Jebman

Sorry man, but you're arguing with no one there. I don't think anyone on this forum is disagreeing that the RB is a more powerful motor. Also, the point you're making here could be made for the SR. There is a reason that Nissan didn't put the RB25 in it's smaller, lighter 180sx/Silvia. Nissan has a history of making balanced vehicles (Skylines being at the top of that list). Also, higher compression? When did that become a good thing for a turboed engine? And finally, I bet you the RB25 doesn't spool any faster than the SR. The SR makes both it's maximum torque (201@4k) and power (205@6k) faster than the RB (217@4.8k and 250@6.4K). I couldn't rattle off both redlines right this second, but would assume they are very close, or the SRs is higher. Those FACTS, not opinions, also show that the SR is in no way an all horsepower motor, but that it makes very comparable torque at a very low RPM given it's size.

Edit: No offense intended with the caps on "facts"; it just seems like a lot of people "think" a lot of things and can't prove them.

jonpowell

We arent really talking about stock motors here, we were talking about things necessary to make 300HP which means that alot more boost pressue is needed for the SR20 to make than the RB25 since there is 25% more displacement in the 25, 50% more cylinder(and in effect injectors) and also higher compression. 9.5:1 isnt high compression for a turbo motor and in the RB25 it allows for tons of power easily. The RB block can easily withstand the power.

We were discussing a 300HP car....either SR20 or RB25. Less displacement, fewer cylinders and lower compression = lower torque, slower boost and higher required intake flow. Im sorry but in your scenario the RB WILL hit 300HP sooner and WILL out perform the SR off boost also.

Dont forget that with proper suspension tuning and moving some HEAVY items like the battery to the trunk you can almost balance an RB25-S13 so close its a moot point.

http://www.240sxforums.com/forums/sh...t=distribution

Jebman

No one is going to change anyone's mind here, so for the thread starter: The ceiling is higher on the RB, so you could push it much further than the SR. However, if you're only after the 300hp your setup would likely produce, the SR is a lighter and cheaper alternative. It's your decision, but either way you'll be getting a great engine and will undoubtedly be happy with the result.

crazydrifter

where is a good place to get springs, retainers and some rocker arm stoppers.

jonpowell

I agree, 300HP is better suited to the SR, 350 and up I would go RB25...600 and up go RB26...

The RB motors dont have rocker arms, if that's what you are talking about.

qnz

in march's import tuner, they had a s15 with a rb26dett swap by Tein. it caused the car to have 58.5/41.5 front/rear balance. they had to make custom mounts move the engine back just to get 53/47 weight ratio.

isnt the reason why silvias are desireable because of the 50/50 weight ratio?

ka-tfresh

well, yes, but the rb26dett is just...a ***in monster, every1 wants a car with one...they're just sooooo damn cool

jonpowell

Almost everyone installing a Skyline motor uses some kind of custom mounts. Using the Skyline crossmember & mounts WILL work, but its has everything about an inch forward & 1.5" too high.

iroc07

no the "50/50" weight is not what makes them so popular because they arent. they are preffered partly because of their front bias, please look up the weight distribution of the car and you will see this.

NismoSX

Ok, I've thought about this , seeing as how i was in the same predicament as you are.... Idk how old you are, i however am a senior in HS....so i have my whole life ahead of me.
The way I see it, if your going RB25, they're right, might as well go RB26.....but.....I would go S15 blacktop with 6-spd manual tranny.....the RB26 is also a AWD engine only [correct me if Im wrong] [ you can remove driveshafts etc tho, which is why the skyline in 2F2F was able to drift those turns at speeds under 50mph, cuz lets face it, 50mph you pretty much cant get a skyline GTR34 to slide like that] where as the RB25 is the engine from the GTS skylines...however from what I read earlier today I dont believe an RB25 comes with a 6-spd.....which sells the RB26 to me straight up....

But I would go with the S15 blacktop, and save that extra 7K you need to get a RB26 in there and running upwards of 600HP, and save your money, so that maybe later in life, you can just buy a Skyline GTR...... R32, R33, and R34 all have RB26 engines.....and R32 skylines aren't near as expensive as the others.....I've seen some under 20,000$

Bryan

If you swap the RB26 into a 240, you cannot use the 6speed gearbox as it is set up for AWD. You MUST swap an RB25 gearbox onto the motor for it to work.

As for the s15 6speed, its weak and prone to breaking under abuse. Alot of people swap to a 5spd due to it being made stronger.

iroc07

just to be an Ahole postwhore, I think you can get an RB25 6-speed. but I think it was only the NEO with tiptronic. I guess thats not really manual, just manumatic, but anyway, whatever.