12.691 1/4 Mile Run
12-16-14, 04:29 PM
#31
With the TVD, Torque can be better targeted to the wheel with higher friction locking potential. This reduces wheel spin, and it is particularly of value when each wheel is on a slightly different surface at the start. The outcome is an increase in propulsion and better times.
Now, how much improvement in launch with the TVD is required to nudge times 2-3 tenths?
Let's hold back the horses until the production TVD car lands in March.
There is no intention to push aside the merits of my IS F. It's a superb car.
I am trying to point to the benefits of the new technology.
Now, how much improvement in launch with the TVD is required to nudge times 2-3 tenths?
Let's hold back the horses until the production TVD car lands in March.
There is no intention to push aside the merits of my IS F. It's a superb car.
I am trying to point to the benefits of the new technology.
I think you just described a torsen/limited slip differential. Only difference that the torsen doesn't use a computer to monitor it. So no...i don't think its worth 2-3 tenths over a regular LSD. Why would it? Especially since it's adding weight.
It's main purpose is for stability in turns and to enhance the cornering capability of the car. I know your intent is to speak to benefits of the added technology. However, you would make a more compelling case if you understood what that technology is actually for...
12-16-14, 04:46 PM
#33
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Guys knock off the personal comments and keep this discussion on the vehicles. If you can't do that, don't be surprised if you suddenly lose access to the RCF Forum.
12-16-14, 05:20 PM
#34
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There are many RC Fs with TVD available NOW... The only difference between them and your ordered car is the carbon fiber roof/spoiler. So excluding some slight performance gain (I'd guess extremely minor at best) from the weight savings - TVD equipped RC Fs are out now.
12-16-14, 06:54 PM
#35
There are many RC Fs with TVD available NOW... The only difference between them and your ordered car is the carbon fiber roof/spoiler. So excluding some slight performance gain (I'd guess extremely minor at best) from the weight savings - TVD equipped RC Fs are out now.
The center of gravity is lowered with the carbon roof, and it sheds some weight. How much I do not know.
12-16-14, 07:05 PM
#36
I think you just described a torsen/limited slip differential. Only difference that the torsen doesn't use a computer to monitor it. So no...i don't think its worth 2-3 tenths over a regular LSD. Why would it? Especially since it's adding weight.
"It's main purpose is for stability in turns and to enhance the cornering capability of the car. I know your intent is to speak to benefits of the added technology. However, you would make a more compelling case if you understood what that technology is actually for...
"It's main purpose is for stability in turns and to enhance the cornering capability of the car. I know your intent is to speak to benefits of the added technology. However, you would make a more compelling case if you understood what that technology is actually for...
Based on this, my comment is valid. I will agree that this is a partial benefit in additional to the exceptional cornering capability, but it is a real benefit. Thus, this is how I see room for improved performance by leveraging the best driving settings (yet to be determined in my opinion) and the benefits of TVD.Torque Vectoring-General Explanation
"The system, which is based on a planetary design - unlike a high-ratio transmission design - is more efficient. The gears of the planetary gear set do not turn when driving straight on. Therefore, the system power losses are limited to oil shearing in the released multi-disk brake and the churning of the planetary gear set rotating without relative gear rotation.
The new rear axle drive also features the familiar benefits of locking differentials, as the torque can be targeted to the wheel with the higher friction locking potential. Thus, drive wheel spin can be avoided, in particular when both wheels of the drive axle are on different road surfaces when starting off. This leads to improved vehicle propulsion; moreover, fewer and less intense brake interventions to reduce wheel spin are required. There is less wear on the brakes and also a positive effect on fuel consumption."
12-16-14, 07:18 PM
#37
Based on this, my comment is valid. I will agree that this is a partial benefit in additional to the exceptional cornering capability, but it is a real benefit. Thus, this is how I see room for improved performance by leveraging the best driving settings (yet to be determined in my opinion) and the benefits of TVD.Torque Vectoring-General Explanation
"The system, which is based on a planetary design - unlike a high-ratio transmission design - is more efficient. The gears of the planetary gear set do not turn when driving straight on. Therefore, the system power losses are limited to oil shearing in the released multi-disk brake and the churning of the planetary gear set rotating without relative gear rotation.
The new rear axle drive also features the familiar benefits of locking differentials, as the torque can be targeted to the wheel with the higher friction locking potential. Thus, drive wheel spin can be avoided, in particular when both wheels of the drive axle are on different road surfaces when starting off. This leads to improved vehicle propulsion; moreover, fewer and less intense brake interventions to reduce wheel spin are required. There is less wear on the brakes and also a positive effect on fuel consumption."
anywho... and according to this....the carbon package is going to save 14.33 lbs. also...there is an illustration showing how the TVD works...in a corner.
12-16-14, 07:21 PM
#38
ummmmm....isnt that saying that the TVD not even working when the car is going in a straight line?
anywho... and according to this....the carbon package is going to save 14.33 lbs. also...there is an illustration showing how the TVD works...in a corner.
anywho... and according to this....the carbon package is going to save 14.33 lbs. also...there is an illustration showing how the TVD works...in a corner.
This is how I read it.
More on both aspects of TVD:
"During straight forward acceleration, torque biasing differential can produce close to ideal 50/50 power split to both drive wheels, resulting in improved traction over a conventional open differential. In cornering, while accelerating out of a turn, a torque biasing differential can bias engine power to the outside wheel, minimizing or eliminating spinning of the inside wheel, thereby allowing earlier acceleration in the curve and exiting the corner at a higher speed."
I understand the cornering application. Appreciate the link.
Last edited by ISF001; 12-16-14 at 07:36 PM.
12-16-14, 07:51 PM
#40
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Just some food for thought...
If this run was done sometime in the past 2 weeks, then the density altitude was likely around 800 feet (Bahrain International Circuit is roughly 50ft above sealevel, 70*F, 70% Humidity, 30.10 inHg). This would result in a very small (if any) correction to ET.
The launch feels a little soft, I would think a high 1.8/low 1.9 sec 60' is attainable given the tire type, weight, and automatic transmission.
And in regards to trap speed, I wonder if the 10% increase in drag coefficient between the IS-F and RC-F (.30 vs .33) is already coming into play here...
But for a first run this doesn't look too bad at all. This time fits in the middle of all the IS-F data on dragtimes website (including modified vehicles). Now we just have to wait for some more data before we can begin drawing trends.
TK
If this run was done sometime in the past 2 weeks, then the density altitude was likely around 800 feet (Bahrain International Circuit is roughly 50ft above sealevel, 70*F, 70% Humidity, 30.10 inHg). This would result in a very small (if any) correction to ET.
The launch feels a little soft, I would think a high 1.8/low 1.9 sec 60' is attainable given the tire type, weight, and automatic transmission.
And in regards to trap speed, I wonder if the 10% increase in drag coefficient between the IS-F and RC-F (.30 vs .33) is already coming into play here...
But for a first run this doesn't look too bad at all. This time fits in the middle of all the IS-F data on dragtimes website (including modified vehicles). Now we just have to wait for some more data before we can begin drawing trends.
TK
12-16-14, 07:58 PM
#41
well few months ago
i did a 1000 m (1km) challenge and i won my class (modern stock class)
the event was called snowy mountain 1000 in australia
@ 3,106 ft / 947m of elevation
i managed a time of 24.020 @218km/h and this was in a warm summer temp
mind you u cant do any burn outs or anything before the run and i was spinning 1st and 2nd gear off the mark
my isf is modded with full IHE running nutto nt05's
suspension is set up for track so massive camber and toe difference from factory 0
Also did a drags once and i managed 12.8 to 400m with 60ft time of 2.3seconds
but i my suspension settings werent for the drags at all so.
i did a 1000 m (1km) challenge and i won my class (modern stock class)
the event was called snowy mountain 1000 in australia
@ 3,106 ft / 947m of elevation
i managed a time of 24.020 @218km/h and this was in a warm summer temp
mind you u cant do any burn outs or anything before the run and i was spinning 1st and 2nd gear off the mark
my isf is modded with full IHE running nutto nt05's
suspension is set up for track so massive camber and toe difference from factory 0
Also did a drags once and i managed 12.8 to 400m with 60ft time of 2.3seconds
but i my suspension settings werent for the drags at all so.
Last edited by ilv1004s; 12-16-14 at 08:02 PM.
12-16-14, 09:02 PM
#43
Lexus Test Driver
I recall reading somewhere that the final gearing on the TVD is lower than the standard differential.
I posted a little more than a month ago the announcer (at 1:40sec) saying the standard RCF's 0-60 is 4.4sec but if you have the carbon performance package it is 4.3sec. The major differences between the standard and performance package is the differential and 15lbs lighter carbon roof and rear spoiler. So there got to be something with the gear ratio on the TVD that is making the RCF run faster. Only true way to tell is to run a non TVD with a TVD and also with a IS-F to settle the arguments.
https://www.clublexus.com/forums/rc-...n-4-3-sec.html
Chu...
I posted a little more than a month ago the announcer (at 1:40sec) saying the standard RCF's 0-60 is 4.4sec but if you have the carbon performance package it is 4.3sec. The major differences between the standard and performance package is the differential and 15lbs lighter carbon roof and rear spoiler. So there got to be something with the gear ratio on the TVD that is making the RCF run faster. Only true way to tell is to run a non TVD with a TVD and also with a IS-F to settle the arguments.
https://www.clublexus.com/forums/rc-...n-4-3-sec.html
Chu...
Last edited by ChuH; 12-16-14 at 09:07 PM.
12-17-14, 05:13 AM
#45
youre not going to notice 5# 15# on the track. Spending the money to get lightweight wheels or brake rotors would make a more noticeable difference. They need to offer the TVD standalone as a permanent option, the $5500 TVD+CF parts arent worth the price to me, but the TVD alone is