S15 6spd Q's

[Nissan2nr]

I heard that the transmission in the s15's are weaker than the previous 5 speed transmissions, is that true?

How strong are the 5 spd's I heard they can handle 400+ hp.

Does anyone have any insight into this?

Thanx

[Mr. Spool]

I am also interestd in this. I would also like to know if the s15 came with shift tronic.

[Yoshi]

I assume u guys mean TIPtronic? like a lot of newer cars have?
no it doesn't.

The reason the 6-speed is "weak" is that the gears are in the same basic bell housing, meaning the gears are narrower to accomadate the extra "speed". A lot of drift and drag guys don't like the 6spd because it gets unreliable past about 350whp.

For me personally, I think that's plenty of power, I'd never want more than 300 max, I like my car streetable :) Most people that whine about it being "weak" will never have that much power anyways, and if you DO, shouldn't you have a better tranny anyhow?

Cliff Notes:
- no it's not tiptronic
- if your definition of "weak" is 350whp, go elsewhere and get a nice sequential setup w/a dual clutch, etc.; otherwise you're fine.

[Jeff240sx]

Go yoshi. And I also wouldn't put slicks on a car with that tranny if you're nearing 300hp.
-Jeff

[curbhuggerrps13]

hey has ne body tried taking the bellhousing of a ka engine and put it with the s15 6 speed? it would be neat for a 6 speed ka...since they dont produce that many horses and 5th gear would be so strained....just a question :fruit:

[Jeff240sx]

And then no spedometer. No fun imo.
-Jeff

[Mr. Spool]

I would go for it, if I could find an s15 tranny, that would deffinitly give better gas millage at highway speeds.

[brianglawson]

youd have to get an s15 differential too, like jeff said, the speed sensor is in it

[Yoshi]

I would go for it, if I could find an s15 tranny, that would deffinitly give better gas millage at highway speeds.

"Mr. Spool" ... "95' 240 soon to be turbo'd"
That's pretty funny man ;)

seriously tho, I could be wrong, but from what I've read, the final drive of the 6th speed is the same as the 5, so your cruising gear would be the same ratio, therefore no benefits in the gas mileage dept. :/

[Ghettokracker71]

seriously tho, I could be wrong, but from what I've read, the final drive of the 6th speed is the same as the 5, so your cruising gear would be the same ratio, therefore no benefits in the gas mileage dept. :/

:wtf: ??? Wtf is the point of making a 6 speed then? Or using one?

EDIT:In other words: Why would nissan make a transmission with an extra gear that essentially does nothing? Maybe I am not understanding something correctly here.

[SilviaDriver]

the reason y the s15 6speed is weaker and is swapped to 5 speed from previous one is becuz..the 6th gear in the s15 tranny is mainly two smaller gears fit in one.

[Yoshi]

:wtf: ??? Wtf is the point of making a 6 speed then? Or using one?

EDIT:In other words: Why would nissan make a transmission with an extra gear that essentially does nothing? Maybe I am not understanding something correctly here.

xtra gear for a better avg powerband?
just my speculation, since the SR is ded for the s-chassis, I guess we'll never know for sure what potential it had.... that makes baby jesus cry ;)

[s15240]

I always heard that the 5 speed was cheap to replace for the drift crowd. 6 speeds cost$$ compared to 5 speed.

[AlexAtPerformanceNissan]

I would go for it, if I could find an s15 tranny, that would deffinitly give better gas millage at highway speeds.

I had my Redtop SR20 at roughly 3k rpm at 80mph in 5th...got 23mpg... gas mileage wouldn't get better with the sixth gear....plus not worthwhile to lose the strength of te 5-speed.

-Alex B.

[Mr. Spool]

Yoshi, My fault, I havent changed my s$!^ yet, When I got the name, I had a stage IV Twin Turbo. and I know have a 96 turbo'd 240. I gotta change it.

Alex what kind of gasmillage do you expect at 3k rpms. put in a 6 speed and be at 1500 rpms and I bet you will get 28-32 mpg on your ride at 90, My buddy has a 6 speed trans am and gets 32 mpg at 85 mph and thats a gas gussling v8.

There is a reason for a 6 speed, its economical on a sports car, keeps it quiter at highway speeds for touring, and alows for more shifting and a sportier feel when driving.

[kazuo]

Ralph Kenyon has a 6 speed S15 tranny on his S13 redtop in a S13 chassis.

I believe he puts down close to 400WHP or something... or he will be with his new mods :D

[90RS13]

The reason to have a 6 speed transmission is for acceleration. Overall you're in you're peak power band more. You can even look at the generation before now, WRX's and STI's. (When we had the wrx in the US, but not the STI) the STI's 6th gear was actually shorter that the 5th gear in the in the wrx's 5-speed. This made the WRX (if they had the same HP, have a higher top speed, but the STI would accelerate quicker.) 6-speeds are usually for quick acceleration. I hope this helps, if it doesn't, let me know.

[steve shadows]

5 speed is stronger thats all there is to it... z32 tranny is best...rb25det is good too. :hug: :goyou:

[Mr. Spool]

How is that all there is to it, do you have 450 horsepower, I sure dont, infact I am just at 230 crank horse power, and hope to be somewhere around 300 crank horsepower in the next few weeks, I dont think a ka will do over 450 very well so what does it matter which one is stronger for the average kat or sr20ed individual. a 6 speed is better for acceleration and for gas millage so for quite a few people on this board it is an advantage.

[steve shadows]

How is that all there is to it, do you have 450 horsepower, I sure dont, infact I am just at 230 crank horse power, and hope to be somewhere around 300 crank horsepower in the next few weeks, I dont think a ka will do over 450 very well so what does it matter which one is stronger for the average kat or sr20ed individual. a 6 speed is better for acceleration and for gas millage so for quite a few people on this board it is an advantage.

actually i just dynoed at 385 tardo :down: :nono: :bash:

[Yoshi]

actually i just dynoed at 385 tardo :down: :nono: :bash:

um.... your point is?
he said 450... 385, while impressive, is still far from 450 :mepoke:

[steve shadows]

um.... your point is?
he said 450... 385, while impressive, is still far from 450 :mepoke:

ok :zzz: what would 385 whp be at the crank :wtf:

[Mr. Spool]

My point is that the tranny would still hold and most people on these forums and with 240s in general will not hit that much horsepower.

[slideways240]

i have the 6speed..i like it.
KA 5spd=.759 ratio in 5th with 4.083 final drive.
S15 6spd=.767 ratio with 3.692 final drive.
it feels taller than 5th with the KA,i've never driven a 5spd SR...so i can't compare. i'm guessing my whp now around 280(ish) i'm trying to find the most effective way to 400. right now mainly in limbo due to deciding on a turbo. i don't expect it to break right at some magical 350 or 400 mark.i think it'll be fine as long as i'm not doing 7000RPM drag launches on slicks,or DriFTiN' .guess i'll find out one day.they really aren't that expensive if you are resourceful.i've priced them at 500-600 shipped from the motherland.if i break mine i'll replace it with another and try shotpeening and cryotreatment.

[Mr. Spool]

How difficult is it to install and does it greatly improve your acceleration and gas millage, also do I need a different drive shaft.

[slideways240]

i dunno about the retrofit application. i installed it all at once.my engine,transmission,driveshaft,and diff all came from an S15.it bolts up real easy in an s14.i've heard that the S13 has tranny mount issues,but that doesn't really make sense as the S13 tranny bolts up fine in an S14 as well.if i remember right the tailshaft was considerably different from the KA

[Mr. Spool]

oh I thought you had matched it with a ka, oh well.

[Yoshi]

ok :zzz: what would 385 whp be at the crank :wtf:
you misunderstood.
he was talking at the crank, I was talking wheel, I could care less about crank HP, that's no kind of reference for actual real world numbers. Crank measurements is what people say when they want their car to sound like it has more power than reality :(

[Mr. Spool]

crank horse power is what is transfured to the transmission which is then transferred to the wheels. we are speaking of the transmission which has to hold the horse power from the crack. My fault, I really dont care how fast my car sounds, I just care how fast it is.

Has anybody matched a 6 speed to a ka,

[Yoshi]

hahaha, no worries man, I think this thread went to hell long ago anyways :rofl:

[Mr. Spool]

I think you are right, the Thread starter is not even posting anymore, oh well.