[borderman]

anyone tell me if a tuning box will improve a 1.7 cdti 57 plate corsa ,i get a around 37-38 mpg around town 57-60 mpg on a run will this improve? .there are a few selling them on ebay from £80 and up anyone recommend a good one to use and what diffrence will i notice in performance and gains

 

[DanDrury]

You may well be better off getting a remap done properly, as some tuning companies can map to your driving style.

I would always be wary of these boxes as they dont take into account the history/health of the engine.

 

[Hardcore]

A lot of them just increase pressure to the fuel pump, but don't increase the boost pressure on the turbo. The result is generally worse mpg and a rear view filled with black smoke when you put the foot down.