rb25det

[ikjyotgill]

Hey all im looking to run a gt3076r on my rb25det series 2 and am aiming for a 450-500 whsp setup. My fuel and engine management system is complete but am looking for advice on building the engine. Should I only build my top end and do camshafts, valve springs, apr head studs, and replace all gaskets.

Also what kind of options do I have for exhaust manifolds for the gt3076r, i know of Full race but Don't want to drop the 1500 if there's better options.

Any help would be appreciated thanks

[fliprayzin240sx]

Personally, I'd upgrade pistons and crank snout before I invest more money on a stock gut RB25.

[ikjyotgill]

so your saying build the bottom end first? I have to a plan to build the bottom end next year. You don't think the setup i mentioned would be reliable my goal?

[zerodameaon]

I am going to have to agree with Flip. 450+ is not going to be so reliable on stock bottom end. People talk about them being good for 500hp but really these motors are getting older and older and those numbers go way down.

[fliprayzin240sx]

I am going to have to agree with Flip. 450+ is not going to be so reliable on stock bottom end. People talk about them being good for 500hp but really these motors are getting older and older and those numbers go way down.

Well, I'm not gonna say it wont be reliable since I've seen folks push 600hp on stock RB25 bottom end. I'm just pointing out the 2 weakest link of these damn engines. If you can fix the oil driver/crank snout issue and eliminate the thin ass ring lands on the RB25 pistons, then you pretty much have a worry free engine.

[zerodameaon]

How long ago was that though? These motors are only getting older.

I agree with the ring lands those things are stupid thin, that's what took my last stock RB out.

[double zero]

but if you get a newer s2 engine. you can maybe wish alittle longer??

[ikjyotgill]

I see what your saying, BTW my engine was honed and decked last year. I can't see my self being able to build the bottom end properly this year so I guess ill have to stick to my plans on the top end and push between 350-400 to keep it reliable

[funktown240]

Also what kind of options do I have for exhaust manifolds for the gt3076r, i know of Full race but Don't want to drop the 1500 if there's better options.

Any help would be appreciated thanks

Your not going to find a manifold better than Full Race and its not going to be lower than $2200. Any top mount manifold is going to be better than stock, even the cheap ebay ones, ran one for a year with a GT35R with no problems except having to cut and reweld it to clear the valve cover.

[fliprayzin240sx]

How long ago was that though? These motors are only getting older.

I agree with the ring lands those things are stupid thin, that's what took my last stock RB out.

Umm...they're still doing it now. Nobody I know in Japan are running built RB25 bottom ends. They blow the engine for some reason, toss another one in. The few that kinda "built" their bottom ends just opted to go stock RB26 bottom ends into their RB25 block (Crank, pistons, rods).

[zerodameaon]

That's the difference between here and Japan, we get their throw always most of the time.

[whereda40at]

That's the difference between here and Japan, we get their throw always most of the time.

They get the first picks. We get the runts of the litters.

[fliprayzin240sx]

^^^This why you dont want to buy an S13 SR20 redtop or blacktop...All 180sx I've seen were beat to shit.

[redline racer510]

I am personally aiming for 400whp on my stock block using a hx35. I don't really care for rebuilding these engines because short and long blocks are so plentiful its just cheaper to swap out be it a couple of engine swaps add up to a built bottom end, what I am planning on doing is running a 26 bottom end at that point and just adding the crank collar.

[Nissan_Alex]

You should be able to get 350-400 whp without building the head. As long as the tune is done correctly. In my experiencing I have seen the pistons crack/atomize because of bad tune's. I have also pushed 450 to the wheel on av gas on a rb25det set up with just injectors tune and turbo/intercooler set-up. If you are going to pop the head just do the bottom and top end. The weak point in America is the pistons ...low fuel quality and cheap builds == destroyed pistons.

[Sforteen]

Pistons will be fine if the guy behind the laptop knows what there doing, get a crank collar and be done.. people do 400-450whp all day on stock block RB25's i personally made 420whp on 18 psi and pump gas on a 3076R a couple years ago. bone stock head, just had a Greddy style intake manifold.. which i doubt contributed much.

[Darius]

You can easily max out the 3076R ~450HP on a stock bottom end with stock head RB25. It is all in the fuel and tuning.

You don't need pistons or rods, but I would definitely do the crank collar, new bearings, head studs, rod bolts, and head gasket while you have it apart for the crank collar.

If you don't do the crank collar, that's okay too. I know you said you just had the block honed and decked. Just make sure you install an oil pressure gauge so you can verify that your engine isn't starving.