing performance taking this to a tailor made plateau.

  • The drawbacks of remapping.
  • Increase the frequency of your car's maintenance, or perhaps shorten the gap.
  • You'll need to fix any parts that fail on a map optimised for high-octane gasoline.
  • Turbos, hoses and pipes, and injectors are all put to the test when extra power is added.
  • The weak spots in an engine reappear months after the tune/remap has been applied. See our instructions if you have engine tuning/remapping troubles.
  • In most cases, a tune/remap will identify problems with the turbocharger and the clutch.

As a side note, 1.9 TDI turbos may fail, and important components like pistons and bearings need to be inspected and repaired. Remaps using NASP? Having a turbo does not need a tune/remap in order to increase horsepower (10 percent is typical).

Be careful of claims of peak power gains from remappers.

Observation: Some tuners are known to produce a power blip or spike in order to attract attention and grab headline power figures.

As an example, have a look at the graph below.

There isn't much to admire about the 200bhp red trace, since peak power occurs at a rather high RPM and is only a blip, compared to the remainder of the RPM range.

Even though it's just 175bhp, the green trace shows a steady increase in power across the RPM range and is better than the 200bhp plan.

At 2500 rpm, on the 1.9Tdi, you can expect peak power, which is ideal for an engine with a 5000 rpm redline.

We want to observe a steady rise in torque with no dips or troughs on the map.

The 1.9TDi's injectors are uprated on the PD130 & PD150.

For the PD130, PD150, injectors with a 1.9 TDI will be suitable for 240bhp so on engines like the ALH with outputs of PD100, PD105 and PD115, injectors will need to be uprated to 170bhp.

For an upgrade, you might use the PD150 injectors or look for any other high-performance options.

Possible 1.9-TDI ALH turbocharger modifications

What's the Point of Getting a New Turbo?

Turbochargers are often upgraded or replaced by drivers for a variety of reasons. You may significantly improve a vehicle's performance by installing turbochargers.

It's inevitable that turbos will need to be replaced over time. The most current turbos use newer technology advancements and provide additional options for car owners.

Due to the low cost and high dependability of the stock 1.9Tdi turbos, there are several ways to improve their performance. Based on comments from our members and my own personal experiences, here are few that TorqueCars has found to be very helpful.

The PD engines generally respond better to turbo upgrades, but there are still options for the ALH and most of these can be made to work ok, even if designed for the PD versions.

The GTB2566VK engine, with a maximum power output of 245 horsepower at 3300 rpm, is available on these units. Up to 315 horsepower is available from the GTB2260VK at 2800 revolutions per minute (rpm), while the GTB2056VK delivers up to 255 horsepower at 2700 revs per minute (rpm), and the GTB1756VK delivers up to 235 horsepower at 2600 revs per minute (rpm).

  • GTD2872VRK, 375-400hp, 3350rpm, 40psi
  • 360hp at 2850rpm and 35psi on the GTB2260VK
  • GTB2056VK 300 horsepower at 2750 rpm and 34 psi.
  • GTB1756VK: 250 horsepower at 2650 rpm, with a 34-psi boost pressure.

The GT2052V, with 225 horsepower at 2200 rpm, is also an option, and our pick for a road vehicle since it spools up rapidly while still delivering respectable boost levels.

If you're willing to alter the engine's pipes and manifolds, there are further turbo upgrade possibilities. GTB1749V and GTB1756V are both capable of produce 205 and 225 horsepower, respectively, at only 1900 rpm. 240 horsepower or even more is possible with certain hybrid turbos, which are available from a number of manufacturers.

Note: Vacuum actuators must be converted to turbos, and the VNT system must be installed.

When selecting a turbo, look for one with a power band that falls within your preferred rpm range.

Hybrid turbo improvements for the 1.9TDI

There are a variety of hybrid turbos that can be bolted on to your 1.9TDi, but the internals have been tweaked to fit your power demands, making them a straight replacement.

You may enhance the turbo's spool time, lengthen the power range, or boost top end power by altering the profile of the exhaust side impeller.

In most cases, you'll be forced to choose a trade-off since you can't have all of these benefits. It's also possible to alter the intake compressor's profile to increase the quantity of air pulled into the engine.

There are two types of bearings used in turbochargers.

Thrust and ball bearings are among the alternatives available. Thrust bearings are often used in OEM turbos since they are less costly to produce, however high power may cause them to break, resulting in oil leaks and premature turbo wear.

It's better to go for a ball bearing turbo rather than a thrust bearing turbo since it can take greater power. Ceramic and cryo-treated bearings, on the other hand, have been shown to have even greater dependability.

It is not possible to convert all OEM turbo housings to use ball bearings; instead, an OEM-shaped turbo unit is constructed to accommodate the improved internals.

A turbo's flow characteristics also depend on its intake design & configuration.

If the metal surface has any ridges, pits, or seams, this might cause turbulence, which would reduce the airflow. When choosing the hybrid turbo's characteristics, keep the following benefits and downsides in mind:

As long as you're on the track, this is good. But when you're on the road, it might be irritating.

Essential 1.9 TDi Tuning Information

Upgrading the fuel injectors on the 110 and 90 VE 1.9 TDi engines is also necessary, since the basic injectors on these engines are not up to greater power ratings. The 150 head bolts are very robust, but in other engines, the standard bolts may suffer head lift at high power levels.

If you don't have any bolts for the 150, you may buy some and use them instead.

It is suggested to use a hard pipe kit for adding an additional 50 horsepower to these 1.9 TDi engines, since old joints and pipes are more prone to tear apart under greater air pressures.

Increases in horsepower up to 220 bhp don't harm new clutches. It is possible to repair worn clutches, however this is contingent on how well the clutch has been cared for. In around half of the situations where considerable power improvements have been installed, worn clutches tend to slide.

The downpipe and manifold designs for 1.9TDi OEM turbos vary depending on the vehicle type in which they were installed, although the turbos themselves are almost all the same.

There are newer diesel engines that are considerably cleaner and more fuel efficient, however short travels may lead to the DPF being clogged up (Diesel particulate filter). For additional information, see our DPF cleaning guide.

Improved intercooler systems for the Volkswagen 1.9 TDI

These engines might benefit from a bigger intercooler that is better able to withstand heat soak.

There is a close proximity between the cold intake charge and the hot exhaust temperature in a 1.9 TDi turbo. In certain cases, this may pose an issue. Even a supercharged engine will benefit from an intercooler because of the significant increase in air intake heat created by the compression of the air itself.

Compression causes the air to become heated. It's common knowledge that compressed air becomes heated as it comes out of a tyre pump nozzle. Because of what we learnt in chemistry and physics class, cooler air has more oxygen.

What's the big deal with intercoolers?

In order to make greater power, the 1.9 TDi needs more oxygen. The turbo adds quite a lot of heat to the intake charge, so the intercooler will chill this back towards ambient temps.

To ensure that the radiator receives enough of cold air, consider installing an intercooler in front of it and leave a space around the sides of the intercooler.

If your intercooler is properly-designed, you should expect a 5–10 percent increase in power from your upgrades, as well as greater resistance to heat soak.

Think about how you want to maximise airflow into your engine. If your intercooler core is obstructing that, you'll lose power. Though bigger isn't always better!

For a boost level of 15PSI, TorqueCars expects a pressure decrease of between.5 and.9 psi. Some applications might lose 1.3 psi in the worst-case scenario. Do not blame the intercooler's design for the loss of pressure, since it is just a portion of the reason for the lower pressure.

Things to look for when buying an intercooler for your ALH engine

Weight is always an issue with high-performance vehicles. A excellent solution for these vehicles is an aftermarket intercooler, which is often both lighter and stronger than the stock one.

If the intercooler is larger, it will be more efficient at cooling, but it will also slow down the automobile. This is a general rule.

This should be given a lot of consideration as to how much additional strain it will place on the cooling process. The better the intercooler works to keep you cool, the more air it retains.

Intercoolers may be sprayed with water or nitrous to further reduce intake temperature as the liquid evaporates with the help of heat from the air that goes through the intercooler, which is available on certain vehicles. This improves the car's performance.

Between 5% and 10% more power may be obtained with a more efficient intercooler design than the stock one (assuming there was a restriction which depends on the way the engine has been tuned and setup). This is predicated on a 35C-40C temperature decrease. The cooling effect increases with the magnitude of the temperature differential between the intake and ambient air.

Even the most efficient intercoolers will overheat with time, even if they are the most efficient. The intercooler becomes heated while you're driving for a long period with a lot of high-boost.

An intercooler's ability to endure heat soak increases with its size.

To make this page as full as possible, we need your assistance. If you know of any 1.9 TDi engine codes, common faults, or upgrade possibilities, such as turbos, please let us know.

Tuning your 1.9TDi's intake and exhaust

After that, we'll look at the best ways to optimise the intake and exhaust of the 1.9 TDi in order to make sure that the engine is getting enough air and exhaust. On this engine, you should be able to get 220 horsepower with the factory configuration.

In the event of a constraint, a complete induction setup increases power gains. All 1.9Tdi models should have a high flow panel air filter installed, as it will enhance "off throttle" engine performance while also improving fuel efficiency.

No matter how hard you try, there's no way to get more air into the turbocharged 1.9-liter diesel engine without blocking some kind of step. We don't see a necessity for port matching on the 1.9 TDI engine, since most DIY port matching occurs on exhaust ports.

In the case of a finely tuned engine, extending the port size only makes sense when the port size has become a bottleneck, and VW has done an excellent job with the 1.9Tdi.

Between 1.5 and 2.5 inches, the largest gains in power are possible.

If you'd like to discuss 1.9TDi tuning in depth, please join our join our friendly international forums and let us know in the comments below what modifications you've made or any ideas you'd want to pass on to our readers.

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