S15 Transmission into S13 fastback.

[puerkone]

Ok I just bought an S15 Transmission yesterday and I was wondering if any of you guys think that I could use an S15 6 speed transmission in my KA24DE. I have 3 transmissions. 1 came out of a 1993 240sx with a KA24DE, the other one came out of an S13 with an SR20DET Redtop transmission and last but not least a wonderful S15 6 speed transmission. Here are the pictures. They are all over my backyard.

KA24DE below

KA24DE left

KA24DE above

SR20DET

S15 transmission 1

S15 transmission 2

S15 transmission 3

KA1

what you guys think? do you think it should bolt right up?

[dc1984]

i am pretty sure u can. ive heard about people using ka24 transmisions on ther sr20, i think there is something that needs to be done with the bell housing though. but i think the reason people do that is because the ka transmission is stronger then the s20 transmission. i just recently read a 500 hp sr20 build up thread on here, and the guy mentioned that "when" his sr20 transmission went out, he was going to put in a ka24 transmission. so i just assume the ka transmission is more reliable. and to make it worse, the s15 transmission is weaker then the s13/14 trannies. from what i heard, it has something to do with fitting 6 gears in the same size transmission that was made for 5 gears, so they made them smaller to fit them in, and when they go smaller, they go less reliable.

i guess it all depends on what u r planning to do with the motor if it will be worth it or not. anybody can feel free to correct me on any of this if need be.

one questions though, why would u buy an s15 transmission and then ask if it will fit your on your KA?

[SullivanRacing06]

why would you want the 6 speed on your ka? invest in other things first,

im pretty sure the guts and tail shaft section of the 5 speed will acept the ka bellhousing, not to sure about the 6 spd

[puerkone]

well now that you are saying why would I get the 6 speed transmission is because I commute in my 240sx really far everyday. I heard that if you use 1 more gear which it is 6th gear you would be able to get to your destination saving more gas. I was planning to swap out my KA transmission for the s15 transmission but now that you guys saw them you guys say its not a good idea.... do you think it would eventually go out in a short time lets say a month or 2?

I was wondering if the high end is stronger on the s15 transmission rather than KA and the SR trannies I also heard that their top end reaches about 125 mph and you cant go beyond that. while the s15 trannies have longer high end and will take you up to 160 mph I was just wondering if its true.......

[SullivanRacing06]

nope, the final ratio is higher in 6th then the 5th in the ka transmission. the 6 gears are for close range, doesnt mean it will give ya better gas milage,

search about the diff in the ratios,

[puerkone]

yeah you are right it is closer... I guess I wasted 300 bux on this transmission damn it.... well why does no body like the 6 speeds on their KA24DE isnt it better because you can reach higher speeds?

[33alez33]

Going fast is fun but even at most tracks if you are using a KA you won't find the top speed with either transmission, keeping in mind that I mean KA with approx. 200Hp or less, I'm sure a turbo monster can get to the top speed easy. I'm not sure of the top speed with either transmission so I'll leave that up to somebody else. The fastest my stock 5sp S13 KA has been run through radar at is 121mph, it had more to give but braking for the end of the pavement was more important.
Modified by 33alez33 at 7:21 PM 4/16/2009

[the converted]

well why does no body like the 6 speeds on their KA24DE isnt it better because you can reach higher speeds?

Could be because they don't bolt up.