# thinking about and RB conversion



## VG30DE (Jul 15, 2004)

Im going to be buying a 89 s13 fastback and I want to do a swap for an RB motor but I cant decide on the 25t or the 26tt, if I got the 2.6 I would probly bore it and make it a 3.0 after I rebuilt my funds, I dont need to be able to turn super fast so im not worried about the extra wieght. I am going to do the swap myself but I am not to educated on these motors yet or the swaps so if anyone has done one of these swaps or has any helpful info I will be very greatful


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## azRPS13 (Jun 7, 2003)

Well... IMO I'd go with the 25... It can easily be tuned to the likes of the 26... No mods or conversions needed... Plus 1 big turbo is better than 2 small ones anyday. With the 26 you would either have to go Right Hand Drive or get the conversion kit to clear the second turbo. You are going to need 25 parts to work with the rear wheel drive unless you want to do 4 wheel drive. It will be cheaper to go with the 25 and you can get equal power.


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## Nizmodore (May 9, 2003)

VG30DE said:


> Im going to be buying a 89 s13 fastback and I want to do a swap for an RB motor but I cant decide on the 25t or the 26tt, if I got the 2.6 I would probly bore it and make it a 3.0 after I rebuilt my funds, I dont need to be able to turn super fast so im not worried about the extra wieght. I am going to do the swap myself but I am not to educated on these motors yet or the swaps so if anyone has done one of these swaps or has any helpful info I will be very greatful


You don't "bore' the motor out, as 86mm bore is quite close to the blocks limit (thats what they start at), You purchase a VL Commodore Serries 2 N/A RB30E motor and put the head (be it 2.5 or 2.6litre) on it......turf the RB25/26 block and crank etc....

The largest you can get a RB motor out as far as capacity wise is 3.1 litres...there was a rumor of a 3.6 litre stroker kit floating around in Australia (remember we got RB motors before the Japanese) I never heard any more of it, and Holden wanted a 4.2 litre or there abouts RB motor for their VN commodore but alas the yen went up and Nissan where not interested....so they put a shitty Buick based V6 in >: 

And yes I have a Twin cam RB30 on the stand for my VL Commodore  Life is good..... :thumbup: My motor is a Serries 2 RB30E with stock internals, and a Head of a 1994 R33 Skyline RB25DE (non turbo) with vvt. If you have one of these heads you need to block of the vvt oil feed in the head, and run a aux oil line from the high pressure side of the oil pump (due to the fact that that the 3 litre block doesn't have a oil feed for vvt) I havent finished my Twin cam conversion, hell I just paid off all the bits.....I'll have to start a sticky on building one! 

The only market that got 3 Litre RB motor's was Australia/New Zealand. The RB's where designed under contract for Holden (Holden is not owned by Nissan) for their VL Commodores....you have to get someone down here to send you a RB30 motor to the States.... 

As for other stuff read this thread of mine 

http://www.nissanforums.com/showthread.php?t=46679


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