Max HP from the stock tranny?

[SRBURG13]

Hey all,

Well I searched around on here and found nothing; at least nothing obvious.

Does anyone know at how much whp you should be upgrading the stock S13 SR Tranny? And if so, what are some options in the upgrades?

Thanks.

[TheSnail]

It depends. My friend has a twin plate, around 375rwh and a running on street slicks, he gets a new tranny every week (no joke). After 5 trannies he swapped out the clutch for a single plate to help eliminate snapping the output shafts. So if you have a street driven set up, with street tires and dont launch the car at 6k. Then I would say it will hold together at 400-450 to the crank.

[Annoying Eric]

I've seen them old to 600 rwhp

[TheSnail]

yep. A guy here in Ga dynoed his rb20, at 590hp. No mods to the tranny. At that power, If you shift hard with a strong clutch, then the tranny will last for a couple of miles. If you are on the dyno, or granny shift then give it gas, it will hold 600hp.

[MakotoS13]

so basically if you want big power and to be competitive another tranny is in order? i've heard of Z gear boxes being used. if the Z32 tranny needs little or no modification to fit i'd say go for that "bomb proof" SOB.

[TheSnail]

Well the 300zxtt tranny is very strong. 900hp+ So you can use what ever clutch and shift how every you want with 5-600hp. Though it does not bolt up to the sr. But for the rb20/25/26 guys, they can get a rb26 bell housing (cheap) and bolt the 300zx tranny (550ish) to it. Just like the sr/ka tranny swap. If you want one on the sr you would have to make a addapter plate. If you gone this far you could also get a t56 for an extra 700$ but it is 10spline, and the nissan 23 spline (24 maybe, cant rem), so you would have to have a custom clutch made. Though the fact that the 300zxtt imput shaft slides right in is anouther bonus of the 300zx tranny.

[SRBURG13]

Might have some sort of Vette dog-tooth (partial sequential) tranny on the go, but I just needed to know.

What about an RB tranny of some sort? Would those be just as good? Of course the bell housing would need to be adapted...

Anyone else have thoughts?

Thanks all.

[silviasichigo]

Well the tranny will safely hold 490 that is with daily driving. I have torn through 4 transmissions in the past year. I "Upgraded" <------ haha to an OS Giken 1 2 3 crossmission and well the only thing that I really kept were the input and out put shafts the the stock gears are just as good if you upgrade your I/O Shafts then you will be fine with a stock gear set. A stillway lock out shifter would benifit you if you are into drag racing. If you do go over 500hp don't expect the mission to last a long haul. IF you really want a mission to last there is a company in austrailia that will build you a bullet proof mission for like $7900 american (Dog mission) that is the way to go but since most of the people here are broke I guess it is not an option. Gotta pay to play the game.

[SRBURG13]

It's going on a road racing car, so drag racing or launching at all should be out of the question. Just lots of slapping beween gears.

[silviasichigo]

Ok well with that being said It would be safe to say stay below 400 because if you have that much power and miss a gear it will destroy your mission that is what happend to 2 of my missions. I grazed third gear a little too much and ripped the gear right from the gear seat. Stillway shifter would probalbly not suit you either hehe.

[SRBURG13]

That may be out of the question too, cause this is gunning for the 600hp range.

[silviadriftr]

well, the snail, is referring to my vehicle which is around 400 hp. I'll put it like this. iIf you're not worried about 60 ft times and launching off the rev limiter then the stock trans will do fine with a non-aggressive clutch. In my case though i am looking at pulling 1.6 or 1.5 60 ft times so i have to have a clutch that will be aggressive. To answer your question about the z trans upgrade, we are in the process of doing it and it should be finished by the end of this week for import shootout at silver dollar raceway in georgia. The 300zx trans will be my daily driver trans though, mainly where i can run 26" et streets and not have to worry about breaking trans. Two weeks after the import shootout is grudge wars with all the mustang and camaro boys. For that i will have a powerglide trans adapted into the car with a 4.56 gear for the rear end and a 4500 stall trq converter so i can be in boost off the line. the power glide will be used only for the track. The out put shaft is not big enough to handle the strain of launching that aggressively nor are the gears. I have gone through 5 transmissions. 2-output shaft sheared off , 2- stripped every toth off of third gear, and 1-broke the 5th and reverse shaft in half inside the fifth gear.

If everything works out with the 300zx trans, the shop that is doing it for me will probably be selling the upgrades for the ka,sr,and rb guys. will post with results.
check these pics out of my previous trans.
http://forums.importatlanta.com/showthread.php?t=20232

[silviasichigo]

Yeah that sounds about right. 600Hp is a little much to be slapping around an auto X course safely. YOu can upgrade (if you can find one may be little difficult) TO a R33 skyline tranny it will safely hold up to 1000hp

[wootwoot]

im not allowed to look at the pics since iam not a member, you should post them up here. im really curious about this z32 tranny because this is starting to make me worry an awful lot about not being able to drive my car and getting really familiar with building bastard trannys. how much is the z32 costing you so far? prepare to get some bigger anxles too

[SRBURG13]

Oh, it won't be autoXing, its for road course.

We're leaning towards the Z32 idea, but we have a contact with that Skyline trannies too. They equaly hard to adapt to the SR?