i was under the impression that low km engines from japan were justified because of the strict pollution guidelines, in other words theyve got a used by date on them but i couldnt agree more about the tamper proof containers, apparently the warfie's open them up and pocket what they want and you might end up buying the same item twice cause he/she has tried to flog it off on ebay

speaking of things with low kms.... i wouldnt be suprised, even though ppl say otherwise, that most of the GTRs engines actually have "low kms". coz when u think about it, japan is not very big at all.... and if u live in a city just having a car costs a fortune (u have to rent a parking space which usually costs around $500-1000 per month!!) then running costs would be kinda crappy then theres the rural areas and sh*t.... i dont really know how much driving u could do over there :/ but i wouldnt wanna buy engine off a dodgy "engine crate" dealer... unless they were a pretty big/well known company, hell i dont even want to buy an engine off ANYONE coz u really dno wtf has gone on. and chances are if u buy a RB26 it'll be nearly dead, soooo, you'll want spare change to rebuilt the f*ck.

can u put a 26 crank in a 25?

Wow, this thread is full or more opinions than I think I've ever read in one thread in my life After experience with about 300rb setups now in the past 2 years, and various first hand experience on customers cars and friends cars, I have come to the following conclusions. 1: RB26's are a POS. Almost everyone I have ever seen or worked on, that is standard, IE original never been rebuilt, has failed either during, or shortly afetr being modified. Often they spin a bearing, as the japanese rarely chang etheir oil, and thrash the absolute ring out there performance cars. I would never buy a stock 26 with the intention of strapping it in, and putting a turbo on and expecting it to last. Unless perhaps it was from a R34=EXPENSIVE RB30's are a good reliable engine. Its been widely proven with good tuning that the stock engine can handle 300rwkw for extended periods and takes it ok. Some people have taken the stock bottom end well past 400rwkw. Despite any opinion, they aren't the best engine in terms of hp development. The simple answer is RPM=HP, and is the reason that the biggest hp performance engines on earth all rev to amazing figures. The higher in the rev range you make peak torque, the more peak power you make, and also the higher in the rpm range in you make peak hp. The RB30 has a relaitively small port size, and after about 7000rpm, even with extensive porting, power just drops away. Have a look at some cars that have big setups, they won't tell you themselves, but the big hp RB30 cars are using 40-50psi of boost to make 500-550rwkw and run 9.1's-8.8's. Compare for example to Gormo's car that run a 9.33 full weight with a 26/30 on 35psi, it has stock valves, $200 valve springs and 254 degree cams with 8.1mm of lift. Yes they have good low rpm torque, but as soon as you modify the ass off them to make big hp, you give all that away to the same level as any twin cam engine out there. The RB25 in my opinion is king of unmodified street engines. They are often in good condition, plentiful and cheap, and the R34 neo engine isn't much more expensive and has RB26 rods and solid cams. I have a customer with a dead stock unopened RB25, stock intake manifold and all, with a GT35 turbo kit, computer, frnt mount and KEAS jatco. On 25psi and pump fuel, it makes 440rwhp, and has run a 10.66@128mph full weight in a VP commordore sedan with stock suspension. Its been absolutely thrashed at powercruise, dyno'd 4 separate times, smashed on the street, it just won't break and gets absolutely hammered, and loves it. We've seen at least 10 RB25's with stock unopened engines go 400-440rwhp regularly with no breakages to date, on no more than 18-20psi, the same setup on a RB30 stock standard would be lucky to make 300-320rwhp. In terms of low down grunt, the RB30 with a GT35 makes full boost at 3700rpm. The RB25 in comparison makes full boost at just 4000rpm. Also, the 30 would drop off power at 5500rpm, and a 6k redline, the stock RB25 makes power to 7200rpm and can rev to 7500rpm all day long. I'm obviously a big fan of this engine, and parts purchased wisely, I honestly think you could build yourself a mid 10 sec VL from SCRATH for less than 20k, with good parts like KEAS, Garrett, autronic etc etc, and a reliable one at that. Break the engine?? So what!! A RB25 rebuild with forged bottom end will actually cost you less than a 30, the rods are $300 cheaper from someone like spool imports. Lastly, onto the outright hp weapons. At the end of the day, there is only 1 single way to make hp. Revs, and airflow. The 26 head by far flows the most, and has bigger ports to allow more top end airflow. The 25 head with solid cams comes a close second, and the RB30 head comes in last. A race prepared RB30 head flows less than a RB26 head with a valve job, pocket port and stock valves. A stock 26 head will also make power at higher rpm's and make more power than the same flow RB30 head due to port size and port velocity, its all in the 'tuned rpm" people, and a 26 head can be had complete with intake for $1500. Add a well done rebuild with mild porting and camshafts/springs, and you have $3500 for a head that will outpower a $2500 RB30 race head and you'd still need an intake for the 30 head for the better part of $1000. Shop smart, have a goal and stick to it so you don't buy twice, or 3 times, or 4 times, and you will be surprised at just how much you can get for your $$. And don't forget people, the bolt ons are every bit as important as the engine!!! Anyway, I'm off to sleep, night!! 6BOOST Some original photos have not been recovered yet.

Quote: Originally Posted by 6BOOST Lastly, onto the outright hp weapons. At the end of the day, there is only 1 single way to make hp. Revs, and airflow. The 26 head by far flows the most, and has bigger ports to allow more top end airflow. The 25 head with solid cams comes a close second, and the RB30 head comes in last. A race prepared RB30 head flows less than a RB26 head with a valve job, pocket port and stock valves. A stock 26 head will also make power at higher rpm's and make more power than the same flow RB30 head due to port size and port velocity, its all in the 'tuned rpm" people, and a 26 head can be had complete with intake for $1500. Add a well done rebuild with mild porting and camshafts/springs, and you have $3500 for a head that will outpower a $2500 RB30 race head and you'd still need an intake for the 30 head for the better part of $1000. 6BOOST read that u fags! haha, thank god someone said that..... and i thought not getting porting done on my head was bad.... hmmm and i have fools around me saying "the sohc rb30 head with porting etc etc is better".... Some original photos have not been recovered yet.

im still going to port mine. port, nice cams and some valve springs should do for the power im after.

Out of interest, i know some people that import Rb26 motors, after they have already been through a couple of peoples hands, they still get them for $600 , and sell them for $3000-3500 ,and don't p.m me for one, they won't sell me one cheap or i would have one , most stuff seems to be imported from malaysia i think now aswell cheers darren Some original photos have not been recovered yet.

Lol, I guess its the old scenario of how much people percieve something is worth Daz, and most people think they are worth squillions. For the record, don't take it as me saying SOHC is sh1t, I wasn't trying to highlight that in the slightest, I am only saying that a 2.5 or 2.6 litre engine that has more head flow, or even equal head flow but can make peak power at higher rpm's than a 3 litre, will make the same or more power. And hence, the best engine would be the biggest one, that has the best flowing head, and makes power at the highest rpm, which everytime, would be a 26/30 with big cams and appropriate prep work to handle 8000rpm. There is 1 or 2 exceptions to this rule in australia, that have HIGHLY developed RB30 cylinder heads, like welded ports and chambers etc, everything moved around, these people could pay for 2x 26 heads for the amount they would have spent on development of the sohc, but then it wouldn't be a VL in their eyes with anything else Should be interesting if they ever get to the racetrack and can use the power it should be capable of. 6BOOST PS, I do think people highly underestimate how much it costs to build a big hp engine though. 100k to me seems a bit high, maybe if you were paying through the nose for someone to do everything I guess it would be about right, but I wouldn't expect much change from 50k for a 8 second 26/30 driveline from balancer to diff cover and everything in between. Some original photos have not been recovered yet.

Kyle, what would be the appropriate work for my 26/30 to rev to 8k

SOHC is **** , The rb25/26 heads would make more "average" power aswell Power definitly drops away with the sohc, over 6700rpm mine felt like someone started to put there foot on the brake, whereas a twin cam that makes peak power at 7000rpm will still rev freely to 8000+rpm, you have to have a light foot to stop it overevving especially with wheelspin. What flow figures do you have for the 25 head Kyle, i still haven't seen any decent 25/30 power yet, 320rwkw auto- 350rwkw manual is about it. Alexs 25/30 Gt72 hasn't made any decent power yet either. Theres a dude on here that went from 25head with baby cams to Rb26 head with baby cams and made his own exhaust manifold. With a Gt3540 i think power went from 320rwkw on 20psi (woudn't make any more), to 380rwkw on 17psi. I remember alexs with poncams and 3540 was the same, at 320rwkw (20psi)auto it woudn't make anymore power. cheers darren Some original photos have not been recovered yet.

I don't have flow figures daz, but we are making 320rwkw on a stock unopened neo 25 with stock intake, no cams, 270x550 intercooler and through an auto. If people aren't making power, its nothing to do with the head, well, based on the power we make with stock engines its nothing to do with the head, it still flows more than a 30 head and has mor eport area, so I can't see how with the same mods it wouldn't make more power than a SOHC. I'd say you'd want good oil system, rods, pistons and appropriate bottom end prep for a 30 to stay together at 8g, then you'd want good springs(not $300 cheap springs) Ferrea valves, and maybe some chromoly retainers and god quality collets. I think there is a valve spring and retainer combo that is about $600-$800, Ferrea and Supertech I believe are 2 of the brands that do them and would suit this sort of work. Keep in mind that while stock engines would prob go to 8000rpm, they don't go to 8000rpm with 11mm lift camshafts and 1200cfm of air going past the valves 6BOOST Some original photos have not been recovered yet.