Known Velocity

Dispatches from the Pit Lane

Build diaries from backyard garages, technical explainers on mapping and suspension, race reports from Killarney and Gauteng, plus lap notes sent in by readers. New posts land every week.

From the current issue

Build diaries, alignment sheets and the arguments that start in the workshop and end on the timing sheet. Three pieces from this month's desk.

Engine bay of a turbocharged car with intake piping and a laptop showing a live tuning map

Engine mapping

Mapping a 1.8T for Killarney's Long Straight

Killarney rewards a clean pull out of the last corner more than a big peak figure, so the map was rebuilt around sustained intake temperatures and safe boost targets rather than a single hero run. The owner logs every session, and the notes show where the first map pulled timing after three laps and where the revised one held steady. The dyno sheet is included with the intake and exhaust changes that made the difference, plus the parts that did not.

Read the build notes
Rally car on a wet gravel stage with mud splattered along the side and a service crew nearby

Rally setup

Suspension Geometry for Wet Western Cape Rally Stages

Wet gravel exposes every compromise in a rally car's setup, and the alignment sheet from this build shows how camber and caster were traded against straight-line stability on the transit sections. The mechanic explains why the original ride height was raised after the first event and how bump stops were reworked to stop the car from skipping on corrugated surfaces. There are also notes on tyre pressures across two different compounds and what the crew changed between stages.

Read the alignment notes
Two car builders standing beside an open engine bay in a backyard garage with tools on a bench

Workshop debate

Naturally Aspirated vs Forced Induction: A Backyard Garage Argument

This is the argument that never ends in a workshop, so two builders put their reasoning on paper: one wants a high-revving naturally aspirated engine with simple electronics, the other wants a turbo conversion with more mid-range torque. The piece covers the actual parts list, the weight difference on the scales, the cooling work each option demands and the reliability history of both approaches in club racing. It ends with the decision they made and what they would change next time.

Read both sides

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