Hi all,

I'm running a 2015 Skoda Octavia vRS 2.0 TDI (184hp model) that has Revo Panel airfilter and air scoop, Darkside Developments Downpipe and been remapped to approx. 227hp / 480Nm. Under full-throttle acceleration in 4th to 6th gear, particularly above 190 km/h, I sometimes get an intermittent P0234 – Boost Pressure Regulation: Limit Exceeded (Overboost Condition).

I’ve logged the car using VCDS during high-speed pulls. Boost specified and actual track very closely (targeting ~2849 hPa at peak), with no spikes beyond requested. However, I noticed charge air temperatures (IAT post-turbo) climbing from ~96°C up to 148°C during sustained WOT — which I suspect is triggering a protective overboost flag due to thermal stress, not actual overboost.

MAF values are healthy, and the VNT actuator is responding properly. This only occurs at high speeds under sustained load.

Has anyone experienced similar behavior with high IATs triggering overboost codes on a remapped TDI? Would a better Charge Cooler pipe resolve this? or should I look into ECU compensation maps?

Here is some logs i did in VCDS and also asked Ai to do a little graph.

Appreciate any insights.

LOG-01-IDE00021_&11.CSV.xlsx

Improving the charge cooler would always be a benefit so probably not a bad route to start with. Afraid I can't offer first hand of the actual thing you are seeing but your logic stands up. How is the clutch coping? Are there any torque increases with the over boost events? Is it WOT only or at other times too?

Did Darkside do all the work as well as supply the downpipe? Worth discussing with them given their reputation for diesel tuning?

Would def agree that charge-cooling will never be a bad idea - but not sure on whether the temps quoted are within tolerances etc. They seem fairly stratospheric - but plenty more experienced than me will confirm or (more likely) correct me!

Edited 9 June9 Jun by travs