# S15 Tranny **URL:** \ **Category:** Canada Nissan Automotive\ **Created:** [April 20, 2007, 5:18am UTC](https://forums.speedlife.net/t/s15-tranny/146480 "2007-04-20T05:18:07Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![RPS13\_180SX](https://avatars.discourse-cdn.com/v4/letter/r/c77e96/32.png) [@RPS13\_180SX](https://forums.speedlife.net/u/RPS13_180SX)\ **Post date:** [April 20, 2007, 5:18am UTC](https://forums.speedlife.net/t/s15-tranny/146480/1 "2007-04-20T05:18:07Z")
Hey guys looking to put a S15 SR into my car and I heard that the S15 6 speed tranny is quite weak… I’ve been searching the net for some info on this but can’t find any solid answers… I was wondering if anyone knew anything on here… Also if it is weak I will try and put a S14 tranny on it or another 5 speed one, does that one bolt right up to it? Also I’m looking for visual differences between an S15 SR and a S14 SR… Any info is good… Thanks again guys! ---
**Author:** ![apex\_drifter](https://avatars.discourse-cdn.com/v4/letter/a/ac8455/32.png) [@apex\_drifter](https://forums.speedlife.net/u/apex_drifter)\ **Post date:** [April 20, 2007, 6:16am UTC](https://forums.speedlife.net/t/s15-tranny/146480/2 "2007-04-20T06:16:42Z")
s14 5-speed tranny is the same as a ka tranny, just a different bellhousing to mate up to the different engines. I’ve heard about the s15 6-speeds being weaker, but no solid evidence either. visual difference between s14/15 sr’s. . .ball bearing T28 on s15’s. . . ---
**Author:** ![Therin](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@Therin](https://forums.speedlife.net/u/Therin)\ **Post date:** [April 20, 2007, 9:56am UTC](https://forums.speedlife.net/t/s15-tranny/146480/3 "2007-04-20T09:56:10Z")
so your saying the tranny internals in my usdm s14 is the same as the jdm silvia s14? ---
**Author:** ![InitialD](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@InitialD](https://forums.speedlife.net/u/InitialD)\ **Post date:** [April 20, 2007, 10:27am UTC](https://forums.speedlife.net/t/s15-tranny/146480/4 "2007-04-20T10:27:51Z")
i have crossed s14 tranny, i definately love gear ratios compared to s13 sr and ca. i also heard that s15 tranny is weak juice. ---
**Author:** ![rastaman](https://avatars.discourse-cdn.com/v4/letter/r/a87d85/32.png) [@rastaman](https://forums.speedlife.net/u/rastaman)\ **Post date:** [April 20, 2007, 11:13am UTC](https://forums.speedlife.net/t/s15-tranny/146480/5 "2007-04-20T11:13:41Z")
you do know this is not a straight swap and will need some custom work done. Blitz has 350hp Sil’ using the stock tranny. ---
**Author:** ![imported\_nismo1](https://avatars.discourse-cdn.com/v4/letter/i/76d3ee/32.png) [@imported\_nismo1](https://forums.speedlife.net/u/imported_nismo1)\ **Post date:** [April 20, 2007, 11:32am UTC](https://forums.speedlife.net/t/s15-tranny/146480/6 "2007-04-20T11:32:00Z")
hmm weak sauce? pps talking about it being weak with respect to what power level? most of you here are under 250whp and those s15 and ka tranies survive 15psi launches ok 500whp+ cars. So i wouldn’t warry untill you get into those power levels. and past 600-700whp you can try z32 tranny. I think some companies offer forged gear rebuild kits for those s15 trannies as well. ---
**Author:** ![jdms13rhd](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@jdms13rhd](https://forums.speedlife.net/u/jdms13rhd)\ **Post date:** [April 20, 2007, 11:43am UTC](https://forums.speedlife.net/t/s15-tranny/146480/7 "2007-04-20T11:43:56Z")
500-700hp 😛 I dont think they would take that. First off all those trans are old. Some over 15 years and they are warn, NOT brand new so dont expect like new condition on any of the parts. I hardly think 500hp would last me longer than a day or 2 in a stock trans. Ive blown Z32/RB25 trans with less than 450hp and I have friends in Japan that have busted cross missions and HKS box’s with 800hp. If you drive like a homo then yes it might last but you all know what I mean by this. 6 speed trans = more parts jamed in a small mission. If you have the 6 speed and want it I would use it. Chances are your not going to have over 300hp and you will be fine. Everyone says theyre going to have 350hp+ but its all in future plans and people smash their cars before getting there “plans” finished anyways so I wouldnt worrie about it. ---
**Author:** ![jdms13rhd](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@jdms13rhd](https://forums.speedlife.net/u/jdms13rhd)\ **Post date:** [April 20, 2007, 11:46am UTC](https://forums.speedlife.net/t/s15-tranny/146480/8 "2007-04-20T11:46:42Z")
p.s. those companies that use stock missions most likely have the OS 1-3rd gear set as well. ---
**Author:** ![InitialD](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@InitialD](https://forums.speedlife.net/u/InitialD)\ **Post date:** [April 20, 2007, 12:03pm UTC](https://forums.speedlife.net/t/s15-tranny/146480/9 "2007-04-20T12:03:33Z")
pps the fastest s13 USDM that i’ve seen had 350hp here in ab, so yea i wouldnt worry. in regard of numbers to my s13, i can bet my left nut that it has well pass 350 at the wheels. :finga: ---
**Author:** ![mikesim](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/mikesim/32/5561_2.png) [@mikesim](https://forums.speedlife.net/u/mikesim)\ **Post date:** [April 20, 2007, 12:18pm UTC](https://forums.speedlife.net/t/s15-tranny/146480/10 "2007-04-20T12:18:36Z")
here’s what an S15 owner told me when i was looking into the S15 6 speed: > [@Nicely](#): > > Bit late on this, but hey. > > Standard ratios > > [1-6] 3.626/2.200/1.541/1.213/1.000/0.767 Reverse: 3.437 > > II know people who can vouch that they gears and synchro assembly on the S15 are marginally better than on an S14a. > > The only issue with the S15 box is the circlip on the 3/4th counter gear. It will slip and blow 3rd or 4th and take the input/output shaft as well as all the bearings in the box with it. If you were wanting to put a lot of power through it, my advice would be to use a pressure plate with as close to stock clamping pressure as possible, and rather than a brand new box get someone to crack the 6-speed open, inspect all the tolerances and fix the circlip issue by either replacing the clip and grinding the retainer gap down slightly so it wont move, or welding it in. this is his website: [http://www.jull.co.uk/cars/s15/nissan\_s15.html](http://www.jull.co.uk/cars/s15/nissan_s15.html) most people on the western side of the world only hear BS about these transmissions. if you want the truth, you have to go to the source: S15 owners.