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?

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

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.

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

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

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.

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

Anyone Need to confirm as opportunities for an RB25DE engine/s have come up... It may soon be bought... I want to limit any mistakes... don't mind a good learning curve but I do mind a thin back pocket.

As the title says... I'm after a Non Turbo RB25DE, preferably out of a 32... Must be in good condition (obviously) and not a thrasher. Will also need ECU, Loom, Coils and everything else to get it going for an empty engine bay. Or, if someone knows of a decent importer that will frieght it, let me know. It's for a RB30/25 Hybrid project... NA engine build up, so I'll need Pistons, Heads etc. I also have a few RB30E's laying around if anyone is interested. If you have the necessary parts and not the whole lot, let me know too. If the price is right I'll pay shipping and a small packaging fee as well. Thanks Benster

Another thing. I 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). But most of the research I've done says that it will lower to something like 7.5:1 (from memory). It did state that there was a difference between the pistons from the rb25de and the rb25det. Is any of this true? In my slow brain it makes some sense to up the compression this way in a non turbo engine for economical reasons at manufacturing... but I'm not educated enough on these matters to guess with any confidence. I'm getting more confused now? I'm assuming that if I could change the pistons over, that the rods from the rb30 will go on them? But somehow this doesn't seem right to me and it seems to easy... So I thought it best to seek advise... I am probably going to order the non VVT half cut from a 32 within the next couple of weeks and sell off what I don't use. I might just rebuild it and buy another head, I dunno. Is there much of a demand for 32 bums with internals and also gearbox's? Thanks Ben

SydneyKid, Is it possible to lengthen the stroke instead? Maybe slightly longer rods or a different Crank that will bolt on, short of having one custom made and ground? Also, are there any known issues with thinner head gaskets? Do they last, etc?

Hi everyone, I'm new to the forum and I'm currently researching some options for my fathers VL RB30... He has requested that it not be turbo'ed but the possabilty of a supercharger may come into play at some stage in the future. After reading through as much as I can on this HUGE topic I haven't found much information on using the hybrid RB's for NA purposes... from what I can tell the biggest issue will be the compression ratio. At the moment all he wants to do are some basic modifications on top of the head change... such as exhaust, larger injecters and the like... With the r32 ecu and loom and a basic setup, what and how can the compression be changed, ie. is shaving the head enough to bring the compression up? How much more performance can we expect to get Naturally Aspirated? We've been told it would be anywhere between 15% - 30% added performance, is this about right? And can we bring the compression down again if he wishes to go with a Supercharger in the future? Maybe a spacer? I'd ask the question on some of the VL forums but IMO it's a bit of a booner cult and information is sketchy at best... I find too many contradictions.... I'm a Nissan owner and have found Nissan owners to be a bit more intelligent and methodical in the ways of mechanicals. Congrats on a brilliant and FACTUAL topic... you all made my day and I've had most of my questions answered. All opinions welcome... and thanks in advance Benster.