R34 Rb20De Neo - Need Specs

[datsunranger]

First time posting, i would just like to thank you in advance for any help you have to offer. I purchased a rb20de Neo from a 1998 R34, I have had a difficult time finding any info on the US forums, seems i have a very odd engine. From what I have read, it looks like the engine never really made it to Australia either, but you guys seem way more informed when it comes to anything RB and would be my best bet for finding info.

I'm trying to build a high comp rb20de Neo engine and wanted to know a few things to calculate compression, like connecting rod length, deck clearance, cylinder head chamber volume...etc.

Does anyone have specs for the lift and duration of the cams?

Motor was in great condition when i received it, however the Crankshaft position sensor mounted in the transmission bellhousing was damaged, does anyone know a part number for this or what other motor would have an interchangeable sensor.

thanks

[screamin']

I'm building one of these for competition use at the moment, to replace my previous R32 RB20DE. I'm in New Zealand and it seems the 2.0 Neo engine made it out here in a few auto R34's.

The Neo is really quite different to the earlier version, with much lighter crank, rods and pistons. The pistons also run just one compression ring, so things look good for a high revving well ballanced engine once we are done. I am not sure on the factory specs of the motor because we are modifying everything to suit my R32 head, so stock measurements in this area are not critical.

Similar to my previous engine the block will be decked and a little more taken off the head. Due to the way the valves sit in the cumbustion chamber hopes to get mega compression are out the window, but hopefully the torque I will miss out on can be made up with rev's -I like that kind of comprimise!

Instead of trying to bash out some calc's on this, we decided to give the parts to the machine shop and get them to go as far as practable with what we have considering the car won't do high mileage. I'm picking the single compression ring will need to be replaced fairly regulary to keep it on song, but it's not a bad thing to get in there every now and then to check how it is all going.

What are your plans for the Neo? Street car?

[datsunranger]

Well i want a street car, but my definition of street car seems to differ from most of my friends. I'm running it in my 280z, stripped down to 952kg(2100lbs), with a subaru 4.44 final drive. The motor was inexpensive, revs high for stock application, and was almost a bolt in swap. I like n/a high rev motors; simply wanted to see what i could get out of it with light machine work. Raise compression, make some extractors(headers), maybe loose the old intake manifold and port match a greddy style intake if at all possible.

Was hoping to take advantage of the cam phasing to make up for some drivability, especially if i were to upgrade the cams.

Not looking to make the worlds most powerful rb20de, just wanted a responsive and rev happy motor with decent power.

Had no idea the pistons only had one compression ring, pretty interesting.

[screamin']

Sounds like fun! If you are really keen, consider some side draft Webbers or independent throttle bodies. I run itb's and some big cams, and oh the sound! More mild cams and itb's would be great street cred emitting sound from an early Zed.

The Neo has the right turning mass for rev's, so I'm keen to see what it will pull if my old RB20DE managed 8,600rpm for six years of rallying.

With a car as light as a 280 I would just look at taking some off the head, induction and exhaust mods, a tune and see how it goes. From there decide if you want to part with a lot more cash for a little more gain.

[iseekool]

IMHO

For constant high revs, I'd recommend an upgrade of oil and water pumps to N1 items as a start before even thinking about performance tuning. I'd also say an oil cooler will be of benefit.

For such a light car under 1000kg, I'd keep the mods minor to start with. Headers, high flow cat and a K&N type high flow panel filter. Run full syn 10w30 engine oil. Don't run an exhaust bigger than 2.5"

Stock RB (both na and turbo) engines sound great at high RPMs with the right exhaust.

GReddy style manifold will be useless on such an application, as you don't have a turbo. Better wth sticking with stock manifold with the variable length intake manifold or go all the way to ITBs.

From memory (somewhere on these forums) someone mentioned the RB20DE NEO/25DE NEO have smaller CC in the heads.

Budget permitting, shave the head slightly to increase the compression, upgrade injectors from an RB25DE NEO and run an aftermarket ECU.