The 1994 and newer Lola Indy/ChampCars have transverse sequential gearboxes very similar to a motorcycle's gearbox. There is a shift drum that is driven by a ratcheting shift arm which moves dog rings into and out of contact with gear dogs via shift forks. Final drive consists of a spur gear set driven directly from the output shaft. Power is supplied via an input shaft, through a set of drop gears at the front of the gearbox then through a bevel gear set which drives the transverse layshaft. The 95 and 96 cars have a dry sump oiling system with the rear cover housing the reservoir while the 99 has a wet sump. All of them use roots style scavenge and pressure pump sections. The Speedway and Road Course configurations use different drive gear sets to control oil pressure at the very different operating speeds.
Most of the show cars out there may have street course wing sets on them but almost all will have a super speedway gearbox setup. This configuration consists of a different drop gear set, different oil pump drive gears and pickup points, much lower first gear layshaft (as opposed to the street course 1st/2nd gear layshaft) and spool instead of a differential. The ratios are also very different with 5th and 6th being Lola wide gear sets.
The first Lola transverse gearboxes were six speed units consisting of five forward speeds and reverse for road course use and six forward speeds with wide 5th and 6th for super speedway use. In mid-96 Lola provided an update kit to convert the gearboxes to seven speed units, six forward and one reverse for road course applications. Given that reverse is seldom if ever used in vintage racing, I have left the six speed gearboxes in six forward gears to give the best possible selection of ratios.
The shift drum has a potentiometer which provides positioning information to the fuel control ECU. There is also a switch in the shift linkage that tells the ECU when the driver is selecting a higher gear. The ECU cuts power when the driver pulls on the shift lever. This allows the dog ring to disengage from the lower gear and move to engage the next higher gear. Once the ECU "sees" the shift drum approaching full engagement of the next gear, it reapplies power. Dove tailed or undercut dogs on the dog ring and gear allow the shift to complete smoothly. When proper shift values are programmed in the ECU, dog ring wear is greatly reduced and the driver never has to lift off the throttle while accelerating.
In short, modern Indy/ChampCars have remarkably well design and built gearboxes that are smooth shifting and trouble free if properly maintained.
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