Rb25det build plan

[RBSilvia1406]

hey everyone. so im geting my rb25 in feb. and im planning to build it for 500hp. so far ive got:
-cp pistons(87mm)
-eagle rods
-stock crank(i beleive it can handle it)
-n1 oil pump
-hks 256 int./264 exh.
-greddy intake man w/ q45 t.b.
-6 boost manifold
-gt35 turbo(not forsure on specs, help will be appreciated)
-z32 maf(can it handle 500hp?)
-apexi power fc
-aeromotive fuel pump n regulator
thats all i think i have. pls tell me if im missing something, if you would go a different route or if you have question. no worries if you want to bash. already planed on it. but im lukin for mid range power and want to see what the more experienced think. ohh money is no issue(im using wholesale accounts and i have three jobs). thanks for all help guys!!

[Skyn]

sounds good to me u knwo stock bottom ends can hadle power too but i guess its good to have replacements

(just got rb20 tongiht ) gonna use it tilli can afford 25 but yeah what shell is it goign in?

[RBSilvia1406]

my buddys buying a s14 for a dd until his rb20 s13 is done in jan then im blowing up teh ka n dumping it in there lol. ya i figured im shooting for some high hp so i mite as well reinforce all i can while i have it out. just to be on the safe side ya know. im looking at a gt35 turbo but i dont know what a/r and everything any suggestions? i see alot of ppl with rb25's using gt3582r's.

[180Sil]

i've heard PFC on RBs has issues with connectivity to harness, something about the pins not making full contact. AEM EMS is what they recommend for RB motors...

[RBSilvia1406]

hmm..really. everyone i know is running pfc and swears by them. ill have to check that out tho. thanks for the heads up man. is it a stand alone like the pfc?

[boosted98gst]

hmm..really. everyone i know is running pfc and swears by them. ill have to check that out tho. thanks for the heads up man. is it a stand alone like the pfc?


Yes the AEM ems is a full standalone with more options the apexi pfc. You might want to look into getting a crank collar also. Using the UEGO and 3 bar map sensor you will not need a crapy "MAF" sensor. You can also use the IAT sensor .

[boosted98gst]

Another thing is eagle rods, if you have endless amounts to spend. Dont get cheap eagle rods they are pretty heavy for forged units.

[boosted98gst]

Id do minor head work with cam's and valve spring, on turbo cars alot of power is made through the head. If you going to use a big lift cam you will also need to swap to a solid lifter.

[RBSilvia1406]

nice im forsure checking that ems out now. ya i have been looking at the jun crank collar and UEGO makes a map sensor? what rods do u recommend(cosworth)? ya i was looking at port and polish, upgrading valve springs, converting to solid lifters. stock valves are gud rite?

[RBSilvia1406]

also what do you recommend for fuel? i was thinking e85 until we hooked it up on my buds s13 rb20 and have had nothing but issues(buying locations, and semi expensive to convert). im now thinking methanol injection.

[boosted98gst]

nice im forsure checking that ems out now. ya i have been looking at the jun crank collar and UEGO makes a map sensor? what rods do u recommend(cosworth)? ya i was looking at port and polish, upgrading valve springs, converting to solid lifters. stock valves are gud rite?

UEGO is just the option to come with the ems to have the wideband, AEM has all the sensors for the 3 bar map sensor , and IAT sensor's to run with the system but cost extra. For rods they have Manley and some other companys, good rods alone are going to set you back around 1600-1800 personally myself if im going forged internal get the best if you're wanting to rev high ect. Light weight rotating mass, balanced bottom end and a nice head will set you up for a nice high rev rb25. Personally id look into other pumps like tomei, greddy, hks . For fuel its all up to you, personally I use e85 in my evo and I just use to different tunes that I have stored in my ems. If I ever run low on gas and can not find e85 I can just run pump.

[GSXRJJordan]

Id do minor head work with cam's and valve spring, on turbo cars alot of power is made through the head. If you going to use a big lift cam you will also need to swap to a solid lifter.

I wouldn't recommend solid lifters on a car that'll see street use... valve inspections every couple months? Not necessary unless for a purpose-built race car.

Also, none of the RB cams on the market are "big lift". They're all around 9mm, very close to stock.

nice im forsure checking that ems out now. ya i have been looking at the jun crank collar and UEGO makes a map sensor? what rods do u recommend(cosworth)? ya i was looking at port and polish, upgrading valve springs, converting to solid lifters. stock valves are gud rite?

UEGO is AEM's air-fuel ratio gauge, the AEM EMS has a model that has it built in... also, converting from MAFS to MAP takes a good tuner, as barometric pressure throws off all the readings, but if you were going to go standalone you might as well.

Manley rods certainly are beast, but any forged H-beam rods would be strong enough for whatever a GT35 can put out... even the stock rods are plenty strong as evidenced by the insane number of R33 GTS-T's with big turbos and stock internals. Check out Skylines Australia.

In regards to fuel, E85 is great for turbo cars if you're OK with running an enormous fuel pump/injectors, tuning for it, and being reliant on finding E85 stations. In my area (LA county) there's only a couple E85 stations. Methanol injection does not replace pump gas as the 'fuel', it simply cools and adds stability (via increased mass) to the intake charge, to let you push a little more timing and/or a few extra pounds of boost. Any change in your methanol delivery from when it was tuned means detonation, or worse, so use with caution.

also what do you recommend for fuel? i was thinking e85 until we hooked it up on my buds s13 rb20 and have had nothing but issues(buying locations, and semi expensive to convert). im now thinking methanol injection.

[eh?]

Get your car running first - do a rebuild later. Trust me so many people have issues getting the RB to run right. You don't want fresh rings being ruined from the car running pig rich in limp mode.
I've ran my totally stock long block RB25 for 4 years with 19psi on a 62-1 before it broke. I recently dynoed after I switched to a 6boost manifold and made 352whp at 10psi and 420whp at 14.8psi. I'm sure I was over 500whp when I was running 19psi. These engines always break the ring lands and I broke 2 through 5.

You really don't need to change the rods for 500hp. Put in a set of SR20 ARP rod bolts and you will be good to go. OR you can get a set of RB26 rods and use VG30 bolts. If you got the money you might as well get Carillo's. I've heard plenty of negative things about eagle rods but nothing to substantiate it. I've had a set of VG30 eagle rods and they seemed well made.

I've had a PFC & datalogit and now an aem ems. At their current prices the AEM is a far better option vs the pfc. Back then the pfc+commander was only $650, now the RB25 version is almost $1k or even more. Add on the prices for the datalogit and boost control and it costs MORE than the aem. To use the EBC option on the aem only cost me $35. The achilles heel of the aem WAS the inability to read certain cam angle sensors properly. But they give out free CAS wheels so everything has been fine. There's a ton of things the aem can do that the pfc can't. I could write an essay about that..

You don't need to P&P, you don't need cams, you don't need solid lifters.
Seriously if you have the money you might as well get the RB26.

[fliprayzin240sx]

My buddy out here is sitting somewhere over 600whp on stock bottom end...

Some of the stuff he got to give you an idea:
RB25 (stock bottom end)
HKS 264 in/ex cams with matching cam gears
Tomei valve springs
Tomei headgasket (stock 9:1 compression)
ARP Headstuds
RB26 oil pump
RB26 individual throttle bodies and surge tank using port matched adapter to RB25 head
100mm intake piping
80mm intercooler piping (ebay special)
4'' (4 core?) intercooler (ebay special)
Full exhaust with RSR catback
RB26 D-Jetro Power FC with boost control kit
Stec top mount stainless manifold
2 Stec 50mm wastegates heavily ported
Holset HX40 turbo with 19cm ex housing

Drivetrain
Stock RB25 5 speed
Undampered OS Giken Triple Plate Clutch
GTR R205 rear diff/axles/hubs with a 4.10 final drive (start breaking R200 axles around 550-600hp)

Fuel Stuff
2 walbro pumps out back
Aeromotive FPR
Tomei fuel rail
-6 stainless fuel lines and fittings
Z32 fuel filter
Shitty ass no name 850cc-860cc injectors (free, so yeah)

[wannabe-silvia]

if u RB guys know anyone who has a crank in good condition let me know... sorry to thread jack

[boosted98gst]

My buddy out here is sitting somewhere over 600whp on stock bottom end...

Some of the stuff he got to give you an idea:
RB25 (stock bottom end)
HKS 264 in/ex cams with matching cam gears
Tomei valve springs
Tomei headgasket (stock 9:1 compression)
ARP Headstuds
RB26 oil pump
RB26 individual throttle bodies and surge tank using port matched adapter to RB25 head
100mm intake piping
80mm intercooler piping (ebay special)
4'' (4 core?) intercooler (ebay special)
Full exhaust with RSR catback
RB26 D-Jetro Power FC with boost control kit
Stec top mount stainless manifold
2 Stec 50mm wastegates heavily ported
Holset HX40 turbo with 19cm ex housing

Drivetrain
Stock RB25 5 speed
Undampered OS Giken Triple Plate Clutch
GTR R205 rear diff/axles/hubs with a 4.10 final drive (start breaking R200 axles around 550-600hp)

Fuel Stuff
2 walbro pumps out back
Aeromotive FPR
Tomei fuel rail
-6 stainless fuel lines and fittings
Z32 fuel filter
Shitty ass no name 850cc-860cc injectors (free, so yeah)

Let me take a guess this car is from my home island Okinawa? DO You have proof this car is 600 whp?? because there are no dyno's either. I personally do not know him but he stated on nico what he think the power might be and it was not 600whp. But who knows I could be wrong

[boosted98gst]

I wouldn't recommend solid lifters on a car that'll see street use... valve inspections every couple months? Not necessary unless for a purpose-built race car.

Also, none of the RB cams on the market are "big lift". They're all around 9mm, very close to stock.



UEGO is AEM's air-fuel ratio gauge, the AEM EMS has a model that has it built in... also, converting from MAFS to MAP takes a good tuner, as barometric pressure throws off all the readings, but if you were going to go standalone you might as well.

Manley rods certainly are beast, but any forged H-beam rods would be strong enough for whatever a GT35 can put out... even the stock rods are plenty strong as evidenced by the insane number of R33 GTS-T's with big turbos and stock internals. Check out Skylines Australia.

In regards to fuel, E85 is great for turbo cars if you're OK with running an enormous fuel pump/injectors, tuning for it, and being reliant on finding E85 stations. In my area (LA county) there's only a couple E85 stations. Methanol injection does not replace pump gas as the 'fuel', it simply cools and adds stability (via increased mass) to the intake charge, to let you push a little more timing and/or a few extra pounds of boost. Any change in your methanol delivery from when it was tuned means detonation, or worse, so use with caution.


You're wrong on the cam's kelford offers 10.5 mm 10.3mm 10.8mm lift cams in stock for 20 and 25. They are stocked and ready in the states.

[eh?]

You're wrong on the cam's kelford offers 10.5 mm 10.3mm 10.8mm lift cams in stock for 20 and 25. They are stocked and ready in the states.

They pretty much say they're not made for RB25DET engines.

[GSXRJJordan]

You're wrong on the cam's kelford offers 10.5 mm 10.3mm 10.8mm lift cams in stock for 20 and 25. They are stocked and ready in the states.

I didn't know that, and neither did any of the engine builders I talked to! Thanks for the tip :)

They pretty much say they're not made for RB25DET engines.

Interesting... so they're more for full-bore race RB20 engines? Why ever would there be such things?? lol

[eh?]

I didn't know that, and neither did any of the engine builders I talked to! Thanks for the tip :)



Interesting... so they're more for full-bore race RB20 engines? Why ever would there be such things?? lol

They say it's not made for NVCS engines (aka vtc- R33 RB25, R34 RB20, RB25) I don't know why. You should possibly be able to use them with cam gears.

[boosted98gst]

Kelford has other cam's they have them for our motors, or cam grind custom set ups. When I lived in okinawa japan the only place that had the set up I wanted was either in AUS or UK (10 years ago )now any kelford seller says they can have a custom or cam they do not list on the chart to a business with in 72 hours in the lower 48.

[boosted98gst]

I didn't know that, and neither did any of the engine builders I talked to! Thanks for the tip :)



Interesting... so they're more for full-bore race RB20 engines? Why ever would there be such things?? lol


My buddy is using a set of the 10.5 in his rb20, the engine was built by m&m a big place in ohio that does alot of work for bushur and john shep. The engine is able to take 10k but he is around 9,700 gt40r the car moves , Its a fully built alum rod set up that he picked up in okinawa when we went back in 2000 and now using the stuff. Pretty scary hitting 30 psi on e85 in a light 240 and 70mph and the ass end is all over.