- 3,957
- Cleveland
So I've been using this speed/rpm calculator to set my gear ratios to what I think will work best for a car and it's working pretty good. I have a couple of standard setups that I usually just leave alone except for changing the final gear depending on what top speed I think I can get on a track. Using this calculator has allowed me to take 1+ seconds off my lap times as opposed to just using the automatic gear setting bar. Now I've just had another breakthu moment and can adjust gears per track more precisely in order to take off perhaps another second from my lap time!
First, though, the basic setting. I look at the power band and consider whether the tranny's got 5 or 6 gears and decide if the the band is tight or wide. If it's tight (usually is) I set 2nd to lowest and 5th or 6th to highest, and basically step up the gears in between (the step to 3rd is often the biggest step).
By my calculator a car with a red line of 8125 rpm and a power band which gives 75% hp at 5600 rpm might have gear ratios that drop to 5000 in 2nd, 6200 in 3rd, 6400 in 4th, and 6600 in 5th. I don't care how long I have to stay in 1st or how low the rpms drop in 2nd, you still have all the power you need and hopefully you won't be that low into 2nd again once you leave the starting line... of course my 400m time would be less than ideal.
If the car has a wide band, I do kind of the same thing, but don't worry about raising 5th or 6th to the max or dropping 2nd to the lowest, and most gear settings are closer to the middle. This way I still have good power if I do drop back to low speed at some point. Alas, many of the otherwise great cars don't have the greatest power band.
That's my first technique for tranny tuning, and it works like crazy.
The second technique is custom to a track.
Watch for the long turns where your car gets caught in low rpms and loses speed, then go back to your calculator and determine what settings will put those speeds in a high rpm range.
Ex: I see in an otherwise good run that I usually enter a turn at 130mph say, but at like 6000 rpm, having just changed up to 5th from 4th at 122mph perhaps, and I end up coming out of the turn at 120mph. Well, if I was higher in the power band, still in 4th, I most certainly would not have lost as much speed.
So I go back to the calculator and figure out where 4th needs to be (and final) to max 4th out at like 133 and then redo the race, and I end up coming out of the turn at 127, into a long straight where that extra speed compounds, and if I haven't otherwise screwed myself with the new setting, I've just knocked a second off my lap time!
Doing this I also got 5th to start out at close to max power (since I didn't need to boost max speed), and since on this track (red rock) you're in 4th-5th a lot, that worked to my favor, too. I lost a little power in the low ends of 3rd and 4th, but not so it mattered overall, since it wasn't at speeds where I needed the power the most.
But dammit the quest for speed can be tedious. Now I've got to keep track of settings FOR EACH COURSE!!!
First, though, the basic setting. I look at the power band and consider whether the tranny's got 5 or 6 gears and decide if the the band is tight or wide. If it's tight (usually is) I set 2nd to lowest and 5th or 6th to highest, and basically step up the gears in between (the step to 3rd is often the biggest step).
By my calculator a car with a red line of 8125 rpm and a power band which gives 75% hp at 5600 rpm might have gear ratios that drop to 5000 in 2nd, 6200 in 3rd, 6400 in 4th, and 6600 in 5th. I don't care how long I have to stay in 1st or how low the rpms drop in 2nd, you still have all the power you need and hopefully you won't be that low into 2nd again once you leave the starting line... of course my 400m time would be less than ideal.
If the car has a wide band, I do kind of the same thing, but don't worry about raising 5th or 6th to the max or dropping 2nd to the lowest, and most gear settings are closer to the middle. This way I still have good power if I do drop back to low speed at some point. Alas, many of the otherwise great cars don't have the greatest power band.
That's my first technique for tranny tuning, and it works like crazy.
The second technique is custom to a track.
Watch for the long turns where your car gets caught in low rpms and loses speed, then go back to your calculator and determine what settings will put those speeds in a high rpm range.
Ex: I see in an otherwise good run that I usually enter a turn at 130mph say, but at like 6000 rpm, having just changed up to 5th from 4th at 122mph perhaps, and I end up coming out of the turn at 120mph. Well, if I was higher in the power band, still in 4th, I most certainly would not have lost as much speed.
So I go back to the calculator and figure out where 4th needs to be (and final) to max 4th out at like 133 and then redo the race, and I end up coming out of the turn at 127, into a long straight where that extra speed compounds, and if I haven't otherwise screwed myself with the new setting, I've just knocked a second off my lap time!
Doing this I also got 5th to start out at close to max power (since I didn't need to boost max speed), and since on this track (red rock) you're in 4th-5th a lot, that worked to my favor, too. I lost a little power in the low ends of 3rd and 4th, but not so it mattered overall, since it wasn't at speeds where I needed the power the most.
But dammit the quest for speed can be tedious. Now I've got to keep track of settings FOR EACH COURSE!!!
