Mapping a 1.8T for Killarney's Long Straight

Killarney does not care about your peak number. The long straight rewards a car that pulls cleanly out of the last corner and keeps pulling, so the first map we ran was wrong in a way the dyno never showed us. It made 214 kW on the rollers and then dropped timing by lap three, every session, like clockwork.

The owner logs everything. Intake temps, boost, ambient, session length, tyre pressures. After two race weekends the pattern was obvious: the charge cooler was heat-soaking, and the map was asking for boost the intercooler could not support once the car sat in traffic on the grid. We pulled the target from 1.4 bar down to 1.15 bar and rebuilt the timing table around what the intake temps actually did on track, not what they did on a single hero pull.

The intake and exhaust changes that made the difference were boring. A larger front-mount core, a proper duct from the bumper instead of the factory slot, and a 76 mm downpipe that stopped the turbo choking above 5,500 rpm. The parts that did not help: a cold air intake that pulled hot air off the radiator, and a blow-off valve that leaked under sustained boost. Both came off.

The revised dyno sheet reads lower at the top end and holds flat past 6,500 rpm. On the stopwatch it is quicker out of the last corner by roughly three tenths, session after session, which is the only number that matters here.