Rb25det Neo Help

[mamooon]

so.....

this is my first rb25det neo (RWD) engine and i will fix it in a peugeot 504 - 76

but i have some questions to the rb specialist i know there is a lot of info. on the internet for this engines but i'm totally lost and i want some one to simply answer this questions :

1- what is difference (mechanically and electrically ) between the neo and non neo engines?

2- did the neo engines came in R33 or it only came in R34 and starting from what models???

3- how can i make sure that my engine is originally a DET engine ???

4- what is the difference between s1 and s2 engines?

5- what is the ECU serial number which matches my Rb25 det neo (because i got the engine with a harness only )?

6- i bought an rb20 gear box with this engine because of the lake of resources (money) is this will be a problem in the future ?

7- what is the difference between an automatic and a manual transmission engine harness and how can i know which harness i have?

8- i need a full wiring diagram for this engine as the wiring is the most challenging thing for me (fixing the motor into the car is the easy part).

this acutely summon my doubts for now

any help from you guys will be very appreciated

if any one have any info for me for fixing an rb engine into my car please let me know

__________________________ proud to be a RB owner ____________________________

[GTSBoy]

Differences mechanically:

1. Neos have RB26 rods, N1 oil pumps. These hardly make much if any difference but they are both that little bit better than the older 25.

2. The Neo has solid lifters, so again like the RB26 rather than the older 25s.

3. These go with a totally redesigned head that doesn't look much different but has a smaller combustion chamber, different valve angle, different ports, which were all directed around making the engine make more power and torque for less fuel consumption. The "Neo" tag is Nissan's name for engine technologies that allowed then to get engines into certain low emissions categories in Japan.

Differences electrically:

There are lots. Some things are compatible back to the S2 engines, some things are totally new. Many of the electrical differences between S1 and S2 25s carry over. So, coils with ignitors inbuilt, newer CAS

1. Neos have traction control (unless they're from a Stagea) so the throttlebody is different, with an actuator motor and extra sensor.

2. Neos have a boost sensor connected to the crossover pipe (that the ECU uses for making some fuelling decisions).

3. Neos have a totally different ECU to the older 25s. If auto, then the TCU is in the ECU.

4. Lots of fiddly little differences around the loom for air-con, etc etc.

No Neos in R33. There were some halfway house looking engines that are a bit confusing. But basically Neos only in R34s and the equivalent Stageas.

You can't easily tell if someone has slapped turbo gear onto an NA engine. The factory turbos have the correct turbo oil drain, oil supply and water supply connections for the turbo, that possibly won't have been done properly on an NA conversion. A compression test could show up sky high compression on an NA Neo.

S1 engines are like an RB20 + VCT. S2 engines have coils with ignitors built in, newer CAS, a few other changes. Otherwise there is precious little difference between them. Some googling on your behalf will find heaps on info on this topic.

ECU part numbers can be googled very easily.

RB20 turbo gear box will only take the torque of a 25 for so long before it will die. You need a bigger box.

There is no difference between the engine harnesses of auto and manual cars, except that of course the Neo has the wiring for the tranny coming out of the ECU plug.

Wiring diagrams are google-able.

[iruvyouskyrine]

Also,

Oh wait nope. That's the most comprehensive standard vs neo RB25 comparison you will ever find.

If you have the inlet manifold off you can see than non turbo Neos have quite small Intake ports compared to the standard turbo ones. Searching google for comparison pics with help you with identifying what you have.

Props to GTSboy for such a detailed response.

[GTSBoy]

[AngryRB]

so how would it go with a neo head and intake mani bolted onto a R33 S2, will all the wiring be compatible or would you have to bolt the S2 mani onto the neo head??

[GTSBoy]

Stratospheric CR ignored?

[Huzqld]

Also,

Oh wait nope. That's the most comprehensive standard vs neo RB25 comparison you will ever find.

If you have the inlet manifold off you can see than non turbo Neos have quite small Intake ports compared to the standard turbo ones. Searching google for comparison pics with help you with identifying what you have.

Props to GTSboy for such a detailed response.

If its a DET head it will have 5l8 on it somewhere. If DE head its 5l7.

I think..?

[AngryRB]

Stratospheric CR ignored?

Yes, as im doing an RB30 bottom end , just thinking about the neo head and manifold mating with the S2 power fc and wires sensors etc etc

I know the Cas is different..

Edited August 10, 2015 by AngryRB

[GTSBoy]

Well.....thinking cap on......um. The only sensor on the head other than the CAS is the TPS. If the Neo one wasn't compatible for some bizarre reason, then I'm sure you could find a way to either put an S2 TPS onto the Neo TB, or better yet, just drop a complete S2 TB onto the Neo plenum and piss off the TCS throttle and crossover.

The VCT is just a solenoid, so can't see that being a problem. Injectors are different, but the ECU shouldn't care. All the other sensors (what's left anyway? AFM, water temp, knock....) are independent of your choice of head. So, can't see it being an enormous issue.

[mamooon]

oh yaaaaah those are the info i was looking for thanks (GTSBoy) .....

And yes you are right the first thing i noticed is that the turbo oil drain has a connection in the engine block not in the oil sump so i think i'm a little bit relieved that this is actually a DTE engine until i get the engine from Dubai and open the intake and exhaust manifold and compare the ports sizes and i can make a compression test after i done the wiring to be completely sure about that .

for identifying a s1 or s2 wiring .. beside the big ignition box you can find in the s1 (which is very noticeable ) i found out that the MAP sensor in s1 have 5 wires connection and in s2 it has only 3 wires.

and after googling for some time i found this great site for identifying the ECU

http://www.rbparts.co.nz/342746/

for the rb20 gear box i hope it lasts some time before the big boooooom ,, then i will get the big box of the 25's

thx for all for the great feed back and if any one have some tips for this project (Peugeot 504 with a RB25DET ) pleas let me know