1998 Maxima Gear Ratio
11-28-2005, 03:43 PM
#44
an auto does not have direct power to the wheels. That is why if you floor it there is no direct relationship between mph and rpm. Just like if you break torque...you can rev your engine to 2000 rpm but still read 0 mph.
11-28-2005, 03:49 PM
#45
It's all mechanically related, so breathing mods wont change a thing, only different gear ratios or tire sizes will.
And you're referring to stall speed when talking brake torquing....not 'direct relationship
'
I agree that an MT is mechanical and an AT is more clutch packs, tranny fluid But still has direct relation (RPM/SPEED)
And you're referring to stall speed when talking brake torquing....not 'direct relationship
'I agree that an MT is mechanical and an AT is more clutch packs, tranny fluid
But still has direct relation (RPM/SPEED)
11-28-2005, 03:58 PM
#47
why is it then that depending on elevation, at 2k rpm I can going anywhere from 45mph to 60mph when in the last gear? or if you quickly push down the gas there will be a jump in rpm but not in speed?
edit...after i saw edit of nmexmax.
I see what your saying about a relationship between rpm/speed but I do not believe it is a direct relationship as in a set multiple between the two. I could see why after the mods an auto can go the same speed a lower rpms, not sure how big difference is but there could be a difference since with the mods at lower rpms you have higher horsepower and torque which could negate the huge powerloss in the auto drivetrain and acheive the same speed at a slightly lower rpm.
edit...after i saw edit of nmexmax.
I see what your saying about a relationship between rpm/speed but I do not believe it is a direct relationship as in a set multiple between the two. I could see why after the mods an auto can go the same speed a lower rpms, not sure how big difference is but there could be a difference since with the mods at lower rpms you have higher horsepower and torque which could negate the huge powerloss in the auto drivetrain and acheive the same speed at a slightly lower rpm.
11-28-2005, 04:13 PM
#49
I see what your saying about a relationship between rpm/speed but I do not believe it is a direct relationship as in a set multiple between the two. I could see why after the mods an auto can go the same speed a lower rpms, not sure how big difference is but there could be a difference since with the mods at lower rpms you have higher horsepower and torque which could negate the huge powerloss in the auto drivetrain and acheive the same speed at a slightly lower rpm.
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11-28-2005, 04:19 PM
#51
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Join Date: Sep 2005
Posts: 60
in a manual transmissoned car, the speed displayed on the speedo is directly related to the rpms on the tach, theres no question about it, ever hit a patch of ice in second gear and spun the speedo up to 65mph when your really only doing 15, its because they are directly connected
11-28-2005, 04:46 PM
#53
Not true. There's a big *** hill going up to my house, and in the rain if I floor it and break traction (auto), I've been able to get the speedo to go up to around ~45 MPH before, when my actual speed on the ground is 15 or 20.
****, I'll make a video of it if you want.
Or, just do this - pour some sort of lubricant under the front wheels (water, oil, etc), pull the ebrake, and floor it. The speedo will rise even though you're sitting still.
****, I'll make a video of it if you want.
Or, just do this - pour some sort of lubricant under the front wheels (water, oil, etc), pull the ebrake, and floor it. The speedo will rise even though you're sitting still.
. . . . .
11-28-2005, 05:57 PM
#55
ok here's what headers do for you:
your rpm will still be the same, however you will notice the engine revs slightly freer (but still keeps the same rpms as before) your speedometer will show you how much faster the car is,
i.e. to go from 60-80 takes much faster with headers than without, because you're making more power
but you still keep the same RPMs as before, just picks up speed faster because there's less restrictions.
before you rip into your tranny get a 00vi, trust me on this one.
your rpm will still be the same, however you will notice the engine revs slightly freer (but still keeps the same rpms as before) your speedometer will show you how much faster the car is,
i.e. to go from 60-80 takes much faster with headers than without, because you're making more power
but you still keep the same RPMs as before, just picks up speed faster because there's less restrictions.
before you rip into your tranny get a 00vi, trust me on this one.
11-28-2005, 09:55 PM
#58
you know what...i reread my last post and just realized it didnt make sense...
my train of thought is that in an auto the speedometer looks at wheel rpm not engine rpm. This is why with an auto if you tap on the gas quickly...the rpms shoot up but not the speed. for example if im going 2k rpm and hit the gas it will shoot up to 2.5k which is an engine speed that is 25% faster. This should translate to 25% faster speed but if you look at the speedometer, the speed did not jump by 25%. This shows that there is no direct connection between speed of car and rpm of engine.
my train of thought is that in an auto the speedometer looks at wheel rpm not engine rpm. This is why with an auto if you tap on the gas quickly...the rpms shoot up but not the speed. for example if im going 2k rpm and hit the gas it will shoot up to 2.5k which is an engine speed that is 25% faster. This should translate to 25% faster speed but if you look at the speedometer, the speed did not jump by 25%. This shows that there is no direct connection between speed of car and rpm of engine.
11-28-2005, 10:57 PM
#61
Originally Posted by Fr33way
Those fractions do not take into account gear ratio, transmission . . . .
Are you serious man?
Are you serious man?
This is in the 4th gear for an auto. If you are in the same gear, 25% higher rpm will equal 25% higher mph if you have direct power to the wheels ie a manual transmission car. If you have an auto its not direct so the road speed lags the engine speed.
11-28-2005, 11:41 PM
#63
not at same speed but there is a ratio. THis means that if you go 60mph at 3k rpm then at 6k rpm your gonna go 120mph. THis is true in a manual transmission but in an auto I can be going 50mph at 2k rpm and at 2.5k rpm in the same gear depending on a variety of factors.
If I put cruise control once I reach 50mph Im at about 1.8k rpm...
but If Im at 50mph and I press the gas half way somewhat quickly but not enough to cause a downshift, I shoot up to about 2.5k rpm but only at like 55mph.
so here are two instances of different speeds at different rpm
50/1.8 = 27.8
55/2.5 = 22
At this point I can keep my rpm at 2.5k but the speed will gradually increase and at some speed it will stop increasing...this shows a definite lag between engine speed and wheel speed. This happens in an auto since autos dont have direct power to the wheel. This shows that the engine rpm does not matter much but the power at that rpm does. By putting mods, the engine is able to put out more power at lower rpm.
There will be a difference in rpm at a set speed but I am not sure if the difference is that big. I am expecting to get my y pipe sometime this week or next week so I will post my before y pipe rpm tomorow once I confirm my rpm at 60mph using cruise control on a fairly flat road. Once I put on my y pipe I will post up new rpm at 60mph. I beleive there will be a change but not sure how much.
If I put cruise control once I reach 50mph Im at about 1.8k rpm...
but If Im at 50mph and I press the gas half way somewhat quickly but not enough to cause a downshift, I shoot up to about 2.5k rpm but only at like 55mph.
so here are two instances of different speeds at different rpm
50/1.8 = 27.8
55/2.5 = 22
At this point I can keep my rpm at 2.5k but the speed will gradually increase and at some speed it will stop increasing...this shows a definite lag between engine speed and wheel speed. This happens in an auto since autos dont have direct power to the wheel. This shows that the engine rpm does not matter much but the power at that rpm does. By putting mods, the engine is able to put out more power at lower rpm.
There will be a difference in rpm at a set speed but I am not sure if the difference is that big. I am expecting to get my y pipe sometime this week or next week so I will post my before y pipe rpm tomorow once I confirm my rpm at 60mph using cruise control on a fairly flat road. Once I put on my y pipe I will post up new rpm at 60mph. I beleive there will be a change but not sure how much.
11-29-2005, 12:24 AM
#64
No, there wont.
With the same auto trans. and wheel/tire combo a bone stock Maxima will be at the same RPM in 4th gear at 60mph as one with 400hp.
I can't wait for the follow up thread . . .
With the same auto trans. and wheel/tire combo a bone stock Maxima will be at the same RPM in 4th gear at 60mph as one with 400hp.
I can't wait for the follow up thread . . .
11-29-2005, 01:34 AM
#65
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I have a RS5F50V FG41 which I've been told has a 4.1:1 (I guess hence the code) it is from a VQ20DE.. what advantage/disadvantage will there be over the standard maxima 5 speed vq30de ratios? IRC I heard I will accelerate quicker but loose top end speed? (I have MEVI with no extended rev limiter)
Anyone know?
Anyone know?
11-29-2005, 02:41 PM
#67
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Posts: 1,108
Originally Posted by JClaw
Top speed is 160 mph. I went up there once and will never do it again. Your top speed will be decreased to 148 mph, which is still more than fast enough.
11-29-2005, 03:41 PM
#69
Originally Posted by killerVQ30DE
Hey was that answering my post JCLAW? So i'm right better acceleration but lower topspeed?
In the real world, it would mean better acceleration at the expense of gas mileage.
11-29-2005, 03:48 PM
#70
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Highway gas mileage. From what I've read, around town gas mileage doesn't go down much if at all because your motor is straining less to pull the car with the more aggressive gearing. 4.1:1 or 4.4:1 gears (both available) would turn even a stock 4g into a torquey little **** around town.
You know that's what I meant.
11-29-2005, 03:56 PM
#73
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Originally Posted by JClaw
Highway gas mileage. From what I've read, around town gas mileage doesn't go down much if at all because your motor is straining less to pull the car with the more aggressive gearing. 4.1:1 or 4.4:1 gears (both available) would turn even a stock 4g into a torquey little **** around town.
11-29-2005, 04:05 PM
#74
There arent any kits available to change gear ratios in an auto, but that doesnt mean it cant be done. The auto has gear plates that determine the gear ratios in each gear, these gear plates are available in other auto transmissioned cars as well. By counting the teeth in the plate you can calculate a drive ratio in each gear. More teeth = higher ratio. When I had my trans rebuilt, I altered the ratios by putting in gear plates with more teeth. The stock gear ratio on an auto 4g Maxima is a 3.23:1. My new gear ratio is 3.91:1. I only lost 4 mph on the top end, but it gets there much quicker. The stock gear ratio on a 4g 5mt is 3.62:1 respectively.
11-29-2005, 04:30 PM
#75
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Originally Posted by NightRider
By counting the teeth in the plate you can calculate a drive ratio in each gear. More teeth = higher ratio..
Same goes for the final drive ratio. Divide the amount of teeth on the final drive gear by the amount of teeth on the mainshaft. In a 5MT there are 65 teeth on the final drive gear and 17 teeth on the mainshaft. Thus 65 divided by 17 = 3.823529412 is the final drive ratio.
Originally Posted by NightRider
More teeth = higher ratio. When I had my trans rebuilt, I altered the ratios by putting in gear plates with more teeth.
Originally Posted by NightRider
The stock gear ratio on an auto 4g Maxima is a 3.23:1.
Originally Posted by NightRider
My new gear ratio is 3.91:1. I only lost 4 mph on the top end, but it gets there much quicker.
Originally Posted by NightRider
The stock gear ratio on a 4g 5mt is 3.62:1 respectively.
With that said, I'm gonna need a timeslip or a video of you pulling on R1's. Good day.
12-02-2005, 11:12 PM
#76
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Originally Posted by killerVQ30DE
I have a RS5F50V FG41 which I've been told has a 4.1:1 (I guess hence the code) it is from a VQ20DE.. what advantage/disadvantage will there be over the standard maxima 5 speed vq30de ratios? IRC I heard I will accelerate quicker but loose top end speed? (I have MEVI with no extended rev limiter)
Anyone know?
Anyone know?
12-03-2005, 11:06 AM
#77
Originally Posted by NmexMAX
a launch shot of N2O .. 
These are photos from MY car, with the auto launching on a 50shot....I did measure it, and it was over 100feet of rubber that got laid down. Following this, I lost 1st and 2nd. Now I have a 5spd. It was a good lesson
12-03-2005, 12:45 PM
#79
Originally Posted by NmexMAX
That's why I was hiding behind the wall ....
12-03-2005, 03:41 PM
#80
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Originally Posted by killerVQ30DE
IIRC there was a chart that showed the Maxima standard gear ratios per gear and with another column showing the 4.1:1 ratio .. I hope its a good ratio as I have a feeling I'm going to have really short gears