Heidfeld’s F1 fire due to ‘cracked exhaust’

Renault has blamed a cracked exhaust for Nick Heidfeld's fiery exit from last weekend's Hungarian GP.

The German driver was forced to abandon his car after it spontaneously combusted on his exit from the pit lane. Leaping to safety, the car then exploded - onto the leg of a track marshal - and smothered the circuit in debris.

Renault's technical director James Allison said: "We ran a slightly different engine mapping strategy in qualifying, which produced hotter than normal exhausts. This elevated temperature and caused a preliminary crack in the exhaust pipe.

"The crack then propagated during the laps to the pitstop - which wasn't evident to us as we believe the failure occurred upstream of the place where we have a temp sensor - which meant Nick came in with a partially failed exhaust.

"This pitstop took longer than normal and the engine was left at high rpm for 6.3 seconds, waiting for the tyre change. Under these conditions, a lot of excess fuel always ends up in the exhausts and their temperature rises at around 100C per second. This rise in temp was enough to finish off the partially failed pipe and start a moderate fire."

Classifying the incident as "highly undesirable", Renault is in touch with the FIA to provide a full incident report. You can watch the fiery drama unfold below, in that handy rectangular portal for viewing moving images.

Elsewhere, both Hamilton and Button have not given up the hunt on Sebastian Vettel's nearly-in-the-bag 2011 championship, Hamilton himself saying "There are 200 points up for grabs and I enter all of the races believing I can win them".

Can he, or anyone else for that matter, do it? Or does Vettel simply have to post the rest of his race victories in?