R33 Rb30 Conversion

[Eug]

benster: from what i read, i believe the vvt would actually prove beneficial on an n/a.

i'm pretty interested in the rb30de as well... but like benster havent found much info on it.

[Benster]

Ok, so far my research has come to this:

RB30DE with 10.5 : 1 compression ratio =

- Rb30e bottom end

- Rb30e Rods

- RB25DE Pistons (Non - turbo)

- RB25DE ECU and Loom

- RB25DE AFM

RB25DE pistons will fit straight on top of the rb30e rods and crank with no aftermarket parts (except the obvious, like bearings etc).

At that compression ratio it should run on both PULP and ULP with no issues.

If you want more compression than that you'll need to run on PULP all the time because of pinging/knock issues.

If a compression ratio of more than 10.5:1 is wanted then a slight shave of the head as well as some off the block (more off the block than off the head) is needed. It's possible upto around 12.5:1 without going aftermarket... This is what I have been told... but have not confirmed... everything else up to 11:1 or so is fine with standard components.

Other people might want to confirm this but I've had enough correspondence now to believe it but don't take it as gospal because I have not yet done it myself.

When the time comes that I get the engine and start building, I'll write up an N/A specific thread and tut. Hopefully within the next 2 months or earlier.

I've also been doing a LOT of research into ECU's... The cheap and good option is to run an RB20DE/T ECU re-mapped for the RB25/30 hybrid... this is possible to do at home with the right equipment but will require a dyno to be close to perfect for each specific engine. From what I can tell currently, the RB25's ECU's cannot be re-mapped as easily and cannot give Real Time information and changes while it's running. The RB20's ECU can give realtime changes and output data.

Hope all this helps others out there... will post more as I learn more

Benster

[Benster]

EUG: I know that VVT would prove more benificial... I have no dought but this is going to be my first hybrid... I figured that I'd keep it as simple as pssible for the first time... I'm planning on building a few of these... so the next time will be with the VVT.

I like doing as much as I can by myself and I feel that the VVT is a little more bite than I can chew for the first time. I know I can just take it in to a shop and have it sorted but I'd rather learn to do it for myself... I figure, learn what I can the first time and do it right then add to that the next time round.

[meggala]

your probably est to go non vvt to start.

the fully built N/a one I saw also had individual throttle bodies it also had the 26 head. my rb25de from an r 32 feels a little flat up top but this could be a tuning issue. If I go further with it I will be doing cams and extractors 105rwkw as it is which is god for a base I would expect 130-140 rwkw from a fully tuned rb25/30

for injectors you could use the stock rb25 de ones to begin with as they are 270's so good for around 270-300 hp.

sounds good there are a couple of rb30 de's getting around one in an r31 wagon he posts in the n/a section and another in a 260z

meggala

[Benster]

Meggala: What compression ratio are you running and what pistons did you use?

[Eug]

the fully built N/a one I saw also had individual throttle bodies it also had the 26 head

I'm quite keen on this, and still looking into it (mate will be helping out big time) - Do you have any more info/pics on this Meggala? Just need to see if the power/torque gains would be worth the money involved.

It would sound absolutely siik though.

Benster I believe the RB25DE pistons are already 10:1 in the RB25, by putting on the bigger block I think you would be shaving alot of head/block.

105rwkw as it is which is god for a base

so is this the power you have for a 25/30de? any graphs? kinda interested if the NA's can still produce the torque?

[Benster]

Benster I believe the RB25DE pistons are already 10:1 in the RB25, by putting on the bigger block I think you would be shaving alot of head/block.

Is this taking into account the difference in crank and rods? I'm pretty sure that the throw is longer in an rb30.. But I could be wrong

[Eug]

just read on the VL Calai forum that changing the pistons from the rb25de into the rb30e will provide a 10.5:1 compression (approx).

I'm not entirely sure on that... but I have also read the above on the VL Forums too...

Then.. again arent some people on these forums using the NA pistons for the DET build? or is that the 30e pistons?

[Benster]

I've actually had a discussion (PM's) with a gentalmen on here who has a 25/30DE running on 25DE pistons... He knows what he's talkng about and he is running 10.5:1... The standard rb30e pistons gives 8.3:1 which is what most people use for turbo applications. Not what I'm looking for in an NA hybrid.

From my readings on here and other forums, the pistons sit differently in the bore... and the rods and crank have slightly different throws.

[Sydneykid]

I'm quite keen on this, and still looking into it (mate will be helping out big time) - Do you have any more info/pics on this Meggala? Just need to see if the power/torque gains would be worth the money involved.

It would sound absolutely siik though.

Benster I believe the RB25DE pistons are already 10:1 in the RB25, by putting on the bigger block I think you would be shaving alot of head/block.

so is this the power you have for a 25/30de? any graphs? kinda interested if the NA's can still produce the torque?

Couple of tricks here.....

From memory the R32 RB25DE (non VVT) had smaller combustion chambers than the R33 RB25DET. It has been 5 years, so don't count on it, best to measure it up first. If the RB25DE combustion chamber was the same size as the RB25DET combustion chamber, then you would get ~12 to 1 compression ratio with the extra stroke (capacity) provided by an RB30 crank ie 20% more capacity being squeezed into the same size combustion chamber.

[Cubes]

My R32 RB25DE (non VVT) head cc'd up at 62.2cc's.

It is smaller than some I've seen. 64cc's right up to 66cc's.

From my measurements the R32 head also has slightly larger valves on the inlet vs the r33 rb25.

I wrote it down in the pdf the actual measurements.

I am unable to remember off the top of my head.

[Benster]

Either way... It's still a reasonable compression ratio for NA applications, isn't it?... Just might have to run it on PULP alone... Not a huge issue. It sounds good to me... should get rid of the "flat" feeling I've been hearing about with a lot of NA's

[Cubes]

Benster, whats the compression height of the RB25DE vs the RB30E pistons?

You may have to fiddle with the headgasket + and or shave the block - to get a nice quench setup.

The only way you will get rid of the 'flat' feeling is a nice high comp RB30DET with a LARGE set of cams. For N/A minimum I would look at a nice 272duration, machine the head to accept the higher lift.

Doing all this you may as well go the rb26 head.

It Depends what your definition of flat is. I consider a stock boost level R32 or R33, modified VS 5ltr and even stock LS1 to feel rather flat.

[Benster]

Cubes: hehehe... over my head .

I've done a little reading on quench/squish but have yet to fully take the time to work it out... I'm still waiting on the funds to get the engine... I thought it was all ready to go, but the ol' man is stalling... Should be rather soon but I think he is waiting to sell the old VL station wagon (If anyone is interested PM me, Blasfamy on a skyline forum, I know).

Till that happens all measurements and the like will have to wait. Maybe someone else can give us the info from their setup?

[masTers]

Getting off topic. Is a standard NEW vl water pump fine to use? or have you all opted for a N1 pump or similar?

[StockyMcStock]

my measurements RE squish:

using RB30E pistons, deck heigh = zero.

standard nissan head gasket = 47 thou

estimated head gasket crush at full torque (head stud kit) = 5-10 thou (can't get a very accurate answer for this)

so anywhere between 42 and 37 thou is where my quench is. easily within the acceptable limits of rod/crank/piston stretch @ 7000rpm

[Eug]

Either way...  It's still a reasonable compression ratio for NA applications, isn't it?...  Just might have to run it on PULP alone...  Not a huge issue.  It sounds good to me...  should get rid of the "flat" feeling I've been hearing about with a lot of NA's

12:1 would be pretty good for NA... I run on PULP in my R33 GTS anyway.

Would be keen to find out the highest CR possible on pump fuel (98RON) without having to use an octane booster or race fuel mixtures.

[Cubes]

I used the std VL waterpump.

Constant high rev's (track work) over 6000rpm and I would seriously look at a N1 pump.

[masTers]

GT35/40's what .AR's does everyone recomend? .82 or 1.02?

Clearly due to a limited rev limit, youd want something on early? I'm chasing 300 rwkw at low rpm with minimal boost. Leaning towards the .82 with a 35mm wastegate.

[dnb]

if thats all you want get a smaller turbo dude.