V-spec Version Discussion And Speculation

[skyline_man]

Well put Garry. Those who still wants a traditional manual in the R35 GTR must be either ignorant, insane or just for plain chest beating, dick wanking value.

[Beer Baron]

don't know if I'd go that far. conventional manual transmissions are fun to drive. but in this case a conventional manual box would removed the biggest feature of the car and drastically diminish it's performance on the strip, the circuit and the street. like I said before it's the DSG that makes the GTR what it is and is the main secret behind it's awesome on track pace. so yeah, no way will they be removing it.

[scathing]

However, its not hard to think of reasons to bin it for a traditional manual gearbox. The first being weight. What does all the electronids/hydraulics etc do for the overall weight? Im guessing the DCT is heavier, technology usually is.

It is heavier. Porsche has publicly stated that the 997T comes with a regular torque converted manual over a twin-clutch system due to its extra weight (20kg, off the top of my head, so that's probably wrong) for apparently "little extra gain" (although the GT-R's acceleration figures would beg to differ).

We all know a regular auto is heavier than a manual so there's probably a good 50kg+ weight saving by going to a traditional manual.

what benefit you could possibly get from the massive effort involved escapes me completely... if any even exists

For the same reason people do random mods - so you can brag about it. Like the guys who cram Chev small blocks into anything from Minis to motorboats. There are a lot of dumb people out there, who want "different" and have no concept of the term "good".

[Gts-t]

Im so over double clutching, i woudl really love something that could do it all much faster than me. Being able to use a foot on each pedal would aslo be fun

If i want the feel of a normal manual ill drive a car with one!

[Sydneykid]

It is heavier. Porsche has publicly stated that the 997T comes with a regular torque converted manual over a twin-clutch system due to its extra weight (20kg, off the top of my head, so that's probably wrong) for apparently "little extra gain" (although the GT-R's acceleration figures would beg to differ).

We all know a regular auto is heavier than a manual so there's probably a good 50kg+ weight saving by going to a traditional manual.

It's not a regular auto, in fact it's not an auto all. It doesn't have bands and clutch packs, no torque converter, they are heavy stuff that makes an auto weigh more. It is a manual gearbox with 2 clutches and a few solenoids, that's it. So the only real extra weight is the extra clutch itself, there's no extra flywheel. A small diameter clutch like that doesn't weigh even 10 kgs, not even close.

Cheers

Gary

[Sydneykid]

For the same reason people do random mods - so you can brag about it. Like the guys who cram Chev small blocks into anything from Minis to motorboats. There are a lot of dumb people out there, who want "different" and have no concept of the term "good".

But that makes them go faster, downgrading the gearbox would make it go slower. Even the Yanks aren't that dumb

Cheers

Gary

[skyline_man]

It is heavier. Porsche has publicly stated that the 997T comes with a regular torque converted manual over a twin-clutch system due to its extra weight (20kg, off the top of my head, so that's probably wrong) for apparently "little extra gain" (although the GT-R's acceleration figures would beg to differ).

Apparently, Porsche couldn't get the DSG system to work properly on the 997 turbo so they abandoned it. Nothing to do with weight.

Now, however, after the Porshe engineers have dismantled the GTR at their headquarters and studied how to apply the DSG system properly - guess what? The next 911 turbo will have a 7 spd DSG gearbox!!

[Sydneykid]

Apparently, Porsche couldn't get the DSG system to work properly on the 997 turbo so they abandoned it. Nothing to do with weight.

Now, however, after the Porshe engineers have dismantled the GTR at their headquarters and studied how to apply the DSG system properly - guess what? The next 911 turbo will have a 7 spd DSG gearbox!!

Porsche just bought VW and their dual clutch manual works pretty well.

Cheers

Gary

[sh@un]

Apparently, Porsche couldn't get the DSG system to work properly....

As Gary said- Porsche just bought Audi, but they've held about 40% of the shares for ages... so technical nous isn't the issue

I think the real reason would be space: the distance between the back seat and the rear bumper (not very blood far) on a 911 Turbo already has to accommodate a flat 6, 2 turbos, 2 intercoolers, 2 air boxes, a transaxle, multi-link suspension and a fairly elaborate exhaust system. Gives me a headache just thinking about it...

[Sydneykid]

Wow, SydneyKid is alive!

I haven't seen a post from you in like..... a year????

Probably been sculking around the Stagea section....maybeeeee????

You obviously hang with a different crowd, I live in the Suspension and Motorsport sections mostly.

Cheers

Gary

[Phoenix AZ]

still waiting to read a reply from 2 pages ago about the plasma bores and if they will handle more then 600hp and if 100 000km rebuild is true?

RE: plasma liner

it is my understanding that the plasma liner has been extensively tested and should pose no problem with most applications; it hasn't been over-engineered necessarily, but it certainly seems to have been designed to operate up to 600 HP (crank) using OEM equipment under racetrack conditions.

The following article published by:

Plasma Spraying of Lightweight Engine Blocks

G. Barbezat

Sulzer Metco AG (Switzerland), Wohlen, Switzerland

K.Harrison

Sulzer Metco (UK) Ltd, Risca, Gwent

Coating Performances in Engines-

Systematic friction measurement studies in gasoline and diesel test engines have shown that the plasma sprayed coating can contribute significantly to the reduction of the friction between the piston group and the cylinder liner in comparison to cast iron. Depending of the choice of the piston ring material and of the tangential stress of the ring a 20 to 30% reduction in friction was measured in test engines. The measurements of friction were done in the Institute FEV in Aachen, Germany. The results show that a significant improvement in comparison with cast iron can be achieved.

In particular, the tangential stresses of the third ring can be significantly reduced, the critical limit is located at about 10 N. A value of 20 N can be recommended compared to the standard value of 40 N for cast iron. The geometry of the ring also plays a certain role. With optimization of the piston ring geometry, materials and tangential stresses, a potential of 30% reduction of friction in comparison with cast iron is possible.

Measurement of oil consumption has also shown that a reduction by a factor two in comparison with cast iron is possible. In this case the topography after finishing plays an important role.

The oil consumption is directly dependent on the surface topography after machining. The best results are achieved with a value of Ra 0.2 microns. If the Ra value after machining is Ra 0.6 microns or more no improvement in comparison with cast iron can be expected.

An extremely low wear rate relative to cast iron was measured in engine testing. After 150,000 km the wear on the top ring area was about only 10 microns. Also in a high loaded diesel engine the plasma sprayed coating showed a significantly lower level of wear in comparison with cast iron. In a diesel engine for automotive with a power level of 50 kw/l the measured wear on the rings and on the liner was a factor of two lower than cast iron [11] after 300 hours full power enduration test.

The results from engine testing have been confirmed in series production engines for both gasoline and diesel fuels.

- Formula1 and Formula3 for racing in 1999

- Motorcycle engine in 2000

- Large volume I5, I6 diesel for VW in 2002

Additionally several prototypes of modern gasoline and diesel engines are now involved in long term testing. The test results havw been confirmed in Europe and Japan by several engine manufacturers."

So it seems the technology has been in place for a reasonable period of time, appears to be economical, and have nominal wear rates under most conditions. According to above data, it should have ~ 10 microns of wear over 150,000 km (93,205 miles). The coating applied to the GT-R bore is 150 microns, which is the same as used in this study. That works for me.

[Roy]

Personally I'd take the sequential every single time, that's as a driver and as the guy who pays the bills. Faster lap times and lower costs, what more could I ask.

Cheers

Gary

You are pooling all sequential gearboxes together, sequential dog boxes, twin clutch boxes and automated manuals. There are too many differences between them to pool them together. The sequential dog boxes that you are mostly referring to arent very versatile for road race production cars. Hell cruising along in 5th gear and you have to bang it all the way back to neutral

I was not raising concern over the sequential nature of the gearobx, but the twin clutch and DCT aspects of a gearbox in a track car.

Plenty of saloon race cars use sequential gearboxes, but not DSG/DCT etc boxes. Ferrari use them, Lambo etc in GT racing. But Prodrive, Porsche etc dont. If the balance was so clear in favour of one option over the other, they would all be using them. But the DCT does appear to be superior to the automated manuals of Ferrari, but still. No way i would want to be racing a car with one, not until they are a known quantity.

[sh@un]

So it seems the technology has been in place for a reasonable period of time, appears to be economical, and have nominal wear rates under most conditions. According to above data, it should have ~ 10 microns of wear over 150,000 km (93,205 miles). The coating applied to the GT-R bore is 150 microns, which is the same as used in this study. That works for me.

very interesting reading

but it begs the question- if the combined bore/ring wear rates are going to be lower than that of an engine with conventional liners, why the hell would a VR38 need a tear-down service at 100kkms?

is this just some internet rumour that refuses to go away??

[Beer Baron]

very interesting reading

but it begs the question- if the combined bore/ring wear rates are going to be lower than that of an engine with conventional liners, why the hell would a VR38 need a tear-down service at 100kkms?

is this just some internet rumour that refuses to go away??

lol, it doesn't need a teardown at 100K Km. that is a rumuour...

[sh@un]

Well you might LOL, i certainly did the first time i read it

But both Wheels and MOTOR have both mentioned the same thing now (that dude in W.A whose car they used in the recent group comparo in MOTOR supposedly confirmed it was true). So as far as effective internet propaganda goes, this one even seems to have fooled legitimate motoring publications

I knew it couldn't be true- coz Californian legislation states that engines in passenger vehicles need to be able to travel 125,000mi (200,000km) without the engine being opened, and still meet C.A.R.B emissions regs.

[SS8_Gohan]

But both Wheels and MOTOR ... legitimate motoring publications

hahahaha, hahaha, that's funny ;D

I knew it couldn't be true- coz Californian legislation states that engines in passenger vehicles need to be able to travel 125,000mi (200,000km) without the engine being opened, and still meet C.A.R.B emissions regs.

now that's an interesting fact and well, there you go, instantly disproves the rumour as i would doubt Nissan missing that knowing the car was going to be released worldwide.

Unless a relining of plasma is somehow not included in that cali law?

one less thing for the Porka/Corvette boys to cling onto

[djr81]

So it seems the technology has been in place for a reasonable period of time, appears to be economical, and have nominal wear rates under most conditions. According to above data, it should have ~ 10 microns of wear over 150,000 km (93,205 miles). The coating applied to the GT-R bore is 150 microns, which is the same as used in this study. That works for me.

A reasonable period of time?

The engineering world has been using it for almost as long as there has been GT-R's.

It is nothing new.

[Beer Baron]

Well you might LOL, i certainly did the first time i read it

But both Wheels and MOTOR have both mentioned the same thing now (that dude in W.A whose car they used in the recent group comparo in MOTOR supposedly confirmed it was true). So as far as effective internet propaganda goes, this one even seems to have fooled legitimate motoring publications

I knew it couldn't be true- coz Californian legislation states that engines in passenger vehicles need to be able to travel 125,000mi (200,000km) without the engine being opened, and still meet C.A.R.B emissions regs.

yeah it's definitely not true. the rumours have gone from "it needs a yearly tear down and inspection which is covered under warranty" to "it needs to be torn down and inspected at 100,000kms" to "it needs to be rebuilt at 150,000kms" none of them are even remotely true. even a standard RB26 will live for hundreds of thousands of kms without needing a rebuild and they certainly aren't going backwards in reliability.

I personally asked an employee at nissan japan about all these rumours and they nearly fell over laughing. I felt like a knob, I didn't believe it but wanted to be sure.

[Roy]

It really is a shame that as soon as tyre manufacturers start making semi slicks big enough for the R35 that ppl are going to have to remove the engine and install custom sumps with baffles, as new R35s spinning big end bearings isnt good for them . Great to see they are keeping the spinning bottom end history of the GTR alive

[Beer Baron]

I think the R35 has some kind of semi-dry sump system now though?