The K04-064, fitted from factory to the MK5 platform Golfs, Edition 30 and Audi S3. Such a great punchy turbo when fitted to a 1.8T engine. Offers superb partial throttle drive-ability around town, and delivers a menacing punch when opened up to the full potential. We created this K04-064 Fitting and Advice guide to guide you through the process of fitting this turbo to your 1.8T engine and the options available for doing so! A few years ago, the first 1.8t K04-064 conversion was trialed back in 2013 and made great results. With a OEM parts catalogue to fit, bar a few custom requirements, there were a few people followed suit and shortly after, its now becoming a fast and often asked about turbo on a 1.8T….and we can certainly see why! This guide will explain what you need in order to fit this turbo to your engine and the different options available for doing so. There are a couple of options available and we will describe each one to you. Lets get started….
- What options are available?
- What’s the expected power output?
- How does it match up to a 20vT head?
- What’s it going to cost?
- How hard is it to DIY?
- Getting it all to fit
- What Part numbers
What options are available?
There are a couple of options available for this turbo. You can use a standard K04-064 as you would get from a dealer. You can have a Anti-surge wheel fitted by Beach Buggy Turbos, which is very popular due to the turbos surge point at low RPM at around 1.3bar boost. Alternatively, there are hybrid options available from the liked of The Turbo Engineers, who produce the massively popular TTE420 thats found on the mk5 platforms. Beach Buggy Turbo’s have also got a hybrid available called the BBT430. Both hybrids are considered excellent upgrades over standard units and always hit bang on the power figures quoted. We must say though, as these are aimed at mk5 TFSI platform, hybrid names are power figures achieved on the TFSI engine, rather than a 1.8T. Typically, hybrids on a 1.8T will be a bit less power than their newer equilivant. As a example, Chris Carse has a TTE420, (named a TTE390 for 1.8T) fitted to his forged 1.8T. During mapping this turbo hit the mark at 386bhp, 360lbft with a set of noisy pistons with R-Tech Performance mapping back in April 2016. So as you can see, even the hybrids make great power from the standard form turbo. What about the BBT Anti Surge option… As most people doing this K04-064 conversion will probably end up buying a used 2nd hand turbo from somebody upgrading or breaking a motor, the best advice for peace of mind is to send the turbo away for a health check-up before fitting to make sure everything is as it should and there is no signs of wear which could cause the turbo to fail when fitted. (It’s best to make sure right?) Probably the most common way to do this is also to fit a anti surge compressor wheel, which is a direct replacement fit, to ensure the surge point is gone at lower RPM when loading the turbo up hard. This allows us to bring the boost in quicker without risk of damaging the turbo.
What’s the expected power output?
With this turbo, you can expect around about 355-365bhp and around the same amount of torque. This can depend on the rest of the setup and also how healthy your engine is. A couple of others have seen a touch more power, but we will say the above power/torque figures are the average. With excellent partial throttle around town driving, and masses of power instantly there when the loud pedal is mashed it makes a superb all rounder and chances are, its going to embarass 99% of cars that fancy their chances off a roundabout 😉
How does it match up to a 20vT head?
There are a couple of options around for fitting this to a 1.8T 20vT head. Port spacing is the same, which is a great advantage for us that want to fit it….however, fitment is completely different. 1.8T uses studs out of the head all round, whereas the TFSI uses a angled bracket at the base of the exhaust outlets and studs across the top. All is not lost though for fitting, and there are ‘Off-the-shelf’ options available which makes our life 1000x easier for fitting. Three options are available… The most common is a adapter plate from CB Auto-solutions. Its around 25mm thick steel and bolts to the 1.8T head with a set of allen fasteners which mimics the TFSI head which allows the turbo to bolt onto. This allows the TFSI angled brackets to be fitted to the adapter and a row of angled studs across the top to match the angled fitting on the top of the turbo exhast manifold. The alternative is The Turbo Engineers do a CNC exhaust manifold and a custom machined retainer plate which allows it to bolt directly to the 20vT head, without the use of an adapter plate, saving ~25mm which is a great option if your limited on space at the back of the engine if its going on anything other than a mk4 golf. Another route, is you can modify the TFSI exhaust housing yourself and buy a kit off eBay which consists of angled spacer pieces to hold the turbo to the head. This is the cheapest way to do it, if you are confident grinding your own manifold yourself, however a drawback is using a angled spacer to hold the turbo to the head will add excess stress to the head studs and could cause them to snap.
WHAT’S IT GOING TO COST?
Probably the most important question right? The trouble here is it all depends how well you can source the parts and whether you are going to be able to fit the parts yourself or need to use of a garage to fit them, which will be fairly labour intensive. Its also recommended that a set up upgraded rods are fitted to the engine due to the torque which in itself a about a £1,000 job to DIY or around £1,500 if labour is required. For the actual getting the turbo reliably running, we’d say budget around £5-6000 when you look at the big picture and all the supporting mods you are going to require such as charge cooling, fuelling upgrades, custom downpipes and boost pipework, air intakes etc and of course custom mapping. It could work out cheaper if you are adding on top of already modified setups which have the parts needed for this conversion. However, we’d hate to underestimate the cost of the conversion and have people think it costs far less, and have them left 1/4-1/2 way through a conversion and run out of cash for parts. If you already have air cooling and fuelling in place, then you ‘could’ get away with a budget of around £1500 for the turbo change if you can DIY it yourself at home…however, this depends on your competence in fabricating a few parts and doing the change yourself. Our advice is to work out exactly how much it would cost you in parts quotes and labour, then decide whether you can financially afford it….the same with any turbo upgrade or modifications.
How hard is it to do a DIY 1.8t k04-064 conversion ?
This all depends how good you are with a set of spanners. We’d say around 90% of the parts needed to fit this are available off the shelf to fit, so in terms of having to fabricate pipework up and go get things welded up etc then its pretty minimal for that. The custom parts you are going to require are going to be, Air Intake, Downpipe, Charge pipe off the turbo, Cold side boost pipework, Dump valve relocation, Oil return pipe from the turbo to sump and a custom turbo support bracket to secure the turbo. However, depending on how you do it, that list could increase a touch. A small modification is required to the mk4 engine bay bulkhead and turbo where the steering rack knuckle comes through. A light tap with a rubber hammer to push the metal back enough to clear the turbo is all that’s needed. There is a block of metal on the rear of the compressor housing which needs grinding flat to aid clearance in this location too. As well as the above, the compressor housing requires ‘clocking’ a few degrees in order to clear the master cylinder and also to clear the side of the head nearest the cambelt. Details of which are shown below. All of the oil/coolant lines (with the exception of the oil return) are available off the shelf or dealer items. Please see our Part Number section below for details of that.
The air intake can be a simple reducer off the turbo, to run along the rear of the engine across the top of the exhaust manifold, and have a 45* bend to bring the air filter and MAF sensor to the normal location for the air filter.
Downpipe fitment is probably the most labour intensive part of the process, however, in reality, its actually a fairly easy downpipe in terms of pre-made bends, and flexi to bring it to match a good quality cat-back exhaust. You are going to need a TFSI turbo exhaust flange, which can be bought off eBay for around £25-30 in 10mm stainless steel. 1x 90* bend, 1x short exhaust flexi, 1x 45* bend to bring your downpipe to the right angle of the remaining exhaust system.
Charge Pipework and Dump Valve
There are a few options that you can route the hot side boost pipework directly off the turbo. Probably one of the easiest methods is the use the OEM ‘red’ charge pipe which clips into the turbo. This will bring the pipe down the side of the crank pulley under the chassis leg. You will need to fabricate a spacer bracket up to secure it to the engine otherwise it will simply hang and flop around and potentially hit the crank pulley and belt setups. You can get a piece of alloy straight pipe welded to this to then head to the front to the intercooler The second option is a 10mm alloy flange that you can bolt to the turbo and make your own custom hard pipework up. However, it is very tight to fit all of this between the chassis leg, crank pulley and driveshaft to get the right angle to head off to the front of the car to the intercooler. Finally, there are billet CNC adpaters available off eBay which you can bolt onto the outlet of the turbo (be careful with the large rubber o-ring) which will allow you to use a silicone elbow rather than a hard pipe. All methods are trialled and proven to work so whichever route you opt for, make sure there is plenty clearance between the chassis leg, driveshaft and crank pulley when the car is loaded on the ground. Its also advised to run a silicone coupler between any hard piping to allow for natural engine rock to avoid stress on any welded joins to give the setup a bit of ‘flex’. The cold side of the pipework is a bit easier, depending which inlet manifold you choose to run; Whether your throttle body is on the left or right hand side. If your running a AGU large port plenum, with the throttle body on the timing belt side, then you will have to be a touch more creative with your pipework as you will end up with a longer run if your using the common wellycooler setup with a inlet/outlet on each side. Some people have done setups feeding the hot side of the pipe across the rear of the radiator to the passenger side and joined into the cooler from that side, and ran pipes up to the manifold behind the drivers side headlight. Just remember with pipework, you want to try avoiding as many tight bends as possible and keep it short and free-flowing to aid flow and air speed. Check out our intercooler choice section for more info. If your running a small port head, and have a inlet with the throttle body on the left (timing belt) side, then we’d suggest the easiest option would be to switch to a BAM inlet (with the throttle body on the right) and run your hot pipework into the drivers side of the FMIC and the cold side out the passenger side and you can get away with a couple of angled silicone spacers and a 90* alloy bend and angle this upwards to the throttle body on the right. Nice and simple and minimum bends. The dump valve is probably best off on the cold side on these setups, as you can again, minimise pipe length and also keep things tidy. Most setup’s we’ve seen have put the dump valve near the battery/top radiator hose and ran a length of silicone pipework to the intake to allow the air to recirculate. Its important any dump valve charge air is put back into the intake post MAF sensor as the air has already had fuelling calculations done for it. Alternatively, you can run it hot side and a pipe up over the cam belt side and into the inlet manifold just before your silicone angled reducer onto the turbo. Which ever way you choose, our best advice is to research people’s builds and see how/what others have done and copy similar results. Please have a look at our Front Mount Intercooler setup/advice page where more detail on selecting a good FMIC core is given and advice on pipework Please click here for the link to the Intercooler section.
The oil return is made up of two halves of a OEM item. The K04-064 part off the bottom of the turbo and the part which bolts to the 1.8T sump, thats off a K03 turbo. These can then be joined with a piece of oil resistant hose thats properly clamped in-between to ensure no leaks. It is also possible to just use the K03 drain but this isn’t as simple. The pipes need modifying to ensure correct fitment and sealing (as can be seen in the pictures below) this includes altering the angle of the pipe and also grinding the side of the flange face to allow it to sit flush against the turbo core. As there is a driveshaft directly below, it should be noted that your pipe is sufficiently clear of it to avoid catching/rubbing in term damaging the pipe.
Turbo Support Bracket
It is vital that you adequately support the turbo to the engine with a bracket to take the weight. This relieves stress on the manifold and the turbo itself and prevents anything from cracking. This one lets you be creative and requires a bit of imagination and welding to make sure its properly supported. We’ll share a few pictures of what people have come up with to give you some idea of what can be done.
Bulkhead and Turbo Modification
With a mk4 engine bay and the TFSI k04-064, there is a tiny bit of modification to do to the bulkhead steering buldge and also the compressor housing. If you look at the compressor housing on the turbo, there is a 10mmx25mm length of alloy block. This needs to be ground down to near flat (dont go totally flat or the casing might become a bit thin). This aids clearance at the rear. Also, the bulge needs knocking back slightly with a rubber hammer for the compressor casing to clear. Ideally, this wants to be a small flat bit around 1.5″square. Make sure that the UJ knuckle inside the car can still clear it on full lock to avoid any interference with the steering column. There a few pictures below showing the necessary modifications to both these areas.
Compressor Housing Clocking
As the 1.8T is slightly different to the TFSI engine. We need to slightly ‘clock’ the turbo in order for it to clear the rear of the head by the cambelt and also the master cylinder. We’ve found the easiest way to do this is to get all the turbo sat on the car with the adaptor plate and have the 4x 10mm retaining bolts on the cold side compressor loosened 1/2 a turn so the casing can be rotated. Now, put your silicone 90* reducer on the turbo intake with a jubilee clamp and rotate the housing so it clears the side of the head but there is enough space in future to remove/refit the silicone reducer onto the turbo if required. With ~10mm space with these parts fitted, it should be in the best position to clear the master cylinder and have the turbo boost outlet in a good place underneath for your boost pipework. As you can see from some of the above modifications that are needed to DIY, there is a bit of custom modification work to be done. Depending on your ability, this may or may not be too hard to do. We’ll go into some more detail about the other parts needed below in detail aswell, but these are more of a ‘bolt-on’ kind due to being a OEM/off the shelf item.
Getting it all to fit
In this section we will explain each process of getting everything to fit. Some of the modifications have been covered above, so this section is in addition to that and will describe the fitting of the OEM off-the-shelf parts. Whilst this conversion is possible with the engine in the car, the task is made harder, to we recommend pulling the engine and box out as one to make access to the rear of the engine easier and also allow modification to the bulkhead as listed above.
If you have chosen to use the CB-Auto solutions adapter plate to assist fitting your turbo, then we are going to fit that first to the 1.8T 20v head. Your kit will have come with all the relevant hardware to fit it (excluding the gaskets). Remove all of the OEM studs from the head using a stud extractor or locking 2 nuts together and winding them out. Use the hex bolts to secure the adapter plate to the head with a OEM 1.8T gasket inbetween to prevent exhaust gas leaks. Once all of the bolts have been tightened and the plate is secure, you can put a stud in the bottom of the adapter plate for the angled TFSI brackets. Due to the clocking of the turbo housing there is a slight modification needed to the drivers side angled bracket to allow the turbo to clear it (see image below). You can fit the two angled brackets at this point and leave them loose until the turbo is fitted if you want at this stage
The turbo is the next part to fit. As we fitted the angled brackets when we fitted the adapter, we can simply sit the TFSI gasket in against them and fit the turbo. It is very important to ensure that the TFSI gasket does not ‘ride up’ or get pushed up when the turbo is sat in as this will mean the gasket sits in the exhaust gas stream and will cause the gasket to fail prematurely. Once you are confident the gasket is properly located. (you can sit the gasket on before fitting the turbo and mark the adapter with a sharpie to use as a reference when the turbo is fitted that the lines are still visible and it hasnt moved). Fit the top row of studs, or bolts if you choose and tighten the turbo up to the adapter plate. Once this is done, you should have your turbo mounted to the 1.8T 20v head properly and your ready for the next step.
The oil feed is a nice easy part to fit, and will bolt to the standard locations. We recommend that you use new copper washers to prevent any leaks from re-using old parts. Firstly though, we have to fit an adapter union (part number listed below) to the turbo to allow the oil feed line to match up to it. Fit the oil feed to the front oil filter housing and run it under the coolant pipes at the side of the head, like the original K03/K04 item would. You will need to bend the last of the hard pipe backwards a bit before the braided section to it fits comfortably. As the turbo is fitted, we can bend it enough so the line is fitting without being stretched. You can tighten this union now.
The coolant feed is a TFSI item which bolts to the rear of the block and to the turbo. This is a easy enough process and will require banjo bolts, washers and a spacer piece that fits to the block with a banjo. The connection to the block requires a longer banjo than originally fitted so you will need to order one using the part number below. You can then fit the coolant pipe, with washers each side of it, then put the little steel spacer with a final copper washer before bolting it up to the block. You can now bolt the last side to the turbo, again with copper washers and fully tighten.
The coolant return is a TFSI item which returns the coolant thats been fed through the turbo to assist cooling and returns it back into the system, just before the header tank. The TFSI item is a great fit and will ‘near enough’ return it to the standard ‘Y’ piece connector thats found on standard K03/K04 setups. So with a small amount of work, you can easily get this to join back into the OEM pipework that’s beside the timing cover/coolant bottle. As we have clocked the turbo, the standard bolt retaining clip will no longer match up, so the bolt which would hold this to the turbo, just below the actuator, cant be fitted. Dont worry too much about it though, the pipe will be perfectly fine without it.
N75 Valve Wiring
Thankfully, the TFSI turbo has a ‘integrated’ N75 valve which fixes onto the compressor housing and is all neatly arranged on the turbo. Our 1.8T ECU’s will work perfectly fine with the TFSI N75, however we will need to do a bit of work. The 1.8T uses a different plug to the TFSI item, so we will need to get a plug and bit of wiring harness that will clip into the TFSI N75. Once we have that, we can extend the wires to the original N75 valve and join them in. A neat little option here is to buy a male junior plug and crimp that onto your extended TFSI harness and clip it into the original 1.8T N75. This makes any further work in the future such as removing the turbo or wiring loom a lot easier as its very tight against the chassis leg once the engine/turbo is in situ in the car.
What part numbers?
We have a list of the major parts you need for your conversion below. Whilst there are a lot more parts that you could need, this list should cover the fundamentals of everything you need in terms of gaskets, coolant/oil pipes and any other necessary parts.
|Oil Return Gasket (turbo side)||06F 145 757 C or L|
|Oil Return Gasket (sump side)||058 145 757 A or C|
|Coolant Feed Banjo to Block||06A 145 541 H|
|1.8T Exhaust Manifold Gasket||058 253 039 L|
|TFSI Exhaust Manifold Gasket||06F 253 039 F|
|Downpipe Gasket to Turbo||1K0 253 115 AB|
|Coolant Feed Spacer to Block||06A 121 279|
|Coolant Return Copper Washers||N 013 814 9|
|Bolt for Turbo Oil Return to Turbo||N 014 702 13|
|Oil Feed Adapter onto Turbo||N 020 704 3|
|Copper Nuts for Downpipe Studs on Turbo||N 102 861 08|
|Coolant Feed Copper Washers||N 013 814 9|
|Oil Feed Pipe||06B 145 771 N or P|
|Coolant Feed Pipe||06F 121 497 G|
|Coolant Return Pipe||06F 121 492 L|
|TFSI Oil Return Pipe||06F 145 735 D|
|Standard K04-064 Turbo||06F 145 702 C|
*Please note, that whilst we try hard to ensure part numbers are accurate…VW are prone to superceeding them on a regular basis with part revisions. However, they should be able to get that parts you require off the numbers above.
With running a much bigger turbo than standard, we are going to have to give our engine a bit more fuel to make sure that it doesnt run look and theres plenty of fuel to keep it cool. Generally, the recommended option for injectors is 600cc @ 3bar which is enough for a standard turbo and hybrid K04-064. However, as with all fuelling upgrades, it’s best to speak to your chosen mapper/tuner to see what they recommend and are competant in scaling into the ECU remap when the time comes. The injectors we recommend are Bosch EV14 with the Bosch part number #0280 158 298. These are Ford Racing injectors and can typically be picked up at a good price off eBay in the USA or through any decent part suppliers in the UK. Beach Buggy Turbos generally keep stock of these. There is plenty of scaling data available to assist mappers/tuners scaling them in and they have a great linear responce unlike other injectors such as ‘Dekas’ where you can get occasional idle misfires or a lumpy idle. You are also going to need a uprated intake fuel pump, if you havent already got one already. Coming up to 10-15year old the 1.8T intank pumps are generally showing their age when they are asked to supply a lot more fuel over standard….even on K03s or K04 setups where higher revs you get a AFR plot that doesnt follow specified in the ECU as it cant supply enough fuel pressure to the injector rail. One of the best aftermarket ‘Drop-in’ fuel pumps for the tank is the DeatschWerks DW65. There are a couple of different revisions available depending on vehicle fitment, such as 2WD or 4WD so take care when ordering. There are many suppliers who keep these in on the shelf and will make sure you get the right fitment for your car.