S15 SR swap, is it worth it compared to an s13 or s14 swap?

[JoHn E]

for a usdm s14

is the stock s15 250hp really worth the extra money to get instead of say a 200hp stock redtop or a 220 stock blacktop?

it seems like the redtop and s14 blacktop is more common in the states

can a redtop have as much potential for horsepower as a s15 blacktop.

it just seems like more trouble with the s15 6 speed transmission

are there going to be more help available for the s13 and s14 swap than the s15?

it seems as though a s14 blacktop would be easiest for a 97-98 240...

but is mileage the only advantage for the newer s15 blacktops? or would it not even really matter?

what accounts for the extra 50 hp from a redtop to a s15 blacktop? besides the turbo

i got most my information from heavythrottle"Fits into US 240SX S13 and S14 chassis with no modifications to motor or transmission mounts. Uses the host chassis driveshaft and differential. Uses the standard turbo SR downpipe and stock catalytic converter location with the 240SX catback exhaust. 89-90 chassis will need tach or cluster, power steering lines and reservoir from 91-94 chassis. "
Modified by JoHn E at 2:42 AM 5/21/2007

[S13FASTBACKSR]

i dont think its worth it..sure its different and sure you'll have the extra power..but the reason its got more power for the most part is really only because like you already mentioned the dual bb turbocharger. you can put that on your s13 or s14 sr for very cheap..the redtops do have as much "power making potential" as any other SR and ya the only other thing about the s15 sr is the mileage but everybody has their own opinion..IMO its not worth it

[BLKTOPS14SR]

Like mentioned, dual BB turbo, larger injectors, VTC, and lower mileage is all. I've heard the redtop has the best transmission though. 6spd doesn't like alot of power. But for daily driver or highway cruiser the extra gear would be nice. Much cheaper with a redtop and swap newer goodies to it, like turbo and injectors.

[JoHn E]

are the s15 SR blacktops that are bought usually THAT much better in terms of mileage?

[GoTRicEo0]

It's different, but not by THAT much. There's some red/black tops running around under 50k miles.

If the miles really bug you that much, just do an engine rebuild. That's a +

[S13FASTBACKSR]

the miles could be significantly different..say you get a '91 redtop..first year of production..compared to a '99 s15 sr..8 years difference..if you can find a front clip with its original sr in it then you can see how many miles are on it which is a plus..look at how many of us have redtops or earlier sr's..and we are all fine..sure some things go wrong but nothing serious

[jdm_master_X]

IIRC s13 SRs (blacktops and redtops) respond better to modification because of the port design in the head. And from what I can recall VTC on s14s and s15s start to become obsolete beyond the 300 HP mark. dont quote me on it, but thats what i hear almost 90% of the time.

i got a 98 S13 blacktop with 14K miles at the moment, so i mean you can always just invest in an s13 SR, rebuild it, and slap it in your car....all for less than would you would have paid for an s15 motor out the box.

[GoTRicEo0]

True, but there's some of those magical SRs somewhere. Hopefully he goes for the frontclip route.

If you know how to do the wire'n. Then by all means get the S15, just do what you want to do. Most the people here would just get the normal Red/black S13 model.

[jdm_master_X]

the only bonus i see in getting an S15 swap is not the motor, but the need for the differential (because of the speedo sensor)

[JoHn E]

i was expecting to get flamed haha

thanks for the answers


Modified by JoHn E at 9:45 AM 5/22/2007

[nyjays]

i got a s15 swap on my 95 and it was a ***** go for a s14 kouki try to get a front clip much cheaper at the end

[exode]

for a usdm s14

is the stock s15 250hp really worth the extra money to get instead of say a 200hp stock redtop or a 220 stock blacktop?

it seems like the redtop and s14 blacktop is more common in the statesthey are just more used motors because they are older

can a redtop have as much potential for horsepower as a s15 blacktop. yes it does

it just seems like more trouble with the s15 6 speed transmission weaker gears

are there going to be more help available for the s13 and s14 swap than the s15?yes, 95% of the people on here will have a blacktop or a redtop swap

it seems as though a s14 blacktop would be easiest for a 97-98 240... or an s13 motor, yeah thats right. S13 or S14 would both be about the same

but is mileage the only advantage for the newer s15 blacktops? or would it not even really matter?You know i say its luck of the draw more. Mileage won't be that much different, since japanese get rid of their cars 2-3 years from owning them anyways because the taxes get so high. Its more the driver of the used motor, did the previous owner take care of it and be nice to it? That matter a hella lot more than milage

what accounts for the extra 50 hp from a redtop to a s15 blacktop? besides the turbo

the bigger intectors (440cc?), vvt

i got most my information from heavythrottle"Fits into US 240SX S13 and S14 chassis with no modifications to motor or transmission mounts. Uses the host chassis driveshaft and differential. Uses the standard turbo SR downpipe and stock catalytic converter location with the 240SX catback exhaust. 89-90 chassis will need tach or cluster, power steering lines and reservoir from 91-94 chassis. "

^^ correction you need driveshaft mods to use the S15 6 speed transmission

good luck and do a redtop =D

[karmakaze]

First off, VTC disengauges after 2500 rpm IIRC. It helps with low end torque and that is it. IT DOES NOT HURT YOUR TOP END.

Everyone makes cams now that works with VTC so cam options are no longer a limiting factor.

The high port head of the s13 sr20det makes the engine snappier and a little more rev happy. this does not make it any more responsive to modifications in comparison to the s14 or s15 sr20det.

The low port head of the s14 & s15 sr20det helps make torque. (which in my opinion is better than the s13 design)

with solid lifters the head of any s13 s14 or s15 can rev to 9k. (thats not to say the bottom would handle it for very long, you also need ARP everywhere, pistons, and rods)

the only mechanical difference between the s14 and s15 sr20det is the transmission and the turbo.

[highmilehatch]

but the reason its got more power for the most part is really only because like you already mentioned the dual bb turbocharger. you can put that on your s13 or s14 sr

The reason it is rated at more power is simply because of the injectors. S14 and S15 turbochargers are IDENTICAL minus the cast divider wall built into the exh. housing for the internal gate, and the turbine wheel is made of inconel. Both turbos good for roughly 300whp without going outside their efficiency.

If I were you, I'd go with the S14 SR, the VTC adds alot to the driveability. Make 300whp on the stock turbo with boltons and when your done with that, upgrade the turbo.