Strengthrehab
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Best post ever. Thank you. My rear tires now are 27.7 in (275/40/19). I was def going to look at a graph with the info uou posted so i could do what your post did.If fifth is 1:1 on your car, and with a 7000RPM rev limit, I can't for the life of me see the need for 6th gear, unless you are SERIOUSLY hauling the mail, and then only on the big end of very few straights in this country...
There are lots of transmission calculators, and if you plug in your gear, trans ratios, tire size and 3500 and 7000 RPM points, you can get a solid idea of min and max speed in each gear. With a 3650 (or a T56), virtually all the tracks in the midwest can be run in 3rd and 4th (which is 1:1). 2nd is rare, and higher than 4th only on two tracks that I can think of... Road America and Mid-Ohio, both of which have some pretty high-speed straights. Like 140mph+ in a stock-ish power level car.
I think you're right in that you're shifting too often. NOT a slam, but constructive criticism to help confirm your suspicion. Also, one failing I see fairly regularly on the downshifts is people trying to get it done too soon in the braking zone. They tend to get the downshift in early, and it's MUCH harder to rev-match with a gear-engagement of 5000+RPM than it is to just wait a tick and do the match at 4000, or whatever. After all, the goal here is to be all done with the shifting and have the clutch out in the correct gear just prior to turn-in. If you find yourself finishing the rev-match, and still dropping more than 6-700rpm under braking, you're downshifting too early. The vast majority of corners only require changing down one gear. A small handful will require dropping two gears. Only a select few will require dropping down three or more.
The MT82 2/3/4/5 ratios are 2.43/1.69/1.32/1.00, and sixth is an unsusable 0.65:1 overdrive. my TR3650, by comparison has 2/3/4 ratios of 2.00/1.32/1.00, so our last two usable gears are identical, but you have a nice "intermediate gear" 3rd, where the 3650's 2nd might be a bit too aggressive by comparison.
Most corners have an entry speed between 45 and 65 mph, and I think we can all agree that we don't really want to up-shift until we hit track-out and aren't relying on the weight transfer from acceleration to plant the back end so much... Think about your "speed in gear" as you reach the track-out point at corner exit. With my TR-3650, 3rd (your fourth) is usable from 54mph up through 99mph, and 4th (your 5th) is good from 71mph up through 130mph. That's with a 6400rpm redline. If you extend the powerband up to 7000, though, that makes the max speeds 108 and 142mph. Assuming 3.73 gears, and 25.5" tires (275/35-18).
Given all that, how many corners do you see where your EXIT speed is below 54mph? Not many. That's how many corners you'd need to use 3rd gear for. So, let's assume, for now, that you're only going to be needing 4th and 5th (1.32:1 and 1:1), so at most, you'll have a single downshift into any given corner. If your entry into the braking zone is under 108, you should be in 4th gear, no downshift required, just brake, turn, go! If you speed into the braking zone is 125mph, for example, and the entry speed is 50mph, you know that you'll need to drop to 4th gear, but you also need to shed the speed to get DOWN to 50. You could downshift as soon as you hit 108mph (top of 4th), but why bang the motor into the limiter just to change gears? Wait. Wait some more. You could also change around 80mph, roughly 4000 rpm in 5th gear, which will bump you up to around 5100-5200 in 4th on the switch. That doesn't sound too bad, now does it? Give it a quick 1500rpm blip, drop down the gear, and finish your braking. The point here is that to have a nice, easy downshift where you're not spinning the motor into the stratosphere, and with not a huge blip required, you just need to wait a while. It takes time to drop your speed from 125 down to 50, and all you're doing in there is braking in a straight line. You also leave yourself some room for error (decelerating from 80 down to 50) in case you miss the gear, or bobble the blip, or whatever. Plenty of time to recover before turn-in.
For now, I would just plan on using 4th and 5th, and then see if there is a corner or two that you're just lugging too badly before thinking about dropping down to 3rd. I would also avoid 6th like the plague, if you can. Again, unless and until your road-speed is north of 140mph, and you still have a ways to go before the braking zone, you won't gain anything by shifting up into an overdrive gear. Essentially, unless you're hitting redline (rev limiter or self-imposed point to keep temps down, or whatever), don't shift up. With a single-gear downshift, leave it for the last 1/3 of the braking zone.
A note on your instructor's note: He sounds like a really good instructor, sensitive to your experiences, supportive and constructive. He's also very wise, identifying that the student/teacher pairing has to have chemistry to work properly. If you worked well with him, then I think requesting him again would be a great idea!
Thanks a ton.
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