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Rebuilding The Rb25det

Girorostar

By Girorostar,
in Engines & Forced Induction

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Girorostar Experienced

Girorostar

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Good day everyone,

I just recently started buying all the parts i need to rebuilt my RB25DET engine. My CP pistons arrived couple of days ago and I was wondering if i need to buy a set of eagle rods too to achieve a reliable 300 rwkw or can the stock rods handle the pressure? Its a street car but will be going to the tracks ones a month.

Some ppl here told me that the stock rods can handle it with no problems as long as i dont over do it but i wanna know what the ppl here would say about it cause you guys know a lot more about these cars.

Thanks in advance for the help.

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The Dan Grand Master

The Dan

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Good day everyone,

I just recently started buying all the parts i need to rebuilt my RB25DET engine. My CP pistons arrived couple of days ago and I was wondering if i need to buy a set of eagle rods too to achieve a reliable 300 rwkw or can the stock rods handle the pressure? Its a street car but will be going to the tracks ones a month.

Some ppl here told me that the stock rods can handle it with no problems as long as i dont over do it but i wanna know what the ppl here would say about it cause you guys know a lot more about these cars.

Thanks in advance for the help.

Standard rods will definitely do the job. Just make sure you get them resized and replace the rod bolts with ARP items.

At the end of the day, it doesn't matter if you get titanium rods or stay with the standard ones. If your tuner mucks up, it's all over anyway. Spend more money tuning the engine than you think necessary. Don't get this mixed up with going to the highest price tuner though.

Depending on where you are, there are plenty of great tuners around.

Status Tuning down south

EFI Performance and Gavin Wood in Brisbane

Could name more but I don't really trust anyone else.

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Girorostar Experienced

Girorostar

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Standard rods will definitely do the job. Just make sure you get them resized and replace the rod bolts with ARP items.

At the end of the day, it doesn't matter if you get titanium rods or stay with the standard ones. If your tuner mucks up, it's all over anyway. Spend more money tuning the engine than you think necessary. Don't get this mixed up with going to the highest price tuner though.

Depending on where you are, there are plenty of great tuners around.

Status Tuning down south

EFI Performance and Gavin Wood in Brisbane

Could name more but I don't really trust anyone else.

Thanks for the reply. I will order a set of ARP rod bolts this week, to be honest i never thought of buying these :D good thing i asked :D

Wish i could go to those tuners but i'm half way across the world D: but there's a very good tuner here thats gonna tune my car. A lot of ppl here trust him, he has built a lot of high powered cars.

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R31Nismoid Grand Master

R31Nismoid

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Stock rods are OK.

but...

You could put GTR items in though, 2nd hand they are super cheap and very strong. :D

Plenty of 400rwkw motor's around with stock rods (forged pistsons, arp bolt, better bearings etc etc).

Stocker GTR rods are excellent, some people have pushed higher than 400rwkw without any issue at all as well.

And better rod bolts = great idea, a must have IMO.

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Girorostar Experienced

Girorostar

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I will see if i can get the GTR rods, it will probably be a very difficult find though but i'll ask around. I've ordered a set of ACL main and rod bearings for rb25, they should be arriving this week. Will they fit the GTR rods?

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The Dan Grand Master

The Dan

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They are all exactly the same. Why go out and buy GTR or Neo rods when you can just use the rods you have in the engine already?

Oblivion makes almost 300rwkw on standard rods in his RB25 with ARP bolts. His limitation is that he has standard injectors but it's still a strong engine and capable of well over that. The weakest link in the RB engine is the factory rod bolts. Replace them and get a good tune and there is no reason why 400rwkw is not out of the question in a reliable engine.

Only 4 things will break these rods at those power levels:

1: Severe detonation

2: Stretching the bolts by over revving

3: Oil starvation causing the bearing to run, then seize.

4: Incorrect resizing or assembly of the rod or rod/piston

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Girorostar Experienced

Girorostar

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Indeed, i'll stick with the original plans and keep the stock rods and get them resized. Ordered the ARP rod bolts this morning, they should be arriving sometime next week. Thanks again for the replies everyone, really appreciate all the help :P

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~Nvied~ Rookie

~Nvied~

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I currently have a RB25DET running all stock internals. Just reconditioned it with new bearings and ARP rods and all. Making 298kw (400hp) no problems (aside from the stupid gearbox :D ) since build and running strong. I would also agree that tunning is vital after build.

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shotter Rising Star

shotter

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I have a R33gtst and the engine was rebuilt all std but with forget acl pistons. I have upgraded alot of things like injectors, ecu, highflow turbo etc.... And the car has a very SAFE tune of 265.5kw because my tuner doesn't know how much the engine will take before it breaks (Because he didn't rebuild the engine). Will just replacing the rod bolts be a good idea and push more power through? Or would it be much better to just enjoy the current power and get a full rebuild later down the track? Can the rod bolts be changed while the engine is still in the car by just dropping the sump?

Edited by shotter
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The Dan Grand Master

The Dan

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I have a R33gtst and the engine was rebuilt all std but with forget acl pistons. I have upgraded alot of things like injectors, ecu, highflow turbo etc.... And the car has a very SAFE tune of 265.5kw because my tuner doesn't know how much the engine will take before it breaks (Because he didn't rebuild the engine). Will just replacing the rod bolts be a good idea and push more power through? Or would it be much better to just enjoy the current power and get a full rebuild later down the track? Can the rod bolts be changed while the engine is still in the car by just dropping the sump?

There is no telling when it will go bang. Some people have blown them up at less power output than that, others have them over 350rwkw without issues.

It's not exactly the power that kills them, it's the rpm you take it to. Anything over 7k on the standard rod bolts and you're asking for trouble. I would even be inclined to keep it at 6500rpm to be safe and just enjoy what power you can make up to that point.

No you cannot just drop the sump and change them. Well you can but it will not last very long.

Rods need to be resized which means complete engine strip apart.

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The Dan Grand Master

The Dan

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Sorry i was meaning just to replace the bolts.

Yea i am reving it no more than 6500rpm.

It's a handfull sometimes so i think i will just enjoy the current power.

Thank You

Yes I know what you meant. The answer is the same

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Girorostar Experienced

Girorostar

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I have a R33gtst and the engine was rebuilt all std but with forget acl pistons. I have upgraded alot of things like injectors, ecu, highflow turbo etc.... And the car has a very SAFE tune of 265.5kw because my tuner doesn't know how much the engine will take before it breaks (Because he didn't rebuild the engine). Will just replacing the rod bolts be a good idea and push more power through? Or would it be much better to just enjoy the current power and get a full rebuild later down the track? Can the rod bolts be changed while the engine is still in the car by just dropping the sump?

For my engine rebuilt i got ARP head and rod bolts, ACL main and rod bearings, metal gasket, cp pistons. Gonna resize the rods, prep the the block and head just so i can enjoy a reliable 300 rwkw or more depending on the tune. My plan is to do it right the first time. I dont think by only replacing the rod bolts would help you get a reliable 300 rwkw without any of other standard parts letting go somewhere down the track. A lot of rb25det's have met a faith like that on this island.

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