Stage 2 - 240bhp - Stock Engine & TD04 Turbo - Tuning a 4E-FTE

Stage 2 is of UKSO's Tuning Walk-throughs is here! After the first guide was so extremely popular and showing owners how to boost performance from the factory 130bhp to around the 200bhp mark, people were soon wanting more and more and to extract that little extra performance from their cars without spending a huge amount of money!

In Stage 1 of tuning your turbo starlet, we maxed out the standard turbo charger. The standard CT9 turbo runs out of puff at the 200bhp mark, however the standard engine is capable of pushing a touch more performance before the internals need changing to handle more power.

Stage 2 is going to cover swapping out the standard CT9 turbocharger setup for a much bigger TD04L unit. The TD04L turbocharger is commonly found on the classic Subaru Impreza Turbo, and because these cars are so popular the spares and parts on the 2nd hand market are just as big. A standard TD04L in good working order can be had for between £40-120 depending upon mileage and their condition.

A Few Things To Think About!

Turbo Kits

Race-Tech's TD04 Conversion Kit

Companies such as Race-Tech & WEPR offer complete conversion kits including everything you need to convert your car, providing you have already tuned your car to Stage 1. If you're converting a standard starlet turbo to a TD04 then additional parts will be required. This guide is going to go through the conversion part by part, as if you were building your own conversion kit up and upgrading from Stage 1!

Lag?

Standard CT9 On Left & Standard TD04L on Right

This always brings in a huge debate, its mainly from keyboard heroes that are still rocking CT9 turbos but here is my opinion on the subject. If you're considering converting to a TD04 turbo setup and you are worried about lag, try and find someone local to you that could take you out for a passenger ride. Until you've been in a well setup TD04 converted starlet then save your judgment. The additional torque and power available for a small sacrifice of maybe 700-800rpms is more than worth it. On top of this, CT9s are out of puff towards 6500rpm and TD04s pull to the limiter. There are many things that can done in the future to help reduce lag, shorter intercooler pipework, electronic boost controllers and even billet wheel hybrid TD04s.

Engine Health

As mentioned in Stage 1, when extracting more power from an engine, its health is a priority. When you're going to be pushing close to double the original power output, then health is a major priority. These engines were produced between 1989-1999, they aren't getting any younger and mechanical fatigue is going to get the better of them sooner or later. I would highly recommend you run a compression test to ensure the engine is of good health and service it every 4000-5000miles if you can to prolong its life. There's no reason why it wont last just as long as it would have on the standard turbo, providing it's cared for, treated right and not thrashed from cold every morning.

Internal Wastegate or External Wastegate

Both the CT9 and the TD04 are internal wastegated turbochargers, their boost levels are controlled by a spring loaded actuator which is connected to a flap that's built into the design of the exhaust housing. When the desired boost limit is reached the flap opens and dumps excess exhaust gas down the exhaust, making the exhaust louder.

On an external wastegate setup, the standard internal wastegate flap would need welding up solid as it would no longer be used. Instead, the exhaust manifold will have a take-off to fit an external wastegate unit. Basically a spring loaded valve, which does the same job, but are far superior when holding a boost level. They usually also vent the excess exhaust gas through a screamer pipe. These are VERY loud and when your car comes on boost, the noise can only be described as a thrusting rocket jet type noise.

An external wastegate setup is far superior over using the standard internal wastegate setup and will hold boost much better when going over 1bar of pressure. They do however cost much more to buy as will the manifold to suit, but it is money well spent!

Collecting Parts Yourself!

Manifold & Downpipe

The first part of the conversion kit that you're going to need is a different manifold and downpipe. As the TD04 has different flanges on both sides and is a lot bigger in size, it needs mounting further away from the engine. This will allow you to physically mount the turbocharger on the engine. The downpipes are designed to bolt up to your existing 3 bolt flanged exhaust system. These can be purchased from UKSO Trader Race-Tech or from other companies such as WEPR or Zisco Performance.

TD04L Turbocharger

The TD04 turbocharger itself can be purchased from a few different places depending how much you wish to spend. Searching 'TD04L' on ebay will bring up lots of them for between £40-£120 depending upon mileage and condition. If you'd rather purchase new, reconditioned units can be purchased from many places including Traders on UKSO. The best and most expensive way is to purchase a Hybrid Billet Wheel TD04 from Race-Tech or Tuning Developments. Spooling much faster, yet still producing more power they are the best out of them all. They do however come with a hefty price tag.

TD04 Oil Lines

The standard CT9 turbocharger is cooled & lubricated by both Oil & Water. The oil lines are different on the TD04 turbocharger. An Oil Feed Line would be required to go from the oil filter housing to the turbocharger and a silicone oil return line to go from the turbocharger to the sump pan. The Oil Feed Line can be had from Race-Tech, Tuning Developments & Zisco Performance. The oil return pipe is just a simple 90 degree silicone bend which can be purchased from any decent silicone hose supplier.

TD04L Oil Return Size - 16mm

4E-FTE Sump Oil Return Size - 19mm

TD04 Water Lines

The water lines aren't actually necessary on the TD04 turbocharger, many users have run them with and without water lines. There have been reports of much cooler engine water temps when not using turbo water lines. The water line kits can be purchased from the same traders as the oil lines. If you're going to run without them a simple 'U' shape blanking silicone pipe will be required to blank off the outputs from the thermostat housing.

Hot Side Intercooler Pipework

The hot side intercooler pipe is also different as the standard CT9 turbocharger outputs upward and the TD04 turbocharger outputs downwards. With the majority of front mounted intercooler kits, all that is required is a 90deg alloy bend and 2 silicone joiners. This will vary though depending upon the intercooler kit you have and which turbo manifold you've chosen.

Air Filter/New Mesh

The TD04's intake is also much much bigger then that of the CT9. So some new mesh or a new filter setup will be required. See a guide on how to do this here:

http://www.ukstarletowners.com/page/articles.html/_/engineandtuning/turbo-mesh-r17

Adjustable Fuel Pressure Regulator

This is not deemed 100% necessary on this conversion as the fuelling can be adjusted perfectly with the ECU. However it is a very useful bit of adjustment for any tuner to get your fuelling just right. A bit of extra pressure may also save you the hassle of having to go to bigger injectors! If you get hold of one with a gauge its also handy to get it setup perfectly! An adaptor will be needed to connect one up to the starlet fuel rail.

Management/Mapping

This is where you're going to save some money if you spent money on an E-Manage Piggyback ECU from the Stage 1 Tuning Guide.

The plug and play ECUs aren't designed to work with a turbo as large as the TD04L so if you went down the mappable ECU route, be it Piggyback or Standalone, you can simply take a slow off boost drive back to your tuning specialist and have the ecu remapped again to suit the larger turbo.

So....

Once again at the end of another stage of a tuning walkthrough! If you've followed the guide your car should now be producing 220-240bhp depending on the health of your engine and turbocharger. Just like Stage 1 it wont take long for you to get used to this kind of performance and the search for even more power will hit you again! Be warned though Stage 3 is where serious money becomes a factor and the engine will require an overhaul with stronger components to be able to handle more boost pressure!

Please Check Back Soon for Stage 3

The spec of aaddzz123's car when he was running a standard engine and TD04L setup: