Source : Stony (240Z with RB26DETT...
http://hybridz.org)
How to swap an rb engine into a z
First you need to figure out what engine and performance you want…
The rb-20 motor is a 2 liter turbo or N/A motor both are considerably stronger then the L motor
The rb-25 is basically the same as the 2.l but has more displacement and can be modded to handle more HP in its stock internal form. A friend of mine took a stock N/A rb25, threw a turbo on it and ran the hell out of it for a year and a half at very high boost levels before he put a hole in a piston!!!! Car dyno’d at 430 RWHP on a chassis dyno
The rb-26 DETT comes twin turbo only… it is a detuned Japan touring car motor. With simple upgrade like a chip , intake, and exhaust you can be well over 300hp. The bottom end is built to with stand 600hp before needing upgrade forged pistons and rods.
This motor is considerably different then the 2.0 and 2.5. The only thing that is swappable between the 2.5 and 2.6 is the block and that has to be bored and some other mods done to fit the head. If possible you want to stick with the 2.6 block especially if your going to build it up for a lot of power… the 2.6 block is a lot stronger
Ill start with the rb-26 swap as this is what I did.
I purchased the majority of the parts from one shop on Okinawa (HAAS) and got a pretty good deal on everything. Here’s what I got
Rb-26dett, trust FMIC, r-33 GTS-T 5 speed tranny, r-200 LSD, drive shaft that I needed, and a bunch of other stuff I ended up not using. 3500.00
Things I didn’t use…
stock computer, stock wire harness, stock oil pan
First thing I did was remove the GTR oil pan , installed the pickup / oil pan from the z-31. Then I installed the z-31 motor mounts. I installed the motor with tranny bolted up. We then took the stock mount from the L tranny cut it up and welding it back together. Then cut and shaped the chassis part of the mounts and bolted everything together. Once everything was in place where I wanted it we tacked it in, then removed everything and welded it all up. It wasn’t till later that we figured out the drive shaft would fit without cutting it ;> I was told this but had never seen it done so I wasn’t sure. From this point it was a matter of fabricating all the stuff to make the engine work.
Other parts I bought from different sources…
Exhaust (Kakimoto) I ordered this thru Matt at motorworx on Okinawa.
http://www.motorworx.tv/
I bought the GTR down pipe from the kinser auto hobby shop USMC then had it modified by matt to fit the 260z install. basically cut it in half then welded a couple of bends in it to fit
Fuel pump I bought off of ebay … bosche 600hp injection pump.
The oil pan and sump I got out of a Japan spec Z-31 rb20det 300zx in a junk yard. the front of the oil pan had to be cut out and lowered to clear the bearing retainers in the 2.6. The block has a spot for a rear pickup but it is not drilled out so I had to use the front port on the 2.6. This meant I had to make a custom oil pickup that went from the front of the motor to the rear.
If you use the rb-25 block this is not necessary, in fact everything from the Z-31 is bolt in!!!!
I purchased the SDS EMS thru matt at motorworx…. I can not say enough about matt… he is awesome and very meticulous… if he wouldn’t do it on his own car he wont tell you or do it to your car
Labor
I did pretty much all the manual labor like installing the motor, tranny, diff, and a bunch of other stuff associated with a body restoration;>
Matt at Motorworx did all the welding on my car…to include the exhaust, down pipe, intercooler in and out mods, and piping
He modified my fuel tank pickup to a –8 for better fuel delivery.
He also did the SDS install, and setup. Which without changing anything the car ran a best 11.138 @ 121!!!!!!
Ok to summarize… with all the parts above everything bolts in
You’ll need to make tranny mounts, and all the associated welding for the exhaust and intercooler piping. From there it just like any other swap.
The motor sits a little fwd with the z-31 mounts so if your looking for optimal handling you’ll need to make custom mounts to set the motor down and back a bit. You’ll also need a custom drive shaft.
I didn’t think the GTR drive train would fit in the car but it will…. but this places the motor so far fwd the radiator has to be mounted on the other side of the core support!!!! But does give the car AWD ;>
The rb-20 is an ok swap but only provides minimal power upgrade from a turbo l-28
The rb-25 is a bit better and can handle more power with its stock internals.
The rb-26 is the ultimate in reliability and performance…. This motor can be built to 600+ HP and be driven to work everyday with a full exhaust. (no earplugs;>)
For anyone considering this mod if you’re in Japan or Australia or have a lot of money go for it…. Anywhere else id go with v-8 or Toyota 2jz TT which is a very similar in performance to the rb26
, $2500-$3500 for RB25DET front cut with manual tranny 
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