SR vs RB question

[auh]

Hey all,

I just bought my s13 about a month ago and love it. Only one problem...its not fast enough for me.

I'm saving up todo a motor swap next summer but was wondering what I should swap in.

I want an RB25 however I've been told by some people that its a good easy swap and I've also heard the complete opposite.

I know the SR is relativly easy swap compaired to the RB but is it worth it?

I really want a lot of power and I know it is possible to get a lot of power from the SR but is it worth it?

Please post pros and cons about each engine and it would be cool if people that have done both swaps could leave there own opinions.

Thanks

[Ni2s4s0aSnX]

Well I would go with the RB25T or the RB26TT. The RB swap is not a hard swap at all, it's a direct swap. The RB motors are bigger, more reliable, more powerful, and have more potential, in my opinion, than the SR motor. I would go with the RB swap if you can afford to do it.

[95lstegman]

more than that, consider this. the SR is an easier swap, but that's not to say the RB is difficult. it's just that the SR is about as easy as it gets, where the RB is is just a bit more challenging. it's not even much more expensive a swap to do. $3500 vs. $2500 or so. i was very strongly leaning on the RB25DET, but i changed my mind when i couldn't find anybody getting even 20mpg with their RB25DET. this is my daily driver and it needs to be capable of decent gas mileage, and 16mpg is NOT decent. besides, the SR is capable of pretty much the same power with only a couple small downsides, and parts for the SR are cheaper, more abundant, and many are available from within the United States. the SR is also lighter.

i did NOT consider the RB20DET here because IMO, if you're going to have the extra size and weight and expense and difficulty and engine bay loss of space of the 6-cylinder, it may as well actually make more power and have more displacement than the SR20DET.

so basically, the SR is almost as capable as the RB25 power-wise, while having better parts availability, cheaper to begin with, easier to install, more widely supported at shops, and getting much better gas mileage. there really isn't much of a downside.

[armysweitzer]

i have a rb20 running 11 psi. All stock minus 3 inch all the way back. I took my friend running a sr20, 12 psi, FMIC, lots of other bolt ons.'

I think the engines are totally different, redlines, etc. It seems to me the rb20 holds more power at higher rpm.

Pro: @1400con:parts/stuff you need for the swap are harder to find and more expensive.

decision is up to you but dont rule it out just cause it has the "same power" as stated before because it doesnt.

PS i get around 24mpg

[95lstegman]

well yes the RB20 will hold better power up high, probably because it has a larger turbo (i'm pretty sure). the SR's turbo is really ghey. and the SR is more widely supported, and parts are cheaper, as well as being lighter than the RB20. for instance, i took my car in to a tuner shop and actually had them help me out with a few little things. SR's are everywhere. use it to your advantage unless you have another car to drive while you're waiting for parts to be ordered for your RB. and the RB doesn't have any better power output as far as maximum and such.

basically, the SR can put out about as much power as you can handle, and it's better supported (everything can be had in the US, and many things can be had at autozone even), very simple to wire, is lighter than the RB, and can put out just as much power as an RB20.

now, the RB25 is a different story. it does have a little more potential, but moreover it has much more power all over. that said, many hardcore 240 enthusiasts including those at XAT and Enjuku believe the RB is really too heavy for the S chassis.

[armysweitzer]

lets see how long a sr20 will hold 400 hp on stock internals then compare to a rb. It is my firm belief it will hold more and better power. Race Bread

[95lstegman]

if you've talked to some of the people on this board and others, the SR will hold that power and even a bit more for a very long time if properly tuned (somewhat safe tune). that's not to say a race motor will last that long, generally because race motors are tuned to the ragged edge of performance and therefore don't last all that long. that's like people thinking a 300whp base model integra won't last long. i know a couple people who've been making that power on stock internals + aftermarket head gasket for over 3 years. similarly there are a few people who have 400whp+ SR's that have had them for at least a couple years. it's all in the tuning. .

i think in the end what motor one should choose is mostly up to personal preference. my preference is the lightweight SR, but some say the CA is SO much better. popcorn if you ask me, but to each his own. i'm just trying to point out that the SR can very easily/fairly cheaply make 300whp, which should be about enough to satisfy most anyone in such a light car, and it will keep almost perfect 50/50 weight distribution (like ~51/49, as opposed to 53/47 stock).

[auh]

I would be very happy with around 300hp, don't need more and I wouldn't expect a 2.0 4 cylinder to make much more safely. How reliable is a 300ish hp sr20?

Also if the s13 has 50/50 with the ka, wouldnt it be more like 49/51 with the lighter sr?

[PDX_S14]

i have an sr in mine, loven it!! you would love it too!! rb are cool if you want to be something different ... some of my buddies have rb 25 and rb 20 in there s13. is fast and feels different from a sr. im talking about stock vs stock. 95lstgman are right is all about how much money you have to play with and do you mine waitting for parts. my buddy waited a month for his rb25 oil pump and something else forgot. good luck and have fun what ever you choose.

[95lstegman]

I would be very happy with around 300hp, don't need more and I wouldn't expect a 2.0 4 cylinder to make much more safely. How reliable is a 300ish hp sr20?

Also if the s13 has 50/50 with the ka, wouldnt it be more like 49/51 with the lighter sr?

300whp done right would be as reliable as stock on the SR, which is to say you'll have precious few problems other than the fact that us S13 owners are always dealing with crappy old vehicle wiring and such.

and, like i said, stock weight distribution is 53F/47R, so the SR just helps it. not like you'll notice a huge difference. the SR isn't that much lighter than the KA. i know i can't notice the difference between driving with and without a passenger, but that's probably about the difference in handling between the KA and SR. not that anyone does this swap to save 75-100lbs or whatever!

[IowaRB240SX]

Rb's are easy if you buy the parts to install it from someone like McKinney who has done many. Then it is a bolt in/plug-and-play swap. If you are looking to fab everything yourself, it won't be real easy. I have an B giong into mine. actually, it is in but not on the road yet. Anyway, it is a pice of cake to install. Plus you are looking at 60 hp without mods, and an easy 300 whp with only minor work(boost controller, exhaust will almost get you there)

[95lstegman]

Rb's are easy if you buy the parts to install it from someone like McKinney who has done many. Then it is a bolt in/plug-and-play swap. If you are looking to fab everything yourself, it won't be real easy. I have an B giong into mine. actually, it is in but not on the road yet. Anyway, it is a pice of cake to install. Plus you are looking at 60 hp without mods, and an easy 300 whp with only minor work(boost controller, exhaust will almost get you there)

agreed. it's nice. i was about to do it, but this is my daily driver, so i opted for the SR since it can actually get pretty good gas mileage.

[armysweitzer]

rb20s come with smaller injectors then your SR, stay off boost and it will bet better gas milage. Trust me

[RogerHinga]

RB25 vs SR20 extra .5 litersextra 2 cyl

I would do the RB..

[95lstegman]

rb20s come with smaller injectors then your SR, stay off boost and it will bet better gas milage. Trust me

who wants to stay off boost? WTF?

RB25 vs SR20 extra .5 litersextra 2 cyl

I would do the RB..

yes, RB25>SR20. still heavier and harder to get parts and bad gas mileage, but FAST.

[eh?]

, but i changed my mind when i couldn't find anybody getting even 20mpg with their RB25DET.

I got 28mpg hwy on a drive from nyc to atlantic city, nj a 125 mile ride. IF someone is getting poor MPG they are probably not running an aftermarket FPR. With the stock FPR and a walbro pump you will be running rich. And as for the weight issue, it's just pure bs. Anyone who owns an RB will tell you the driving characteristics is close to or the same as stock.As a bonus with the RB25 or 26 is the transmission, which accounts for most of the weight difference between the SR/KA and RB. But it's extremely strong and is used for an upgrade for the SR in japan and australia.

[95lstegman]

i don't know about you, but i don't gauge my fuel economy on my personal best. i base it on my average in mixed driving and on my worst. my worst yet with the SR has been 23.5mpg, and now that i've replaced a couple bad sensors i can't get below 25mpg even in aggressive city driving.

and the stronger transmission is only a plus if you plan to make more than 350whp. i don't.

and FPR thing is a joke. the NISMO one is just as restrictive as stock. i mean, it's built the same, just adjustable. so it's not going to flow better. i seriously doubt the stock FPR can't get rid of the extra fuel a Walbro is pumping. i've gotten 25-28mpg in town on my SR with Walbro and stock FPR.

for power, the RB is the only answer. but i went with the SR because you can have most of the power with WAY better support here in the US as far as OEM parts and such. one call/drive to a local shop (XAT, Enjuku) and they already have pretty much every reasonable OEM part for the SR in stock. thank god for that, too, b/c i had a few weird problems early on. the RB is still reliable, just much harder to get odds and ends for.

again, it comes down more to preference. i see no reason that the SR is not fast enough for any but the most hardened HP junkie, so power isn't the reason people go RB. it's uniqueness i guess, although it's done more and more so even that's getting moot. if you're wondering which to go with, assess your goals as far as HP and ultimate reliability and budget, and decide from there.

[armysweitzer]

i went with it so i could fell full boost at 9000rpm and not worry about my aluminum block falling apart.

this is not a ragging post just seems your favoring SRs so ill favor RBs to fair to the man posting this thread.

[95lstegman]

i went with it so i could fell full boost at 9000rpm and not worry about my aluminum block falling apart.

this is not a ragging post just seems your favoring SRs so ill favor RBs to fair to the man posting this thread.

hey, my last whip was a honda, so don't tell me aluminum isn't good for the revs. and NO honda blocks prior to the year 2000 were built even as well as the SR20, yet i've seen MUCH worse motors making 13,000rpm a routine yummy, mmmm mmmmm. if it weren't boosted, maybe such a rediculous redline wouldn't be unheard of . . .

i still wish i had gone with the RB25DET. after owning the SR for less than 2 weeks i decided it wasn't fast enough. or maybe that's just how the speed bug is.

[eh?]

and the stronger transmission is only a plus if you plan to make more than 350whp. i don't.

and FPR thing is a joke. the NISMO one is just as restrictive as stock. i mean, it's built the same, just adjustable. so it's not going to flow better. i seriously doubt the stock FPR can't get rid of the extra fuel a Walbro is pumping. i've gotten 25-28mpg in town on my SR with Walbro and stock FPR.

Dude it's KNOWN and documented the Stock FPR on the RB can NOT handle an upgraded fuel pump. It's a mandatory upgrade like the fuel pump. There is no disputing that.And as far as RB MPG it's good that you didn't get an RB, for alot of peope it's not their DD and I'd tell anyone who considered it for one not to get it. And again if all you wanted was 350 rwhp it would be pointless to get one. A stock KA-T would have made you happy.But as the poster said he wanted a lot of power. Go RB. Someone put down a 10.6 1/4 mile. Recently he put down a 116mph 1/8th mile..before he broke his transmission. 116mph 1/8= ~140mph 1/4mile. Guess what? It's on a stock bottom end.

[95lstegman]

nice. my dream car is an S14 w/ RB26. hey, we can all dream, can't we?

[eh?]

How bout a stock RB26 running 7.7x 1/4's all day long http://img108.echo.cx/img108/9414/hpnx00205le.jpg

[JimmyMethod]

Also if the s13 has 50/50 with the ka, wouldnt it be more like 49/51 with the lighter sr?

240s aren't 50-50. They're closer to 55-45. If you really want to improve the weight distribution, the VQ is the way to go. The VQ is aluminium opposed to iron of the KA (and I think SR, too). A few people around here have done VQ swaps and the front of the car sits several inches higher than the back because of the much lighter weight in the front.

[armysweitzer]

very true, friend has one and we both love it. Gotta love 3 liter torque

[95lstegman]

240s aren't 50-50. They're closer to 55-45. If you really want to improve the weight distribution, the VQ is the way to go. The VQ is aluminium opposed to iron of the KA (and I think SR, too). A few people around here have done VQ swaps and the front of the car sits several inches higher than the back because of the much lighter weight in the front.

like i said, stock is 53/47. and i'm rather sure the VQ is heavier even though it's aluminum. the SR is aluminum, which is why now my car sits a little higher in the front than in the back. it looks a little funny, but eventually i'll get full coilovers and i'll have more adjustability than you can shake a stick at .

[JimmyMethod]

very true, friend has one and we both love it. Gotta love 3 liter torque

Well, I was thinking the VQ35DE, MUCH more output than the VQ30DE, about the same as the VQ30DET, but that's hard to get.

[95lstegman]

VQ35DE and VG30DETT are quite different. i know the VG30DET came single turbo, but i think that was only for FWD Maximas in other markets than the USDM. i don't think a FWD motor would fit in a RWD car . . .

[eh?]

He actually ment VQ30DET which i believe came out of the Cedric?VG30et came in the Z31's and the VG30e's came in 2nd and some 3rd gen maxima's.Here's a VQ-T on ebay: http://cgi.ebay.com/ebaymotors...ZWDVW

[armysweitzer]

ooops i meant VG30dett out of a z32...

[Aworkinprogress]

Sr if you want to drift Rb if you want to drag.. or both with ka-t.

no replacment for displacement! even for four bangers.