Six speed box, is it really that weak?

[NICKO]

Was just wondering who is running a gt2871/ Hks GTRS turbo with the S15 gearbox?

Is the extra torque from these bigger turbo's really that bad for these gearboxes?

I want to upgrade to this turbo but just a bit worried the extra torque is going to kill the box, and I know that the Nismo upgraded six speed is dam right expensive :no:

If I did upgrade to this turbo im most likely only going to run 340bhp on high boost and then have a lower boost setting aswell

My car will never go on track tbh and I very rarely drift it, just a bit of fun every now and then when the roads are quiet

Cheers Guys :thumbs:

 

[andeep]

The 6-Speed will cope fine mate.

 

[DeanS15]

i've been convinced mine will break before long - its been 2 years.....

the input shaft bearing will become noisy but it will still work fine

 

[AllanOrr]

If you are going to change from a 6 speed DONT just buy a gear set as you will be p*ssing your money up a wall dude, get a RB conversion it will be a 1/3 of the cost and will last alot longer if your going to run some big power

 

[craig8585]

It seems to be pot luck but adding extra torque isn't going to do the box any favours. Clutch kicking is the biggest killer IMO. Search the word 'gearbox' in thread titles and see what comes up.

 

[DeanS15]

it's also worth mentioning that though mines lasted well, it's been apart at some point in japan due to red sealant around the box casing - possibly circlip fix

 

[LuPix_S15]

Circlips on the 6MT is renound for being the weak point on an S15 gearbox but put it this way I've drifted and tracked for 3 years in my previous S15 and only had a noiser gearbox as a result... like Dean the input shaft bearing makes a whirring noise but it's not got any worse and that's how it was over a year ago!!

As Allan says there's deffo no point in paying for expensive gearsets, dogsets etc specially for a non-track/drift machine... I was quoted around £1,200 by Polo @ S-Body Automotive for a complete RB gearbox conversion and that will comfortably take 400 bhp or similar torque rating. For 350 bhp the stock box will be fine

 

[Adam L]

My car ran a gt2871r for 12k miles at 1.4 bar running 340hp and there's no noises from the box. I'll just have to see how things go with the 56 trim 3071 at more boost.

 

[Nicely]

As stated, it's pot luck. Just like running a 5MT with more power. Contrary to popular believe, 5MTs aren't invincible: they break just as frequently. It's just that people just accept it because they don't have the mythical 6MT reputation. Maybe not as mythical as the S15 ceramic turbos, but still...

 

[gunner93]

As stated, it's pot luck. Just like running a 5MT with more power. Contrary to popular believe, 5MTs aren't invincible: they break just as frequently. It's just that people just accept it because they don't have the mythical 6MT reputation. Maybe not as mythical as the S15 ceramic turbos, but still...

The supplier Borg Warner also manufactures gearbox for the mighty GTR it seems...? Should be good then...

 

[Auss15]

A lot of it also has to do with how you treat your gearbox,the type of clutch you are using and if its the stock diff,1.5 way or 2 way. I'm running the 2871R,have had no issues but I am very gentle on my clutch and gearbox

 

[raytsang]

hks gt-rs @ 1.3bar running 415bhp and 350ft/lb torque for the last 2 year no issue with gearbox. orc 409 single clutch.
with a couple for track days and hill runs no issue at all.
i dont abuse my car. i.e clucth kicking, handbrake.

have just put in a 2 way diff so see how it last now.. lol

 

[AllanOrr]

Av just got the 1st part on my inbred Gearbox project paid for :wack: Z32/RB box

 

[Benne]

a gearbox oilcooler will also help!

 

[craig8585]

It sure would, especially considering how little oil these gearbokes hold. I have thought about this but it would be a fairly big job to do. The pump from a S14 diff may do the job well though.

 

[GTuned]

The supplier Borg Warner also manufactures gearbox for the mighty GTR it seems...? Should be good then...

I have personally smashed to hell 2 standard R32/33 GTR boxes (on a GTR)... R32/33 GTR boxes have a notorious design fault; 3rd gear has a well-known issue, and they have terrible syncro problems (even when stock). That being said, I have never heard of 1st gear breaking on any R32/33 GTR despite plenty of 8,000+ RPM full power launches.
I also unfortunately managed to break a Holinger 6 Speed sequential box on the GTR... but that was due to the gear selection rocker breaking and engaging 5th gear while 3rd was still enageged

So basically gearboxes can break for many reasons.. Driver Abuse/Misuse, Design limitations/too much troque, crazy pressure plate weights slamming down hard, Oil quality, sudden traction...and I guess bad luck!

Some R32/33 GTR owners swear that changing oil over to a really heavy-duty oil like Redline MTL is the secret, and that even on a stock 'box it works wonders.. They have the same issues with aftermarket gearsets breaking (like the OS Giken gearset). They said that Redline MTL did the trick for them..

Personally, I would just run awesome quality oil before a problem appears and consider the extra cost of the oil as insurance. Just make sure that the gearbox properly warms up on cold mornings before you go running through the gears like mad!