RB ?'s (tried searching)

[gr8bryt]

I'm considering an RB25 swap for my S13 hatch, but I have a few questions. I tried searching but to no avail, please bear with me though just in case these have already been address. Just post a link that I could read on if applicable.

Q1: Does anyone know where I could get a custom spark plug cover made? I see cars with billet covers w/ their favorite tuner (ie. HKS, Apex-i, etc) on them. I don't mean etched, more like extruded/superimposed on the top of the cover.

Q2: How much could I safely overbore the RB25? I'm thinking somewhere in the range of +2 (rb25-->rb27) but IDK. I know they have stroker kits, but most are for the RB26 so I figured that I would have to improvise.

Thanks in advance for all the help. I hope I don't get a for this.

[Joe]

im pretty sure theres no way to get a rb25 +.2l with boring. thats a TON of displcament to add and the cylinders are too close together. not to mention that would require very custom pistons wich in turn mean very lots of money.

why are you trying to gain .2l? its not that much more power. the money could be better spent elsewhere.

[gawdzilla]

the most you can bore to is 2mm over to 88mm, giving you ~2690cc displacement on a 26.. so you could technically round to 2.7L. but since you're working with a 25, you'll only get up to ~2616cc's. haven't heard anyone going past 88.. risky too

[gr8bryt]

I'm not reaching for that much, I was just curious as to how far I could go. I believe the RB25 is about 2,495cc or somewhere in there, so I guess I just to increase to an even 2.5 ltr. I don't wanna spend a lot of $$, but I do realize it will cost a little bit to get the block milled. I guess I was getting too carried away trying to follow up on stuff that I see and hear. A lot of times when these performance mags publish stuff that they do to their project cars, usually the price isn't included in the article. Would it be possible to just use some slightly oversized pistons, but keep the same cylider bore?

[gr8bryt]

Forgive me, but could you translate the cc's to mm's please. I'm guess that the RB26 has 86mm cylinders. I know that I could search the formula, but there's always that chance that I'll still be clueless. In all honesty, I probably won't even pursue the displacement bump, like Kamin said my money could be better spent on other things. I suppose that my main focus of my engine build will be power delivery. I really want to be able to have a flexible powerband and not just top end.

[Joe]

no you cant use oversized pistons in the stock bore (they wouldnt fit!) your dealing with clearances about 2 or 3x as thick as a human hair, so even a mm is a HUGE difference.

CC's (cubic centimeter) dont translate to MM (milimeter). CC is a measure of volume and MM is a measure of distance

the CC's he is talking about is overall displacment (i.e. 2495cc = 2.5l) and the mm is the size of the piston/bore

[250sxGTST]

if i understand your post you are looking to change the internals of your rb to gain low end and midrange power? talk to anyone with an rb 20 or 25 and ask about power delivery. you dont have to do anything they come with incredible low to midrange power stock. better yet, go drive one, leave your engine alone internally and just put the car together. go buy some big drive tires and an lsd cause you'll need it.

[Carl H]

toss a hks rb28 or tomei rb28 kit in there and call it a day.

[gr8bryt]

toss a hks rb28 or tomei rb28 kit in there and call it a day.

That sounds like a good idea, but would that fit the RB25? I'm thinking that most skyline stroker kits are for the RB26, but I'll search.

Anyone have input on the spark plug covers? All I found was stuff for SR's.

[Cubes]

RB25 and 26 internals (crank/rods) are interchangable.

There's a wealth of information on the rb25det over at http://www.skylinesaustralia.comhttp:// ... wunder.com

And for the conversion...

http://www.nissansilvia.com/

[gr8bryt]

CC's (cubic centimeter) dont translate to MM (milimeter). CC is a measure of volume and MM is a measure of distance

the CC's he is talking about is overall displacment (i.e. 2495cc = 2.5l) and the mm is the size of the piston/bore

That's the mm that I was refering to. I'm thinking that overall displacement is determined by piston diameter in some way, but idk.

Thanks for the links Cubes. I'm assuming the last one is for swapping the RB into a silvia chassis.

[Joe]

That's the mm that I was refering to. I'm thinking that overall displacement is determined by piston diameter in some way, but idk.

Thanks for the links Cubes. I'm assuming the last one is for swapping the RB into a silvia chassis.

its determined by bore, stroke and # of cylinders.

[gr8bryt]

Oh, ok thanks for clearing that up 4 me. I'll check out those other links to see if I can find more info.

[gr8bryt]

if i understand your post you are looking to change the internals of your rb to gain low end and midrange power? talk to anyone with an rb 20 or 25 and ask about power delivery. you dont have to do anything they come with incredible low to midrange power stock. better yet, go drive one, leave your engine alone internally and just put the car together. go buy some big drive tires and an lsd cause you'll need it.

That would be great, but unfortunately I don't know anyone with a skyline in their driveway or under their hood. I'm thinking that most bolt ons will deliver the most benefit towards the top end of the power band and only slightly improve on low and midrange. Sure it depends on what parts you choose and their specs.....I'll just do more research so that I can save myself from looking like an idiot. The internet just frustrates me sometimes because there is sooooo much info that it can be overwhelming and tedious looking for something.

[northstar ninja]

just to let you know, dsport recentally had an article on stroker kits, and thier stroked 26. it has most of the information youll need there. unfortunately of all the stroker kits listed for various apps, none are for the rb. they are running the hks stroker kit, (from what i remember). if for nothing other than just knowing a little more the article(s) were a good read.

[gr8bryt]

If that's the article that features the green drift 240sx, I actually have that mag. I was reading up on the RX6B turbo. I noticed that they've got that R33 w/ 2.8 ltr but I didn't read about what kit they were running. I'll read up on it more when I get off from work today.

[northstar ninja]

its the hks kit. and theres a silver s2000 on the cover.

[RBTALLY]

just put the stock rb25 in u will be happy with it...as for the cover I can make u one that says whatever u want. I can powder coat it or anodize it what ever u want.

[gr8bryt]

Oh, ok well I guess I don't have that one. I'll see if I can pick it up or find the article online. I checked out some of those links that were posted earlier and found a little bit of info on OS Giken vs. Tomei. The OS Giken kit uses differentiating metals on their kit, whereas Tomei in homogenous in all their materials. I'll check out the HKS kit to see what I can find.

Hey RBTALLY, I'll have to keep you in mind when I'm ready for that cover. I still have a while b4 I will have the motor. I'll send ya an email or something to let you know what kind of ideas I've got.

Of all you RB-powered 240 owners, were you able to keep power steering and ac? My last car didn't have ac and when it gets hot in the South, the humidity is really a PITA. I would hate to be in that situation again, and I've been driving so long with ps, that I might to learn to drive all over again if I didn't. lol

[gr8bryt]

just put the stock rb25 in u will be happy with it.

I'm rarely ever satisfied with anything. My output goals are somewhere around 550 whp, I don't think stock will cut it. At the same time, I want a comprehensive build up that is also reliable. I want to have a good all around car whether it be for just cruising around town, getting a few trophies at a show, or laying pipe (stripe) at the track. Of course I could have a well balanced car with less hp, but I guess I'm a little power junkie

[gr8bryt]

Hey all, check this out0http://www.toprpm.com/videos/HKS_R32_GTR.zip

I thought it might be interesting since it relates to the thread. Hope you enjoy.

[RBTALLY]

mid 500;s is doable but not dependabe on a stock block. start saveing now, it will take a shoe box of money.

[gr8bryt]

lol, maybe two shoe boxes. I know that this project is gonna be expensive, but I've got my mind set on it. Sure I could go sr or ka-t, but I want the RB and I've gotta do what I gotta do....GREATNESS REQUIRES SACRIFICE.

[gr8bryt]

Ok, I've been doing a little bit of reading....I've decided not to go with a stroker kit. The idea of maintenance comes into play as the major factor I guess. The bit about custom internals for the increased stroke doesn't really sit well with me, although the HKS kit would seem to be less of a headache. They position the piston a little differently so that the con rods don't have to be shortened. If anything, I may just do a slight .25mm overbore to freshen up the block some and the appropriate sized pistons. Maybe just enough to get an even 2500cc (or as close as possible).