Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (Kamin) | 11:20 AM 9/15/2005 |
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thread has been updated and cleaned. please feel free to keep commenting on thisi like where its going.
-Joe 1997 240sx SE - LS1 2005 Nissan Titan SE - Tow Vehicle/Daily driver

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TOPSECRT88
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1235 posts
S14
USA USA
4-3-2005
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (Kamin) | 1:21 PM 9/15/2005 |
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Awesome sticky man. This should eliminate the 100,000 RB20 v RB25 v RB26 swap topics. We shoulda thought of this earlier.
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (BuddyClub240) | 1:36 PM 9/15/2005 |
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i agreei also think we need a RB VS SR VS KA sticky but i dunno if that would go over well in the RB forum needs to be in 240sx general haha
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Nameless EJ6

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1229 posts
What the **** do you think.
Seattle, WA
5-12-2003
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (Kamin) | 3:01 AM 9/17/2005 |
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I'll chime in soon.  Excellent sticky!
89' 240sx hatch RB26DETT in the works.http://www.myspace.com/twistingmearound
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Kansei240sx

Online
1231 posts
91 240sxHatch RB25DET, 86 AE86 Hatch 5SPD, 2008 Honda Ruckus 49cc gas saver!
Tulsa Ok
11-1-2004
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I think you guys should differentiate the series of RB motors with in the 20 and 25
Modified by Kansei240sx at 8:31 PM 10/26/2007
SI RB25DET -313rwhp on stock turbo New HOLSET HX35 build approaching
 -Racing House Shift- ( Tulsa, Oklahoma )
| Quote, originally posted by S13 240SX » | one time, i ate a whole bag of marbles |
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Eikon
Super Moderator

Online
6706 posts
'92 240sx 'vert with RB20
Green Bay WI
4-24-2004
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| « Re: (Kansei240sx) | 9:51 PM 9/20/2005 |
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I beleive this info is correct: (**Edit - info reviewed and corrected by Gawdzilla)RB20det = Top feed high impedance injectors. Stock is 270cc. Each injector will pass on about 10 ohms. Each is wired in parallel so that the total return to the ECU is ~10 ohms. RB25det = Side feed high impedance injectors. Stock is 370cc. Each injector will pass on about 10 ohms. Each is wired in parellel so that the total signal return to the ECU is ~ 10 ohms. RB26dett = Top feed Low impedance injectors. Stock is 440cc. Each injector will pass on about ~ 2 ohms. Each injector is wired in parallel to the ECU but in Series with a resistor. That resistor passes on about 7-8 ohms. The two signals add up to ~ 10 ohms returned to make the ECU happy.
Modified by Eikon at 7:55 AM 9/21/2005
Wisconsin Nissan and Import Meet and Greet. 9-20-08 Fond du Lac, WIhttp://www.240sxconvertible.com - The internet's only 240sx 'vert site!
 Joshua 1:9 "Have I not commanded you? Be strong and courageous. Do not be terrified; do not be discouraged, for the LORD your God will be with you wherever you go."
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gawdzilla
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1617 posts
none
9-18-2004
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| « Re: (Eikon) | 11:38 PM 9/20/2005 |
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| Quote, originally posted by Eikon » | | RB26dett = Top feed Low impedance injectors. Stock is 440cc. Each injector will pass on about 1.5 to 2 ohms. All injectors are wired in series so that they add up to return ~ 10 ohms to the ECU. (6 x 1.67ohms = 10 ohms)
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that explanation/calculation should be corrected... injectors are still wired in parallel, but a resistor is put in series on the +12v side of each injector. Each resistor (there are 6 in the box) is ~7 ohms, and the calculation is ~2 ohms per injector + ~7 ohms per resistor = ~9 ohms per injector pin for the ECU to ground, reducing the current going through your ECU so it doesn't fry.
Modified by gawdzilla at 12:18 AM 9/21/2005
Just your average dreamer looking for a 240
 http://forums.racebread.com
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TOPSECRT88
Offline
1235 posts
S14
USA USA
4-3-2005
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| « Re: (gawdzilla) | 8:52 PM 9/21/2005 |
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Just a quick question......exactly how much power can the stock internals hold on an RB20? Thanks
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masticatingcow

Offline
2412 posts
94 Mazda FD3S
CA
11-7-2003
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| Quote, originally posted by TOPSECRT88 » | | exactly how much power can the stock internals hold on an RB20? |
http://forums.nicoclub.com/zerothread?id=135005Maybe this will help.

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dezi
Offline
26 posts
1992 nissan 240sx
calgary ab
6-27-2005
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how much are you looking at for a custome drive shaft for the rb 25
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krayton

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936 posts
Tucson, Az
6-24-2003
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| « Re: (dezi) | 4:42 PM 9/29/2005 |
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| Quote, originally posted by dezi » | how much are you looking at for a custome drive shaft for the rb 25
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i paid 330 for mine. that was a complete driveshaft including new ends. if you use parts you have, it would be cheaper.
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JDMEnthused

Offline
1056 posts
Nissan 240SX
Rock Hill SC
7-19-2005
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hmm i think imma order me a RB20 from Jarco and stroke it out using RB26 internals( i need torque!)
Anyone Wanna Trade their Manual SW20 MR2 for my S13? NICO REGIONAL MEET MARCH 18TH, 2006 - GREENVILLE,SC... PEOPLE ARE INVITED FROM ALL OVER BUT MOST WILL BE FROM SC/NC/GA
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dsm007
Offline
99 posts
1990 nissan 240sx
Vero Beach florida
5-8-2005
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| « Re: (Eikon) | 7:30 PM 10/10/2005 |
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so I guess with| Quote, originally posted by Eikon » | | I beleive this info is correct: (**Edit - info reviewed and corrected by Gawdzilla) RB20det = Top feed high impedance injectors. Stock is 270cc. Each injector will pass on about 10 ohms. Each is wired in parallel so that the total return to the ECU is ~10 ohms. RB25det = Side feed high impedance injectors. Stock is 370cc. Each injector will pass on about 10 ohms. Each is wired in parellel so that the total signal return to the ECU is ~ 10 ohms. RB26dett = Top feed Low impedance injectors. Stock is 440cc. Each injector will pass on about ~ 2 ohms. Each injector is wired in parallel to the ECU but in Series with a resistor. That resistor passes on about 7-8 ohms. The two signals add up to ~ 10 ohms returned to make the ECU happy. Modified by Eikon at 7:55 AM 9/21/2005
| so I guess an RB20 is topfeed fuel rail,and it uses low impedance injectors,the injectors use a fat nose like a bosch?Or one that slims down and inserts inside on the head instead of like sitting on top of an o-ring,the DSM(eagle talon turbo's and eclipse's) 450's are LOW's and insert inside of the head,they would seem to be an easy one to find and could work.....anyone try them?
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masticatingcow

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2412 posts
94 Mazda FD3S
CA
11-7-2003
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| « Re: (dsm007) | 7:48 PM 10/10/2005 |
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RB20 injectors are high impedance top feed. The 26 injectors are a better match, since you need to wire in resistors parallel to the ECU anyway... and at 440cc, they're nothing to scoff at.
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: (Kansei240sx) | 12:38 PM 10/11/2005 |
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| Quote, originally posted by Kansei240sx » | | 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. |
S2's have VVT, thats what the big hump on the front timing belt cover next to the CAS is.
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Swedish Mike

Offline
1199 posts
Golf TDI, Volvo 850T5 and 200sx S13 Hatch
Sweden
9-28-2005
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How about the crank shafts, can you use RB26 crank in a 20 or 25? Only asking about lenght and bearing size, not stroke. This engines got pretty much the same block right? (Accept bore.)
Wanted: Visa or Greencard, e-mail me if you need a personal car slave. Open for ideas, husband or wife.
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eh?

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1125 posts
1-24-2004
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| « Re: (Swedish Mike) | 4:24 PM 10/15/2005 |
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| Quote, originally posted by Swedish Mike » | How about the crank shafts, can you use RB26 crank in a 20 or 25? Only asking about lenght and bearing size, not stroke. This engines got pretty much the same block right? (Accept bore.) |
Yes you can use rb26 cranks in both. No they're not the same block. RB26 supposedly had larger or stronger webbings.
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Swedish Mike

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1199 posts
Golf TDI, Volvo 850T5 and 200sx S13 Hatch
Sweden
9-28-2005
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| « Re: (eh?) | 4:37 PM 10/15/2005 |
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| Quote, originally posted by eh? » | | Yes you can use rb26 cranks in both. No they're not the same block. RB26 supposedly had larger or stronger webbings. |
Thanks! Ah, ok. But the RB20 and 25 is probably strong as hell, even the small CA18 block or the aluminum SR20 can handle a lot with forged internals. The crank thing is good, I found forged ones to the 26 but not the others. Do you know if I can use 26 cams in the 25 head? Diameter and lenght? /Mike
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Nismochick240
NICO Spokesmodel

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2011 posts
95 240sx- BONE STOCK.. for now
Greenville SC
9-7-2005
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ok i have a question. I am starting to think that ka-t is not the way i want to go. Its about the same amount of money for an rb25 but you just dont get that SKYLINE sound! hehe! So anyways, on this custom driveshaft, where can you purchase one at? I was looking at the "where did you get yours" thread and saw 300plus picked a rb25 clip from jarcoinc.com and it came with a stock driveshaft. Can I use that one or would it have to modified in someway? thanks guys!
My Wish List- Sell me your PARTS! 91 240sx Hatchback- RIP 90 240sx Hatchback- SOLD 95 240sx coupe- (bought 7/25/08) MODS so far: S Tech Springs Next: 5spd swap and Kouki front end....
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: (Nismochick240) | 2:46 PM 12/5/2005 |
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| Quote, originally posted by Nismochick240 » | | ok i have a question. I am starting to think that ka-t is not the way i want to go. Its about the same amount of money for an rb25 but you just dont get that SKYLINE sound! hehe! So anyways, on this custom driveshaft, where can you purchase one at? I was looking at the "where did you get yours" thread and saw 300plus picked a rb25 clip from jarcoinc.com and it came with a stock driveshaft. Can I use that one or would it have to modified in someway? thanks guys! |
it needs to be custom. you use the yoke (part that goes into the transmission) from the skyline/300zx and the rest needs to be shortened/made.call a local driveshaft shop for estimates, they are in the phone book. BTW that could have been easily found by searching if your seriously considering a RB swap the search function needs to be your best friend because its not anything like a KAT or SR.
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Nismochick240
NICO Spokesmodel

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2011 posts
95 240sx- BONE STOCK.. for now
Greenville SC
9-7-2005
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yea i'm searching right now for stuff on the RB. hmmm...My dad owns a machine shop. I wonder if he could shorten it. I'll search a lil bit more before i ask any questions
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Wulfgang

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908 posts
Champaign IL
10-28-2003
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Hmmm... maybe we should also get a sticky (or just another thread) where people post FACTS about the weight change. I did not weigh my S14 before or after the swap, but here's my fact:My floor jack now has MORE clearance (about 1/8") when I push it under the front lip. This is after swapping to RB20, including everything but cruise (kept stock A/C, battery location and size, SMIC, etc). In addition, I now have two PermaCool High Performance fans in front of the radiator, which probably weigh about 5 lbs more than the stock fan setup (they have steel frames and heavy motors). I also have the N1 Dual exhaust, which would seem to be heavier than stock, but I did not weigh it. At any rate, the springs don't lie. There is no arguing that the RB20 is heavier than the KA24DE, but the center of gravity must have shifted backwards a bit to make the front lip come up. Perhaps that is the extra weight of the exhaust. No matter... the balance has shifted toward the rear, and that ain't bad. [EDIT] In case I am not being clear, my basically stock RB20 swap shifted the balance favorably toward the rear wheels.
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: (Wulfgang) | 10:43 AM 12/6/2005 |
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im all about getting the weight balance bull**** taken care ofonly problem is only a very select few people have weighed their cars PROPERLEY before and after the swap. and only 1 to my knowledge has corner weighed the vehicle. i have access to corner scales at work but have never gotten around to doing my car. maybe i should..
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Shocker

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1636 posts
Youngstown Ohio
8-1-2004
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| « Re: (Kamin) | 11:56 AM 12/6/2005 |
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I was considering this idea as well, i have a local Lafarge around here.. "mining company" they have trucking scales all good to within 10 lbs, i might bring my daily up there sometime, fully wet, and put her on the scale, then take the project once thats done.. see the difference.
RETIRED NRRB Since 3-17-08 RETURNED to the NRRB 8-9-08
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Flicktitty

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3367 posts
92 Z71 / S13 Coupe
Delavan Wi
9-21-2004
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thanks!
I was here when you were still on honda-tech PROJECT 300SX
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andrewmp6
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72 posts
kentucky
9-25-2005
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2 kinda dumb questions will the rb26 main bearings fit the rb25 and will a intercooler kit for a r33 fit a s13 or will i have to make it fit
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mugengsr
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76 posts
SKYLINE GTS-T TYPE-M
Mount Pearl nfld
3-8-2005
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| « Re: (andrewmp6) | 11:04 AM 2/6/2006 |
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main bearing in all three rb`s are the same
http://WWW.NFDRIVER.COM89' NISSAN SKYLINE GTS-T (RB24) 97' NISSAN 240SX LE (RB26 SOON)
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David_NISMO
Offline
44 posts
RB26DETT powered S13
Kalamazoo MI
4-3-2006
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| « Back on Topic | 2:38 AM 4/3/2006 |
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The RB25 crank is not FULLY counter balanced. The RB26 is.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 response Stock bottom end has been taken to over 1000hp. RB25DET is 9:1 Compression, better low end torque RB26DETT is 8.5:1 Compression, bring on the boost baby!! All RB motors are basically Factory Blueprinted. I love seeing the look on people's faces when I tell them that.
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: Back on Topic (David_NISMO) | 8:39 AM 4/3/2006 |
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its individual throttle bodies, not internal. sure the engine can see 425whp without much modification but the 10,000$ pricetag for a 26 swap you could fully build a 20 or 25 and see 600whp. all engines are "blueprinted" thats the list of specifications found in any service manual that is used when the engine is assembled.
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David_NISMO
Offline
44 posts
RB26DETT powered S13
Kalamazoo MI
4-3-2006
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| « Re: Back on Topic (Kamin) | 8:50 AM 4/3/2006 |
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I'm totally borrowing this from Race BreadYes, different engines have different size bearings. Instead of a one-size-fits-all-hope-it-works system like some low budget engine manufacturers we won’t mention here (Chevrolet, Ford, etc.), Most Japanese manufactured engines run on exact clearances (blueprint). Because the machines work engine after engine after engine, tolerances vary. To make up for this, there are different bearings, pistons, etc. to choose from. For example: Standard main bearing thickness for grade 1 for the SR20 is 1.977-1.980mm and grade 6 is 1.995-1.998mm (There is only one size for undersize bearings). That’s a 0.021mm or 0.0008” difference between the thinnest and thickest shell for a total of 0.042mm or 0.0016” total difference per journal. This system works awesome in two respects; it ensures that every engine leaving the factory has spot-on clearances (Yes, this means that the RB26 is, for the most part, “blueprinted” in stock form), and it gives high performance engine builders a range of clearance options. The “old” way for “the other” engines is to mike bearing after bearing to try and find a thicker or thinner one to meet your needs. all of this is from Matt... the skyline pimp... i take no credit i just was lucky enough to get the information That's all I know. Thanks for the correction on the ITB, I was a bit tired.
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Joe
Moderator

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6009 posts
Tucson, AZ
2-9-2003
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| « Re: Back on Topic (David_NISMO) | 9:03 AM 4/3/2006 |
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dude all engine manufacturers use a specific set of clearances for bearings and wall clearances and runout and thrust and everyother thing you measure in an engine when assembling. thats what blueprinting is.
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David_NISMO
Offline
44 posts
RB26DETT powered S13
Kalamazoo MI
4-3-2006
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o.k. so what's the big deal with people having their motor's blueprinted.Does that mean that a lot of rebuilds, people used to just slap in some bearings and call it good? And those who get theirs "blueprinted" just means they took the extra time to get their tolerances as exact as they can? Note to Moderator: Thanks, and feel free to delete these last few posts as they are definately off topic
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Joe
Moderator

Offline
6009 posts
Tucson, AZ
2-9-2003
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| « Re: (David_NISMO) | 9:58 AM 4/3/2006 |
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if anyone just slaps bearings in an engine they are building, they should not be building an engine. measuring for exact tolerances is a necessity when building an engine and every good engine builder on the planet knows this.all blueprinting means is its built within the specs as the manufacturer reccomended in the service manual.
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David_NISMO
Offline
44 posts
RB26DETT powered S13
Kalamazoo MI
4-3-2006
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| « Re: (Kamin) | 10:02 AM 4/3/2006 |
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okay, thanks
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Black on Gold
Jagermeister

Offline
5594 posts
White Zenki
Cohoes NY
10-12-2005
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (TOPSECRT88) | 10:48 AM 6/12/2006 |
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| Quote, originally posted by TOPSECRT88 » | Awesome sticky man. This should eliminate the 100,000 RB20 v RB25 v RB26 swap topics. We shoulda thought of this earlier. |
Word. Thats my dilema right now
 NICO's Hockey Player
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tyndago

Offline
113 posts
3-28-2003
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| « Re: Back on Topic (David_NISMO) | 6:54 PM 6/26/2006 |
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| Quote, originally posted by David_NISMO » | | The RB25 crank is not FULLY counter balanced. The RB26 is. |
The factory 26 crank is not fully counter balanced. | Quote, originally posted by David_NISMO » | 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 response Stock 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...
--Sean Morris http://gtrusa.blogspot.com/
http://tyndago.googlepages.com/
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jimapaloooza
Offline
2 posts
Atlanta GA
6-27-2006
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton) | 11:27 PM 6/27/2006 |
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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
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TougeRBSilvia
Offline
2 posts
RB25det S13 Widebody
Del Mar CA
7-19-2006
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (krayton) | 1:00 AM 7/20/2006 |
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| Quote, originally posted by krayton » | -custom driveshaft required (unless you use RB20 tranny?) |
under the the Rb25 cons you listed the aboveok 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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gbaz77
Offline
190 posts
240sx
columbia md
3-27-2006
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| « Re: RB20DET vs RB25DET vs RB26DETT FAQ (TougeRBSilvia) | 12:45 PM 7/20/2006 |
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rb20 trans will work with s13 drive shaft. many people have done it, including myself.
you know you're driving a real car when you can let your shaft hang.

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