Looks like the GT-R isn't so great after all...

Spectre said:
Most of the cars that came with the TH400 from the factory had less than 250 SAE Net HP. The GT-R is known to have more than 500.

Most of the cars on Pinks, for example, that have TH400s are running about what the GT-R does in the quarter, despite being moderately to heavily modified. And there've been plenty of them that grenaded the transmission going down the strip one too many times. Almost all of them being thermal failures due to overheated fluid, since TH400s are hard to break any other way.
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I would hesitate to use Pinks as any kind of resource. I've seen lots of people run TH400's with a good synth fluid like Amsoil Supershift or similar and go a hell of a longer than 20 passes between changes. I do agree that this is a thermal issue of some kind, but I suspect that the dual-clutch design requires a weaker fluid that breaks down easier, rather than it being a straight transmission issue.
 
I'm using Pinks as an example that anyone can simply go download and see.

In reality, I'm basing my opinions off of watching people go down the local dragstrips in person, as well as the drag racers on the local car fora. Some people get 10 passes out of their TH400 before the fluid fails, some people get 50. More towards the low end of that, though. The smart people change their trans fluid well before 20, though, and at the end of every night.

The GT-R's manual calls for a special fluid to be used in the transmission. I doubt that it's weaker than, say, Dextron or Mercon. Those two don't even have any standard viscosity, for god's sake!

For those that want to see what's in the manual itself, the NAGTROC has scanned in the US owner's manual and made it into a PDF: http://nagtroc.org/files/R35Owners_Manual.zip
 
Spectre said:
In reality, I'm basing my opinions off of watching people go down the local dragstrips in person, as well as the drag racers on the local car fora. Some people get 10 passes out of their TH400 before the fluid fails, some people get 50. More towards the low end of that, though. The smart people change their trans fluid well before 20, though, and at the end of every night.

The GT-R's manual calls for a special fluid to be used in the transmission. I doubt that it's weaker than, say, Dextron or Mercon. Those two don't even have any standard viscosity, for god's sake!
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The going sentiment around here is 25 passes or so, depending on your power output. Anyway, the PDF with the fluid specs is available in that link I posted, feel free to draw your own conclusions.
 
Heh. Well, if you riced out the GTR with a body kit, giant wing and such, the whole car SHOULD be X-ed out. :p
 
I actually think it's kind of funny that the picture shows a front lip on the body kit.... one of the ugliest things one can do with a body kit. Ironic that nissan allready put one on themselves, and riced it out. I'd rather just get rid of it and put on a smooth front bumper.
 
BerserkerCatSplat said:
The going sentiment around here is 25 passes or so, depending on your power output. Anyway, the PDF with the fluid specs is available in that link I posted, feel free to draw your own conclusions.
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Judging by the product data sheet, the Pentosin is a tougher fluid than Dextron-VI and is more or less tied with Amsoil Supershift. I'm pasting the appropriate data here, with some of the extraneous stuff removed and reordered for better comprehension.


Mobil DEXRON-VI ATF
Viscosity
cSt @ 40?C 29.5
cSt @ 100?C 5.83
cP @ -40?C 11,500
Viscosity Index 145
Flash Point, ?C (?F) 220 (428)


AMSOIL Synthetic Supershift Racing Transmission Fluid (ART)
Kinematic Viscosity @ 40? C, cSt (ASTM D-445) 41.3
Kinematic Viscosity @ 100? C, cSt (ASTM D-445) 7.1
Viscosity Index (ASTM D-2270) 133
Flash Point ?C (?F) (ASTM D-92) 248 (478)
Fire Point ?C (?F) (ASTM D-92) 266 (510)
Pour Point ?C (?F) (ASTM D-97) -49 (-56)


Pentosin FFL-4
Kinematic Viscosity at 40 ?C mm?/s 34,7 DIN EN ISO 3104
Kinematic Viscosity at 100 ?C mm?/s 7,0 DIN EN ISO 3104
Viscosity Index 168 DIN ISO 2909
Dynamic Viscosity at -40 ?C mPa*s 7400 ASTM D2983
Flash Point COC ?C 220 DIN EN ISO 2592
Pour Point ?C -54 ISO 3016


So, basically, it has much higher viscosity (it lubes better), the same flash point as the leading full-synth Dextron VI, and a lower pour point than the Amsoil, indicating a greater range of temperature handling ability.

So, basically, it's at least as good and in most ways better than typical synthetic Dextron VI, and is more or less tied with the specialty fluid from a niche manufacturer. There goes the theory of "it's worse than Dextron".

Sources:
http://www.amsoil.com/StoreFront/art.aspx
http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_Dexron-VI_ATF.asp
http://www.pentosin.de/flexxtrader/...4_GB.pdf?sid=e60b3691403f3a172f482935bf457158
 
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BerserkerCatSplat said:
I would hesitate to use Pinks as any kind of resource. I've seen lots of people run TH400's with a good synth fluid like Amsoil Supershift or similar and go a hell of a longer than 20 passes between changes. I do agree that this is a thermal issue of some kind, but I suspect that the dual-clutch design requires a weaker fluid that breaks down easier, rather than it being a straight transmission issue.
Click to expand...

Spectre said:
Judging by the product data sheet, the Pentosin is a tougher fluid than Dextron-VI and is more or less tied with Amsoil Supershift. I'm pasting the appropriate data here, with some of the extraneous stuff removed and reordered for better comprehension.


Mobil DEXRON-VI ATF
Viscosity
cSt @ 40?C 29.5
cSt @ 100?C 5.83
cP @ -40?C 11,500
Viscosity Index 145
Flash Point, ?C (?F) 220 (428)


AMSOIL Synthetic Supershift Racing Transmission Fluid (ART)
Kinematic Viscosity @ 40? C, cSt (ASTM D-445) 41.3
Kinematic Viscosity @ 100? C, cSt (ASTM D-445) 7.1
Viscosity Index (ASTM D-2270) 133
Flash Point ?C (?F) (ASTM D-92) 248 (478)
Fire Point ?C (?F) (ASTM D-92) 266 (510)
Pour Point ?C (?F) (ASTM D-97) -49 (-56)


Pentosin FFL-4
Kinematic Viscosity at 40 ?C mm?/s 34,7 DIN EN ISO 3104
Kinematic Viscosity at 100 ?C mm?/s 7,0 DIN EN ISO 3104
Viscosity Index 168 DIN ISO 2909
Dynamic Viscosity at -40 ?C mPa*s 7400 ASTM D2983
Flash Point COC ?C 220 DIN EN ISO 2592
Pour Point ?C -54 ISO 3016


So, basically, it has much higher viscosity (it lubes better), the same flash point as the leading full-synth Dextron VI, and a lower pour point than the Amsoil, indicating a greater range of temperature handling ability.

So, basically, it's at least as good and in most ways better than typical synthetic Dextron VI, and is more or less tied with the specialty fluid from a niche manufacturer. There goes the theory of "it's worse than Dextron".

Sources:
http://www.amsoil.com/StoreFront/art.aspx
http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_Dexron-VI_ATF.asp
http://www.pentosin.de/flexxtrader/...4_GB.pdf?sid=e60b3691403f3a172f482935bf457158
Click to expand...


*looks at user title* You two have managed to bore me with all this discussion of tranny fluid.

https://pic.armedcats.net/t/th/thedguy/2008/10/11/clap.gif
 
The really important question is: Why is the launch control there at all?

If it damages the car and has no other sense, than boosting the driver's ego in a drag race, then why not simply leave it away?

It's there, because the car maker brags with a certain 0-62/0-100 figure, which can hardly be achieved by an average driver without LC (and often not even with it). But that figure is important in the war of numbers among car makers, since it targets the young generation, the hot shots, who actually do race their cars against others (mostly in an illegal way of course) to prove their manhood.

So basically launch control is a feature for immature people with small dicks, who are not ripe enough to drive such a car in the first place :)

I still think Nissan is legally not on save ground to deny warranty in that way - but on the other hand I have absolutely no sympathy for the guy who wrecked his car that way.
 
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That sums it up pretty well. Like I have shown, BMW has done it as well. The only difference in their case was that they documented how to use the LC. Still, they also ruled out warranty claims in case of damage.
 
Spectre said:
So, basically, it's at least as good and in most ways better than typical synthetic Dextron VI, and is more or less tied with the specialty fluid from a niche manufacturer. There goes the theory of "it's worse than Dextron".
Click to expand...

Then, if it's not the fluid, what makes this transmission so comparatively weak? I'm out of ideas. It seems like the system is being subjected to fair amount of force, but the components should have been designed to handle it. The tranny is apparently very similar to the VW Borg-Warner unit, perhaps Nissan just didn't beef up the internals enough.
 
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You said yourself that most people with TH400s got about 25 passes out of them before needing to change the fluid or having the box grenade. Well, 20 hard launches under LC isn't that much different, is it?

When I had the XKR, we all knew that you wouldn't get more than 10-15 neutral drops before you'd blow up the box, for much the same reason.
 
the Interceptor said:
No. There's no launch control system in any car that respects the mechanical limits and therefore holds back performance. That's why manufacturers say that you shouldn't use it very often or even not at all, cause things can break. A launch control simply is there to find the perfect relation between power input (revs), clutch slip and wheelspin to accelerate the car from a standstill as quickly as possible. Also, it will usually generate more stress than a manually operated car. As I described earlier in this thread, this is especially hard on AWD cars, as there is a lot of grip from the wheels. That's why in cars such as the GT-R, the maximum of mechanical stress goes into the driveline when you do an LC start.
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I know this conversation is basically over, but I just wanted to pull you up on this. The LC feature on the EVO X is one that doesn't strain the driveline like the GTR one does. The LC in the GTR can be alikened to "dumping the clutch" in a manual vehicle. It puts a lot of strain on the gearbox and driveline.

[YOUTUBE]http://au.youtube.com/watch?v=LKcyJ960WBY[/YOUTUBE]

Then compare that with the LC in the EVO X. It's much more placid and doesn't "dump" the clutch but rather slips it enough to get going quickly without putting stress on the driveline or wearing the clutches out too much.

[YOUTUBE]http://au.youtube.com/watch?v=5S5D6wA6ZJw[/YOUTUBE]
 
Well, that explains why the EVO X burns through clutches like crazy. If you're slipping the clutch, you're shaving life off it. They're also sacrificing speed and power to do it, too.
 
Disciple said:
I know this conversation is basically over, but I just wanted to pull you up on this.
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May I just say that I am happy to take any conversation up again, given that someone has something of importance to bring forward. :)

Disciple said:
The LC feature on the EVO X is one that doesn't strain the driveline like the GTR one does. The LC in the GTR can be alikened to "dumping the clutch" in a manual vehicle. It puts a lot of strain on the gearbox and driveline.

Then compare that with the LC in the EVO X. It's much more placid and doesn't "dump" the clutch but rather slips it enough to get going quickly without putting stress on the driveline or wearing the clutches out too much.
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An interesting feature for sure, and one I didn't know of. But it makes sense, as Mitsubishi has introduced the double-clutch gearbox in the Evo X, a line of cars which have always been optimised by advanced electronic systems.

Unfortunately, every system that doesn't put the stress onto the gearbox actually gives away performance. Whether you let the clutch slip, allow wheelspin or choose a lower initial rpm figure, you will lose tenths compared to a full-blown LC start. Additionally, you will concentrate wear on one specific part. I agree that it's better to wear the tires or the clutch than to destroy the gearbox, but in terms of performance, you can only lose. Like the guy in the video says, the Evo X doesn't just dump the clutch, but it loses performance in the process. So while this won't wreck the gearbox, it isn't the ideal solution either.
 
I know it's not the ideal solution, but I'm just pointing out that LC doesn't have to be so brutal that it ruins the gearbox after 20 launches.

I haven't read of a single clutch failure in any SST gearbox yet, plenty in the manual cars because the clutches are always made as the weak point and are considered a consumable item on an EVO.

Point is, yes you'll lose some performance on the LC in the EVO X compared to the GTR, but I look at it as tho the engineers at Mitsubishi would've considered all options available and chose this option. It slips the clutches enough to get going quickly, but doesn't dump them to ruin the gearbox. When the gearbox gets too hot, it will simply go into limp mode and not let you launch anymore. The clutches are strong enough to be slipped in this fashion for a long, long time. So while you may lose 0.2s off your 0-100 time, it'll do it consistantly without breaking anything. I'll take reliability over slight performance increase anyday.
 
So would I. Yet, it is to be determined what leads to gearbox failure on the GT-R. Given it actually is the gearbox fluid that has to be changed when you use LC continuously, this problem probably can be addressed easily. However, the LC obviously wasn't intended to be used regularly by customers, so Nissan probably never thought that this problem would occur, which is why the manual doesn't even mention it.
 
the Interceptor said:
So would I. Yet, it is to be determined what leads to gearbox failure on the GT-R. Given it actually is the gearbox fluid that has to be changed when you use LC continuously, this problem probably can be addressed easily. However, the LC obviously wasn't intended to be used regularly by customers, so Nissan probably never thought that this problem would occur, which is why the manual doesn't even mention it.
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If the manual doesn't mention it that doesn't make it an excuse. Nissan cannot be that naive as to not think that some internet videos would pop up on how to perform a LC start. From there it's like Albert Einstein once said - "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

On the GTR damage, I would imagine if it isn't the clutches, then it's possibly a broken driveshaft, gear selector forks or the actual gears themselves have stripped some teeth off. Either way, I imagine it's a sealed unit meaning none of the above mentioned parts can be replaced indivually and so the entire transmission needs to be replaced, hence the $20k bill.
 
Disciple said:
I know it's not the ideal solution, but I'm just pointing out that LC doesn't have to be so brutal that it ruins the gearbox after 20 launches.

I haven't read of a single clutch failure in any SST gearbox yet, plenty in the manual cars because the clutches are always made as the weak point and are considered a consumable item on an EVO.

Point is, yes you'll lose some performance on the LC in the EVO X compared to the GTR, but I look at it as tho the engineers at Mitsubishi would've considered all options available and chose this option. It slips the clutches enough to get going quickly, but doesn't dump them to ruin the gearbox. When the gearbox gets too hot, it will simply go into limp mode and not let you launch anymore. The clutches are strong enough to be slipped in this fashion for a long, long time. So while you may lose 0.2s off your 0-100 time, it'll do it consistantly without breaking anything. I'll take reliability over slight performance increase anyday.
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From what I have heard from a source that I believe (an owner of an Evo X MR) Mitsubishi does not warrant the gear box on them.........
If the manual doesn't mention it that doesn't make it an excuse. Nissan cannot be that naive as to not think that some internet videos would pop up on how to perform a LC start. From there it's like Albert Einstein once said - "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."
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My car has an automatic that has N on it. I can put the car in N rev it to the limit and dump it into D. Do you think I will have a transmission for very long if I do that? It doesn't say not to do it in a manual, it also doesn't say to do it in a manual. Main thing that you seem to have missed is that since the manual does not list that particular feature means simply that if you discover it you are on your own. You can argue that the car was not reliable or that GT-R sux that is all fine and good, however using an undocumented feature in any product generally obsolves the manufacturer of any responsibility.
 
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