RB20DET vs RB25DET vs RB26DETT FAQ

Discuss the RB20, RB25 and RB26 series engines.
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tyndago
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Re: Back on Topic (David_NISMO)

Postby tyndago » Mon Jun 26, 2006 3:54 pm

David_NISMO wrote:The RB25 crank is not FULLY counter balanced. The RB26 is.
The factory 26 crank is not fully counter balanced.
David_NISMO wrote:My favorite part about the rb26 is that the entire motor will support over 425RWHP before any modifications need to be made. This includes, injectors, mafs, turbos, and ofcourse all internals.it also has internal throttle bodies which create better engine responseStock bottom end has been taken to over 1000hp.
Around 400 whp you run out of MAF. Stock injector is a 444cc that runs out at about 440 hp at the motor safely. Stock turbos lose ceramic exhaust wheels.

I have done 654 rwhp on an internally stock 26, and I have ran 137 mph with an all stock internally 26.

The 26 has individual throttle bodies.

As far as stock and 1000hp....like a ticking time bomb. 500 rwhp it will last ok. 600 whp its iffy...


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Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton)

Postby jimapaloooza » Tue Jun 27, 2006 8:27 pm

Well this is my first post on this site, hopefully I won't sound like a total idiot. But, I, like so many others have to come to the conclusion that front wheel drive cars just aren't near as much fun as rear wheel drive cars, so in following this train of thought I have decided to do an RB swap, the trouble I am having is, like all of the other poor "ignorant to the nissan world saps", is which engine is best suited for my needs/goals.

At first glance I, of course, wanted an RB26, seeing as the cost difference in the actual clip was only about 2-3k more than an RB25, but then I began researching what actually went into a swap and what the actual cost would be, and I think I have come to the conclusion that the RB26 is going to be a much more expensive swap compared to an RB25 swap, or perhaps I am just under estimating the cost of an RB25 swap?

So I guess my real question is, If I do an RB25 swap how much more am I going to need after I buy the engine, trans, ecu, wiring harness and how much will it all end up being? Also how much HP can I expect out of a 25, my goal is around 400WHP, would that achievable with an RB20?

Thanks in advance guys.

-Jim
Modified by jimapaloooza at 11:39 PM 6/27/2006

TougeRBSilvia
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton)

Postby TougeRBSilvia » Wed Jul 19, 2006 10:00 pm

krayton wrote:
-custom driveshaft required (unless you use RB20 tranny?)
under the the Rb25 cons you listed the above

ok i need someone to clarify this one for me... will an RB20 tranny mate with an s13 drive shaft??? or do you need to get r32 gts-t drive shaft or is it a trip to a drive shaft shop and a shaft in the wallet

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Re: RB20DET vs RB25DET vs RB26DETT FAQ (TougeRBSilvia)

Postby gbaz77 » Thu Jul 20, 2006 9:45 am

rb20 trans will work with s13 drive shaft. many people have done it, including myself.

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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby acside » Sat Jul 29, 2006 6:45 am

how can the r32 crank coller issue be resolved

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Joe
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (acside)

Postby Joe » Sat Jul 29, 2006 6:50 am

acside wrote:how can the r32 crank coller issue be resolved
by searching.

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krayton
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (acside)

Postby krayton » Sat Jul 29, 2006 5:26 pm

acside wrote:how can the r32 crank coller issue be resolved
JUN crank collar. can be welded on or bolted on.

looks like findings show that all our RBs have this problem, i believe except the new r34 RBs.

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Re: (Kansei240sx)

Postby GTR Shop » Sun Aug 13, 2006 7:42 pm

Kansei240sx wrote:I think you guys should differentiate the series of RB motors with in the 20 and 25

I have the SII motor and it doesnt not have the ceramic wheeled turbine, nor does it have VVT.
RB25DET ALL had VVT, they also ALL had cermaic turbine wheels.If you don't have VVT, then you have a RB20DET or somsone has slapped a turbo on a R32 RB25DE.NO Ifs or Buts - FACT.SI -> SII differences were mainly switch from external ignitor to internal ignitors on coils.

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Re: (GTR Shop)

Postby Darius » Mon Aug 14, 2006 6:27 am

Correct me if I'm wrong, but not ALL RB25DET's have VVT...only the R34 NEO does. The rest have VCT on the intake cam.


Modified by Darius at 4:22 PM 8/14/2006

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Re: (Darius)

Postby GTR Shop » Mon Aug 14, 2006 1:53 pm

Darius wrote:Correct me if I'm wrong, but not ALL RB25DET's have VVT...only the R34 NEO does. The rest have VCT on the intake cam.
Its actually NCVS.All the RB25DETs have it on the inlet.Exhausts are all fixed.The R34 NEO is no different except solid lifters and top feed injs in later models along with different inlet manifold. - turbo slightly different, and different CAS.AFM is same as SII R33.

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Re: (GTR Shop)

Postby jrb92se » Fri Aug 25, 2006 4:56 am

what about hp #'s i didnt see anyone mention them i know the rb26 will have more hp stock then a rb25 but what are the #'s from the factory for all three?

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Eikon
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Re: (jb96s14)

Postby Eikon » Fri Aug 25, 2006 5:10 am

jb96s14 wrote:what about hp #'s i didnt see anyone mention them i know the rb26 will have more hp stock then a rb25 but what are the #'s from the factory for all three?
RB20det = 220 hpRB25det = 250 hpNEO RB25det = 280 hpRB26dett = 280 hp

Keep in mind that these are simply factory ratings for hp. It common knowledge that the RB26 numbers were held to 280 to keep with Japanese manufacturer agreements. It's easily over 300hp.

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jrb92se
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Re: (Eikon)

Postby jrb92se » Fri Aug 25, 2006 5:13 am

thats at the crank not the wheels correct?

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eh?
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Re: (GTR Shop)

Postby eh? » Mon Oct 02, 2006 9:32 am

NEO head CC is smaller, valves are somewhat larger, RB26 rods, different ecu pin out. Basically a diffenent motor.

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Re: (eh?)

Postby Nismo Mark » Mon Oct 09, 2006 6:43 am

eh? wrote:NEO head CC is smaller, valves are somewhat larger, RB26 rods, different ecu pin out. Basically a diffenent motor.
What about the pistons? Have been told you cant use R33 RB25DET pistons in a NEO engine? If this is true why not?

There dont seem to be many reasonably priced suppliers of forged pistons for the NEO so would like to use R33 ones

Thanks in advance

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Postby bamr33 » Sat Oct 21, 2006 2:50 am

rb25det all the way. They are far cheaper than 26's and still can be tuned to 280kW with only PFC, hi-flow turbo, injects, fuel pump and boost controller.

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Re: cost (rection47)

Postby Joe » Sat Oct 21, 2006 10:38 am

rection47 wrote:Does anyone have a ballpark cost on the rb20, rb25 , and rb26?Including the absolutely necessary parts for a swap.Like all 3 so i can compare prices with the rest of the pros and cons? Instead of just knowing the rb26 is more, i wanna compare it a little better.

Thanks
its very hard to give an accurate estimate because everyone does things differently.

this is a ROUGH GUIDE and assuming you do things the right way (new clutch,water pump, etc)

RB20 - 2500-3500

RB25 - 4000-5000

RB26 - 8000+

89 GTR R32
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (Kamin)

Postby 89 GTR R32 » Fri Dec 01, 2006 7:55 pm

I Have been searching for a JUN crank collar but I can't seem to find one does any one hear know where I can?

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Re: RB20DET vs RB25DET vs RB26DETT FAQ (89 GTR R32)

Postby mugengsr » Sat Dec 02, 2006 2:17 pm

scimotors or the skyline shop i think they go by now .. they are in abbotsford ,bc,canada and have them in stock ..

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Re: RB20DET vs RB25DET vs RB26DETT FAQ (mugengsr)

Postby DORI-DRFT » Mon Dec 18, 2006 5:13 pm

Ive been searching for awhile now but still havent found anything use full my question is what crossmembers would i use for a 89 S13 for RB 20,25, & 26 Thanks

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Re: RB20DET vs RB25DET vs RB26DETT FAQ (mugengsr)

Postby minivan_don » Mon Dec 18, 2006 5:49 pm

the skyline shop is local to me ... and im in need of one too.

group buy ?

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Re: (eh?)

Postby melloscreama05 » Sun Jan 07, 2007 7:25 pm

eh? wrote:NEO head CC is smaller, valves are somewhat larger, RB26 rods, different ecu pin out. Basically a diffenent motor.


So can you swap the motor into an S14 just like a normal rb25 swap??? 280 hp outta the box seems appealing to me especially since the engine itself can be found for around $3k

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apollo500
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Postby apollo500 » Mon Jan 08, 2007 10:20 pm

i got a question, it might be stupid but here it goes, does the NEO work with the McKinney RB25DET mounts? what needs to be modified on the NEO to fit a 89 Hatch?

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Re:

Postby acside » Thu Jan 11, 2007 5:21 pm

is it true that the older rb26 engines are stronger (better) than the newer r33 or 34 engines. if its true do u mind explaining

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Sil240
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Postby Sil240 » Wed Mar 07, 2007 10:25 am

Taken from PaulR33's site

Rule of thumb for Air Flow meters RWKW & Engine BHP

------ ---- OD ---- RWKW ---- RWKW ---- BHP ------ BHPNo of AFM's ---- ------- 1 -------- 2 -------- 1 -------- 2RB26 ------ 65 ------ 149 ------ 299 ------ 271 ------ 474RB20/25 --- 80 ------ 226 ------ 453 ------ 376 ------ 683Z32 ------- 80 ------ 255 ------ 511 ------ 415 ------ 763Q45 ------- 90 ------ 302 ------ 605 ------ 479 ------ 890

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eh?
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Re: (Sil240)

Postby eh? » Wed Mar 07, 2007 12:28 pm

I think sydney kid made that little chart. Anyway we should know it's not accurate since some have made more 500whp on the z32 maf. The Q45 maf acutally reads less than the Z32.

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Siline
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Postby Siline » Fri Mar 23, 2007 10:14 am

Hi,You all talk about the RB25 & RB26 Engines & trannys...How about using an RB20 Tranny on a RB26?Can it be done?As far as I know, the block is the same (at least the part of it where it conects with the tranny.So, Can it be done???

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Re: (Nismochick240)

Postby chemao » Tue Mar 27, 2007 9:28 am

Don't write off a KA-T yet. Remember, A/C won't work with the RB swap, and you'll have to tear down your dash to put a new trip computer in or you'll get wierd readings. Plus, there's a new wiring harness to worry about, fitment issues, etc. Getting 400RWHP on a KA-T is relatively simple these days, and gets 25-28mpg off boost.. not to mention the luxury of a lighter overall vehicle, servicable parts. The displacement is roughly the same, at 2.4 vs 2.5. There are now stroke kits upping the vehicle to 2.5 and 2.6 litres. With lower compressoin, 500+RWHP is attainable on 93 octane, with a BROAD torque curve. Overall, KA-T is quite a bit cheaper than an RB25 swap. Just food for thought.

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eh?
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Postby eh? » Tue Mar 27, 2007 11:07 am

A built KA-T is not going to cheaper than an RB25 swap. 1)AC can work it's been done before.2) I don't know why you'd tear into the dash for a trip computer (lol)3) Search the KA forums for all the lovely snapped rods.4) The RB25 tranny is a much much stronger than the KA/SR's. Almost half the cost of the RB25 is due to it. 5) Sure the displacement is almost the same but 6 pistons see less stress than 4 pistons at the same HP level.

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Siline
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Postby Siline » Wed Mar 28, 2007 2:31 pm

What about the RB26DET with the RB20 tranny...Can it be done?Will it hold?


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