Keep my built SR20 or build an RB?

So I need everyone's help. I don't know what to do next for my engine. I just rebuilt my SR20 with forged internals and it runs beautifully, I'm really happy with it. I'm getting it dyno'd soon, but I'm estimating ~425ish whp. I'd like to hit upper 400 or right around 500 whp on high boost. The problem is, I'm maxing out my GT2871R .64 turbo. The obvious answer is get a top mount and a GT30 or GT35. But, I'm also close to maxing out my fuel system. I'm running 740cc injectors and at WOT I'm hitting 93-93.5% injector duty cycle. So, I should get a top mount manifold, bigger turbo, and bigger injectors. But, I'm using a stock ECU. Stock ECU can't handle bigger injectors, so I'd have to go standalone. So, long story short, to get any more power out of my current motor, I'll need a new turbo manifold, bigger turbo, bigger injectors, and a standalone. That's a lot of cash. If I do it right, I'm looking at $4k-$4.5k to eek even a little more power out of my current setup.

Now, I've been playing with the idea of selling my whole motorset, buying a stock RB25 motorset (maybe a Neo, not sure yet) and putting a little money into it to get it to 450-500 whp. I've read plenty of skylineaustralia.com threads about hitting 450-500 rwhp on stock RB25 blocks with just cams, intake manifold, bigger turbo, bigger injectors, and a tune. I'd already have the supporting mods (fuel pump, FPR, EBC, big intercooler, big radiator and electric fans, suspension work, rear end work, etc) so it could be reliable if I do the motor work right.

So I guess it would come down to how much money I could sell my current set up for and if I could safely and reliably hit 475ish rwhp with an RB25 without major internal work.

Thoughts everyone? I really need opinions. I'm so torn

I say go rb.

You will need at least a turbo, injectors, some sort of EMS to make those numbers on an RB. 475 on a stock block isn't shit though. You don't need cams either.

If you want a setup thats already built and makes your 500whp send me a PM. It is kind of unlikely but I have toyed with selling my swap.

Why do u feel the need for 500 whp on an s chassis?

Anyway. How's the spool time on that 2871r? Is it laggy as fuck?

Eckominds wrote:Why do u feel the need for 500 whp on an s chassis?

Anyway. How's the spool time on that 2871r? Is it laggy as fuck?

^^ I'm with him.

What are you doing that you need 500whp? What do you use the car for?

You also don't need a standalone to get the fueling right. A ROM tune or nistune works great with the stock ECU.

Just as noted by 240sxguy.. All of the parts which are still remaining to buy on your SR you would also need to buy to get the RB to do what you want it to. So I'm not sure why you think it would be close to the same price?!

Honestly I say keep the SR and put the extra cash towards that... You will never get out what you paid for the aftermarket stuff that is a given. So stay with the platform you got or otherwise if you are dead set on an RB then you would be paying more money, but you might be okay if you get a full XXXwhp setup from someone and let them take the hit on aftermarket stuff.

One last note, if you do go RB25 remember it will mean more weight... but also more torque and a better transmission.

2871r shouldnt be laggy at all, its a a t2 flanged turbo.

my advise would be to just get a bigger turbo that will fit. why not go with a gt3076?
itll still work with your setup but with a larger compressor wheel youll be able to reach you power goal, as long as your injectors arent maxxd out.

Well, I DD the car but I also take the car to the drag strip on some weekends. My particular group of friends are drag heads. There are a few 5.0 Mustangs and a Trans Am, and they are fast. So my goal is to make a daily driver that can be a drag monster on weekends.

I understand that I'd basically be doing the same upgrades to the RB as I would be doing to my SR, but I have this gut feeling that 500whp on a 2.5L straight 6 will be more reliable and will be easier to DD than 500whp on a 2.0L 4 cylinder.

To make 500whp on my SR, I'd have to get a big turbo and big cams, meaning more lag and more difficult to DD. Also, I don't know how I feel about 500whp through the stock SR20 trans...

But there are plenty of examples of stock internal RB25's using GT3076 turbos and medium-sized cams reaching nearly 500whp on a good tune (and I'd run E85) so I guess I'd feel more comfortable pushing that than my SR. Not to mention the strength of the RB25 transmission.

Say, in either case, I need to spend maybe $4500 in upgrades to hit 500 whp. I figured if I sold my motor set, I might get $5000 for it (is that a little far fetched?), and an RB25 motor set is ~$2200-$2500. Figure with mounts and basic maintenance, might hit $3000. That still leaves me $2000 for upgrades. That means I'd only spend an additional $2500 out of pocket, rather than $4500 to get the same upgrades and same power level on my SR.

I don't know, maybe I'm delusional to think this might happen. I've also been contemplating an RB26DETT so yes, I must have lost my mind

fastSRmedic wrote:Well, I DD the car but I also take the car to the drag strip on some weekends. My particular group of friends are drag heads. There are a few 5.0 Mustangs and a Trans Am, and they are fast. So my goal is to make a daily driver that can be a drag monster on weekends.

I understand that I'd basically be doing the same upgrades to the RB as I would be doing to my SR, but I have this gut feeling that 500whp on a 2.5L straight 6 will be more reliable and will be easier to DD than 500whp on a 2.0L 4 cylinder.

To make 500whp on my SR, I'd have to get a big turbo and big cams, meaning more lag and more difficult to DD. Also, I don't know how I feel about 500whp through the stock SR20 trans...

But there are plenty of examples of stock internal RB25's using GT3076 turbos and medium-sized cams reaching nearly 500whp on a good tune (and I'd run E85) so I guess I'd feel more comfortable pushing that than my SR. Not to mention the strength of the RB25 transmission.

Say, in either case, I need to spend maybe $4500 in upgrades to hit 500 whp. I figured if I sold my motor set, I might get $5000 for it (is that a little far fetched?), and an RB25 motor set is ~$2200-$2500. Figure with mounts and basic maintenance, might hit $3000. That still leaves me $2000 for upgrades. That means I'd only spend an additional $2500 out of pocket, rather than $4500 to get the same upgrades and same power level on my SR.

I don't know, maybe I'm delusional to think this might happen. I've also been contemplating an RB26DETT so yes, I must have lost my mind

Hmm, I understand why you want the power then. Although honestly the S-chassis itself isn't exactly the best for drag racing, but it is good for an all-around setup.

I think you are planning on a lot for the SR and not nearly enough for the RB. Visit http://forums.nicoclub.com/zeroforum?id=135 for more realistic costs on the RB stuff. If you start over with the RB I am sure it will be much more than just keeping what you got.

But yea I hear ya on the RB25 trans though. It is A LOT more stout.

Other notes about 500whp:
It is not only injectors. At 500whp through E-85 a single pump wont work... maybe an 044 but definitely not a single walbro.
Rear end? Rear diff and axles aren't exactly known for their strength over 400whp. Especially if you are trying to keep up with your buddies by running slicks at the track.

The way I see it is. You need a bigger turbo (although you can sell your 2871 for a pretty penny), you need 1000s, and a new tune... That's not $4500 worth of stuff.
(The above mentioned stuff I think you need for either motor)

Hmm, I understand why you want the power then.

Haha yeah, I'm running around with a bunch of American muscle jackasses that have nothing but bad things to say about Japanese cars. I'm trying to flex a little Nissan muscle!

But yea I hear ya on the RB25 trans though. It is A LOT more stout.

If I was to keep my SR, is it possible to mate an RB25 trans to an SR? I think I remember something about bell housing bolt patterns not matching. Hmm.

The way I see it is. You need a bigger turbo (although you can sell your 2871 for a pretty penny), you need 1000s, and a new tune... That's not $4500 worth of stuff.

Well, that wouldn't be a bad setup. If I got 1000cc squirters I could probably sell my 740cc ones, and if I could hit ~500 with a 3076 that will mount on my stock exhaust mani I could sell the 2871R also... Same with a Bosch 044 pump, I could sell my Walbro. Maybe this could be more attainable than I thought...

Rear end?

R32 GTS-T (or maybe GTR, still unsure) rear end ok? With Tein Basic adjustable coilovers and Cusco strut tower bars.

2871r shouldnt be laggy at all, its a a t2 flanged turbo.

Yeah, definitely not a laggy turbo. I'm starting boost at like 3000 RPM with full 18 psi at ~4200ish, maybe even lower because I haven't gone WOT with the new build yet, only ~80% throttle. It pulls nice and hard though, and was a direct bolt-on to my stock exhaust manifold.

it sounds like you have a pretty well done SR. I would keep it. do some sort of dual ball bearing turbo (GT3582R) look for a AEM EMS, and a fuel system (1000cc or do a E85 setup with your SR) with another walbro pump or a aeromotive pump. and get the car tuned. Look at the Sound Performance "quick spool valve" it's about $600 www.spracingonline.com if you strap one of those on a DBB GT35 through your SR i think it would really take away any lag time you would have.


I think you'll have way more money just doing the RB swap ($300-500 for wiring) $500? for mounts,$2500 for motor. money for a driveshaft, THEN you can figure out the extra cash for modding, personally i wouldn't do it.

The more I weigh the pros and cons of my setup, I'm thinking of staying with my SR. I have too much time, sweat, blood, and money into my engine to just sell it. But mostly money haha.

What would you all think of this http://www.full-race.com/catalog/product_info.php?products_id=1736 and a Bosch 044 pump (or could I run a second Walbro 255 out of the tank?), 1000cc injectors and a tune?

Hahaha, I just remembered I'm still using stock cams. That might help a bit, don't you think?

do a E85 setup with your SR

Done, I already run E85.

Ahh shit.. I dunno how I forgot about the rear end so quickly. Yea that rear end should be good. Even the GTS-T (which is what I used to have) held up pretty good when I was making over 500whp. I even launched it on slicks a few times. If you have a GTR (6x1 style axles) then it will be even better.

As for the trans. The RB25 trans is essentially the same thing as a Z32 trans... In fact many RB guys will use the z32 trans because it is a little cheaper (although doesn't fit in the tunnel as well, but I digress). Mazworx does make an adapter kit to mate the beefy Z32 trans to the SR, but it's kind of pricey. http://www.mazworx.com/index.php?l=product_detail&p=2759

fastSRmedic wrote:The more I weigh the pros and cons of my setup, I'm thinking of staying with my SR. I have too much time, sweat, blood, and money into my engine to just sell it. But mostly money haha.

What would you all think of this http://www.full-race.com/catalog/product_info.php?products_id=1736 and a Bosch 044 pump (or could I run a second Walbro 255 out of the tank?), 1000cc injectors and a tune?

Hahaha, I just remembered I'm still using stock cams. That might help a bit, don't you think?

do a E85 setup with your SR

Done, I already run E85.

You could get away with 500whp and E-85 with if you ran your existing 255 into the Bosch 044 running external in series. The 044 is a great pump.

Yea the stock cams would be hurting you a little bit but its not the worst thing in the world either. You could always run them for now and then do something about them later. Like you said the biggest thing holding you back from the 500whp is surely the turbo.

Shotgun Turbo! I want, hit me up if you sell.

fuck an RB

That's such a Samantha thing to say

well if you decide to keep the sr, ur gunna want hp wherever you can get it. i do cylinder porting if your interested. this would be a good time to upgrade your headparts as well (cams, valve springs, ect.) porting can get you anywhere from 15-35hp depending on application, and cams are all over with hp but itd be pretty easy to gain reliability on your head, plus 50-75hp.

...plus a tune. id visit touge factory for a nice tune, plus theyd be able to definately help ur hp situation

After mulling things over, I'm gonna keep the trusty SR. Hell, I built the thing with my bare hands, that engine is like my child. But I am going to do some big upgrades. I want it to be a street/track monster with as little lag as possible, so I'm thinking twin scroll GT35R setup. Expensive? Yes. Quick spooling and huge power? Hell yes. I'd have to do the aforementioned fuel and ECU upgrades as well so the price is going to be big, but I think it'll be totally worth it. Thoughts?

...what!? gt35r is laggy as hell...especially on a sr..? u do know how big that turbo is right? if ur going with a t3 flanged topmount setup u should go for a midsized t3 turbo liek a t3/to4 57trim. thatd get your power goals with very little lag.

I'm selling a T3/T4 .57trim turbo, and SR peakboost manifold, downpipe, and testpipe. PM me if interested.

RB's are for faggots

35r is a great turbo but would be a little big for 500whp. It would just be more lag than needed for "only" 500whp. If you were looking upper 500s or 600 I would say go for it.

As for the 57 trim, IMO what you got now is better than that. A standard 57 trim is old and outdated and also probably won't flow enough for 500whp.

Have you ever considered one of the new billet BB PTE turbos? Cheaper than the full race 35r by a LONG shot and considering you can get one closer to the correct size for 500whp it will probably out spool it as well. Did a little research and looks like the PTE5857 or maybe even the PTE6057 look like they would fit the bill well for you. My guess is you would see full boost between 4000 and 4500 with a turbo that would be very happy at 500whp and still provide a little extra head room if you wanted.

What's all this "RB's are for faggots" talk about anyways?!

Yeah, I hadn't really looked at the specs on the GT35R but it is rather big. That PTE5857 looks sick. That's really funny that you mention the billet wheel WhatsADSM because my buddy who has a turbo K20 RSX had a standard T3/T04E 50 trim and he JUST bought the PTE6262 with the billet wheel last week and he is so excited to use it. Sounds like a really sweet turbo, and costs significantly less than the 35R. Probably spools faster too, and a 605 HP max is PERFECT for what I'm looking for. Damn, good call on this one DSM. Plus with my high compression and overbore, it should spool a little faster than a normal SR. This may be a go for me, pending the sale of my 2871R.


And RB's are definitely NOT for faggots. I'd kill for a built 25 or 26. Actually, if I had money to spend I'd do an RB30/26 hybrid. Siiiiiiiick.