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Discussion Starter #1
Hi all,

I know we've talked before about the amount of poke that the R33 gearbox can handle, we never did get a real accurate answer though.............I think about 650 was the average.....................I digress.....

What I was wondering was if anyone out there has any comments on the Getrag box in the R34. Mines not up to the HP to worry about it yet, just wanted to get an idea so I've got a heads up on what I need to save for !

Do I only need to worry if I'm palnning on big launches from the lights ??? ...............didn't know you were a secret drag racer DCD ! :)

Comments fellas ?

Fraser
 

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Hi canman...might as well be the first one to answer you since most people in the UK are at sleep at this time!

The getrag should be pretty solid up untill the 600 figure. The Mines demo car is running this figure with 60kgm of torque and it still uses the standard box.

Must admit I like the odd drag race off the traffic light the here and now:)
I always seem to get tuned RX7s trying it on....
 

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Canman

The Getrag is considerably weaker than the stock Nissan 5 speed.

Depending upon how you drive (as in if your prone to doing big launches), the amount of grip your tyres provide and the quality of clutch acutation, you could kill either 'box with as little as ~200kW (~270 HP) at the wheels.

I would say that if your a careful driver and have some mechanical sympathy, you could expect about ~320kW at the wheels to be an acceptable maximum. I'd work that to be around ~550 HP at the flywheel or thereabouts.

The Getrag 'boxes are shite. Just try to get one repaired or even get parts for them. Shocking.

On that note, I would really appreciate if someone in the UK could take the time to ask Nissan UK how much (in both cost and availability) it is to obtain a replacement bell housing for an R34 GTR Getrag 6 speed 'box - then pass on their response to this list....

Mario.
 

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It is interesting that the general consensus is that a 33 or 32 box is the weak point of the car (early 33's where re-called in Japan to have different Sinc's fitted) and now it would seem that the 34 box is even weaker!!?

I don't know the answer but I have experienced breaking Dennis Stepneys 700 plus bhp 33's gear box changing from 4th to 5th at just under 150mph and 8300rpm showing. As I went into 5th and floored it again 5th gear just dissapeared! The good thing was that 1st to 4th was still avaliable so we didn't get stranded. I've seen lots of 500 plus conversions run ok with the standard box but this particular car had serious poke and the box unsuprisingly let go.

Now to the 34. I've heard rumours (Which Middlehurst did not deny) that the 34 box is a development of the M5 gearbox and having driven both cars I would say that they are almost identicle to use. A standard M5 is 400bhp and 400 pounds of torque so if it is true the 34 box is less stressed in standard form than a standard M5. Now, I have a friend in Germany who has Supercharged his M5 and is reportedly in the 550 bhp plus zone on the standard gearbox. So when I tune my 34 I'm working on the assumption that the box will be good for around 500 bhp.
 

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Jamie/Pete

The Getrag 6 speed as used in the R34 GTR is a development based upon the design of the 'box used in the 6 speed Toyota Supras.

Infact, the 'box isn't even supplied to Nissan directly. It is made for Nissan by Toyota Tooling Japan under license from Getrag GMBH. Go figure.

The Getrag is weak. It may be similar to the M3 'box, but your misinformed if you think it is under less stress in a GTR. The GTR is placing way more load upon the 'box simply due to the design of the drivetrain and amount of grip (ie: loading).

Basically, under heavy load conditions, you are in 4WD mode and you have twice the tyre grip placing inordinate amounts of load onto the shafts and gearset. On a RWD M3, traction is piss easy to break (and if you have ATC on, you lose engine power to compensate, so load is reduced).

Onto basic physics: Torque is the twisting force applied to a shaft. Power is the amount of work performed by the twisting force applied to a shaft in a given timeframe.

If the shaft can not twist (due to imense loading) then torque will be present until the ultimate load point, which in a car is usually the engine stalling. Yes, this is a 'bad thing(tm)' for any gearbox to cope with.

If there is motion in the gear clusters and shafts, then power is present (as it is a function based upon torque) which then brings shaft and gearset speeds into the equation. The speed of said shafts, or more importantly, the delta between the various speeds of shafts (like your gearbox input vs. the output shaft of the rear differential) translates to shock loading.

This shock loading is normally experienced during hard launches and gear changes - it is why 'boxes almost always break when changing from or into a gear. Hence, as motion is involved, it is techinically power that is responsible, not torque.

To sum up: The Getrag is not a very strong unit. Ask the Japanese tuners how many have been destroyed as opposed to the stock 5 speeds. Infact, just ask HKS or Holinger how many R34 conversions/upgrades they've sold for R34's.

I hope I've got it conveyed across. It's too early here. ;)

Mario.
 

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Superior Traction

As I recent convert to skylines, I was amazed that I could drop the clutch at 5.5 - 6k rpm and get no wheelspin. Of course nothing comes free so it is the transmission that is going to suffer. My 5th gear needs a double declutch to avoid a crunch and I Spoke to Andy Middlehurst about it. I said that it was rebuilt by his garage 2.5 years ago and he said that I was lucky it had lasted that long. He rebuilds some gearboxes every year! Like Mario says, you have to pay the price for the traction. Maybe it is not the gearboxes that are bad, it is the traction that is too good.
Brilliant explanation Mario :smokin:
 

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and I thought I was full of information!!

I feel a large bill coming in the future.........!
 

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Discussion Starter #10
Oh joy !

And I thought I was doing myself a favour jumping into a R34 VSPEC II.

Thanks for the heads up Mario...........

One interesting angle though is the Blitz R348 project that apparently has 700BHP or somewhere there and they claim to only have modified engine and body kit, they don't talk about replacing any drivetrain equipment, I wonder if it's really true or if it's more of a marketing exercise ?

Thanks to all for the info though.

Cheers
Fraser :smokin:
 

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Canman,

I talked to some guy from Blitz when the R348 was showing here in the US. The guy said the only thing modified on the drivetrain of the car is a stronger clutch, it has 850HP at the flywheel. He said the car was never dragged, they only use it for top speed testing, maybe that's why the stock gear box is still intact. He also told me the car was in sixth at 8200rpm when they reach 214 mph in Germany.

Just some info to share with everyone.

Jeff
 

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Discussion Starter #12
Those gearboxes

Yeah that was my understanding too. But I'm not interested in dragging the thing, I just want to be able to drive around, do the odd track day and have the odd high speed drive around the motorway.

Mario if you're still watching this thread, does your statement re the strength of gearboxes really only apply to hard launches over and over or is it just big power that pops them no matter what you're doing, there's just more chance if you launch hard ?

Thanks again Jeff, good to see a fellow VSPEC II owner........I don't think they're available in the UK as an official car yet.

Fraser
 

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Hi Fraser,

Yeah it is nice to meet a R34 V-spec II owner, I am in the USA. My car is still in the US emission lab being tested. Have you done anything to your GTR yet?

Jeff
 

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Discussion Starter #14
Have a look

on.... www.600plus.com, under rides.

it's a mate of mine who's just setting it up. He's a Z fan but he's keen to get into a Skline once the budget fits.

Lucky us in NZ don't have to worry about that, virtually anything goes.

Cheers
Fraser

:smokin:
 

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R34 Bellhousing

Mario,

Contacted my local Nissan dealer in Aberdeen about the cost of a replacement bellhousing.

He said that the bellhousing is an integral part of the gearbox and not available separately.

Do you have a part number and I will try him again
 

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Gear box

I am glad this thread has open up again,
The Gear box in my car is getting better,i have had it in and out of the car 18 times now in the last month doing a bit here and there to it on the way and things are starting to get exciting, it WONT BREAK it is the strongest gear box in the world and it has 6 speed,
I know it wont break because i gave it so much stick the other night and actually put the center, center plate of my HKS triple plate clutch through the side of the bell housing it was amasing made a hole the shape of a letter box but i still drove it home.
When all my testing is done on my unbreakable gearbox the modifications are going to be released to tim at SVS and only to him and from then on there will be a very reasonably priced six speed gearbox that dont clunk dont crunch and dont jump out of gear and will withstand anything the rb26 engine can give it.
After that it will be diffs driveshafts bellhousing jackets and lot and lots of rear tyres.
Whilst on the subject i am going to start a thread on some oil i have been testing
Gary
GTART.CO.UK
 
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