bradc
01-01-2006, 12:46 PM
This is something I've been meaning to do for ages and ages, I've been quite keen on changing my car to an EVO 8 gearbox, and I was always curious to see how it would actually feel, and how much quicker it would be.
Tonight I was kind of bored and very wide awake after going to sleep at 4am for 2 nights in a row, so I jumped into Need For Speed Underground 2 and started looking for a car to make perform like a VR-4. I know this won't be 100% accurate, I don't really care, this is just designed to throw the topic out in the open and get peoples comments on it.
I picked the Nissan 240sx because it has very little power and I would be able to tune it's dyno curve to look similar to the dyno output my car has. I did that, with max power at around 5500rpm and set the gear ratios to the same as a 5spd auto VR-4. I did a drag race first to check the performance, it was too slow at around 7 seconds to 100kph, so I upgraded the turbo, re-did the dyno plot then tried again and got 5.62 seconds which is about right. I also tested the acceleration from 80-120kph which was around 4.5 seconds, NZ Autocar tested the VR-4 back in 1999 and recorded 4.66 seconds. All changes were done at about 6400-6500rpm.
Then I did the drag run with gearing from the manual gearbox and the 6 speed evo 8 gearbox.
100kph/400m:
5.62/14.34 5spd auto
5.27/14.23 5spd manual
5.41/14.04 6spd evo
The reason for the 5spd manual being so quick to 100kph is that 2nd and 3rd gear are quite short to each other. The evo gearbox was a little slow to get the car to 100kph because of it's long first gear, but it made up for it by the 400m mark because of it's overall shorter gearing. The auto was the slowest because of it's tall 2nd gear, and it's other gears are fairly tall too. It was accelerating hard in 4th at the end though, whereas the manuals were in top gear at that point.
I ran these tests 5 times, and the results were fairly consistant, maybe .10 seconds out at worst. I also tried a longer drag, all cars were within .50 seconds of each other and all were between 264 and 267kmh at the end, after about 50 seconds of acceleration. This was around some corners though on the race track, the cars go through a 180 degree turn during the length of the race.
The next thing I tried was on a race track. NFS UG2 has a test track you can race on, this track has a couple of 100kph sharp corners, but most of the track is fairly open and you are doing 170-220kph most of the time.
I ran around there 5 times for each car, and recorded:
1:30 5spd auto
1:30 5spd manual
1:29 6spd evo
I noticed that in a couple of sections the auto and evo gearboxes could hold onto their 4th and 5th gears respectively at around 6000rpm, while the 5spd manual had to go into 5th gear and lose quite a few rpm. I think this is the reason why the auto and manuals would consistantly record the same time. The auto seemed to drop too many revs on gear changes, especially from 3rd into 4th and 4th into 5th and was a little slower than the other cars in some scetions. The evo gearbox was never short on gears and was very quick from 2nd up to 5th gear.
Then I tried another track which is up in the mountain ranges and has a short straight to start off with, then a section where you accelerate from 130kph to 210kph downhill, then go up a long mountain stretch. After that there are some corners that are taken at 140-170kph before the finish line.
1:11 5spd auto
1:08 5spd manual
1:07 6spd evo
From the start line to going down the hill there wasn't that much differance between the cars, with the evo accelerating a little bit quicker, but going uphill there was a massive differance, the auto needed to be in 5th gear, which was too tall for the uphill section and it couldn't maintain it's speed up the hill. The manuals were about the same going up. Through the corners at the end the evo gearbox was again the quickest due to being able to change between 4th and 5th and keep the engine right on it's power band. The auto needed to be in 4th which suited it fine, and the 5spd manual was in 5th for most of it and was just out of it's power band, the auto was quicker in this section, but it couldn't make up for the crap going up the hill.
Take it for what you will, I am not claiming it is very accurate to real life, but the overall conclusion I came to is that:
The auto's gears a little too tall, with too wide gaps between them, but the slightly higher 4th does make up for it a bit in some situations.
The 5spd manual was great, the only problem was that on the tracks I tested it sometimes kept the engine out of it's power band
The 6spd evo was defiantely the best, even if it was a little slow off the line due to the tall 1st gear, it was very very quick once moving, there isn't much spacing between the gears, and it always seems to have the right ratio available.
Tonight I was kind of bored and very wide awake after going to sleep at 4am for 2 nights in a row, so I jumped into Need For Speed Underground 2 and started looking for a car to make perform like a VR-4. I know this won't be 100% accurate, I don't really care, this is just designed to throw the topic out in the open and get peoples comments on it.
I picked the Nissan 240sx because it has very little power and I would be able to tune it's dyno curve to look similar to the dyno output my car has. I did that, with max power at around 5500rpm and set the gear ratios to the same as a 5spd auto VR-4. I did a drag race first to check the performance, it was too slow at around 7 seconds to 100kph, so I upgraded the turbo, re-did the dyno plot then tried again and got 5.62 seconds which is about right. I also tested the acceleration from 80-120kph which was around 4.5 seconds, NZ Autocar tested the VR-4 back in 1999 and recorded 4.66 seconds. All changes were done at about 6400-6500rpm.
Then I did the drag run with gearing from the manual gearbox and the 6 speed evo 8 gearbox.
100kph/400m:
5.62/14.34 5spd auto
5.27/14.23 5spd manual
5.41/14.04 6spd evo
The reason for the 5spd manual being so quick to 100kph is that 2nd and 3rd gear are quite short to each other. The evo gearbox was a little slow to get the car to 100kph because of it's long first gear, but it made up for it by the 400m mark because of it's overall shorter gearing. The auto was the slowest because of it's tall 2nd gear, and it's other gears are fairly tall too. It was accelerating hard in 4th at the end though, whereas the manuals were in top gear at that point.
I ran these tests 5 times, and the results were fairly consistant, maybe .10 seconds out at worst. I also tried a longer drag, all cars were within .50 seconds of each other and all were between 264 and 267kmh at the end, after about 50 seconds of acceleration. This was around some corners though on the race track, the cars go through a 180 degree turn during the length of the race.
The next thing I tried was on a race track. NFS UG2 has a test track you can race on, this track has a couple of 100kph sharp corners, but most of the track is fairly open and you are doing 170-220kph most of the time.
I ran around there 5 times for each car, and recorded:
1:30 5spd auto
1:30 5spd manual
1:29 6spd evo
I noticed that in a couple of sections the auto and evo gearboxes could hold onto their 4th and 5th gears respectively at around 6000rpm, while the 5spd manual had to go into 5th gear and lose quite a few rpm. I think this is the reason why the auto and manuals would consistantly record the same time. The auto seemed to drop too many revs on gear changes, especially from 3rd into 4th and 4th into 5th and was a little slower than the other cars in some scetions. The evo gearbox was never short on gears and was very quick from 2nd up to 5th gear.
Then I tried another track which is up in the mountain ranges and has a short straight to start off with, then a section where you accelerate from 130kph to 210kph downhill, then go up a long mountain stretch. After that there are some corners that are taken at 140-170kph before the finish line.
1:11 5spd auto
1:08 5spd manual
1:07 6spd evo
From the start line to going down the hill there wasn't that much differance between the cars, with the evo accelerating a little bit quicker, but going uphill there was a massive differance, the auto needed to be in 5th gear, which was too tall for the uphill section and it couldn't maintain it's speed up the hill. The manuals were about the same going up. Through the corners at the end the evo gearbox was again the quickest due to being able to change between 4th and 5th and keep the engine right on it's power band. The auto needed to be in 4th which suited it fine, and the 5spd manual was in 5th for most of it and was just out of it's power band, the auto was quicker in this section, but it couldn't make up for the crap going up the hill.
Take it for what you will, I am not claiming it is very accurate to real life, but the overall conclusion I came to is that:
The auto's gears a little too tall, with too wide gaps between them, but the slightly higher 4th does make up for it a bit in some situations.
The 5spd manual was great, the only problem was that on the tracks I tested it sometimes kept the engine out of it's power band
The 6spd evo was defiantely the best, even if it was a little slow off the line due to the tall 1st gear, it was very very quick once moving, there isn't much spacing between the gears, and it always seems to have the right ratio available.