i recently bought a rb30et block and i have a few questions: before i start i am just going to say that labour costs will be kept to a minimum because i am going to do the majority of work myslef all except machining etc i am planning on building up this engine and converting my n/a vl to turbo, i am thinking about buying an rb25de engine from an import wreckers and using the head, oil pump, sump. oil pickup, and manifolds from it to put on my bare turbo block is this a good idea? is it possible to use the crankshaft and the bearing caps from the rb25 too? how does the rb25de oil pump flow when compared to the rb30et? would i be better off running a gtr pump form nispares or something? i have been reading the forums and have come to the conclusion that if i put the rb25 head on my block and use standard vlt pistons that the compression will be lower than 7.8:1, i was thinking that maybe a good compression ratio might be 8 or 8.5:1, what pistons should i use to achieve that figure? i am either going to run a kalmaker management system or go to straight as and use a spark only computer, what is reccomended? after all this i am not sure what sort of transmission i should use, and i would probably have to replace my diff with something stronger after a short while too oh btw, i am hoping to be running a highflow t3, or maybe a larger GT series garrett turbo, any suggestions?

i would assume that you would be better off to change the cams to something that suits the pwoer delivery of a turbo engine, as opposed to a n/a engine. not sure about the rest without thinking properly about it Some original photos have not been recovered yet.

thanks sin, i hadnt even thought about that, i assumed that everyone that went twin cam just used the standard ones i think i will have to give this alot of thought

I didn't think that you could use Kalmaker software with the VL computer. If you are on a low budget and don't want massive amounts of power why don't you just buy a RB25DET front cut and transplant it into your car?

bump can anyone help me out? maybe go into a bit more detail?

from memory if you use n/a pistons with an rb25de head you get 8.7:1 compression. dont know bout the rb25de oil pump but i'd get an RB30ET or GTR one... cant hurt. apparently the n/a rb30 one works fine with a turbo but i wouldnt be counting on something not going wrong. musta been a reson they put a better one on the turbos. put a VL Turbo diff in or if you have trouble finding one there is always a 9" conversion. I havent heard of the kalmaker used on an RB motor yet (although there are kits available somewhere). I presume it'd do the job quite well, in fact its one i may look in to sometime. 6B00ST (turbo ford 4L) uses one i think so you can talk to him on performance forums. BTW for those that dont know the kalmaker is software to program a modified delco (VN onwards, camira and lots of others) ECU and someone has made a loom to fit the RB's.

thanks natho, i was just wondering when you say n/a pistons, do you mean the rb25 pistons or rb30 ones?

i mean the n/a rb30 pistons in an n/a rb30 block. a stock n/a vl bottom end for example. there is some info here (http://trinity.frontierisp.net.au/~rowan/twincam.htm). The info i got about the compression ratio is from a magazine i had lying around though.

8.3:1 is the comp ratio from a mag artical, thats RB30E pistons and a RB25DE head. The Rb25DE oil pump is very good, better than a RB30ET pump, I did a comparrison to a GTR pump here http://www.users.bigpond.com/allanreynolds/twinvl/ RB25DE crank has a shorter stroke and smaller big end bearings, it can't be used. Also the series 2 n/a and turbo blocks are identical so there's no need to buy a turbo block for to build a turbo engine, hope u didn't pay extra... And u have to use a ECU that can read a nissan CAS and drive multi coils. Most of the bigger 1's do this. The Vlt MX7 manual gearbox's will handle the power. Diff, u need something good! A spool locker and 28 spline axles in the borg warner rearend should be ok if your kind. T04 turbo is a minium, get a garrett. U can use a RB20DET exhaust manifold as a cheaper option to a hand made 1. Remember, these engines make big power so if u were to use n/a pistons, don't let it ping!

my mistake, 8.3:1 is what the article says, its just been a while since i read it.

twinvl: i got the turbo block for $20 lol ban anyone say BARGAIN??? lol it has a standard bore so still plenty of 'meat' on it lol and i am thinking of using a garrett 700hp GT35 i have been told i could get approximately 300rwkw on about 18-20psi now just getting it to the road lol p.s how much does an rb20 exhaust manifold go for? and would it flow enoguh for a gt35?