RB20DET vs RB25DET vs RB26DETT FAQ

Discuss the RB20, RB25 and RB26 series engines.
Kalypso
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Re: (bigblak06)

Postby Kalypso » Fri Jun 26, 2009 12:02 am

bigblak06 wrote:do rb25 and rb26 you the same motor mount kit
I believe this is a yes


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HxC_Nismo
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Re: (Kalypso)

Postby HxC_Nismo » Sat Jul 11, 2009 10:03 pm

Kalypso wrote:
I believe this is a yes
sorry but there different. i know this from seeing it myself. my freind has rb25det swap(mckinney mounts) in his s13 coupe and his mounts are completely different to my RB26 mckinney mounts. now the tophat garbage mounts are suppose to have all 3 rb mounting points but the mounts are real poor qualitly from what ive seen.

Kalypso
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Re: (HxC_Nismo)

Postby Kalypso » Sat Jul 11, 2009 10:56 pm

HxC_Nismo wrote:
sorry but there different.
not a problem, im glad he got the right answer....

any answer on my original post above?

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Re: (Kalypso)

Postby stylepointzz » Sun Jul 12, 2009 12:47 pm

Kalypso wrote:
not a problem, im glad he got the right answer....

any answer on my original post above?
kalypso i got a question for you, can you get on AIM for a sec?

Kalypso
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Re: (stylepointzz)

Postby Kalypso » Sun Jul 12, 2009 5:18 pm

my comp is in bad shape and is crashing often.

email me, and when its not acting up i'll hit you back.


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Re: (Kalypso)

Postby stylepointzz » Sun Jul 12, 2009 6:39 pm

done

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amakadius
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (2fast4urass)

Postby amakadius » Mon Sep 28, 2009 3:14 pm

2fast4urass wrote:1. R34 engines are easy to find on ebay but cost around $8,000

2. can you put HICAS on a regular 240sx

3. how would i make a 240sx all wheel drive
you should be slapped for question number 3

bm3r
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (amakadius)

Postby bm3r » Wed Nov 04, 2009 8:47 pm

Anyone have dyno #'s with BPU upgrades on their RB25?

BPU upgrades would include:

Intake ManifoldFMICDPExhaust

kermit5327
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Postby kermit5327 » Thu Nov 12, 2009 9:33 pm

im sure u guys are going to eat this up but did any rbs come with auto trannys

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mmm240
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Re: (kermit5327)

Postby mmm240 » Fri Nov 13, 2009 4:55 pm

Yep

supersayianjim
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THE BOTTOM LINE

Postby supersayianjim » Sat Mar 06, 2010 8:49 am

Speaking from experience and doing my own rb20det swap by hand(my own) heres a break down for those unsure..

-1989 240sx(blown head gasket) no rust 89,000 miles(from ak) $800.00

-Rb 20det motor set(including harness,ecu,intercooler,fuel pump) $700.00(SHIPPED)

-harness work(carl h) $220.00(only thing i sent away)

-R32 crossmember$115.00 (j-hot)

-inteercooler,piping,fluids,spark plugs $3,000.00

doing this swap your self(if you have a garage do it) is not expensive.. easy to do and things fall into place.

i didnt get my diff installed yet(got a j-30) and didnt install my urethane kit. going to pull my oil pan and replace it.

the engine is very very clean. like a new one. runs like a champ(on stock psi) and is great on gas..

i don't have a tach(dont need it) and with a 5spd vss you can use it on the rb tranny and get mph readings.

if youre not good on wiring(like me) just pay to get the harness put together..

i have the send the ecu away(to carl h again) to eliminate the speed limiter(it stops at 120mph) and to adjust maps with my turbo upgrade...

geartech4
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton)

Postby geartech4 » Fri Apr 02, 2010 12:44 pm

krayton wrote:Ok here it is. Im thinking we make a faq comparing all the engines. Now we know the rb26 is top, and the rb20 is bottom. Lets just shoot some info out on all the engines to help other people decide on engines. Also lets leave price out of comparing engine to engine cause that always turns into the deciding factor anyways. Everyone shoot there feelings or good info on a specific engine. I can edit it in to make it easier. try not to get in arguments. if you disagree just say so. no need to make a fuss about it. Mod is gonna be strict on this one to make it clean. damn right i am. if this turns into a flame fest ill lock it and we will never discuss this topic again -Kamin

*this is just trying to make things a little easier for other people

General

Pros

-its an RB! from a skyline!-closest thing to a real skyline-I-6 potential-the awesome sound.

Cons

-Yes, it is more weight, around 150lbs more for a rb25 swap. the weight isnt important tho, its the weight shift. it really depends on engine/transmission and how you mount it (i.e. crossmember or aftermarket mounts), but realistically your looking at 2-3% overall weight shift. if you look at the numbers in a 3000lb car thats only a 60-90lb shift forward. just to put that in perspective, 12 gallons of gas weighs roughly 100lbs so there is more of a shift between a full and empty tank, than a RB swap. IT DOES NOT DESTROY THE WEIGHT BALANCE OF THE CAR

-Parts are still rare and expensive, but things are starting to come over-mounts or crossmember swap required

RB20

Pros

-cheap-skyline engine (?)-WD-racing was saw near 400hp with his-easy swap-free revving up to 8k is possible on stock valve train-excelent gas mileage off boost (it is a 2l after all)-can make good power with minimal mods.-sensors interchange with lots of usdm cars

Cons

-SR is easier with same potential (for your lower goal people). out of the box both will make near the same power, and upgrade easily to near the same numbers. -cheap turbo (ceramic wheel)-"weaker" tranny, nearly the same as KA/SR trans-akward intake manifold- its getting old 89-93 production years-high mileage engines need proper mantinence ie timing belts and water pumps- tiny injectors (270cc)-intake manifold flange is diffrent from rb25 (greddy manfold does not bolt on)-some rb20's can have the same problem as the early rb26 engines with the crank collar issue

RB25

Pros

-good potential (500+ on stock internals)-VVT-strong tranny (also include this when you price rb25s)

Cons

-expensive clips (when you get that strong tranny)-becoming rare and expensive parts-weak pistons ring lands-not full glory as rb26 -another lame turbo, but better than the RB20's-factory hp overrated (easily achieved with basic swap upgrades though)-side feed injectors (hard to find)-akward intake manifold-custom driveshaft required (unless you use RB20 tranny?)

RB26

Pros

-the GODZILLA of RBs-most potential of all-twin turbo stock-upwards of 300+ out the door-bullet proof

Cons

-$$$$$-$$$$$-r32 crank coller issue (kills motor)-need for rb25 tranny-hard to find r33 motors-impossible to find r34 motors-did we mention $$$$$?

RB30det hybrid

Using the higher displacement 3 L block from the RB30 engine mated to the RB25 or RB26 head can yield a very powerful engine. Here's a thread with details. zerothread?id=188136

For Specs on engines and good info also check:- http://www.meggala.com/nissanrb3css.htm
Very nice bro, you broke that down very well. I have a S14 rb25 with upgraded turbo and aem ems and some other stuff, and i love it. I made 447hp and 400 ft lbs at 23 psi. I would love to have more power but it is a monster and sounds awesome.

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Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton)

Postby S13_RB25 » Fri Apr 09, 2010 1:23 am

Ok what I was wondering, looking off of the rb30 hybird, was that can a rb26 head fit a rb25 block?? If so what are the pros and the cons?

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Coolwhip
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (S13_RB25)

Postby Coolwhip » Fri Apr 09, 2010 2:31 am

S13_RB25 wrote:Ok what I was wondering, looking off of the rb30 hybird, was that can a rb26 head fit a rb25 block?? If so what are the pros and the cons?
Biggest con... price of a RB26 will be cheaper to purchase than trying to mate a RB26 to a RB25. The end results would not justify the cost associated with the head swap. Best route to go on the RB25 block is with a R34 NEO RB25 Head.

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S13_RB25
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (Coolwhip)

Postby S13_RB25 » Fri Apr 09, 2010 10:25 am

Coolwhip wrote:
Biggest con... price of a RB26 will be cheaper to purchase than trying to mate a RB26 to a RB25. The end results would not justify the cost associated with the head swap. Best route to go on the RB25 block is with a R34 NEO RB25 Head.
. Well does the neo head flow in more air then the rb25 head it self or the valve train is better on the neo compared to the rb25.

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S13_RB25
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Re: RB20DET vs RB25DET vs RB26DETT FAQ (S13_RB25)

Postby S13_RB25 » Sat Apr 10, 2010 2:07 pm

S13_RB25 wrote:. Well does the neo head flow in more air then the rb25 head it self or the valve train is better on the neo compared to the rb25.
Ohh I forgot lol the RB25 neo has VVT. But just to make sure does that give the rb low to mid range torque right??

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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby S14Zilvia » Tue Jun 01, 2010 11:27 am

So no new information on engine weights?

One would think that an importer could throw their motor sets on a scale and document the results.

EJ8 944
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby EJ8 944 » Tue Jun 01, 2010 11:25 pm

When I got my RB26, completely stock, everything included minus trans and flywheel, UPS clocked it at 830 lbs with two wood pallets. If that helps any.

Abaker13
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Abaker13 » Sat Apr 02, 2011 8:25 am

this is an old thread but ive got myself a frankenstein rb engine with the RB20DET engine RB25DET turbo and RB26DETT cams and injectors................:)

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Vkoslak
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Vkoslak » Thu Jan 12, 2012 10:34 am

OEM Cam gears, specifically rb20det and rb26dett, are there any differences?
I had an rb20det, now I have an rb26dett, rb26dett cam with rusty adjustables, can I use my oem rb20det cam gears without issue?

Orthank
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Orthank » Sat May 26, 2012 7:18 am

RB25DET series 1
Ceramic POS Turbo like the RB20
Side feed injectors like SR20

RB25DET series 2
Plastic compressor wheel turbo
Different CAM angles and sensor

RB25DET NEO
NEO head with ome GT-R head internals (solid lifters)
different combustion chamber size
IN EX CAMs are different sizes 236°in, 232°ex
IN EX NVCS (r33 is only IN)
Traction control
Improved coil packs
Largest stock RB turbo
MT ECU is expensive and rare as hell due to different wiring loom compared to all other RB engines
Top feed injectors same as Z33 Z34 (370cc)
Highest power (STOCK) of all RB single turbo engines
Practically every head component is unique to this engine therefore sourcing parts can be a b****

outlaw7
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby outlaw7 » Mon Oct 01, 2012 6:43 pm

you know ive been doing a lot of reading on these engines and ive heard a few different issues with each engine from different threads but i dont think(i could be wrong though) anyone's compiled them into one place, i think it would be a good idea if someone knowledgeable posted all the good reliability mods and things that should be replaced or upgraded before looking for big power for each engine

i know from different places ive heard about rb25 ring landing issues and other engines ive heard something about oil starvation from the pump, but is their anything else major that should be taken into account when building these engines?
sorry if this has been covered already, still trying trying to get my bearings on this site

Miguelone
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Miguelone » Sun Nov 11, 2012 6:06 pm

Orthank wrote:RB25DET series 1
Ceramic POS Turbo like the RB20
Side feed injectors like SR20

RB25DET series 2
Plastic compressor wheel turbo
Different CAM angles and sensor

RB25DET NEO
NEO head with ome GT-R head internals (solid lifters)
different combustion chamber size
IN EX CAMs are different sizes 236°in, 232°ex
IN EX NVCS (r33 is only IN)
Traction control
Improved coil packs
Largest stock RB turbo
MT ECU is expensive and rare as hell due to different wiring loom compared to all other RB engines
Top feed injectors same as Z33 Z34 (370cc)
Highest power (STOCK) of all RB single turbo engines
Practically every head component is unique to this engine therefore sourcing parts can be a b****

It doesn't have VCT on the exhaust, only intake like R33 RB25's, it does have more aggresive stock cams though.

kiwiDET
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby kiwiDET » Sun Nov 25, 2012 10:57 pm

Fuk i feel sory for you guys, in new zealand we have more then enough rb parts lol. We get the rb 20 25 26 30, every silvia and skyline regardles of it being gtr or just gtst. Plus we get the nisan cefiro a31 and c33laurel. We have a website cald www.trademe.co.nz have a look there for parts guys.

lazyman18
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby lazyman18 » Tue Jan 08, 2013 11:27 am

This might sound like a dumb question trying to see what ppl think I should do I'm having a toss up what motor I should buy the rb20det or rb25det I'm goin to leave it stock for now and its goin to my first Nissan motor and I'm putting it in a 1976 Amc gremlin thanks for the help

Trini94
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Trini94 » Wed Oct 16, 2013 6:39 am

when u say the rb20 tranny is weak do u mean the internals (clutch flywheel and pressure plate) or is it something else?

TheRoadShark
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby TheRoadShark » Wed Oct 16, 2013 4:50 pm

Trini94 wrote:when u say the rb20 tranny is weak do u mean the internals (clutch flywheel and pressure plate) or is it something else?
Internals as in the shafts and gears and forks and synchros and stuff. The RB20 tranny is a KA tranny is an SR tranny, just different bellhousings - IIRC. The RB25 trans (same as Z32 n/a) is massive by comparison and can withstand alot more power. So it's weak by comparison, and weak for high power purposes.

32GTR
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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby 32GTR » Thu Aug 07, 2014 10:55 pm

hey guys does anyone know what the torque tension is for a rb26dett for the cams brackets??

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Re: RB20DET vs RB25DET vs RB26DETT FAQ

Postby Dontletmefall » Sun Jul 19, 2015 8:37 am

Random question. Would the standard fpr's off a rb25 bolt straight onto an rb20? Without needing an injector ungrade or tune?


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