I have been banging my head endlessly trying to move from paper to reality to find the ideal gearbox ratios for a SLC, this application is intended for the street 90% and tracking on the weekends the other 10%. I plan to use a stock LS3 that may be upgraded with a cam at a later date, so max RPM is about 6500 RPM, I have determined three important areas of variables: 1) first gear. 2) Top gear, 3) Gear ratios (RPM drop)
1) First gear needs to be gear short enough that daily driving with starts and stops in northern VA traffic jams are able to be managed without feathering the clutch excessively, the other slow speed consideration is being able to drive it up into (on) a trailer with a certain degree of control. On the other hand how tall does first gear need to be? With the Ricardo gearboxes stretching first gear to 60MPH is a neat idea for 0 to 60 times and with a 2400 to 2700lb car that may be ideal for traction limits. Where is the happy medium????
2) Top Gear for the street needs to give you a nice engine RPM at 70 MPH, and keep in mind this is meant to be a super-car so the top speed needs to be in the super-car range (220+), Also keep in mind this can may never see that speed but it’s nice on paper. So how much gearing is too much or not enough, where is the happy medium?
3) On some gearboxes I have seen almost a 50% RPM drop from first to second I feel this is a little excessive endless you plan to start out in second and have that nice 60+MPH starting gear and just keep first for slow occasions. Close ratio gears are Ideal for the track, with the torque of a LS3 power plant and a 2400 to 2700lb car how wide of a ratio is too much or too little, so again where is the happy medium?
And now that I have explained my quandary, I ask for the vast knowledge input and years of experience on this wonderful forum come forth and solve this problem so I may stop banging my head.
Thank you
Tom
1) First gear needs to be gear short enough that daily driving with starts and stops in northern VA traffic jams are able to be managed without feathering the clutch excessively, the other slow speed consideration is being able to drive it up into (on) a trailer with a certain degree of control. On the other hand how tall does first gear need to be? With the Ricardo gearboxes stretching first gear to 60MPH is a neat idea for 0 to 60 times and with a 2400 to 2700lb car that may be ideal for traction limits. Where is the happy medium????
2) Top Gear for the street needs to give you a nice engine RPM at 70 MPH, and keep in mind this is meant to be a super-car so the top speed needs to be in the super-car range (220+), Also keep in mind this can may never see that speed but it’s nice on paper. So how much gearing is too much or not enough, where is the happy medium?
3) On some gearboxes I have seen almost a 50% RPM drop from first to second I feel this is a little excessive endless you plan to start out in second and have that nice 60+MPH starting gear and just keep first for slow occasions. Close ratio gears are Ideal for the track, with the torque of a LS3 power plant and a 2400 to 2700lb car how wide of a ratio is too much or too little, so again where is the happy medium?
And now that I have explained my quandary, I ask for the vast knowledge input and years of experience on this wonderful forum come forth and solve this problem so I may stop banging my head.
Thank you
Tom
