My quest for the RB23DET..

[nelsonmxmarc]

I am planning to put together an RB23DET.

No, i do not want an RB25 even though its more cost effective, the head flows better and will achieve greater hp for the price.

No, i do not want an RB26, i'm not interested in dealing with transmission/driveshaft swaps.. broken halfshafts or LSD failures at the track..

23 is simple - on paper.

- RB20DET Block
- RB20DET Head - with various porting to match the new flow of the motor
- RB26DETT Crank - Balanced/blueprinted and machined to match the RB20DET block
- RB26DETT Rods - stock, ideally have them shot peened if the price is good or go forged
- 4AGZE Pistons - 81 mil (Stock is 78mil)

Extras;
N1 oil pump - Increased oil flow? Or is RB20 pump sufficient?
N1 water pump - Increase water supply to sufficiently cool cylinders? Or stock sufficient?


As it is now;
- I have an RB20 block in good form - needs to be bored to 81 mil
- I have an RB20 head - needs to be ported (i'll be doing the porting over the winter) and decked which, i cant do.
- Mitch is kindly donating RB26 crank - needs to be balanced/blueprinted/collar pressed
- Mitch is also kindly donating Rb26 rods - need to fit a bronze guide to fit the 1mm different wrist pins on the 4agze pistons
- Need to purchase ACL main bearings
- Need to also purchase a gasket kit/top and bottom end
- Need to purchase cams - Tomei Poncams on the RB20 Hydraulic lifters (not going solid)
- Also need Tomei Valve springs

All tuning via Nistune..

Can be done for about 2000$..

Thoughts?

[DreadedFist]

Sounds fun. Not as fun as an rb20 crank and rods + custom pistons in an rb25 block, though. laughably short stroke + 86mm bore sounds fuuuun

But anyway, I'd try it out and see how it goes, frankenstein engines are fun.

edit: I've heard N1 water pumps aren't ideal for streeters, something about the engine not spending much time in the higher rpms or something like that causing foaming or something.... No idea if this is the case or not, just repeating what I've heard.

[M13]

N1 waterpump on a street set up would suck.

Unless you are making a track only car I'd run oem pump.


2k for all that? YOU SURE? lol

[archaeic_bloke]

ACTUALLY.... i run an N1 water pump and have done so for 2 years now... never had any heating/cooling water problems.

pretty much everyone who got a timing belt service done recently in montreal by autoworx it seems has the N1 water pump... with only $20 price difference IIRC.

the reason to go N1 as i was explained was that IF you wanted to rev high all the time, it could handle that... where as compared to the oem pump. which creates cavatation under high RPM thus resulting in air bubbles in the cooling system...

so just to clear it up once and for all.

N1 pump = no problems at normal street driving + no problem for high revving all the time
oem pump = no problems at normal street driving + potential problems for high revving

for $20 extra the choice was simple.

[M13]

ACTUALLY.... i run an N1 water pump and have done so for 2 years now... never had any heating/cooling water problems.

pretty much everyone who got a timing belt service done recently in montreal by autoworx it seems has the N1 water pump... with only $20 price difference IIRC.

the reason to go N1 as i was explained was that IF you wanted to rev high all the time, it could handle that... where as compared to the oem pump. which creates cavatation under high RPM thus resulting in air bubbles in the cooling system...

so just to clear it up once and for all.

N1 pump = no problems at normal street driving + no problem for high revving all the time
oem pump = no problems at normal street driving + potential problems for high revving

for $20 extra the choice was simple.

Good to know.


Just overheard lots of stories about having "hot spots" with N1 pump sitting in traffic, that's all.


I went to underdrive pulleys on my oem for my accessories and my temp stays awesome now.

[Skym]

I've heard the same about overheating with N1 waterpump in traffic on RB26 engine. Sometimes the overheating could be due to not bleeding cooling system properly, not enough coolant vs water, radiator fan clutch is faulty, headgasket leak, etc.

I've seen a 700hp R34 GTR idle for ages on the spot with I think was a N1 water pump (crate engine) and stock coolant temperature gauge and didn't rise above halfway (low temp thermostat makes needle sit below halfway on stock coolant temperature gauge).

But Nismo use stock waterpump on 400hp S-Tune and they must do it for a reason (street use).

N1 oilpump has metallurgy problems with gears and the result is they crack, fail. There are upgraded gears available for N1 oilpump (used in Nismo oilpump) and I would use them over stock N1 oilpump gears. Stock oilpump looks to have stronger gears than N1 oilpump.

[jdms13rhd]

I always sigh with rb20 franks. You said yourself...
"No, i do not want an RB25 even though its more cost effective, the head flows better and will achieve greater hp for the price."
So, with that said, why wouldnt the rb25det be the better choice. Cheap to replace, really dont need to be built, head is way way better so at least down the road you could go over 400hp without the head holding you back, newer electronics ecy ect.Tho I suppose if you have all the parts why not.

If you have the nistune already then 2K is reasonable depending on the head gasket, collar and what your machinist charges for the rotation assy balance. I bet you will go over your 2K mark with out a doubt but might not be too much if you do things right.

When i was a mechanic for Toyo's driver back in 08 for dmcc pro east, we built a rb25 into a 2.7L. Bored it out, decked it to ****, high compression, big cams, tdo6-25G (already had one crank grind from a previous build). It made something like 580whp but in the end it was the worse decision to be made (all by the driver wanting stupid dyno numbers). If you keep things simple you can always fix it with conventional parts. Keeping the smallest bore so your good for at least one more bore on it (rb25/26 already have 86mm). Use fresh crank which you are using I assume. And keep the piston in the block for future builds and head conversions. I could go on and on but from what I've dealt with over the years, in the end I know a simple build is easiest and most reliable. Starting with whats going to work in the long haul wont leave you regretting anything down the road.

I guess Im going a little off track as your not doing some of the mistakes he did but still, the rb25 is such a better engine then the 20, Newer harness, newer ecu. You can still use the Z32 ecu for the nistune, Just gives a build more options. I've drivin 380whp rb20's before and a stock rb25 with a turbo kit is something I would prefer personally any day. Maybe i am just a hater for rb20 :P Plus, the 20 would do much unless your high in the revs. RB25 you got the torque down low to push you through the revs faster.

Anyways, im rambling. Let us know how she goes

[Skym]

RB20DET with stock cams, adjustable camgears doesn't hold engine back until over 560hp at engine.

Have to remember, port size, valve size, etc matches bore size and RB20DET only has 78mm bore, not 86mm bore like RB25, RB26.

For RB23, probably would need to lightly port head, fit 1mm oversized Supertec valves, Tomei bronze valve guides, Tomei valves springs, more aggressive cams than Poncams (Poncams are like reground stock cams for stock ports, stock valves, stock valve springs, etc). Port size, valve diameter, cams specs work together. But best to talk to head specialist, as they would give you better advice on what to do, as can flow test head, etc.

For track work, 400hp from RB20DET engine is enough and won't need to go overboard with RB23. With correct sized turbo, good FMIC, etc and running on E85 fuel, should be easy to achieve over 400hp at engine. A HKS2530 turbo should produce full boost by 4000rpm (less with adjustable cam gears + stock cams) and over 400hp at engine while running on E85 gas.

With pure E85 fuel, some have seen 67hp bump in hp with 2psi less boost, ECU tune over normal 98 octane (downunder) pump gas (HKS GTRS turbo).

In RB20DET dyno result thread on SAU, there's a few dynochart's with RB20DET engine tuned on low octane and higher octane gas. I think was around 50hp bump in hp (post number 272 with 98 gas and 276 with E85/98 gas mix) -

http://www.skylinesaustralia.com/forums/Rb20-Turbo-Upgrade-Dyno-t103095.html&st=260

[M13]

just to stir the pot.

VQ45

[nelsonmxmarc]

Isn't that what Charles is doing? Or is it a VQ35?

Bah.. i'd love to.. But it just kills the whole concept of the vehicle IMO.. LS1 would be most ideal.

I stripped this down today.. We'll see!

[M13]

Isn't that what Charles is doing? Or is it a VQ35?

Bah.. i'd love to.. But it just kills the whole concept of the vehicle IMO.. LS1 would be most ideal.

I stripped this down today.. We'll see!

Charles is doing a VQ35 (second gen)

I'm thinking of VK's...

[Skym]

If aiming for 800whp, twin turbo VR38, twin turbo Nissan V8 would be better, as get more bottomend over RB20, RB25, RB26, RB30.

There is a stock Nissan V8 that produces around 390hp (VK50VE) from Nissan Infiniti FX. But VK56DE supposedly has iron sleeves, so is better for boosted applications and is used in NA trim in GT1 racing in R35GTR chassis (producing around 600hp).

[nelsonmxmarc]

If aiming for 800whp, twin turbo VR38, twin turbo Nissan V8 would be better, as get more bottomend over RB20, RB25, RB26, RB30.

There is a stock Nissan V8 that produces around 390hp (VK50VE) from Nissan Infiniti FX. But VK56DE supposedly has iron sleeves, so is better for boosted applications and is used in NA trim in GT1 racing in R35GTR chassis (producing around 600hp).

Too much to wrap my head around .. lol

As soon as i see race application, GT1.. 800whp.. I see a whole lot of $ signs and a real sharp pain in my chest cavity - followed by dizziness and nausea..

[Skym]

RB20DET, cheapest of the RB engines if something goes wrong (around 1k for replacement engine).

[jdms13rhd]

Too much to wrap my head around .. lol

As soon as i see race application, GT1.. 800whp.. I see a whole lot of $ signs and a real sharp pain in my chest cavity - followed by dizziness and nausea..

me too