1/4 mile predictions for G37 Coupe?
#62
06-01-2007, 01:26 AM
Why would the 7 need a 6K drop to make an optimal launch?
#63
06-01-2007, 01:27 AM
Originally Posted by trey.hutcheson
The 07s do that with a power:weight ratio that will be nearly identical to that of the g37 coupe. The gear ratios are the same, but the FD in the g37 will be ~5% shorter than the z. And a shorter final drive doesn't always equal better ET's.
For example, if you look at the top25 list on my350z, you will find two z's in the top10 that are only trapping 103mph. One is an auto, and the other is a six speed. They have nearly identical launches, and traps. The auto was on street tires, while the 6mt was on DR's. The auto's launch was marginally worse, as was his trap, but his ET was almost 2 tenths faster than the guy in the 6 speed.
What makes this comparison even more interesting is the fact that that particular auto even has a 3.5FD swap, so the final drives are the same. That just means that each of the gears in the auto is longer than in the 6 speed counter part.
Go look at that list again and let it sink in. Notice anything about the ET's versus the trap speeds? Those two guys with the 103mph traps had ET's of 13.3 and 13.1.
My last trip to the track netted me a 13.622@103.63 with a 2.082 sixty foot. Take one and a half tenths off my sixty foot, and it would be close to these two guys. But that would put my ET as a low 13.4. I'm trapping higher than both those guys, and even if I could launch like them, I wouldn't be able to match their ET's. And it's certainly not shifting.
So don't get so hung up on the coupe besting the 07z's.
For example, if you look at the top25 list on my350z, you will find two z's in the top10 that are only trapping 103mph. One is an auto, and the other is a six speed. They have nearly identical launches, and traps. The auto was on street tires, while the 6mt was on DR's. The auto's launch was marginally worse, as was his trap, but his ET was almost 2 tenths faster than the guy in the 6 speed.
What makes this comparison even more interesting is the fact that that particular auto even has a 3.5FD swap, so the final drives are the same. That just means that each of the gears in the auto is longer than in the 6 speed counter part.
Go look at that list again and let it sink in. Notice anything about the ET's versus the trap speeds? Those two guys with the 103mph traps had ET's of 13.3 and 13.1.
My last trip to the track netted me a 13.622@103.63 with a 2.082 sixty foot. Take one and a half tenths off my sixty foot, and it would be close to these two guys. But that would put my ET as a low 13.4. I'm trapping higher than both those guys, and even if I could launch like them, I wouldn't be able to match their ET's. And it's certainly not shifting.
So don't get so hung up on the coupe besting the 07z's.
#64
06-01-2007, 01:32 AM
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#66
06-01-2007, 03:40 AM
Originally Posted by FAST1
It has nothing to do with the number of cylinders but everything to do with the engine torque and at what RPM the maximum engine torque is produced. Unless you are launching a torque monster like a C6 Z06 or a Viper or any of the MB AMG cars, you have to launch at high RPM to get the best time.
My brother has an '06 997S which we've taken to the dragstrip a few times. We were never able to match the low 12 sec 1/4s listed in magazines like Road & Track and Car & Driver. I then read where Car & Driver launched the 997 at 5K RPM to get their best time. I was launching at 3K RPM and getting 12.6 - 12.7. That's why I don't believe that 1/4 mile times listed in the magazines are all that important since not too many people are willing to abuse their cars to get their absolute best times, and 5/60 times are a far more revealing measure of a car's capability on the street.
If you look at the 0/60 and 5/60 times of cars with a lot of torque like the 400 lb/ft C6, you'll find that they are nearly identical. On the other hand you'll find that the 5/60 times are slower on cars with moderate torque outputs because they require that high RPM launch.
My brother has an '06 997S which we've taken to the dragstrip a few times. We were never able to match the low 12 sec 1/4s listed in magazines like Road & Track and Car & Driver. I then read where Car & Driver launched the 997 at 5K RPM to get their best time. I was launching at 3K RPM and getting 12.6 - 12.7. That's why I don't believe that 1/4 mile times listed in the magazines are all that important since not too many people are willing to abuse their cars to get their absolute best times, and 5/60 times are a far more revealing measure of a car's capability on the street.
If you look at the 0/60 and 5/60 times of cars with a lot of torque like the 400 lb/ft C6, you'll find that they are nearly identical. On the other hand you'll find that the 5/60 times are slower on cars with moderate torque outputs because they require that high RPM launch.
Define "high rpm launch", because to me, high rpms is already 5k+.
High RPM launched are ideal on cars such as the S2000 or RX8 due to its power/torque curve.
But anything over 3.5k on a car like the G35 on street tires and your times are going to suffer dramatically.
Have you tried your method on a G35? Just wondering...
.
#67
06-01-2007, 07:17 AM
Originally Posted by skaterbasist
Obviously the more the cylinders the more the power/torque.
Define "high rpm launch", because to me, high rpms is already 5k+.
High RPM launched are ideal on cars such as the S2000 or RX8 due to its power/torque curve.
But anything over 3.5k on a car like the G35 on street tires and your times are going to suffer dramatically.
Have you tried your method on a G35? Just wondering...
.
Define "high rpm launch", because to me, high rpms is already 5k+.
High RPM launched are ideal on cars such as the S2000 or RX8 due to its power/torque curve.
But anything over 3.5k on a car like the G35 on street tires and your times are going to suffer dramatically.
Have you tried your method on a G35? Just wondering...
.
A 5K RPM launch is what I would call a high RPM launch, and it's not something that most of us would subject our cars to on a regular basis, but since the G35 makes its maximum torque at 4800 RPM, I'd be surprised if the magazine drivers aren't launching near that RPM. My point is that I find a 5/60 time to be far more pertinent in giving us a good idea of what kind of performance that a car will deliver on the street, than a 0/60 or 1/4 mile time, especially if the magazine doesn't let us know what their launch RPM was.
I rarely take my car to the dragstrip but when I do, I don't launch at high rpms to avoid abusing the car. I launch by holding the rpm (usually 3600-3900 on an average prepped track) and then quickly but smoothly release the clutch with a full engage occurring over the first 4-10' of movement. I try not to feed it more throttle until I think the tires are hooked. There is a delicate balance to find. But it entails squeezing the throttle progressively to the floor between 10-25 foot off the lights. Drag radials will take throttle more quickly than stock tires, but it's still a "squeezing" action rather that a "stomp." Another big advantage of DRs is that they do a great job holding the shifts to 2d, 3d, and 4th without spinning (much).
Last edited by FAST1; 06-01-2007 at 11:59 AM.
#68
06-01-2007, 10:00 AM
Originally Posted by tekknikal
could you post the spreadsheet?
Ok. I have attached the spreadsheet, but here are my comments:
1. It's MY spreadsheet so please no comments on formatting or "hard to read".
2. These are based on eye-ball HP numbers from the dynos. It is also done in 250 rpm increments. Sometimes, if a car shifted at a point in between 250 rpm increments, I just started it at the nearest 250 rpm increment.
3. The numbers are based on 1:1 ratio (dyno). In reality, a car will put down more torque in 1st gear (torque multiplication) than it will at 1:1. If someone wants to add the multiplication, please do so.
4. A better way to represent this would be using a MPH vs. HP curve. The graph would be made up of 4 lines (1 for each gear). This would better show what is happening at any simultaneous MPH of each car. If anyone knows how to quickly graph that using my spreadsheet please do so.
5. If I recall my 04 G35 6mt shifted out of 3rd very early (80+ mph). Is that correct? Because the new car doesn't get out of 3rd until 103 mph. The BMW doesn't shift out of 3rd until 107!! (I checked my calc using a BMW road test data from road and track).
#69
06-01-2007, 10:09 AM
Originally Posted by trey.hutcheson
The 07s do that with a power:weight ratio that will be nearly identical to that of the g37 coupe. The gear ratios are the same, but the FD in the g37 will be ~5% shorter than the z. And a shorter final drive doesn't always equal better ET's.
#70
06-01-2007, 04:30 PM
Originally Posted by Hypnoz
Reading comprehension should be a requirement to post.
"12s no doubt with DRs and 5-6K launch."
I said stop speculating, and why would this car need a 6K launch.... Hmm, yeah, I can't read.
#71
06-01-2007, 08:49 PM
Originally Posted by Sukairain
Oh God, somebody go buy a Camaro or a SRT-4. These 1/4 mile BS is getting real tiring.
#73
06-03-2007, 06:00 AM
"12s no doubt with DRs and 5-6K launch."
I said stop speculating, and why would this car need a 6K launch....
There are some engines that produce maximum torque at relatively low rpm and hence there's no need to launch at high rpm to get the best time. If you have an engine that makes peak torque at 3K rpm, why would anyone want to launch at 5K-6K rpm where it would be challenging to control wheel spin.
As far as speculation about times, you are right on target. It's essentially meaningless, and certainly nothing to get worked up about.
I said stop speculating, and why would this car need a 6K launch....
There are some engines that produce maximum torque at relatively low rpm and hence there's no need to launch at high rpm to get the best time. If you have an engine that makes peak torque at 3K rpm, why would anyone want to launch at 5K-6K rpm where it would be challenging to control wheel spin.
As far as speculation about times, you are right on target. It's essentially meaningless, and certainly nothing to get worked up about.
#74
06-03-2007, 11:00 AM
^^ Fast1,
That same car that you are talking about that makes good low-end torque, still makes MORE power up higher in the bank. Traction MAY be limited, so you would not want to go to high or lose time spinning your wheels.
That being said, alot of torque may make it hard to get a hard launch because of the sensitivity to losing too much traction. Too low, and the car may bog. Then again, this is true of all cars.
That same car that you are talking about that makes good low-end torque, still makes MORE power up higher in the bank. Traction MAY be limited, so you would not want to go to high or lose time spinning your wheels.
That being said, alot of torque may make it hard to get a hard launch because of the sensitivity to losing too much traction. Too low, and the car may bog. Then again, this is true of all cars.
#75
06-03-2007, 12:15 PM
Originally Posted by muscarel
^^ Fast1,
That same car that you are talking about that makes good low-end torque, still makes MORE power up higher in the bank. Traction MAY be limited, so you would not want to go to high or lose time spinning your wheels.
That being said, alot of torque may make it hard to get a hard launch because of the sensitivity to losing too much traction. Too low, and the car may bog. Then again, this is true of all cars.
That same car that you are talking about that makes good low-end torque, still makes MORE power up higher in the bank. Traction MAY be limited, so you would not want to go to high or lose time spinning your wheels.
That being said, alot of torque may make it hard to get a hard launch because of the sensitivity to losing too much traction. Too low, and the car may bog. Then again, this is true of all cars.