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Grant McGrath

Rb25 gearbox in to s15. what do I need?

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Hey everyone just wanted to get some in site into what parts I need to purchase to swap my recently blown 6speed to rb25 5 speed into my 200sx s15.

 

Obviously I need the gearbox but apart from that I have no Idea what parts I should NOW be looking for.

E.g. do I get a skyline clutch and flywheel or a 200sx one?

Do I need a skyline tailshaft?

 

If someone who has already done this or knows exactly what is needed could let me know what they did/I need to buy and any tips, it would be greatly appreciated as I have no car atm and would love to get the problem fixed ASAP!!

 

THANKS AGAIN :D

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you didn't search?

 

just go the powertune kit coz you don't seem mechanically minded and you can keep your current clutch.

 

otherwise the forced motorworx kit is the go if you need a new clutch/flywheel.

 

if your car is still stockish powered you should look at your driving style

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When I bought the car the box was already buggered.

I have parts sitting at my house ready to put in and I'm looking to make 250rwkw so I thought it would be smart to put the rb box in now instead if putting a 6 speed back in and having to change it over once all the other parts are in??

 

Thanks Bling for the quick response!! If You had Time I'd Like To Know what the parts I need just so I can start to know pickup/learn more about these cars:P and I will need a new flywheel and clutch as mines f**ked!!

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I have a really good 6-speed box for cheap compared to eastern states prices if you don't go the 25box way, but it will definitely be worth it if you already have parts sitting and want to set it and forget it whilst strengthening your driveline.

 

Do you need to bash the trans tunnel in S15s to accommodate the bigger bell housing and box section?

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2nd and 5th won't go into gear at all, the rest of the gears are crunchy and it sounds like a piece of something is smashing about in the box when driving. Soo its pretty bad!

Thanks for the offer man but I have a spare 6 speed at my place which I was going to put straight in but I thought I might just sell it and put the dosh towards a rb box setup.

 

So that is why I made this post just to see what I would need and what people think. So thanks again to everyone who has been commenting all your info is definitely being considered

 

Well 2 of my friends have done rb26 conversions to there s15s with rb25 boxes and they said they both did minor bashing to the tunnel to get to fit.

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would be less f**king around to give the other box you have a freshen up and the circlip mod

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Can you redo a 6 speed to be able to comfortably take 270rwkw. I just thought it was either a huge/overly expensive job or just not worth while as you always hear about people smacking in z32, rb25 and sr20 5 speeds anf I haven't really heard of anyone re doing the 6 speed to handle decent power?

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There's a brilliant thread only very recent on here (but not recently replied in enough for the "my replies" section on my phone to locate it) that covers a couple of our lads rebuilding there's with cryo treated Nismo gears and better circlips.

 

Truth be told it isn't a cheap option but I think with the gears out of Japan treatment and re-assembly is was only a little over the cost of a 25box and adaptor kit.

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You like to pick me apart don't you bling lol !

I'm looking to make 250 so a box that is made for 270 would definitely cover me... is that OK enough for you bling :P

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Grant its me again! lol. Sam from neat gearboxes and myself are coming up with a solution to the circlip problem and should be more than capable to handling 250wkw all day every day. Sam is possibly looking to put a kit together with bearing/seal kit/ new counter shaft I believe with a machined groove then shot peen the shaft and he'll make up some custom thrust washers to suit the deeper groove for under $1000 don't quote me on it but that's what we spoke about. Ive gone with some nismo gears cryo treated as well and I cant see why the box wont last with 250wkw. don't loose that 6 speed goodness! contact same from neat gearboxes, these boxes only have issues with the the thrust not the circlip. An they also have probs with stripping 3/4 gear. It sounds like you have issues with your thrust and now your box is sloppy and falling apart. If you didn't continue to drive it you may of only had to replace the shaft/ modified. give sam a call and just get him to have a look for you. it will be cheaper to rebuild and strengthen your box then doing a dodgy rb box that's still secondhand with different ratios.

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I'll have my complete z32 setup for sale within the next month or so. Includes an almost brand new (under 1000kms) box, ETS adapter, 1 piece tailshaft, shifter, etc.

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mate of mine has an s15 making around 280kw, still has stock box, been like it for a year or so, like bling said, hows your driving style?

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If you shift nicely it handle the power ok. It's when you slam in to third n slam in to forth that'll strip the gears or put to much pressure on the thrust.

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So which do you think is going to be stronger a 6 speed redone as you have said before or a standard s14 5 speed conversion?

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I personally had my gearbox rebuilt (running 225rwkw) because one of the bearings seized. I researched the 5 and 6 Speed options before rebuilding my 6.

 

Reason I went with 6 Speed again:

 

My box has lasted me 7 years with 225rwkw, so rebuilding it for $1,000 is more cost effective for me. If it lasts me another 7 years I am super happy.

I wanted to stick with the 6 Speed to keep the original theme of the car

 

No doubt the 5 Speed options are stronger, but going 5 speed would mean more $$$ changing my setup. Plus the ratio's would be all out meaning I would need new diff gears to match the acceleration of the old 6 speed ratio.

 

If I was making over 250rwkw and abused my car which I dont, I would definitely switch to 5 speed.

Edited by NISSAN_200

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The s14 5 speed has the same gear strength. The 6 speed fails on the thrust setup which the 5speed doesn't. A modified 6 speed should be much stronger depending what you do. Just buy The 6 speed that's for sale and use that. It won't break unless u slam 3rd n 4th. Ya cars not even built yet. Get his box and drive it.

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Stick with 6 speed if ya can man. Makes everything easier.however if you do decide to go to a 5 speed dont forget a big hammer.

 

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Oh man what a shame I'd totally buy that if it still had a 25 bellhousing on it!

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The s14 5 speed has the same gear strength. The 6 speed fails on the thrust setup which the 5speed doesn't. A modified 6 speed should be much stronger depending what you do. Just buy The 6 speed that's for sale and use that. It won't break unless u slam 3rd n 4th. Ya cars not even built yet. Get his box and drive it.

 

Hey Stuss when you say slamming 3rd and 4th gear is what breaks these boxes is it up shifting or down shifting that does the damage or both??

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