Which tuning stage should you start with?Build Ladder blog

Start with how you use the car

Before you look at horsepower numbers, be honest about what the car is for. A car you drive to work every day needs to start, idle and behave like a normal car in traffic. A weekend car can be louder and less comfortable. A drag or track build can give up comfort completely.

• Daily driver: Stage 1, maybe Stage 2.
• Daily driver that sees the occasional track day: Stage 2 with good cooling and brakes.
• Weekend or track car: Stage 2 or Stage 3.
• Drag or show build: Stage 3 or Stage 4.

Stage 1: the best place to start

Stage 1 is a new file on the factory engine computer, with no parts. On modern turbo cars it is usually the biggest gain for the least money, it keeps the car comfortable, and most tunes can be flashed back to stock. If you are not sure where to start, start here.

Two things are worth adding early: a gearbox tune on automatic and DSG cars, so the extra torque does not wear the clutches, and an intercooler upgrade on cars that heat-soak easily in hot weather.

Stage 2: more power, more decisions

Stage 2 adds breathing parts, most importantly a downpipe, and a file written for them. This is where you have to think about the law: a downpipe without a catalytic converter is not road legal in most countries. Choose a catalysed downpipe if the car has to pass inspection, and check whether your gearbox or clutch needs an upgrade at this torque.

Stage 3: a different kind of project

Stage 3 means a bigger turbo, and usually a better fuel system and gearbox to go with it. The turbo is often not the most expensive part of the job once you add the fuel system, gearbox work and labour. Many Stage 3 files are designed around ethanol fuel such as E85, so check that you can actually buy it where you live.

Stage 4: an engine build

Stage 4 means rebuilding the engine with forged internals so it can take much more boost. It is a project for drag, roll-race and show cars, and it works best when one shop builds, tunes and stands behind the whole package.

One car up the ladder: the Golf GTI Mk7

The Golf GTI Mk7 guide shows how cost and effort grow at each step. Figures are the tuners' claims and list prices.

• Stock: 210 hp from the 2.0 TSI EA888 Gen 3 with the small IS20 turbo.
• Stage 1: 290–337 hp, depending on the file and the fuel, for $500–$560 of software. On DSG cars the 6-speed DQ250 is rated at 350 Nm and most Stage 1 files make more, so budget $399.96–$549.95 for APR's gearbox software as well (see do you need a DSG tune?).
• Stage 2: 334–351 hp. APR uses the same $560 file, but you add a downpipe ($850–$880) and usually an intercooler ($540–$1,200). That is about $1,400–$2,100 in parts for roughly 45 hp more at the bottom of the range.
• Stage 3: about 380–400 hp with the Golf R's bigger IS38 turbo. ECS lists an IS38 kit at $1,075.44, and a fuel pump kit ($339.99) and a front differential ($1,495 for the Wavetrac DSG diff) often follow.
• Stage 4: 500+ hp on a forged bottom end. The bottom-end build is roughly $2,000–$3,000; a connecting rod through the block of a stock engine is a $5,000–$8,000 repair.

Stage 1 gives by far the most power per dollar. Each later step costs several times more, and at Stage 4 most of the money goes into making the engine survive.

How much each step adds

Our Stage 1 vs Stage 2 comparison puts numbers on this for eight cars. Measured from the bottom of each range, Stage 1 adds 13–38% over stock, and Stage 2 adds a further 4–15%. The Audi S3 8V is a clear case: +22% at Stage 1, then only +4% at Stage 2 with an intake and an intercooler. The GTI Mk7 gains more (+15%) because its factory downpipe and intercooler are small. On a well-equipped car, Stage 2 is mostly about keeping power on hot days.

Common mistakes

• Running a Stage 2 file without the parts. Without the downpipe and cooling it was written for, the car runs outside what the tuner tested.
• Reading the E85 figure. On the Golf R Mk8, APR's Stage 1 runs from 398 hp on US 91 to 442 hp on E85. E85 isn't sold at Israeli pumps, so the lower figure is the real one there.
• Forgetting the gearbox. On DSG and manual cars the clutch is often the first part to complain. Ask for a low-torque file or a gearbox tune from the start.
• Tuning a tired car. Worn plugs and coils show up as misfires once boost goes up.
• Buying a turbo before a plan. A turbo needs its own file, and usually a fuel pump and gearbox work. If you expect to pass 450 hp on a GTI, our guide suggests a hybrid turbo from the start, so you don't buy a turbo twice.
• Mixing suppliers at Stage 4. It is the most common reason big builds fail.

Five questions to answer before you choose

1. Will the car still be used every day?
2. Can I buy the fuel the tune needs, every time I fill up?
3. Is my gearbox or clutch ready for the extra torque?
4. Does the car need to stay road legal and pass inspection?
5. Have I budgeted for maintenance, not just the tune?

Our advice

Start with Stage 1 and a gearbox tune, drive the car for a few weeks, and log how it behaves. Most people discover that Stage 1 is all they need. If you want more, you will then know exactly which part is holding the car back, and our guides show what each next step asks for.

Quick answers

Can I skip Stage 1 and go straight to Stage 2? Yes, if the parts go on first. On the GTI Mk7 our guide lists the same $560 APR file for Stage 1 and Stage 2, so the extra cost is the hardware and the fitting.

Can I go back to stock? Most flash tunes can be returned to the factory file. Ask what that costs first, and keep the original parts.

Does Stage 1 need 98 octane? Not always. Many tuners sell one file for 95 and another for 98. Choose the one for the fuel you actually buy: see 95 or 98 after a tune.

Is a tuned car legal in Israel? Only with approval. Under Regulation 380, a software or exhaust change needs written approval from the licensing authority. See getting a modification approved.

Keep reading

• How to tune your car, step by step
• Keeping a tuned car legal and insured