Sooo I got my RB25 and I have a few questions

[TheRealNap0le0n]

I've been searching and searching and just ending up more confused.

I got the motor and transmission, ecu, wiring harness ( set up for S14 but i have an s13 ), and N62 maf for an awesome deal...

It didnt come with a turbo but thats ok my goals around 500whp. In reality im looking for 450 or just over that but i want to set the build goal higher than that to keep some head room.

I was thinking GT35 or an equivalent turbo, 800cc injectors, greddy type intake manifold, arp fasteners, tomei headgasket, meth injection, etc.

As far as tuning goes im still up in the air.

Also will a GT35 fit on the stock exhaust manifold or will i be sourcing something aftermarket. Im leary on the aftermarket after reading about so many fitment issues.

I've read alot of different things but I heard the RB25 is safe to 500hp. Is that true? if i need to put some pistons in it i'd rather do it out of the car.

Does the RB25 have the weak crank issue i keep reading about IE do i need a crank collar?

Also when i got the motor it has some black ign coils on it now, and he also gave me a set of blue ones.... whats up with the blue ones?

And how can i tell if i have an S1 or S2 set up because i read about an ignitor somewhere and something about humps on the coil packs but im just like... uhhhh

Sorry for the long post, im not new to high performance motor builds but im new to this motor and this is my DD so i want to do it right the first time and take my time on this build.

[S13_RB25]

I've been searching and searching and just ending up more confused.

I got the motor and transmission, ecu, wiring harness ( set up for S14 but i have an s13 ), and N62 maf for an awesome deal...

It didnt come with a turbo but thats ok my goals around 500whp. In reality im looking for 450 or just over that but i want to set the build goal higher than that to keep some head room.

I was thinking GT35 or an equivalent turbo, 800cc injectors, greddy type intake manifold, arp fasteners, tomei headgasket, meth injection, etc.

As far as tuning goes im still up in the air.

Also will a GT35 fit on the stock exhaust manifold or will i be sourcing something aftermarket. Im leary on the aftermarket after reading about so many fitment issues.

I've read alot of different things but I heard the RB25 is safe to 500hp. Is that true? if i need to put some pistons in it i'd rather do it out of the car.

Does the RB25 have the weak crank issue i keep reading about IE do i need a crank collar?

Also when i got the motor it has some black ign coils on it now, and he also gave me a set of blue ones.... whats up with the blue ones?

And how can i tell if i have an S1 or S2 set up because i read about an ignitor somewhere and something about humps on the coil packs but im just like... uhhhh

Sorry for the long post, im not new to high performance motor builds but im new to this motor and this is my DD so i want to do it right the first time and take my time on this build.

Ok well I'll answers couple of your questions to the best of my knowledge and if not I'll point you in the right direction. Well as for the stock internals, they are good for 500hp and for the crank issue i am not full aware of it myself but most people that put the rb in s-chassis do use a JUN crank collar or something similar. For the exhaust manifold you will be better of replacing it with a aftermarket one, since you will be using a aftermarket turbo, i mean its a 15+ year old manifold and you can't expect it to hold up against a gt35 or a 30r and especially to your goal of 450hp.

ALSO BEFORE YOU DO ANY OF THAT DON'T forget to replace the key components that are prone to fail sooner or later, like: water pump, fuel pump, belts, cam gears, and etc... Its better to get it running before you think about reaching your 500hp mark.

If you have more questions, just ask but don't forget RESEARCHING will get you alot further then just being spoon feed...

[TheRealNap0le0n]

oh i hear that... im just not good with search terms

[GSDKinked]

Stock manifold can handle a 30r or 35r past 500hp. The set of blue coils are probably older spitfires or something. Ask rawbrokerage or go to their page and ask them. I personally had a 35R on my stock manifold and all it took was a 1 in spacer, 2 gaskets and extended studs.

If the motor is out I suggest getting the crank collar. My next motor that I am building is getting one. Also, do research on Skylines of Australia (forum) they have SUPERB info. They also have a thread of dyno sheets for various set ups listed by engine.

[TheRealNap0le0n]

Stock manifold can handle a 30r or 35r past 500hp. The set of blue coils are probably older spitfires or something. Ask rawbrokerage or go to their page and ask them. I personally had a 35R on my stock manifold and all it took was a 1 in spacer, 2 gaskets and extended studs.

If the motor is out I suggest getting the crank collar. My next motor that I am building is getting one. Also, do research on Skylines of Australia (forum) they have SUPERB info. They also have a thread of dyno sheets for various set ups listed by engine.

ooh... thats SAU that i keep seeing....

cool i figured the GT35 would need a spacer at least. thanks guys

[S13_RB25]

ooh... thats SAU that i keep seeing....

cool i figured the GT35 would need a spacer at least. thanks guys

Ohh and about the crank collar, the reason people run that is cause the stock crank is vital to slipage and not connect with the oil pump fully during high rpm. So the crank collar helps make sure that they both connect fully. Thats the purpose of the collar but correct if I'm wrong guys, I was earlier about the exhaust mani....

[TheRealNap0le0n]

Ohh and about the crank collar, the reason people run that is cause the stock crank is vital to slipage and not connect with the oil pump fully during high rpm. So the crank collar helps make sure that they both connect fully. Thats the purpose of the collar but correct if I'm wrong guys, I was earlier about the exhaust mani....

oh i see... i thought it had something to do with the crank breaking off or something.... I agree with you on the exhaust manifold because even tho i can weld i dont want to have to be fixing things all the time. ( yea i know right... ) I want to put it together once, legit, and have it run suhweet.

[SullivanRacing06]

ALSO BEFORE YOU DO ANY OF THAT DON'T forget to replace the key components that are prone to fail , cam gears,

If you have more questions, just ask but don't forget RESEARCHING will get you alot further then just being spoon feed...

how do stock cam gears fail???

[S13_RB25]

how do stock cam gears fail???

I didn't mean like that but its something that you might want to do since the motor is out... But mostly everything like water pump and fuel pump, etc.

[Mistaken]

Most people will never use the adjustment that adjustable cam gears gain you. Fix the oil pump drive for piece of mind, arp head studs, head gasket, water pump, oil pump, timing belt and tensioners, new accessory belts....all of the basic maintenance parts.

If you replace it now, you may not have to later. Replacing the water pump and oil pump while in the chassis would not be that fun.

[TheRealNap0le0n]

Most people will never use the adjustment that adjustable cam gears gain you. Fix the oil pump drive for piece of mind, arp head studs, head gasket, water pump, oil pump, timing belt and tensioners, new accessory belts....all of the basic maintenance parts.

If you replace it now, you may not have to later. Replacing the water pump and oil pump while in the chassis would not be that fun.

should i get a nissan N1 oil pump or spend the money for a tomei, greddy, etc one.... what is it that actually fails?

and i've been reading all day in the RB forum and only noticed the RB20 and Rb26 crank collar issue... i assume the RB25 has it just not as often?

and when ppl say they are breaking oil pumps due to high revs what is considered high? ive never owned a car that reved past 6k so anything past that is high to me haha

[Carl H]

the engagement on the snout is shallow and at high revs/power it slips and shreds the oil pump drive gear.all rb engines except for the REALLY late r32 and up rb26 engines are affected, no ifs ands or buts.

[LSDrift]

RESEARCH is key here. I applaud how civil the conversation has been to this point from everyone seeing the nature of the questions. Not to change this but you clearly haven't searched and read posts for the hours that are required to answer these questions.

But, if you didn't catch what was being said about the oil pump in S13_RB25's post, go here--> zer...65539 go to the part where TriniGT so explicitly answers that question. Took me all of five minutes to find.

Tip for searching: put what you want in search bar, choose RB20/RB25/RB26 Forum, click post bodies radio button if you're not getting results in topic post radio button. and then READ, READ, READ, READ...READ.

[LSDrift]

Dang it Carl you beat me to it.

[TheRealNap0le0n]

RESEARCH is key here. I applaud how civil the conversation has been to this point from everyone seeing the nature of the questions. Not to change this but you clearly haven't searched and read posts for the hours that are required to answer these questions.

But, if you didn't catch what was being said about the oil pump in S13_RB25's post, go here--> zer...65539 go to the part where TriniGT so explicitly answers that question. Took me all of five minutes to find.

Tip for searching: put what you want in search bar, choose RB20/RB25/RB26 Forum, click post bodies radio button if you're not getting results in topic post radio button. and then READ, READ, READ, READ...READ.

yea i really appreciate the help... i kinda expected to come out of here charbroiled... but in all ive already been helped alot...

so taking from trini's post and carl's post its not really a matter of the oil pump but the crank slippage that kills the oil pump so in essence and what im taking from this is get a new nissan oil pump and the crank collar and im golden

[LSDrift]

Meh...you don't necessarily need a whole new oil pump unless yours is damaged or you're in serious need of serious oil. The crank collar will fix the problem. A new pump, if N1 or something, will flow oil better but that's a matter of how hard you're actually beating on the engine.

[RustspecS13]

I'll take a pic of my rb25 with this issue, but its pretty bad.

Basically the oil pump drive is only about 1/8 of an inch wide at the part that it actually contacts. So pushing all that oil pressure puts a lot of force on the 2 small spots that actually drive the pump. There's maybe a 1/4 of total contact point. And that wears out really easy.

Don't get an n1 pump, most cars don't need them, and they actually have weaker gears then regular pumps. They make more pressure and flow but have thinner gears.

~Alex

[S13_RB25]

I'll take a pic of my rb25 with this issue, but its pretty bad.

Basically the oil pump drive is only about 1/8 of an inch wide at the part that it actually contacts. So pushing all that oil pressure puts a lot of force on the 2 small spots that actually drive the pump. There's maybe a 1/4 of total contact point. And that wears out really easy.

Don't get an n1 pump, most cars don't need them, and they actually have weaker gears then regular pumps. They make more pressure and flow but have thinner gears.

~Alex

wait so if the gears are weak on the n1 is plssible to change just the gears between the n1 and the oem unit? If so would the n1 move still move the same amount of oil or it will move same oil as the oem unit?

[TheRealNap0le0n]

well the motor i got i was told had 34k miles... not KM but miles... and from the looks of it it seems to be close or atleast well taken care of....

the motor and transmission both have oil residue on them but who knows what that could be from as far as leaking gaskets or transportation/ messy swaps....

I am replacing the stuff i really wont want to replace in the car haha.

[Carl H]

n1 has been show to flow the same as the standard rb26 pump but just have a higher pressure.its a good idea to pair a new updated pump with the crank collar, my stock pump hardly showed any wear but i decided it was best to swap it out for a new one when the collar went on.

[RustspecS13]

wait so if the gears are weak on the n1 is plssible to change just the gears between the n1 and the oem unit? If so would the n1 move still move the same amount of oil or it will move same oil as the oem unit?

No, the gears are different diameters, the N1 is smaller in diameter or thinner. I don't remember exactly which but from what I was reading/seeing the inner rotor is smaller and cracks easier.

But it does flow more oil and the relieve valve is set to make more pressure. So it is an upgrade in terms of that but its actually weaker strength wise.

SRs and DOHC KA's use the exact same oil pump style, and the outer diameter is the same, but the RB crank diameter is bigger so the inner rotor is smaller and thus breaks, in addition to the drive surface for it is too small.

DISCLAIMER!!!! I only have experience with a stock RB20 and stock RB25, with new OEM non N1 pumps. All this knowledge comes from reseach on here and skylines austraila and other RB forums. I do like to do things right once, so I research everything objectively and form my conclusions when I'm done so I hope my info is pretty much correct.

~Alex

[TheRealNap0le0n]

Well i'll be stopping by raw brokerage later this week so maybe they will have some stuff i can actually get a visual on... i learn alot better with visuals...

i cant wait to get this beast going... im sooo excited. BTW i've googled and searched but is there a gasket behind the input shaft cover on the RB transmission... i wanna reseal it while im there...

or better yet does anyone have a exploded view of the RB transmission....

edit NM on the transmission gasket question i found a pic
Modified by TheRealNap0le0n at 12:49 PM 4/13/2010

[RustspecS13]

Heres my S1 RB25 with the issue at hand:



The crank has a little of a 1/4in worth of flat spot, and the pump has a little more then that, but the drive is in further then where it really needs to be. So as it the pump and the pump drive only contact about 1/8in and it just wears out fast.

A crank collar engages the whole pump drive and helps extend the oil pump life.

~Alex

[TheRealNap0le0n]

Heres my S1 RB25 with the issue at hand:



The crank has a little of a 1/4in worth of flat spot, and the pump has a little more then that, but the drive is in further then where it really needs to be. So as it the pump and the pump drive only contact about 1/8in and it just wears out fast.

A crank collar engages the whole pump drive and helps extend the oil pump life.

~Alex

crank collar it is!