Help; r34 rb25det neo swap

[amnash]

see post #11

So, I've ordered a full R34 GT-T RB25DET NEO swap including transmission full wiring harness and ecu.
Picked it up from http://www.jdmsource.ca/index.php I spoke to a guy named Shoaib (sho-hab) and he was super helpful. i did a couple hours of research of were to buy from and these guys had almost 100% positive feedback on multiple forums. so once i seen that i felt in good hands.

when this motor gets here i want to be ahead of the game and try to know about all the things that are going to have to be changed so that there is minimal down time.

i know there is quite a few people on here that have done a rb25 swap so im hoping you guys can help me out,
is there anything you could give me a heads up on that needs to be changed or bought to make it work?

questions of my own are;

can i use the hcr32 drive shaft with the rb25 and rb25 gear box?
how to fix the speed sensor to work?
can i use the hcr32 accelerator cable?

i have done some research, and as for the wiring ill be doing what this guy did: http://www.skylinesaustralia.com/for...r-conversions/

[cschepp]

I have all your answers. Pm me and I'll shoot you my number for help. All things said and done its not a bad swap. I wish I had done things differently when I did it but can tell you what not to do lol. Anyways shoot me a pm man

[amnash]

and what would be some things to inspect, change once receiving the motor? i was going to pull the transmission off just to have a look at the clutch, might change the spark plugs?

[Skym]

R34 NEO RB25DET CAS base ignition timing can wander (inaccurate). From what I understand, they are known to do this when cambelt is loose and can create wear / play on front of exhaust cam to CAS joint.

Some with R34 NEO RB25DET change to crank trigger kit from Ross + Link or ViPEC ECU + IAT sensor, Mac boost control solenoid.

Ross crank trigger kit -

http://blog.rossperformanceparts.com/nissan-twin-cam-trigger-kit/

[amnash]

Shoaib just gave me a call and said the transmission on the rb25 is actually a rb20 transmission someone else put on and can give me 450 back if i still want it.. or can take the transmission of a series 2 rb25 and put it on the neo for me. what should i do keep the 20 transmission or grab the rb25 trans? i was really hoping for the full swap. damn

[Skym]

On R32 chassis the RB25DET trans takes up more room in driveshaft tunnel. What this means is less air gets around gearbox to cool it and need to run a tranny oilcooler setup to solve this problem when used on racetrack. Might happen on motorway as well, as are at higher speeds.

RB20DET trans is quite strong, as it can sit behind a 413rwhp RB20DET in a R32 racecar and not suffer the above problem due to there's more room around gearbox.

This is the 413rwhp RB20DET powered racecar -

http://www.youtube.com/watch?v=-Lk1PZcHaUs

There's a writeup on the differences here (from the owner of above mentioned 413rwhp RB20DET racecar) and how he had to modify driveshaft tunnel to get more air around gearbox, can run other gearbox's, etc -

http://ljracing.co.nz/

You'll need to click on months under calendar to scroll back to where he mentions the problems he had with both RB20, RB25 gearboxes.

As long as you don't hard launch car on slicks and trans hasn't got bearing, synchro's, oilseal problems, a RB20DET transmission should last. Also avoid quick shifters, as they supposedly can cause damage to synchro's.

Nismo solid shifter doesn't have this problem and they explain how the quick shifters cause problems with synchro's -

http://www.nismo.co.jp/en/products/competition/mission/solid.html

[Bee-RSkyline]

My rb20 transmissions didn't hold that kind of power, maybe just my poor luck with cars, but I went through 2.

Ended up with a modified GTR transmission and custom driveshaft to hold the power. no problems now.

It all depends how you will be driving the car, and if you are planning to modify the engine for more power.

[Skym]

That's behind a RB20DET that's not known for huge amounts of torque. Behind a RB25, RB26 or RB30 engine with decent amount of torque a RB20DET transmission might not last long. Don't think it's stronger than a S14 gearbox which seems to share similar parts, but I gather a SR20DET has more torque than a RB20DET engine.

Also he said his RB20DET gearbox had done around I think was 130,000km? But he doesn't seem to launch hard at start of races, so probably explains why it didn't fail. RB20DET trans always seems to fail on dragstrip.

I agree, stock GTR gearbox with transfer case cut off, plate over hole, welded up, etc is another option. If fit GTR differential (subframe, halfshaft's, diffhead, shocks, etc) probably can use stock GTR propshaft.

But can use the RB25DET transmission, etc, just have to fix the weak points when put into a R32 chassis (overheating).

[amnash]

ok so i now have the motor and im going to keep using this thread for all of my questions. i have a ton of questions and all of them will be accompanied by a picture. i wish i knew someone that knew a lot about rb25s close by so that they could just come help me for half an hour and answer all my questions. would be a lot faster then all of this online stuff. so if you what something is just mention it and then ill remove the picture to make the thread smaller. here we go..

[speed]

I might be driving my gtr over to nanaimo this weekend but your still quite long ways from where I'll be!

[amnash]

1) this is my idle control valve i believe. im wondering why there is 3 coolant lines going into it? this seems like a stupid design and makes no sense to me.


2) this is a oem looking sensor thats right on the turbo. whats it used for on the r34? and can i use this on the r32?


3) these are rigid tubes used for the recirc bov and the pcv valve. the one for the bov has a hole in it that looks oem and was made that way. why would there be a hole there? plug it or leave it?


4) this is the rubber pcv valve tubing, it had this metal thing hanging out. what is it??(looks like a restrictor?) i just pushed it in and then connected the hose.


5) this is a vacuum line, i followed it behind the belt cover and then up to intake manifold. what would that be for?


6) this is the wastegate actuator. vacuum line was plugged. i removed the 2 vacuum lines and check valve thingy and put on a new piece of vacuum line. i checked turbo(45v1) for damage because of this and it seems fine with no play. anything else i should check? im thinking it was boosted to **** because of this


7) this is a "T" fitting in the vacuum line from fuel dampener to manifold. what would that of been used for? i removed and put one piece new.


8) this is on the oem oil cooler. some kind of sensor. what is it? can i use it?


9) this is on the oem oil cooler. electrical pin. what supposed to connect to it?


10) what is this electrical valve? it has 2 vacuum lines going to it. one line goes to intake manifold. and the other once wasnt hooked up anywhere and there's no obvious spot for it.


11) *bonus question* can someone explain the throttle body system on this engine? its f**in huge and there's two plates. one of the plates remains open.

[amnash]

to try keep this tidy and easy to follow, could you guys try and write it out like this
1)
2)
3)
4)
5) ....etc

thanks fellas

[LettoGTST]

(1) Dont remember
(2) My RB25 Neo did not have that sensor, its looks aftermarket because it looks like someone cut the hole through the heat shield for the sensor
(3)There use to be a nipple for a vacuum line on the pipe( I just deleted the recirculation pipe)
(4)I just left mine the way it was
(5)The Vacuum line by the timing belt cover was for the factory R34 power steering pump
(6)The lines off your wastegate and intake elbow went to the factory Boost controller Also there should be a turbo pressure sensor to go with it
(7)The "T" might be for a aftermarket map sensor or a boost gauge, could be anything
(8)I dont remember off hand what the sensor is for
(9)If your putting the engine into a R32 the plug is on the chunk of harness on the battery side, there should be a black single pin connector for it
(10)The Valve you have there is for venting to your charcoal canister
(11) The second throttle body is for Cruise control and your TCS

Anything else just ask!

[amnash]

wow thanks letto, so all the sensors/valves and stuff at the back of the engine by #10 can i just delete some of those? im not running a charcoal canister. what can be removed and just capped there and have everything still running fine?

[Volden]

i capped most of that stuff you mentioned in my swap. i will look tonight when i get home about #8
i removed alot of emission crap and extra wiring with mine. its been so long since i have seen a neo swap. props to you ! your going to love it once its done.