# 98 S14 or RB25?



## Dyran (Jul 5, 2005)

I recently put my 89 in the local car shop for the RB25 swap. Their engine source is having difficulties getting me my motor so I wanted your opinions about maybe doing the S14 motor swap instead. Thanks...


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## '91 240sx (Feb 17, 2003)

why not just do the s13?


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## Dyran (Jul 5, 2005)

I thought about the S13 swap but I kinda want something that everyone else doesn't have


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## ABuSD (Jun 28, 2005)

Dyran said:


> I thought about the S13 swap but I kinda want something that everyone else doesn't have


Blacktop is a little better cos of its larger turbo and vvti head.
See if u can stick with the RB25, u wont be disappointed!
You changing the box aswell?


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## Nismo240 (Jul 24, 2004)

are you wanting to drift or drag?


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## Dyran (Jul 5, 2005)

Yes I will be changing the box and I am building the car up for drag


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## bakimono (Aug 10, 2005)

if youre doing drag, try to stick with the RB. if you cant get the RB, go with the s13 swap. the s13 motor has much more potential than the s14 motor, even though the s14 motor has vtc. basically, unless you're leaving the motor stock, youre much better off with the potential of the s13 motor.

RB = tons of power and boost
S13 = lots of potential and straighter intake runners
S14 = more stock output due to larger stock turbo and vtc

all SR's and RB's are bad boys though so take your pick :thumbup:


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## ABuSD (Jun 28, 2005)

Very true bakimono, if you want the most power, RB25 then SR, if your building for drag and gonna get an SR, better of sourcing a cheaper red top, as Bakimono said the vvti is useless if u change the cams anyway.


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## bakimono (Aug 10, 2005)

if you were planning on leaving the swapped motor stock (or relatively stock) i would say go with the s14 SR but im assuming you're going for big power and ive heard that the s14 engine acts funny when you get over about 300hp. RB or s13 SR all the way if you want a drag car running mid 13's or under. But like i said before all three are very good choices for motors and you cant really go wrong with any of them....god im glad i have a nissan now and not a honda. haha.


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## Nismo240 (Jul 24, 2004)

since you want to drag, you should go with the RB25.


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## Joel (Jun 11, 2003)

bakimono said:


> if youre doing drag, try to stick with the RB. if you cant get the RB, go with the s13 swap. the s13 motor has much more potential than the s14 motor, even though the s14 motor has vtc. basically, unless you're leaving the motor stock, youre much better off with the potential of the s13 motor.


The s14 has just as much 'potential' as the s13 engine. Actually the VCT allows the turbo to spool faster.


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## Nismo14-180 (Mar 31, 2004)

true, but its worthless over 400hp. the cams just get swapped over to S13 style.


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## zellx2004 (Sep 30, 2004)

Nismo14-180 said:


> true, but its worthless over 400hp. the cams just get swapped over to S13 style.


Good point. Go with a black top from a s13.


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## Joel (Jun 11, 2003)

Nismo14-180 said:


> true, but its worthless over 400hp. the cams just get swapped over to S13 style.


HKS, Apexi, Jun and Toda all have cams for s14 and s15 that retains VCT. Besides, you shouldnt use stock s13 cams over 400hp anyway.

And how does this covert into s13 having more potential? From the engines ive seen both SR variants can produce the same HP figures on similar if not exact mods.


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## bakimono (Aug 10, 2005)

are you going to straighten the intake runners somehow by yourself or find someone to do it for you? i see what youre saying about having the same potential but at what cost? i dont know how easy it is to get these japanese made parts in austrailia, but over here it gets kind of tough. you cant just walk down to a shop and buy JIC magic exhaust or an HKS f-con off the shelf. 

all im saying is that from what ive heard, the s13 is a common swap for a 2 reasons:

1. its cheaper
2. its got more potential

truthfully, this is the first time anyone has really debated and disagreed this so whole-heartedly against me over this topic.

im open minded about this and i know you shouldnt be using stock cams in a motor putting out 400 hp, but as i said earlier, it may be easier for us in the states to get replacement cams for an s13, than vtc cams that dont go crazy when you try to modify the engine.


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## bakimono (Aug 10, 2005)

and yes i realize redtop cams are made in japan also but its most likely easier to get some high performance cams for a redtop than to get cams with vtc for a 2001 s15 black top motor.

i dont know, correct me if im wrong. maybe im just stupid.

DYRAN- you should just boost that KA and show some fools some real power


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## Nismo14-180 (Mar 31, 2004)

Joel said:


> HKS, Apexi, Jun and Toda all have cams for s14 and s15 that retains VCT. Besides, you shouldnt use stock s13 cams over 400hp anyway.
> 
> And how does this covert into s13 having more potential? From the engines ive seen both SR variants can produce the same HP figures on similar if not exact mods.


Didnt know those companies had cams for the VCT SRs. I was talking about aftermarket S13 cams, not stock. Id hope no one is that dumb.


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## [High-Octane] (Jun 2, 2005)

bakimono said:


> and yes i realize redtop cams are made in japan also but its most likely easier to get some high performance cams for a redtop than to get cams with vtc for a 2001 s15 black top motor.
> 
> i dont know, correct me if im wrong. maybe im just stupid.
> 
> DYRAN- you should just boost that KA and show some fools some real power


RB25 vs ka-t???
hmmmmm....lol


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## Joel (Jun 11, 2003)

bakimono said:


> i dont know how easy it is to get these japanese made parts in austrailia, but over here it gets kind of tough. you cant just walk down to a shop and buy JIC magic exhaust or an HKS f-con off the shelf.


We import it same as you. Are you telling me there are no companies in the US importing parts from Japan? Now come on! Look at the sponsors to this site or over at 240sxforums - there are heaps.



> all im saying is that from what ive heard, the s13 is a common swap for a 2 reasons:
> 
> 1. its cheaper
> 2. its got more potential


Yes its cheaper,I agree with you there.
Its got more potential? Why? You have provided no evidence for this. This statement makes it seem like its hard to get increased horsepower on an s14 SR compared to an s13 SR. Last time I looked if you put a GT30 on an s14 sr you will get just as much HP if not more than an s13 sr.

A ga16 is cheaper than an SR, does it have more potential?



> truthfully, this is the first time anyone has really debated and disagreed this so whole-heartedly against me over this topic.


Im just trying to stop the internet rumourmill. 5 years ago some guy posted that the VCT on the s14 makes tuning more difficult when you get up into high horsepower numbers and there are issues with aftermarket cams not supporting it. That translated into 'its better to start with the s13 sr' which translated to 's13 sr has more potential' which today I believe is incorrect.



> im open minded about this and i know you shouldnt be using stock cams in a motor putting out 400 hp, but as i said earlier, it may be easier for us in the states to get replacement cams for an s13, than vtc cams that dont go crazy when you try to modify the engine.


True, I see that many shops carry a range of S13 parts on shelf and its quick to order and get these, but there is nothing stopping you from phoning an HKS-USA dealer and ordering in a set of cams for an s14. This fact doesnt justify the statement that s13 has more potential though, its misleading.


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## bakimono (Aug 10, 2005)

*evidence*

all i can say is i have never read any articles in a magazine or seen any tuning shows, or talked to anyone, who has told me otherwise. heres a quote from sport compact car-

"early sr20's were rated at 202 hp and used the desirable high-port head, with straighter intake runners and ultimately, more power potential. later engines used a low-port head, but added vtc, variable intake cam timing, and more boost for higher stock output. any sr20det has hugh power potential."

Just figured i would post that so that people didnt think i was talking out of my ass or something. i'm not saying that i believe everything i hear, but why would sport compact car lie?


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## bakimono (Aug 10, 2005)

[High-Octane] said:


> RB25 vs ka-t???
> hmmmmm....lol


^^^^ that was just a joke (incase some people didnt get it)

ill take an RB over a KA anyday of course. :thumbup: personally though, im really starting to like the idea of keeping my turbo KA rather than an SR because my KA is meaner than a gradeschool bully that can see and hear, in a school for the blind and deaf. :banana:


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## bakimono (Aug 10, 2005)

ive found hks cams for "89-02" sr20s for $200ish. if they eliminate or help the vtc not go nutso when you tune the engine thats great. its good that someone did something about that. I'd like to have the other matters addressed though. intake runners and high port head.


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## Joel (Jun 11, 2003)

Cheers for finding that Bakimono!
Im sure Sports Compact was referring to the general consesus that high port head and straight intake runners are desirable for greater top end power. Its not specific to the SR20 by any means. I think the point is moot because when modifying the engine to produce enough power where intake and head flow design become a significant factor, the intake manifold is usually replaced with a better designed one anyway (like an apexi or veilside one)
Factoring an engines power potential down to a single difference in design was probably not the purpose of the article. Sure its a factor (a small one) but it shouldnt be considered as a major reason for selecting one engine generation over another. 
This argument is becoming age-old and wont be solved here but I can tell you that the intake runner and head design difference is only a few horsepower and it doesnt significantly contribute until you reach levels of 350+

I suppose though if you have to find a reason to choose then design difference are fair game!


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## bakimono (Aug 10, 2005)

im glad we agree. :cheers: these are very small and minor differences in design. i dont know how much difference they really make, but ive heard that it makes some kind of a difference. Then again ive never really built an s13 and an s14 motor side by side with the same mods to actually see the difference for myself. If you build the motor to 500hp for drag, these differences could make a 2hp difference or a 20hp difference. who knows? :crazy:


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## [High-Octane] (Jun 2, 2005)

bakimono said:


> ^^^^ that was just a joke (incase some people didnt get it)
> 
> ill take an RB over a KA anyday of course. :thumbup: personally though, im really starting to like the idea of keeping my turbo KA rather than an SR because my KA is meaner than a gradeschool bully that can see and hear, in a school for the blind and deaf. :banana:


LMAO thanks for confirming that... lol i thought i would be automatic 2 most people u know


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