Alfa Romeo 147
Join Date: Jan 2014
Location: United Kingdom
This is an argument that will never be "done" but here is my two pence anyway.
As someone who has owned an array of cars mostly petrol. I have had turbo, non-turbo, wankel, piston, front wheel rear wheel etc etc, the honest answer is a turbo petrol will be faster then a turbo diesel regardless of torque figures that is just how it is BUT diesels are not as far off as they used to be and for real world driving a turbo diesel is better then a naturally aspirated or turbo'd petrol because it has it's peak torque output lower down the rev range meaning you can accelerate easier and have access to that 'instant power' more easily without having to downshift.
Tuning wise turbo cars are particularly easy to get more power from when dealing with remaps vrs naturally aspirated engines and as most diesels come out of the factory with maps focused on passing emissions tests rather then optimal power, applying a new map unlocks that potential power, petrols generally have the allot squeezed out of them from factory making tuning harder as it means upgrading parts rather then just software.
As for the torque debate my old RX7 was a powerhouse after all the work I had done, upgraded to just over 600bhp through remaps and allot of mechanical upgrades. As a wankel engine it revved freely pass 9k revs but its torque figures were very low, this made the car rapid on a track and I could quite easily destroy allot of cars but in real world applications of start stop traffic and city driving it was hard to drive.
They both have their charms and pitfalls drive what you think is best, for me I am very fast becoming a sporty turbo diesel convert, my JTD is fantastic although it is no track car lol