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Rb engine


zmaster

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I have a few questions that I am not really finding on here in the search.

 

First I would like to know whcih engine is better (performance wise) the RB25dett or the RB26dett?

 

The second question is, how high can the boost be set on the stock motors?

 

The r3eason I am asking this is because I am starting to lean away from a LS2 engine, and back into wanting a RB motor. I want to stay l6 because it should be lighter, and faster than the ls2

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rb25dett????

 

No such monster unless it’s a custom build... if you mean rb26dett vs. rb25det... well that HAS been discussed many times and if you want my opinion.... if you’re in the states build a turbo v-8. The technology in these engine is catching up to the import turbo motors and for the same amount of money you would spend to do a rb26 swap and get say 550 rwhp you could probably do a turbo v-8 and get much more torque and HP for the same amount of money.

 

AND if you break something you are a overnight shipment away from getting parts.

 

But if your stuck on the rb swap... then rb26 will net your more HP in the end then an rb25.

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one point worth noting with standard RB turbos is that most of them have ceramic turbine wheels (for low inertia quicker spool) however these tend to grenade centrifugally if you push them much over 12 psi

having said that ,12 psi through an rb25/26 is pretty exciting in a Z,however when you get to wanting more it can get pretty expensive so set your HP/torque/$ goals early and pick your powerplant accordingly

another thing to consider is that no matter how much power you have,it is no use unless you can get it to the pavement early....especially on launch,this i feel is one of the big advantages of a turbo engine,with a new engine managment system you can dial in the boost for each gear and so tailor traction

in your stateside situation i would go turbo 302 windsor,easy reliable 500HP

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My buddy Carlos has a rb25dett, lol. He is using the rb26dett turbo setup. the rb25det is cheaper, and unless you're building a ridiculous drag car will suit your needs just fine. I recently bought a 260z, and decided to swap in the rb25det i have laying around. after the chassis, suspension brakes are all sorted out, i'm going to shoot for ~400- 450 whp, easily attainable with the RB25det.

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So lets just say I wanted 15 lbs of boost, I first need a bigger turbo, but will the stock internals of a rb26dett be able to handle that much boost?, or should i replace the internals with forged?

 

I want a rb motor because the only ls2 engines i am finding are really expensive like 8 grand, and when i figure in all the other expenses to make that setup work, i start to think i will get more power with less money with a rb 26dett setup

 

I will look into twin turbo setups on ls1 and ls2 engines today to see what i come up with.

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yep bottom end will handle a ton along with the rb25 tuning is the key to any motor. I was running 25+psi on the stock bottom end of my rb25det and it took it no prob. The only reason mine failed was due to tuning with the haltech i have, problem is fixed now tho :).

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detonation killed mine but only the number 5 piston is bad in mine judging from the compression test. I wouldnt just put 25psi on any engine without understanding how to tune it. It was my fault it broke but it did take a hell of a beating before breaking and still runs. I have a t3/t4hybrid turbo on my rb25, do a little more searching with the guys with different turbos to see how they perform and compare. Mine has a .70ar ont he compressor a 60-1 wheel and on the exhaust side i have a full t4 trubine with a stock t3 housing machined out to accept the t4 wheel.

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If I wanted to run a little nitrous with 10, 15, and 20 lbs of boost, how much nitrous do you think the motor will be able to handle (SAFELY) in each of those boost levels.

 

I am thinking at least a 50 shot maybe a 100 shot if I run 5 lbs of boost, but as i will say again I am unsure how strong this motor is. Is it really as bulletproof as I keep hearing?

 

I really don't know how strong this motor really is, and I want at least 500hp out of it and I will be happy.

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I would go and ride in or drive a car with 500hp before you decide that. I work on Ferrari's so I know what its like. You can use that power above 80 miles an hour, if your car hooks up. My motor is stock and its a lot of fun. Trust me 500hp is a handfull. haha

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Until you have broken tires loose in a car from a roll in 3rd gear, you don't understand what your getting yourself in to. I am not sure quite how much power my 240sx is making at this point, but its enough for me to know that if my car were to fall into the wrong hands it would end up wrecked in a heartbeat.

 

Evan

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I was lucky enought to drive my cousins pontiac GTO with the LS2 in is, which I believe is 400hp/400trq. Ever since then, I've wanted a high hp car 300-600hp It is really fun

 

Vin Diesel is your cousin? coooooool man. :eek:

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I was lucky enought to drive my cousins pontiac GTO with the LS2 in is, which I believe is 400hp/400trq. Ever since then, I've wanted a high hp car 300-600hp It is really fun

 

Remember though, that is a modern chassis, without much wear on it, with modern suspension, big tires, etc. And, the car itself is heavy. Putting that much power into a 30 or so year old car, without a redone suspension setup, on the narrower tires (unless you get flares), and it weighs FAR less, that is going to be a whole 'nother thing.

 

Heck, my ~230whp is insane at WOT.

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