Pros & Cons of the RB Swap

Pros & Cons of the RB Swap
Topic Started: Nov 5 2009, 03:33 PM (1,637 Views)
Deleted User	Nov 5 2009, 03:33 PM Post #1
Deleted User	Well first of all, if you are considering an RB swap do realize that you are in for a project and a half. RB swapping an s-chassis requires a good amount of work and a lot of time. But I am going to list the pros and cons of each RB engine so you can make your decision on which one you want. quick note about the RB20, there are 2 versions of it that can be found, the red-top and the silver-top. The silver-top produces more HP stock and is a stronger engine, so my list below is for that motor, not the red-top. RB20DET PROS: Cheap to buy and install Good power and torque Lightest RB swap Rev happy (due to a very short stroke) Very strong bottom end Great power potential stock (~400hp+) Loves to be abused (it takes it like a champ!) CONS: Its a 2.0L 6 cylinder Ceramic Turbo (max psi is about 13.5 safely, stock is 10) Outdated engine Aftermarket support is limited Head design is not the greatest Torqueless wonder (no real power below 4000RPM) Transmission is weak All in all the RB20 is the best bang for the buck, its cheap and produces a good amount of useable power in stock form. Also, with relatively little work this motor can be in the mid to high 300hp range. But, like i said, it is a torqueless wonder, the RB20 makes almost no power before 4000RPM but it will wrap out RPMs like they were yesterdays news making it a great mid to high range powerband motor. There is discussion about the RB oiling issue plaguing the RB20 as well as the RB25, I personally have never heard of the 20 having an oiling issue but my recommendation would be to check your motor out for any problems. Read the link i have posted under RB25 for more info. Some turbo upgrade info for the RB20DET http://hubpages.com/hub/RB20-Turbo-Upgrades RB25DET (Series 1 and 2) PROS: More hp stock than RB20 2.5L 6 cylinder rather than a 2.0 Has low end torque Very smooth powerband (pulls great all the way through the RPM range) Stronger Transmission Very strong bottom end More efficient head design ~400hp on stock internals Newer! More aftermarket support Series 2 motor uses a Coil on Plug setup (no igniter) Only RB to have Variable Cam Timing Has that "Skyline" exhaust note that everybody loves CONS: Still has ceramic turbo Higher compression ratio than RB20 (cannot be boosted as high in stock form. 7PSI stock as opposed to 10 Series 2 turbo uses a nylon compressor wheel (stay away from high boost) More expensive Heavier Not as rev happy as the RB20 Not as loving of abuse as the RB20 or RB26 OILING ISSUES!!! (not going to write about it, it would take up too much space. so click the link below to find out more) http://www.skylinesaustralia.com/forums/Comman-Problems-Rb25det-t249968.html The RB25DET is an incredible engine. It has a very smooth powerband, and pulls very good even stock. This engine with some minor upgrades makes great power for the street at a good RPM range. But due to a higher compression ratio than the RB20, the RB25 cannot be boosted as high in stock form. Also, the Series 2 turbo is still just as weak as the RB20 turbo and should not be boosted to 1 bar (14.7psi) due to the risk of the turbo blowing. RB26DETT (The Godzilla Engine) I really dont need to say much here, if you don't know about the RB26 then you should not even be reading this thread. PROS: It's a fking monster Twin-Turbo Steel turbine wheels 400HP out of the box (with the boost restrictor removed) Cast iron block with aluminum head Bulletproof bottom end Best head design of any RB 650HP+ on stock internals No oiling issues Best aftermarket support Best RB engine ever produced. Period. Can rev out to 10,000RPM on a good build CONS: VERY expensive (~$12,000USD to swap into an S-Chassis) Difficult to swap Expensive parts Other than cost. The RB26 really doesnt have any cons. Its an indestructible motor that will take abuse all day long and love it. It is a high horsepower motor that will handle just about anything you throw at it. It is called the Godzilla motor for a reason. All in all, RB engines are excellent engines, but you will pay for them as parts are not cheap and most OEM parts are very rare (especially for the RB20). My advice if you plan on buying an RB, get your hands on all the OEM parts you can and stock up on them until you decide to rebuild, or have to rebuild. This write-up does not have all the information in the world on it, I highly advise anyone looking to purchase an RB engine to do your research before hand. Make sure you know what you are getting into. And remember, the RB was never sold in the States, so don't expect to go into AutoZone and start buying gaskets and what not, you will have to order them from an aftermarket parts company or direct from Nissan. Heres the RB Engine Wiki. Has some facts and specs about the different RB engines, as well as the other RB models that I did not talk about. Good info. http://en.wikipedia.org/wiki/Nissan_RB_engine I will post more in here when I have the time
Deleted User


240Smoke	Nov 5 2009, 04:04 PM Post #2
[]D [] []\/[] []D Posts: 4,419 Group: Members Member #52 Joined: March 8, 2009 My Ride: 1992 RPS13, 1992 240SX	I didnt know there was a con when swapping the KA out to an RB? lol.



Rummel Autosport	Nov 23 2009, 12:52 PM Post #3
Posts: 239 Group: Vendor Member #242 Joined: October 20, 2009 Location: Q-town, representing the Bunker-Mall My Ride: 92 Skyline GTR, 89' 240SX with RB26DETT not yet installed.	That has a lot of ...... I don't want to say wrong, but somewhat missleading, or confusing info in it. It sounds like it was coming from a good place, but to someone that is not familiar with these motors it might be a bit missleading. Oiling issues on any RB motor depend on the size of the engine, and the year, and these requirements change if you build the motor and increase the REV limit.



S13_Nater	Nov 23 2009, 03:10 PM Post #4
ChiNegro Posts: 628 Group: Members Member #110 Joined: June 10, 2009 Location: Wilmington, DE My Ride: 1989 240sx Coupe	you know something i found out today wen researching rb's the crank collar issue



Deleted User	Nov 23 2009, 03:26 PM Post #5
Deleted User	good read....
Deleted User


Deleted User	Nov 23 2009, 03:28 PM Post #6
Deleted User	S13_Nater Nov 23 2009, 03:10 PM you know something i found out today wen researching rb's the crank collar issue that is the oiling issue i wrote about. it is caused by the crank collar.
Deleted User


Rummel Autosport	Nov 23 2009, 05:15 PM Post #7
Posts: 239 Group: Vendor Member #242 Joined: October 20, 2009 Location: Q-town, representing the Bunker-Mall My Ride: 92 Skyline GTR, 89' 240SX with RB26DETT not yet installed.	Short oil pump drive collar, which is on any RB if it is a pre 93ish engine, is what leads to catastrophic oil pressure loss. This can be fixed a number of different ways, if it appears it needs to be. A stock bottom end RB20, dont bother, a modded higher revving RB26 that you have invested a lot of money into, that is worth the insurance. I have never had, nor have I worked on, or even met anyone that had this fail on an RB20, or RB25 since most RB25s had this problem fixed. Any R33 RB26 will also have the problem fixed.



S13_Nater	Nov 23 2009, 10:45 PM Post #8
ChiNegro Posts: 628 Group: Members Member #110 Joined: June 10, 2009 Location: Wilmington, DE My Ride: 1989 240sx Coupe	Didn't the early RB26's in the R32's have this issue too according to what i read.



Rummel Autosport	Nov 26 2009, 01:46 PM Post #9
Posts: 239 Group: Vendor Member #242 Joined: October 20, 2009 Location: Q-town, representing the Bunker-Mall My Ride: 92 Skyline GTR, 89' 240SX with RB26DETT not yet installed.	Yes early RB26s. Thats why I said R33 motors have the problem fixed.



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