s15 gearbox qusetions

Sheck · Postby **Sheck** » Mon Mar 05, 2007 9:58 am

Hey guys, just wondering if anyone knows weather the bell housing and rear housing of the MX5 6 speed will fit on the center section of the s15 6 speed? Just wonderinng cause i would like their ratios in the mx5 (i'm assuming they are better, can correct me here too)

Thanks
Dave

Oh and i realise the output shaft is bigger but thats as easy as getting a new clutch, ie change the center section to suit the s15 shaft the rest all mx5

16bit · Postby **16bit** » Mon Mar 05, 2007 10:27 am

s 15 gear boxes are sh*t. my mum has one and they are week, notchy and just crap compared to the 5 box. get a quaife gear set.

Sheck · Postby **Sheck** » Mon Mar 05, 2007 11:45 am

quafie is 3.5k us and only for the 5 speed, if i had that kind of money i'd rather slap in an rx7 box

From what i've heard the s15 boxes only break cause of some circlip that is weak, but if you recess it properly or weld it in they are strong as.

Dave

PT · Postby PT » Mon Mar 05, 2007 11:47 am

16bit wrote:s 15 gear boxes are sh*t. my mum has one and they are week, notchy and just crap compared to the 5 box. get a quaife gear set.

Such a highly technical, well scripted response. Top marks!

16bit · Postby **16bit** » Mon Mar 05, 2007 12:19 pm

if you look at every high hp (the boxes tend to sh*t them selves at around 300hp) s15 they all have had either a 180sx, r33 skyline or z32 300zx conversion on them. Nissan fit 6 gears into the same space as they fit the 5 speed. They are a weeker box because their is simply less material making up the gears. I agree with pt use a series 5 driveline. they are much stronger and more people have done that conversion then putting a gear set from a different make and model of car. by the time you got that gear set to fit not only would you have a weaker unit it would probably end up cost not too much less. there would be a lot of fab work that would probably not be that reliable. and when it shits its self its going to cost a fortune to fix.

JSE · Postby **JSE** » Mon Mar 05, 2007 12:48 pm

The S15 6 speeds are crap...the same as the S14's except they stuff an extra gear into it. I don't know much about these boxes though. Best mate owns an S15 and he is not happy with the gearbox - he prefers the S14s box. Thats about all I can tell you Sheck. Hit up Nissansilvia, you will get a whole lot of response from a post there mate. I would imagine the ratios would be better on the S15 but I imagine the Mx5 box would be much better quality. Let us know how you go in your research - I'm interested to know.

Sheck · Postby **Sheck** » Mon Mar 05, 2007 12:53 pm

sorry can you expand this section a bit:

I agree with pt use a series 5 driveline. they are much stronger and more people have done that conversion then putting a gear set from a different make and model of car. by the time you got that gear set to fit not only would you have a weaker unit it would probably end up cost not too much less. there would be a lot of fab work that would probably not be that reliable. and when it shits its self its going to cost a fortune to fix

I cant read it right, the s15 box question i'm talking about would involve just bolting the mx5 bell housing and rear end and puttingthem onto the s15 center section (part with all the gears) so no fab work except for clutch.
Pt didnt mention the s5 box, i did, and that is a big conversion the only way i'd want to do it is if i could get someone to cut and weld the bell housings and ppf attachment points to save on the custom mounting and welding to the chassis. Then i still need tail shaft and clutch - no biggie.

Yea i've read about the s15 boxes exploding but i've also read about the fix for it i mentioned which apparently works quite well (ie drift car with 350hp, they take much more abuse than road/track car). Also alot of jap guys were running them when they drove the s15's, couple of drivers that came over said to aussie drifters that if you drive them right they dont break (stock s15 box). That's all been read on a forum tho so its not first hand info.

Shmeh i might just have to go for a 3.9/3.6 rear end make things a bit easier. :mrgreen:

Dave

Sheck · Postby **Sheck** » Mon Mar 05, 2007 4:30 pm

yea thats why i mentioned welding the ppf mounts and the bell housing onto the rx box, similar to what they do to rb25 box into sr silvia conversion.

Dave

Sean · Postby **Sean** » Sat Mar 10, 2007 12:42 am

Sheck wrote:Hey guys, just wondering if anyone knows weather the bell housing and rear housing of the MX5 6 speed will fit on the center section of the s15 6 speed? Just wonderinng cause i would like their ratios in the mx5 (i'm assuming they are better, can correct me here too)

Thanks
Dave

Oh and i realise the output shaft is bigger but thats as easy as getting a new clutch, ie change the center section to suit the s15 shaft the rest all mx5

Simple answer is NO.
THere is plenty of BS flying around that they are the same box, they are not, similarities yes, some parts teh same yes, but not interchangeable.

mr_rotary · Postby **mr_rotary** » Sat Mar 10, 2007 4:23 pm

16bit wrote:s 15 gear boxes are sh*t. my mum has one and they are week, notchy and just crap compared to the 5 box. get a quaife gear set.

Both boxes come out of the same factory however with different ratio's. They are just as brittle as each other. I have never tried to swap them over however the only difference I could imagine between the boxes would be the size and length of the output shaft. I don't see why you could not swap the bellhousings over?

Here is the URL to the manufacturer - the box type is the 'AZ6'.

http://www.aisin-ai.co.jp/english/products/fr.html

Sean · Postby **Sean** » Sun Mar 11, 2007 5:59 pm

I dont understand why people still like to pretend this is easy?
Has anyone here (besides me) lined the two up side by side?

No?

Well then take my word for it that it's not as simple as some of you are suggesting.

If you don't want to take my word for it, go and get both and try it. :roll:

Sheck · Postby **Sheck** » Mon Mar 12, 2007 7:47 am

Cool thanks sean, i only had pictures to go off and the center section looked the same so i thought it'd be nice to have those ratio's in the 5.

Strength wise i'm not too worried cause the 6 speed has handled what i've thrown at it so far pretty well. the two 5 speeds a broke just cant hack drift abuse.

Dave