1988-1989 Busby Porsche 962
Images copyright Lance Zabrowski, Jeremy Banks and Mark Windecker
Text copyright Michael J. Fuller
The proximity of the wing to the tunnel exits is evident here, and a drastic change over the standard factory 962 bodywork.
The height of the standard 962 tunnels was barely above the drive shaft.  Here you can see that there is quite a lot of clearance, giving a better idea of how different the Busby car's tunnels were.
Busby Porsche 962C, Road America 1989Busby would also run a water cooled 962C, side by side with the single turbo air-cooled car, during the 1989 season.  The water cooled car (here) is identified by the lack of large inlet ducting on the engine cover.  Porsche delivered the 962C (962-009), still in its Porsche Supercup Shell livery, at the Lime Rock race weekend.  The team tested the car back to back against their single turbo, air cooled car on the Monday following the race, with Bob Wolleck doing all the driving, and  acting as the control.  Colucci indicates the 962C was much slower (Busby says up to 1 second slower, an eternity at a place like Lime Rock): it was still fitted with a spool differential and, “Understeered like a pig.”  Given its recent delivery there hadn't been any time to fit the Busby mods to the water cooled car so it tested as stock from the factory. 
Later in the season the team would upgrade 962-009 to "Busby" aero spec, minus the underfloor update; the twin-turbo layout of the 962C was simply in the way of the underfloor modifications and it wasn't deemed to be worth the major effort required to relocate the turbos and all the associated plumbing.  Back to back testing against the 962C modified to the Busby upgrades (sans underfloor) still showed the air cooled car to be superior.  The water cooled car would end up being the team's spare chassis and was raced infrequently.  

Note the lack of the massive overhead intercooler.  Intecooling for the twin turbo 962C engine was handled separately for each turbo.  The intercoolers were much smaller and located one in each side pod.
ęCopyright 2008, Michael J. Fuller