FD gears comparison
09-20-2010, 06:48 PM
#101
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Originally Posted by thomsbrain,Sep 20 2010, 05:23 PM
Didn't read the entire thread, but the gear comparison seems to confirm the obvious:
The vast majority of the "benefit" of a shorter FD happens in first gear. After all FD ratios get into the power band, the shorter FDs no longer offer any continuing meaningful benefit.
What this means is 4.77s aren't going to make much of a difference for anything except stop-light racing. On the move at the track or canyons, stock FD will be roughly as fast.
The vast majority of the "benefit" of a shorter FD happens in first gear. After all FD ratios get into the power band, the shorter FDs no longer offer any continuing meaningful benefit.
What this means is 4.77s aren't going to make much of a difference for anything except stop-light racing. On the move at the track or canyons, stock FD will be roughly as fast.
02-01-2011, 03:42 PM
#102
Totally agreed with Sean2k
Totally Disagreed with thomsbrain
-Theory and Practicality are never always identical. Theory... Well? is Theory.. It gives us an approximation and idea, unless a high number of variables are very well accounted for.
I was watching best motoring with an S2k at 4.32?? FD vs the Stock 4.1 FD, the 4.32 moved ahead by 2-3 car lengths and sean2k is right, the small difference does make a big difference, especially if you have power upgrades.
Now keep in mind a secret....
Final Drive ratio change is done in racing applications and works even better in conjunction with a sequential Transmission.
-Shifts are so short and quick,
-Makes ALL gears available for FULL use on the track
-FD Selection is also based on the top speed the vehicle will achieve in the longstraight of the fastest track. IE F1 Bar Honda calculates the FD from a specific position on the track (usually a few meters before braking zone of the fastest sector on a circuit) determining Top Gear, Highest RPM, the FD is then calculated.
Think about this one....
-------------------------------------------------------
How often will a driver aim to hit TOP Speed in the driving life of the vehicle? 1-4 times? maybe? 5% of the time
How often will a driver aim to accelerate quicker in daily driving, autox, accelerating or even track racing? Most of the time, if you own an S2000, I would say many times 95%+ of the time.
-------------------------------------------------------
It's ideal to shift the FD Ratio:
-TOP speed potential is traded for better Engine Torque Equivalent (ETE, mechanical advantage) Personally, I don't and rarely would need to drive 125mph (200km/h)
I personally am seriuoslly getting the 4.57 or 4.77 Gears, some people may think " your revs are 1000rpm higher than normal" than we can respond, don't buy the 4.57 or 4.77s then.
Honda select a FD ratio (4.10)to meet ALL types of driveability:
Acceleration
Cruising
Fuel Economy
Top speed ability balance with quick acceleration ability.
Totally Disagreed with thomsbrain
-Theory and Practicality are never always identical. Theory... Well? is Theory.. It gives us an approximation and idea, unless a high number of variables are very well accounted for.
I was watching best motoring with an S2k at 4.32?? FD vs the Stock 4.1 FD, the 4.32 moved ahead by 2-3 car lengths and sean2k is right, the small difference does make a big difference, especially if you have power upgrades.
Now keep in mind a secret....
Final Drive ratio change is done in racing applications and works even better in conjunction with a sequential Transmission.
-Shifts are so short and quick,
-Makes ALL gears available for FULL use on the track
-FD Selection is also based on the top speed the vehicle will achieve in the longstraight of the fastest track. IE F1 Bar Honda calculates the FD from a specific position on the track (usually a few meters before braking zone of the fastest sector on a circuit) determining Top Gear, Highest RPM, the FD is then calculated.
Think about this one....
-------------------------------------------------------
How often will a driver aim to hit TOP Speed in the driving life of the vehicle? 1-4 times? maybe? 5% of the time
How often will a driver aim to accelerate quicker in daily driving, autox, accelerating or even track racing? Most of the time, if you own an S2000, I would say many times 95%+ of the time.
-------------------------------------------------------
It's ideal to shift the FD Ratio:
-TOP speed potential is traded for better Engine Torque Equivalent (ETE, mechanical advantage) Personally, I don't and rarely would need to drive 125mph (200km/h)
I personally am seriuoslly getting the 4.57 or 4.77 Gears, some people may think " your revs are 1000rpm higher than normal" than we can respond, don't buy the 4.57 or 4.77s then.
Honda select a FD ratio (4.10)to meet ALL types of driveability:
Acceleration
Cruising
Fuel Economy
Top speed ability balance with quick acceleration ability.
06-30-2018, 08:07 AM
#106
Registered User
Been probably 5 years since I've bumped a thread.
This entire thread is missing some VERY important info IMO. There's some very misleading info which is why I'll post the following:
1. Traction!
2. Shifting (lag time)
3. Turbo boost lag (in turbo applications)
*While high boost my car is built for 786whp, I generallly (Always) drive it at 375whp. So I'll work these numbers based on my very high tq but lower 375whp setup as I daily drive it.
*I'm currently looking to go with 3.63 gears. I'm not going to be surprised if my car is actually faster 0-100mph or at 0-150mph. They even make 3.30 gears which I would love to have if I was to run 700whp+ all the time but I don't and won't.
1st gear -- 0-39mph -spin the wheel easily at any time just pushing on the throttle, thus I lower boost because at no time can I put 100% of 375whp to the ground in 1st gear. This means I have to just give away hp/tq. 1st gear is wasted, it's a bunch of noise and wasted technology because the tires are nowhere near able to keep up with the demands of the tq to the ground. I leave this gear at around
2nd gear -- 39-60mph - the same as 1st gear, tons of wheel spin, tires can't hold it as they're not drag tires. Worse yet I have my worst turbo lag here because I can't brake boost as I can in 1st gear and worse yet, this gear is so damn short the turbo has less time to really be working. Limiting boost here still a little bit, thus giving away more hp/tq. I leave this gear at
3rd gear --60-82mph - heavy wheel spin for (1 sec) upon first entering the gear at and then hooks up great and pulls to about 82mph. The turbo is now getting to really be put to use finally and % of time under boost is now very effective.
4th gear --82-105mph - tiny chirp and then hooks up, turbo spending 90%+ of it's time making peak boost.
5th gear --105-130mph - now the turbo sees lots of fully loaded boost time. turbo at full boost nearly the whole time.
6th gear --130-160mph pulling until the rev-limiter approaches. turbo at full boost nearly the whole time.
************************************************** **************
If it wasn't for clutch wear, I'd just skip 1st gear all together, since at any point in time I can put enough tq to the wheels to spin them in 2nd gear and any more tq than that is pointless. Hell, it should be faster than using 1st because I wouldn't have to shift and I'd stay on boost the whole time. Granted, I'm not going to because of the wear factor on the clutch.
All of the gains being had in the graphs above are had in 1st gear for the most part, then they just carry over. That gear in a boosted application isn't very useful as you can see. That means all you're doing by shortening gears in a turbo application is wasting time shifting and spinning wheels when you could have stayed on throttle and on boost longer.
Thus.... I'll be going with 3.63 gears.
Stock 4.10:
1st: 39mph
2nd: 60
3rd: 82
4th: 105
5th: 130
6th: 160
3.63
1st: 44mph
2nd: 67
3rd: 93
4th: 119
5th: 146
6th: 181
3.30
1st: 48mph
2nd: 74
3rd: 102 < so the end of 3rd gear gets you over 100mph in just two shifts. That's a time saver if you're racing to 100mph without a doubt. Stock doesn't happen till the end of 4th gear.
4th: 131
5th: 161
6th: 199 < Obviously we'd bang the rev limiter to make 200mph happen
I often go to long drives out in Eastern WA, these days. 85mph typical cruise but often sitting at 100mph for long whiles. Have a look at how much less busy the engine will be the whole time. Likely better mileage too. I hate seeing the engine sit at over 5100rpm at 100mph. 4500 will be much less stressful to watch.
4350rpm = 85mph in stock 4.10's
3850rpm = 85mph in 3.63's
5150rpm = 100mph in stock 4.10's
4525rpm = 100mph in 3.63's.
So, while in N/A these graphs hold better weight, besides perhaps shift time wasted, turbo applications and even supercharged applications to a lesser state may want to think twice. It's my opinion that a SC setup doesn't need to lower gears unlike a turbo because for one thing they make far less torque and the second reason is they don't have lag time so they're less punished by shifting. Though I might say a 450whp+ SC car could benefit from say 3.93 gears.
Just for fun:
-Greg
This entire thread is missing some VERY important info IMO. There's some very misleading info which is why I'll post the following:
1. Traction!
2. Shifting (lag time)
3. Turbo boost lag (in turbo applications)
*While high boost my car is built for 786whp, I generallly (Always) drive it at 375whp. So I'll work these numbers based on my very high tq but lower 375whp setup as I daily drive it.
*I'm currently looking to go with 3.63 gears. I'm not going to be surprised if my car is actually faster 0-100mph or at 0-150mph. They even make 3.30 gears which I would love to have if I was to run 700whp+ all the time but I don't and won't.
1st gear -- 0-39mph -spin the wheel easily at any time just pushing on the throttle, thus I lower boost because at no time can I put 100% of 375whp to the ground in 1st gear. This means I have to just give away hp/tq. 1st gear is wasted, it's a bunch of noise and wasted technology because the tires are nowhere near able to keep up with the demands of the tq to the ground. I leave this gear at around
2nd gear -- 39-60mph - the same as 1st gear, tons of wheel spin, tires can't hold it as they're not drag tires. Worse yet I have my worst turbo lag here because I can't brake boost as I can in 1st gear and worse yet, this gear is so damn short the turbo has less time to really be working. Limiting boost here still a little bit, thus giving away more hp/tq. I leave this gear at
3rd gear --60-82mph - heavy wheel spin for (1 sec) upon first entering the gear at and then hooks up great and pulls to about 82mph. The turbo is now getting to really be put to use finally and % of time under boost is now very effective.
4th gear --82-105mph - tiny chirp and then hooks up, turbo spending 90%+ of it's time making peak boost.
5th gear --105-130mph - now the turbo sees lots of fully loaded boost time. turbo at full boost nearly the whole time.
6th gear --130-160mph pulling until the rev-limiter approaches. turbo at full boost nearly the whole time.
************************************************** **************
If it wasn't for clutch wear, I'd just skip 1st gear all together, since at any point in time I can put enough tq to the wheels to spin them in 2nd gear and any more tq than that is pointless. Hell, it should be faster than using 1st because I wouldn't have to shift and I'd stay on boost the whole time. Granted, I'm not going to because of the wear factor on the clutch.
All of the gains being had in the graphs above are had in 1st gear for the most part, then they just carry over. That gear in a boosted application isn't very useful as you can see. That means all you're doing by shortening gears in a turbo application is wasting time shifting and spinning wheels when you could have stayed on throttle and on boost longer.
Thus.... I'll be going with 3.63 gears.
Stock 4.10:
1st: 39mph
2nd: 60
3rd: 82
4th: 105
5th: 130
6th: 160
3.63
1st: 44mph
2nd: 67
3rd: 93
4th: 119
5th: 146
6th: 181
3.30
1st: 48mph
2nd: 74
3rd: 102 < so the end of 3rd gear gets you over 100mph in just two shifts. That's a time saver if you're racing to 100mph without a doubt. Stock doesn't happen till the end of 4th gear.
4th: 131
5th: 161
6th: 199 < Obviously we'd bang the rev limiter to make 200mph happen
I often go to long drives out in Eastern WA, these days. 85mph typical cruise but often sitting at 100mph for long whiles. Have a look at how much less busy the engine will be the whole time. Likely better mileage too. I hate seeing the engine sit at over 5100rpm at 100mph. 4500 will be much less stressful to watch.
4350rpm = 85mph in stock 4.10's
3850rpm = 85mph in 3.63's
5150rpm = 100mph in stock 4.10's
4525rpm = 100mph in 3.63's.
So, while in N/A these graphs hold better weight, besides perhaps shift time wasted, turbo applications and even supercharged applications to a lesser state may want to think twice. It's my opinion that a SC setup doesn't need to lower gears unlike a turbo because for one thing they make far less torque and the second reason is they don't have lag time so they're less punished by shifting. Though I might say a 450whp+ SC car could benefit from say 3.93 gears.
Just for fun:
-Greg
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