Upgrade guide for rb25det

[amplifi3d]

I'm on my way to swapping in my rb25det and I was wondering what would be the best path on upgrading it to for more power. All the normal wear and tear stuff are being swapped like clutch,thermostat, and water pump. What would you guys suggest?

[coreansurfer]

greddy intake manifold, q45 throttle body, fmic, power fc, bigger turbo, bigger injectors.

there are people throwing down 500+hp at the wheels with that set up

[drift freaq]

It depends on how much power you want. People suggest Greddy Intakes but the truth is you can run a stock intake with higher hp no problem. There are lots of guys in Australia doing it. Plus the Greddy intake actually does not do much in the HP department what it does do is clean up the the overall setup looks and piping wise. Also do not put a Q45 maf on unless your going with a decently larger turbo,even if you do the Greddy intake mani. Reason being is you sacrifice a bit of low end torque to the larger throttle body which means your bottom end response is not quite as peppy. Now if you go larger turbo that becomes somewhat of a non issue.
Now you have to ask yourself, how much boost am I am going for? How big of a turbo do I want? what kind of hp do I want.
A PowerFC is nice because its pretty much a bolt on power upgrade and gives you a lot of tuneability. If you want a PowerFC I suggest looking for one now though as Apexi has discontinued them for RB25DET's series I and II.
I went with a HKS GT2530 Turbo which was actually sold setup to bolt on our cars. I got a deal and to say honestly its a pretty kick ass mid level turbo. Good for 370- 375 hp at around 1.2 bar its rated lower but HKS only rates their turbos at 1 bar it was rated at 320 at 1 bar. Now if you do go with this turbo or larger, than you will need Injectors and a MAF for higher boost, fuel and air flow. I can run this turbo at around .9 bar on the stock injectors and maf and I am running close to 90% duty cycle. It spools like no tomorrow though. Now 550 injectors are the the minimum size I would start with which will give you headroom. Though if you plan on going much larger turbo wise or upwards of 400-450 hp than you might want to put in 750's. MAF pretty much is a Z32 should satisfy your needs. Other stuff is up to you. I.E. Tomei PonCams and gears. stronger head gasket etc..
Its all dependant on what your after HP wise.

[cmcdougle]

Just do the intake manifold. It is worth it. Way less piping crap from the intercooler, and it doesn't cut across the engine so it is cooler air. It adds a bunch of power, too.

[amplifi3d]

Thanks for all the replies. As for power wise 375 should be more than good enough for now. I wanted something with a quick spool kind of like what the gt2871r does for the sr20det. I'm already planning to upgrade the head gasket, headstuds, and all the other common wear and tear parts. What else would you guys suggest?


Also what are you guys experience with mounting kits. I've heard good things about the skyo kit but I can get a pretty good deal on the mckinney kit. Pounding the firewall doesnt bother me either. I also don't have a R33 transmount. Thanks!

[coreansurfer]

mckinney mounts are sexy, i love em

[250sxdet]

Syko mounts FTW! The syko kit is great, and Gary is a very nice and knowledgable guy. If you run his kit, I guarantee you wont be sorry. I run them and they are great. iirc, the rb25 tranny mount is the same as the ka tranny mount. PM kouki_s14, he can hook you up with the mount kit, and if need be, a front clip too.

[drift freaq]

Just do the intake manifold. It is worth it. Way less piping crap from the intercooler, and it doesn't cut across the engine so it is cooler air. It adds a bunch of power, too.
Actually it does not add a bunch of power. Its been tested in Australia against the stock manifold and it was proven to be marginal. The reason for doing it is it cleans things up under the hood esthetically. CM you have a habit of posting random statements with no real facts.
Even the Neo came with a crossover manifold and was still rated at 280 hp so your statements ring pretty false CM.

P.S. CM look at my Avatar I run the Greddy. Though its not so much for power as what I stated previously. You run a RB20 not a 25 so you don't even know for sure.

[s13gold]

It depends on how much power you want. People suggest Greddy Intakes but the truth is you can run a stock intake with higher hp no problem. There are lots of guys in Australia doing it. Plus the Greddy intake actually does not do much in the HP department what it does do is clean up the the overall setup looks and piping wise. Also do not put a Q45 maf on unless your going with a decently larger turbo,even if you do the Greddy intake mani. Reason being is you sacrifice a bit of low end torque to the larger throttle body which means your bottom end response is not quite as peppy. Now if you go larger turbo that becomes somewhat of a non issue.
Now you have to ask yourself, how much boost am I am going for? How big of a turbo do I want? what kind of hp do I want.
A PowerFC is nice because its pretty much a bolt on power upgrade and gives you a lot of tuneability. If you want a PowerFC I suggest looking for one now though as Apexi has discontinued them for RB25DET's series I and II.
I went with a HKS GT2530 Turbo which was actually sold setup to bolt on our cars. I got a deal and to say honestly its a pretty kick ass mid level turbo. Good for 370- 375 hp at around 1.2 bar its rated lower but HKS only rates their turbos at 1 bar it was rated at 320 at 1 bar. Now if you do go with this turbo or larger, than you will need Injectors and a MAF for higher boost, fuel and air flow. I can run this turbo at around .9 bar on the stock injectors and maf and I am running close to 90% duty cycle. It spools like no tomorrow though. Now 550 injectors are the the minimum size I would start with which will give you headroom. Though if you plan on going much larger turbo wise or upwards of 400-450 hp than you might want to put in 750's. MAF pretty much is a Z32 should satisfy your needs. Other stuff is up to you. I.E. Tomei PonCams and gears. stronger head gasket etc..
Its all dependant on what your after HP wise.
+1 for a good guy...real talk...all u need right there.

[amplifi3d]

2 more questions guys! What kind of radiator do i need? Will s13 koyo fit? What if im not getting the r33 crossmember? Can i still use the mckinney kit? Thanks!

[coreansurfer]

im running the stock nissan radiator, its dual core so itll be ok until you start moving to big numbers

[eh?]

The Greddy IM will make a difference IF you take advanatge of the ability to run more timing. A standalone is a a requirement with the RB25 otherwise whatever you do is pretty much worthless. With the Greddy IM and a standalone like the PFC or aem EMS you can see 300 WHP with stock boost. But like I said You need a standalone to take advantage of it.
This is first hand knowledge.

[ECR33S14]

I run a greddy manifold for ease of maintanence as well. theres less stuff in your way plus it adds room under the hood of your car. if you do get one i suggest putting it on before the swap itll be less trouble. Power FC is the way to go for engine management. Splitfire coil packs. and BPU upgrades, FMIC, exhaust, intake ect.... you need to make sure the S13 radiator will work i know an S14 lines up perfect with hoses. other than that if your gonna do the swap make sure you do it right the first time so you dont have to spend money in the long run.

[drift freaq]

The Greddy IM will make a difference IF you take advanatge of the ability to run more timing. A standalone is a a requirement with the RB25 otherwise whatever you do is pretty much worthless. With the Greddy IM and a standalone like the PFC or aem EMS you can see 300 WHP with stock boost. But like I said You need a standalone to take advantage of it.
This is first hand knowledge.
Much better stated, I did say marginal i.e. as some difference but not a super crazy amount. Though like I did state it really cleans things up engine wise and underhood wise. I also concur on the Standalone, The PowerFC was definitely one of the best things I could do on the stock engine. Props for posting with real info.

[MELLO*SOS]

Amplified; there is a decent thread on Skylines Australia that you should check out.. It's 13 pages of people posting their RB25 dyno printouts and mod lists:

http://www.skylinesaustralia.com/forums/index.php?showtopic=55845

Read through there, it will give you some idea as to what combinations work, and what kind of power to expect from those combinations. Remember, the real key to making any power with any motor is the tuning... You can bolt on thousands of dollars worth of bling and still be slower than a less-modified engine with a better tune. As said a couple times already in this thread you should look into a PowerFC or a similar stand alone asap, then focus on your turbo and injectors.

As far as maintenance goes, here's some items you should think about replacing: Timing belt, Timing belt tensioner, timing belt guide, oil pump, crank collar mod, water pump, head gasket, valve job with resurfaced head, all new gaskets, fresh exhaust mani studs, new thermostat, new clutch, lightweight or resurfaced flywheel, new spark plugs, replace any aging rubber hoses.

[kouki_s14]

The Greddy IM will make a difference IF you take advanatge of the ability to run more timing. A standalone is a a requirement with the RB25 otherwise whatever you do is pretty much worthless. With the Greddy IM and a standalone like the PFC or aem EMS you can see 300 WHP with stock boost. But like I said You need a standalone to take advantage of it.
This is first hand knowledge.

i really dont think you can run 300whp on stock boost, go check out the skyline forums you dont see anything above 220-230whp on stock boost, some even around 200whp. i myself dynoed a little over 250whp at just under 10psi, with a Mine's tuned ECU. power fc/aem can only give you so much, to get to 300whp you need the tune AND the boost turned up. Also you're correct about the intake manifold, if not taken advantage of, you probably loose some power if anything. The only way to take advantage of the Greddy is to turn up the boost, preferably with a new turbo.


2 more questions guys! What kind of radiator do i need? Will s13 koyo fit? What if im not getting the r33 crossmember? Can i still use the mckinney kit? Thanks!

Radiator you can use any KA spec one, Koyo works but may heatsoak if you're unlucky.
Mckinney kits work ONLY with the KA crossmember, with the use of their um questionable quality brackets and mounts
You only need the R33 crossmember for the Syko Kit, which many people would recommend over the Mckinney. Like 250sxdet said, i can get you the kit if you want it over the Mckinney.

[eh?]

I've been following SDU and SAU for a good 4 years now. SDU was a good website until they had server issues. SAU is just plain horrible. Unless Sydney Kid provides an answer I take everything on the site with a huge grain of salt.
Unless someone tunes their car themselves, or have intimate knowledge of tuning I really don't care for their opionion. From what I've seen very few aussies tune their car themselves let alone have a WBO2. They wonder why they crack piston lands...

Did you tune your mines ecu? I would never run one or recommend anyone to run one even on a stock setup.
A couple guys with aem ems pulled 300whp with stock boost. I know one guy pulled 285whp with stock boost/PFC/greddy im. Stock dyno on the aem mule was ~245whp...

Just my opinion and my knowledge over the years.

i really dont think you can run 300whp on stock boost, go check out the skyline forums you dont see anything above 220-230whp on stock boost, some even around 200whp. i myself dynoed a little over 250whp at just under 10psi, with a Mine's tuned ECU. power fc/aem can only give you so much, to get to 300whp you need the tune AND the boost turned up. Also you're correct about the intake manifold, if not taken advantage of, you probably loose some power if anything. The only way to take advantage of the Greddy is to turn up the boost, preferably with a new turbo.




Radiator you can use any KA spec one, Koyo works but may heatsoak if you're unlucky.
Mckinney kits work ONLY with the KA crossmember, with the use of their um questionable quality brackets and mounts
You only need the R33 crossmember for the Syko Kit, which many people would recommend over the Mckinney. Like 250sxdet said, i can get you the kit if you want it over the Mckinney.

[kouki_s14]

I've been following SDU and SAU for a good 4 years now. SDU was a good website until they had server issues. SAU is just plain horrible. Unless Sydney Kid provides an answer I take everything on the site with a huge grain of salt.
Unless someone tunes their car themselves, or have intimate knowledge of tuning I really don't care for their opionion. From what I've seen very few aussies tune their car themselves let alone have a WBO2. They wonder why they crack piston lands...

Did you tune your mines ecu? I would never run one or recommend anyone to run one even on a stock setup.
A couple guys with aem ems pulled 300whp with stock boost. I know one guy pulled 285whp with stock boost/PFC/greddy im. Stock dyno on the aem mule was ~245whp...

Just my opinion and my knowledge over the years.


The Mine's ECU came with the front clip i bought, so it is tuned for my motor.

Where have you seen these 300whp aem ems guys? they must be running at 100% the potential of the stock setup if they pulled that much to the wheels. Also are you sure it is stock boost, not just stock turbo? The aem ems controls boost, so who would run 5-6psi when the turbo can safely spool to 11-12psi? Sorry it's not that i dont believe you, it's that it find it VERY hard to believe people pull 300whp at 6psi with just a tune. that's like 80whp on a tune alone. i mean the EMS is good, but i didnt think it was THAT good. If you could, please post the sources you found these 300whp rb25s, thanks.