Tony Lockhart
Avoiding Stress, at Every Opportunity
It depends how close to the edge some of the components are in endurance terms, a 10% peak force change and related excitation will have an effect on the fatigue calcs for the engine and ancillaries. All engines are designed around a defined performance limit, and given weight targets I would be very surprised if there weren't components where design life was just sufficient at design rating and hence reduced when running above that.
Thats all just fluff to me. How many people have suffered crank/rod/head gasket failure after fitting a tuning box/remap? If you fit one to a 200k mile old car that has missed the odd service, maybe it’s to be expected. Most engines are pretty tough now. A well looked after standard engine will easily see 300k miles.