Audi TT Turbo

Reconditioned Audi TT Turbo: fixed geometry on petrol engines, variable geometry on diesel engines

The range covers six petrol engines — from the original 1.8 T through to the latest 2.0 TFSI units — and two diesel engines, the 2.0 TDI 170 and the 2.0 TDI 184. This distinction matters greatly when it comes to the turbo: the TT's petrol engines use turbos with fixed geometry and a wastegate, where boost pressure is regulated by a mechanical valve; the 2.0 TDI engines use variable geometry, with movable vanes that direct exhaust gases according to engine speed. The thermal demands differ considerably: a 2.0 TFSI producing 306 or 310 hp puts the turbo under significantly higher temperatures and pressures than a 1.8 T 180 hp, which is why OEM references differ even between engines of the same capacity.

1.8 T and 2.0 TFSI: one petrol family, very different turbos

The 1.8 T engines (engine codes AJQ, APP, ARY, AUQ, ATC, AWP, BVP, BAM, BFV) cover the early generations of the TT, from 180 hp to 240 hp in quattro form. The base 1.8 T is the only engine on this page for which a reconditioned turbo is available; all other engines are covered by new turbos. The 2.0 TFSI units represent a clear break: the 230/220 hp (engine codes CHHB, CHHC, CNTC, CWZA) and the 1.8 TFSI 180 hp (engine codes CJSA, CJSB) use turbos that are distinct from those fitted to the 2.0 TFSI 306/310 hp (engine codes CJXA, CJXB, CJXC, CJXE, CJXG, CJXH, CYFB, DJHA, DNUA, DNUC, DNUF), which is associated with the IS38 reference and its equivalents. Identifying the engine code stamped on the block is the only reliable way to avoid confusing these turbos, whose CHRA dimensions and actuators differ.

2.0 TDI: variable geometry and specific points to watch

The 2.0 TDI 170 covers a wide range of engine codes (BMN, CBBB, CEGA, CFFA, CFFB, CFGB, CFGC, CFGD, CFJA, CFJB, CLLA, CLLB, DLUB); the 2.0 TDI 184 has just one, CUNA. On these variable-geometry engines, clogged vanes — often caused by a blocked diesel particulate filter or excessive exhaust gas recirculation — are a common cause of seizure and whistling. On both petrol and diesel engines alike, a failing turbo is frequently accompanied by engine oil contamination or deterioration of the oil supply circuit: fitting a new or reconditioned turbo without addressing the root cause will invariably lead to another failure.