shifting to 5th gear DOES NOT hurt your 1/4 time!
Jun 27, 2005, 02:21 PM
#1
shifting to 5th gear DOES NOT hurt your 1/4 time!
I am so sick of seeing comments abouts this. There is an extremely small difference in your ET if you have to shift to fifth gear. Do some calculations for heavens sake!!
At 120mph you are traveling 176 feet every second.
When you shift to fifth you loose about 5 feet. In other words you have to travel another 5 feet as oppossed to not having to shift.
It takes .028 seconds to go 5 ft at 120mph. Thats not even 3 hundreds of a second.
So instead of running a 11.500 you will run 11.528.
So the question is the five speed a better tranny if it saves having to shift to fifth gear? I would have to answer a HELL no. Does your car have higher g-force in 5th or 4th? Does your car have more g-force in 4th or 3rd? Does your car have accelerate harder in 3rd or 2nd? Shortening the gears in your tranny improves acceleration. If you have a 4.5 rear end and you switch to a 4.8 your e.t will improve. If you have a 4.5 and you switch to a 4.1 your e.t will suffer. Get this through your head people. My car is the perfect example of how you can improve your e.t by shortening your gears. I run a 23 inch tire on a tranny designed for 24.5-25 inch tires. I have to shift to second 2-3 car lengths before the sixty, and I use all five gears. I have on two occasions installed my rims on other dsms just to show how much faster the car gets by shortening the gear ratios. Its nuts really. Easily half second ET improvement.
At 120mph you are traveling 176 feet every second.
When you shift to fifth you loose about 5 feet. In other words you have to travel another 5 feet as oppossed to not having to shift.
It takes .028 seconds to go 5 ft at 120mph. Thats not even 3 hundreds of a second.
So instead of running a 11.500 you will run 11.528.
So the question is the five speed a better tranny if it saves having to shift to fifth gear? I would have to answer a HELL no. Does your car have higher g-force in 5th or 4th? Does your car have more g-force in 4th or 3rd? Does your car have accelerate harder in 3rd or 2nd? Shortening the gears in your tranny improves acceleration. If you have a 4.5 rear end and you switch to a 4.8 your e.t will improve. If you have a 4.5 and you switch to a 4.1 your e.t will suffer. Get this through your head people. My car is the perfect example of how you can improve your e.t by shortening your gears. I run a 23 inch tire on a tranny designed for 24.5-25 inch tires. I have to shift to second 2-3 car lengths before the sixty, and I use all five gears. I have on two occasions installed my rims on other dsms just to show how much faster the car gets by shortening the gear ratios. Its nuts really. Easily half second ET improvement.
Jun 27, 2005, 02:27 PM
#2
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Couple problems with your logic.. That assumes you are not accelerating.
If you loose out on the time to shift, plus that time you would have been accelerating there is a larger difference.
Now on to the Hurt or help question. It depending on what you are trapping at and your power curve, changing to 5th gear may help or hurt you.. It depends on your setup sometimes it is better to strech out 4th, sometimes if your power band drops off in the top of a gear it is better to short shift and go to fith.. Also if 4th can not make it to the end of the quarter that is also something to look at.
-Zach
If you loose out on the time to shift, plus that time you would have been accelerating there is a larger difference.
Now on to the Hurt or help question. It depending on what you are trapping at and your power curve, changing to 5th gear may help or hurt you.. It depends on your setup sometimes it is better to strech out 4th, sometimes if your power band drops off in the top of a gear it is better to short shift and go to fith.. Also if 4th can not make it to the end of the quarter that is also something to look at.
-Zach
Jun 27, 2005, 02:38 PM
#4
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Shifting into 5th gear and losing shifting time is only relative to the amount of hp the car is producing, correct? Where the car's redline is set plays the major role.
Just an example. If you are bouncing it off the rev limiter for the last 20-40ft. It would not be necessarily beneficial to switch gears because by the time you engage the clutch again you are already across the beams cruising.
Seeing where the beam actually is when the shifting point is hit is the only way to find out if shifting into the last gear will actually improve your time. Pulling in the last gear for that split second might yield a .10 faster time.
edit: Driver ability, horsepower, and redline are the key factors. Each vehicle is different.
Just an example. If you are bouncing it off the rev limiter for the last 20-40ft. It would not be necessarily beneficial to switch gears because by the time you engage the clutch again you are already across the beams cruising.
Seeing where the beam actually is when the shifting point is hit is the only way to find out if shifting into the last gear will actually improve your time. Pulling in the last gear for that split second might yield a .10 faster time.
edit: Driver ability, horsepower, and redline are the key factors. Each vehicle is different.
Last edited by EVOONYOASS; Jun 27, 2005 at 02:40 PM.
Jun 27, 2005, 02:40 PM
#5
Very strange logic... measure how long a shift takes from 4th to 5th. It is by far probably the hardest and longest shift to make. You lose a lot of time due to the fact of not being under power for x amount of feet while shifting. If you had a sequential shifting system like an air shifter for a bike or even a bike type transmission where it is up for up gears and down for down gears than sure... it will help your time due to having more power to the ground. It also depends on where exactly on the track you would need to shift. If earlier enough fine but if it is at the very end of the track (Which I assume anyone's would be) you would probably not be in your best power band by then and trying to shove the car forward in 5th not in your peak power zone could hurt badly.
Jun 27, 2005, 04:03 PM
#6
Well, I assume you are referring to all of our commentary about the 6spd recently due to my inability to go over 111mph in 4th gear and saying how 5th gear slowed me down considerably, but I may be mistaken.
Here's the deal...the 6spd with stock rev limiter (7606rpm) can't quite get to 111mph in 4th gear, or at least that's what I've found at 2 separate tracks in 2 days. My max at each track was 110.71 and 110.62...both were low 12's (12.34 & 12.24, respectively) and both had me hitting the rev limiter a good 4-5 taps before crossing the line. What I mean by "taps" is that's how many times I heard it hit the rev limiter in succession...pop pop pop pop pop. Since I wasn't just barely hitting the limiter right at the line and getting only one pop, I decided to try to shift to 5th.
On my first attempt, I tried to make the 4-5 shift at 7300rpm, thinking that was right at the peak of my hp and hoping to put me in the power zone of 5th immediately while still having time to actually accelerate in 5th gear after shifting (keeping in mind the time to shift that late on the track). When I tried doing a quick shift into 5th at that rpm, I completely missed. I didn't grind or get locked out...I simply couldn't make that movement fast enough to get in gear. Instead of going back to 4th, I just coasted across the line. Unfortunately, I may have ruined what would have been my best run ever, since I still got a 12.3x@101!!!! It was my best 60' and 1/8th-mile to date at that point.
On my 2nd attempt, I decided to shift earlier around 6800rpm so that I could make the shift easily (a little more slowly) then have time to actually pull hard in 5th. Well, I had a great launch and 1/8th-mile, so I still had plenty of room to shift into 5th when I was only at ~6800rpm in 4th. I made the shift, which felt like an eternity, then pulled the rest of the way in 5th. It felt like a dog in 5th at that rpm, which was lower than it would have been had I been able to shift at 7300 in 4th, and the result was an astonishing 12.34@105.94. I hit a lower mph than I did on my 3-month old 12.83@106.3 with ONLY an S-AFC, but I was a full half second faster. Does this mean shifting to 5th gave me an artificially low mph while keeping me accelerating nicely and getting the same ET as I had gotten while popping the rev limiter in 4th, or was it a potential 12.1s run that was ruined by 5th gear and a loss of over 4mph? I'm not sure, but I stopped trying 5th after that and decided to hold it in 4th at 7500rpm through the traps so as to avoid the rev limiter, and that's how I got my 12.22@109.19. The mph is lower than it would have been had I been able to keep it in 4th through the traps...
Here's the deal...the 6spd with stock rev limiter (7606rpm) can't quite get to 111mph in 4th gear, or at least that's what I've found at 2 separate tracks in 2 days. My max at each track was 110.71 and 110.62...both were low 12's (12.34 & 12.24, respectively) and both had me hitting the rev limiter a good 4-5 taps before crossing the line. What I mean by "taps" is that's how many times I heard it hit the rev limiter in succession...pop pop pop pop pop. Since I wasn't just barely hitting the limiter right at the line and getting only one pop, I decided to try to shift to 5th.
On my first attempt, I tried to make the 4-5 shift at 7300rpm, thinking that was right at the peak of my hp and hoping to put me in the power zone of 5th immediately while still having time to actually accelerate in 5th gear after shifting (keeping in mind the time to shift that late on the track). When I tried doing a quick shift into 5th at that rpm, I completely missed. I didn't grind or get locked out...I simply couldn't make that movement fast enough to get in gear. Instead of going back to 4th, I just coasted across the line. Unfortunately, I may have ruined what would have been my best run ever, since I still got a 12.3x@101!!!! It was my best 60' and 1/8th-mile to date at that point.
On my 2nd attempt, I decided to shift earlier around 6800rpm so that I could make the shift easily (a little more slowly) then have time to actually pull hard in 5th. Well, I had a great launch and 1/8th-mile, so I still had plenty of room to shift into 5th when I was only at ~6800rpm in 4th. I made the shift, which felt like an eternity, then pulled the rest of the way in 5th. It felt like a dog in 5th at that rpm, which was lower than it would have been had I been able to shift at 7300 in 4th, and the result was an astonishing 12.34@105.94. I hit a lower mph than I did on my 3-month old 12.83@106.3 with ONLY an S-AFC, but I was a full half second faster. Does this mean shifting to 5th gave me an artificially low mph while keeping me accelerating nicely and getting the same ET as I had gotten while popping the rev limiter in 4th, or was it a potential 12.1s run that was ruined by 5th gear and a loss of over 4mph? I'm not sure, but I stopped trying 5th after that and decided to hold it in 4th at 7500rpm through the traps so as to avoid the rev limiter, and that's how I got my 12.22@109.19. The mph is lower than it would have been had I been able to keep it in 4th through the traps...
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Jun 27, 2005, 04:14 PM
#8
Originally Posted by MyCre8n=Evlshn
Warrtalon, did you launch with the 5K rev limiter in effect? Have you thought about defeating the rev limiter and running to 8000rpm?
I have thought about raising the limiter to 7800 or 8000, but it's not worth deflowering my ECU just to get a flash for that purpose. I don't really make the power to make use of 7800/8000 rpm without cams, so the only purpose would be to cross the traps in 4th gear...not worth it, although I'm very curious...
Jun 27, 2005, 04:15 PM
#9
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I have a hard time believing that you'll only travel 5 feet in between shifts at 120.
Who the hell can shift at .023 sec?
What about spooling back up in those last 40 feet?
Who the hell can shift at .023 sec?
What about spooling back up in those last 40 feet?
Jun 27, 2005, 04:32 PM
#12
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shifting to 5th gear DOES NOT hurt your 1/4 time!
l8r)
Jun 27, 2005, 07:06 PM
#14
Warrtalon, I wasn't referring to your post. But since you brought it up. It makes no difference wether you stay in forth and bounce off the limiter, or shift into fifth and lug the car the last 200 ft. The difference being traveling the last 200 ft at 107-110mph or 102-105 mph is agian about 3-4 hundreds on your ET. The difference in your ET are coming from how well you perform in the eight mile.
Fot those who posted this thread as the dumbest post of the day. You will never go fast. You obviously have no knowledge of this game.
Fot those who posted this thread as the dumbest post of the day. You will never go fast. You obviously have no knowledge of this game.
Jun 27, 2005, 07:13 PM
#15
Originally Posted by 94AWDcoupe
Warrtalon, I wasn't referring to your post. But since you brought it up. It makes no difference wether you stay in forth and bounce off the limiter, or shift into fifth and lug the car the last 200 ft. The difference being traveling the last 200 ft at 107-110mph or 102-105 mph is agian about 3-4 hundreds on your ET. The difference in your ET are coming from how well you perform in the eight mile.