VW/Audi 1.8T 20v Stage 4 Tune (Big Turbo) AWW/AWP/AWM/BEA

STAGE 4: BIG TURBO, CUSTOM CALIBRATION

Fits

1.8T 20v with engine code AWW (150 hp, 2000-2005), AUM (150 hp, 2001-2005) or AWP (180 hp, 2000-2005) in the MK4 Golf, GTI and Jetta, AWV (150 hp, 2002-2005) or AWP in the New Beetle, and the same AWP in the Audi TT 180 (8N, 2000-2005). AWM (170 hp, 2001-2005, longitudinal) in the Audi A4 B5 and VW Passat B5.5. AMB (170 hp, 2002-2005, longitudinal, returnless fuel system) in the Audi A4 B6. BEA (225 hp) in the US Audi TT 225. They are grouped on one listing because a big turbo build takes the same path on all of them. The calibration itself is written for your engine code and your build. Not sure which code you have? Find your engine code in two minutes. AWD, APH, AMU and ATC are narrowband and need a wideband conversion first. That is not optional here.

What Stage 4 does

Stage 4 is a custom calibration built around your turbo, your injectors, your MAF setup and your fuel. It is for big turbo builds, GT28 class and up. Written for 93 octane / 98 RON and adapts to 91 / 95. Speed limiter removed, rev limit raised to 7500 with a stock head. The factory ME7 has a hard internal ceiling at 2550 mbar. We run the 5120 patch, which lifts that ceiling, so the ECU can ask for what the turbo can actually deliver. We have done a lot of 500 to 600 whp builds on the stock ECU over the years. It is not the limit. Program switching and launch control are built in. Tested on the street and the track to be smooth yet powerful. If the turbo is a K04 or a K04 hybrid, you want Stage 3 instead. Previously sold as Gonzo Tuning Stage 4.

What you need on the car

• Turbo: GT28 to PT6262 class or similar. Garrett GTX2867R, GT28RS, GT2871R, GT3071R and GT35R, BorgWarner EFR 7163, Precision PT5858 and PT6262 are all common here.
• Injectors: 630cc minimum, and sizing scales with the turbo up to 1000cc. E85 needs 830cc.
• MAF: an S4 3 inch ID housing with the stock sensor inside, or MAFless. Tell us which.
• MAP sensor: a 3 bar or 4 bar sensor if you are targeting anything above 2550 mbar. The 5120 patch goes with it.
• AMB: the returnless fuel system has no return line to fit a regulator to. Convert it to a standard return-style system before you order anything for a big turbo build.
• Also required: turbo-back exhaust, front mount intercooler, upgraded diverter valve. Wideband conversion if the car came narrowband (AWD, APH, AMU, ATC).
• Rods: at this power the factory rods are a liability. Plan on forged rods for anything meant to be driven reliably.
• Clutch: plan on one. A factory clutch will not hold this.

After you order

1. Order. Choose Remote Tuning. Put your turbo, injectors, MAF housing or MAFless, and fuel in the order comments, or email us before you order if you are not sure the build is ready. A GTS cable ships with your order for a one-time $40 and it is yours to keep for every tune after this one. Already have one? Choose "I already have a GTS Remote Tuning cable".
2. Read. Plug the cable into the OBD port and a Windows laptop, Windows 10 or later. An Intel Mac on Boot Camp works too. Our software identifies your ECU and saves your original calibration before anything is written.
3. Flash. We build the calibration for your engine code and your build. You get a message the moment it is ready, and you flash it yourself in your driveway in about ten minutes.
4. Log. Drive, log, send. A big turbo build takes a revision or two to dial in, and we read every log. Revisions usually come back the same day, and within 72 hours at the outside.

Prefer to mail the ECU in? Mail-in is free within the USA and Canada. We flash it on the bench and send it back in one to two days. How remote tuning works, start to finish.

Options explained

• Launch control: Soft (no pops) is included free. Hard 2-step / antilag is an add-on, for off-road and competition use. Pick None if you do not want it.
• No-lift shift: included free with every GTS tune.
• Program switching add-ons: Stage 4 runs Stock and Tuned on one flash, switched from the driver's seat with no laptop. Add an E85 program, a 100 octane program, or a Valet program to the switcher.
• Pops and bangs: exhaust crackle on lift-off.
• Hard cut: a hard fuel cut at the rev limit instead of the factory soft limiter.
• IMMO delete: removes the immobilizer check so a swapped or spare ECU runs without the key and cluster handshake.
• Spare ECU: we supply a tuned ECU so your original stays untouched on the shelf.
• Mail or Remote: remote is what most owners pick. Mail-in if you would rather not touch a laptop. Own cable if you have tuned with us before.

Stage ladder by engine code

Stage 3 and Stage 4 are custom calibrations built for your turbo; what each one needs on the car is on its own page. On the TT 180, the AWM and the AMB, the lower stages are one listing with a Stage option. Read the 1.8T 20v Tuning Guide for what each stage really gains and which codes need a wideband swap first.