S15 6SPD GEARBOX!!

[SLYSIL]

Hey guys ,(and girlz.)

Obviously got a s15 with standard 6speed in it but i have already gone threw 3 gearboxes.

Can any 1 suggest what is a good gearbox to put in? Something that can still handle abit of power (320hp atw) and more to come, with out it smashing the whole gearbox to bits when it lets go and apart from going ppg?
And if it does smash i can just get another box to replace it but not to pricey ie 1500 or does some1 recomend something totaly different?

any suggestions would be great thanks heaps
Dan

[Brockas]

Nismo make a heavy duty cross mission set, I'm guessing similar to what OS Giken do for the GTR's.

It's about $3500 landed from Greenline.

Probably a fair whack cheaper than using PPG, and they're also helical gears, so not an issue for street driving.

I thought an S15 6-speed would handle 320rwhp pretty easily, maybe adjust your driving style a bit?

[MRO]

try an s13/14 5 speed. I hear they are a bit tougher.

My 5 speed has given me no worries including many 12 and 13 second quarters and autokhana events.

[1JZNOSHIT]

i heard the s15 box is pretty weak, however smashing 3 of them, perhaps its time to look for a cross mission yet. you wont get anything decent for $1500. I cant imagine it would be entirely easy to mate a RB25/Z32 5spd to it?! That would be the only other option id say.

[RICEY]

My ex neighbour has an S15 with around 300rwhp and kept smashing gears, even after fitting straight cut gears.

Fixed the problem by not going on cruises anymore hahaha

[upgarage]

r33/z32 box

[SLYSIL]

yeah i have been told to go a s14a box and for a 25 conversion i was looking at around 5500 obviously including box but c-red said they would do a s14 box for i think it was 2200 if i gave them my 6 speed. And is that nismo cross mission set for 6 speed?
Cheers for the replys so quik fellas

[JazRad]

Yeah im waiting for mine to smash its already feeling close to it after i get a new clutch it will probably go

I'm going to go down the RB25 Box path more then likely

Z32/RB25
Box and shifter
Custom tailshaft
Flywheel/clutch/pressure plate of your choice
Conversion plate
Possible shifter modifications

Overall Cost depends on what price you can get a box for but i'd say your up around $3k - $4k for the full conversion. If anyone knows of anyone that can do the conversion please let me know!

[SLYSIL]

And let me know aswel please
well im gonna ring around tomoz and c wat people suggest thanks heaps again
But yeah 25 sounds likw the way to go

[Brockas]

yeah i have been told to go a s14a box and for a 25 conversion i was looking at around 5500 obviously including box but c-red said they would do a s14 box for i think it was 2200 if i gave them my 6 speed. And is that nismo cross mission set for 6 speed?
Cheers for the replys so quik fellas

Yes, the Nismo set is for a 6-speed. All 6 gears included.

[upgarage]

if all the parts are there any competent mechanic should be able to bolt it all together.

theres some discussion about s15 gearbox options on silviawa
pretty sure a dude has done the rb25/z32 gbox conversion

[Joe]

S15 Gearbox

http://www.dairy.com.au/consumers/images/dairyaustralia/agda_07_tatura_butter.jpg

SAME!!! (and this is coming from a WRX owner :))

[OneJ]

Driving style could have a fair bit to do with it as said before... 3 boxes at the output is a decent effort

[Skitzo]

what about an R154? Would that be a failry pricy option? Which is better out of an R154 and 25 box?

[mys1]

having said that, You guys might remember the green sil80 that Jarrod took out a few times, That thing was making what 400, and that had the 6speed in it on R comps, and doign track work, Sounds like a bit of abuse to go through 3 with that output.

[AGIT8D]

haha yeah 6 speed boxes suckk. i had one in my s13 and i pretty much killed it with 230hp lol..

i was basically told that once you approach about 300hp it comes a decision between replacing stock clutches a fair whack or replacing boxes a fair whack..

do you have an aftermarket clutch? this might explain why you're chewing thru boxes.. it's generally 3rd to 4th that drops out in these boxes.

[redline07]

Never had a problem with the sil80. 430 rwhp, hks twin plate, s15 box and only ever got thrashed. Just depends on how you treat it. If you've killed 3 i'd think there is something wrong.

[180SXTCY]

Never had a problem with the sil80. 430 rwhp, hks twin plate, s15 box and only ever got thrashed. Just depends on how you treat it. If you've killed 3 i'd think there is something wrong.

+1

i had a 180sx making simular power just a tad more, had the 5 speed in it just with a puck brass button, didnt have any dramas with it. but it just comes down to how u treat it as u drive. if ur smashing gears, droping clutch etc then this will cut down life on teh box

[Skitzo]

is a box rated on power or torque?

[Brockas]

Obviously the stress on the metal of the gears is directly proportional to the torque applied to the surface area.

The metal will fracture at a certain stress/strain point dictated by it's Young's Modulus (between 50-200GPa depending on composition of the box).

Of course the stress levels vary while using the box. Smashing gears at high RPM (with large levels of torque behind it, indicated by the power it makes at that RPM) is going to create high levels of stress on the box, compared to simply rolling on the power.

[TJ]

5500 to go RB25 box?

Must include a decent and pricey twin plate.

[SLYSIL]

yeah it has aftermarket clutch just single plate push button!! maybe it is my driving and yeah all three times was from 3rd to 4th and all im left with is reverse. i want to use the car mainly for strip but i dont want to go auto coz i personaly dont think thats driving:P

[JazRad]

I've heard plenty of stories about boxes breaking. Some people are lucky some people aren't. Rumour is that its the circlip from 3rd to 4th as thats usually where the box breaks in most cases.

I'd defiantly be looking at going RB25DET conversion, send a private msg to STR8E180 on nissansilvia.com and he might be able to help you out with some bits and pieces

[200SXY]

Jaz pretty sure it's the circlip from 2nd to 3rd that normally fails... :(... either way three boxes and on to your fourth in such a short time frame is a worry.

I'm still running the stock box with over 400 at the treads and loads of torque ... but would go for the S14 5 speed if and when I change out. I tend to find I am not using the sixth gear that much anyhow with the tune so it won't worry me too much.

[AGIT8D]

+1

i had a 180sx making simular power just a tad more, had the 5 speed in it just with a puck brass button, didnt have any dramas with it. but it just comes down to how u treat it as u drive. if ur smashing gears, droping clutch etc then this will cut down life on teh box

That's the 5 speed. They're a lot tougher than the s15 6 speed...

[AGIT8D]

Jaz pretty sure it's the circlip from 2nd to 3rd that normally fails... :(... either way three boxes and on to your fourth in such a short time frame is a worry.

I'm still running the stock box with over 400 at the treads and loads of torque ... but would go for the S14 5 speed if and when I change out. I tend to find I am not using the sixth gear that much anyhow with the tune so it won't worry me too much.

Generally it's 3rd to 4th. Snap the selector forks or that dodgy clip.. 4th gear in them is supposed to be weak as, that's why they generally straight cut 1st to 4th and leave the last 2 gears..