S15 vs S14

[2Si4lv0ia]

In the coming months I am looking to drop either an S14 or S15 motor in my 240sx. Could someone tell me some, if not all the differences between the S14 and S15 motors. I know the S15 is a newer motor, but I'm looking for all the differences performance wise. Thanks.:ylsuper

[maxpower]

it makes more power (revised turbo) and comes with a 6-speed transmition. s14 vs. s15 your main concern should be getting the drive-train to hook up; it's not exactly a "drop-in" or a "bolt-on" job.

[burgy240]

Didn't I hear somewhere that the s15 has a reinforced crank???? maybe I'm just lost... anyway, the s15 has vvt on both intake and exhaust cams where as the s14 only has it on the exhaust cam. Both are more difficult to deal with at high HP ranges than the s13 motor. If you plan on only going with mostly stock set up however the s15 will get you more power from the start.

[midwestdrifter]

s15=6 speed trannys14=5 speed transmission

i believe the choice is clear. you will have a bit of a time getting either to go in if you have an s13 though. you should talk to daunt.

[hokiruu]

Yes, the aforementioned differences are true. The following is just stuff I have herad from talking to various sources: Rumors abound that the s15 6 speed is a weaker transmission than the s14 5 speed or something. For the record, the notorious Ricky Chu recently removed his built s13 in favor of an s15 and told me the s15 into s14 isn't that hard. He also denied the transmission's weakness. A local shop (Frisbee's-questionable reputation apparently) who performed the same swap for a guy I know said "whatever you do- don't put that motor into that car-it was a pain in the ****ing ***!" But I took a ride in it and was impressed with the performance. I wasn't impressed by the fact that getting the VVT to work at all is kind of a hassle involving reprogramming the ECU. The drivetrain and gauges also present some problems. His spedometer didn't work because of problems somewhere between the speed sensor and its signal.

[pampadori]

s14 has vtc on INTAKE cam from what i can tell. the s15 transmission doesn't have a speed sensor in it. it is in the differential. that is need for the swap. the swap shouldn't be too much harder. i don't see why the ecu needs reprogrammed. the s14 and s15 have crazy small throttle bodies so keep your ka one to use. ka throttle =O s14 =oshaun

[AznRide]

Oh, S15 is about $2000 more than the S14

[C-Kwik]

I believe the S15 receives it's speed signal from the ABS sensor at the rear diff. It shouldn't be terribly hard to convert the signal to match, but you'ld need to be familiar with modern electronics.

[SpeedRacer1]

One other power mod that the S15 has is larger 480cc injectors. These coupled with a better T28 Turbo on the S15 give it about 30 more hp stock. These mods could both be transfered to the S14 with similer results. There may be a need for slight tuning to get the mixtures right.

[midwestdrifter]

now that i think about it if you want a lot of power just go for the rb. even the rb20 is really powerful. it is more work but is much rarer.

[jzoku]

its S16 coming out in Japan?

[S14Life]

OMG, S16?

[Movingviolation240]

they killed the Silvia allmost a year ago, no more S15's and no S16, sorry

Paul

[hokiruu]

the s14 and s15 have crazy small throttle bodies so keep your ka one to use. ka throttle =O s14 =oshaun

F'real? Wow its amazing that i've never heard anyone mention that before. Are there any siginifant power gains from this? Dang, now I gotta go and switch to KA and get a step hose to adapt 'em.

[sr20detpower1212]

i didnt realize that the KA mafs was bigger than the sr20det......how much bigger? and whats the HP ceiling now with the KA mafs?

[hokiruu]

yeah, we want more info. anyone? is this worth me switching back?

[SmithSR]

SR20DET Specs - (info is straight from http://www.srswap.com)

---180SX 91-93 and Silvia 91-93---Displacement: 1998cc (2.0 liter) Cam type: DOHC 16 valve, chain driven cam sprocketsBore and stroke: 86mm x 86mm Compression: 8.5 : 1Horsepower: 205ps at 6000rpm Torque: 203 ft/lbs at 4000rpmStock boost: 7 psi Throttle body bore: 60mmInjector size: 370cc/min

Tomei oversized throttle body:The throttle adapter allows the use of the 70mm Nissan factory throttle body for the N15 Pulsar on the SR20DE(T).http://splparts.com/Silvia/Engine/Tomei.asp

The Nissan 240SX, 60mm throttle body is a must for applications above 350Hp. http://www.angelfire.com/extreme/280zxt/page9.htmlpage has excellent info

The Nissan 240sx throttle body is 60mm vs. the 54mm of the stock 300zx throttle body. The Nissan stanza throttle body will also work and is the same size as the 240sx. http://www.angelfire.com/mo2/n....html

http://www.autowerksmotorsport....htmlhttp://old.soliton.net/old/tech.htm

"I got a TB unit from a 1989 240SX...The SX throttle body has a 60mm bore"http://www.zcarcreations.com/howto/240sx-tb.htm

Parts in the U.S. that fit the SR20DET Throttle Body - 91-98 - Nissan 240SX DOHC MAFS(will need plug) - 89-90 - Nissan 240sx 12 valvehttp://sr20det.nismo.org/srtech.htmthis last link almost has me thinking the TB/MAFS from SR to KA are in fact a direct interchange!!

Google owns

-Phil

[Onizuka]

so SR and KA throttle bodies are the same size, but you can upgrade to the N15 70mm throttle body for about $250, is that a worth while upgrade?

[SmithSR]

Well, some other guy in another thread is saying the throttle bodies are NOT the same size. I do not have the two side by side for comparison. Specific information about TB size is a bit hard to find. The Tomei 70mm TB will still suffer from the MAFS bottleneck....you need to change MAFS also.....so I'm told.

[Onizuka]

that info you just posted said both the SR and KA throttle bodies are 60mm.

[Movingviolation240]

I'll tell you all for a fact that the KA TB is bigger, I've held them together and the KA is bigger, I don't have any sizes but "I have seen the light" That's why I'm running a re-wired KA TB on my S13 SR (and the S14 SR has an even smaller TB than the S13)

Paul

[yoyoS14]

Another reason that the s15 is more powerful is that stock boost on a s15 is about 10 psi.

[Doriftomodachi]

In the coming months I am looking to drop either an S14 or S15 motor in my 240sx. Could someone tell me some, if not all the differences between the S14 and S15 motors. I know the S15 is a newer motor, but I'm looking for all the differences performance wise. Thanks.:ylsuper

Did you do a search?

[DriFt3r]

noob here so what does "mafs" mean?

[Doriftomodachi]

noob here so what does "mafs" mean?

Mass Air Flow Sensor

[GodzillaFan]

Another reason that the s15 is more powerful is that stock boost on a s15 is about 10 psi.

I'm pretty sure its still 7 psi stock. o well, find out soon enough (hopefully)

another good thing about the s15 setup is you can max out the turbo w/ stock managment (theoretically) because of the larger injectors. unlike s14 where overboost = death

[nisstek]

My stock S15 boosts 10 psi. The 6 speed is sweet. And you must have the rear diff from the S15. The gear ratios on the 6 speed mandate that. If you leave your 240SX 4.11:1 gears in you can forget about 1st gear in the 6 speed and you'll get real tired of shifting.

[hokiruu]

I'm pretty sure its still 7 psi stock. o well, find out soon enough (hopefully)

another good thing about the s15 setup is you can max out the turbo w/ stock managment (theoretically) because of the larger injectors. unlike s14 where overboost = death

Yeah I am gonna have to be really careful with my s14. I think I'll dial in 10psi max for now.

[Hijacker]

one quick note on the S15. from what i understand, the S15 transmission is weaker than the S13 or S14 trannies

[f8sjester]

one quick note on the S15. from what i understand, the S15 transmission is weaker than the S13 or S14 trannies

as noted earlier in this thread (and other threads throughout NICO). . . this is just a rumor that seems to be unfounded. . .