400kw rb25

[32pwwr]

G’day guys,

So the time has come for me to throw the mighty RB20 away after blowing it and I’ve managed to pick up a healthy rb25det s2 150-155 across all 6 and bores in perfect condition which surprised me, I’m aiming for hopefully the 400kw happy for more if I can and with the engine in good condition I don’t have the time to pull it apart to go forged. Specs I’m looking to run are the following:

• Studs 
• 1.5mm Nitto gasket
• Kelford 246-A2 vct Camshaft Set: 262/272 Degrees advertised duration, 9.30mm/9.35mm lift with there valve spring kit
• Billet gears in oem oil pump
• g30-770 with a 6boost and 45mm gate
• plaz FFP with BPP Fuel Rail Kit inc Bosch 2000cc Injectors and FPR
• Going to be powered by a haltech 2500

And probably missing some other stuff. 

Is this a realistic and achievable power goal with This setup ? Any musts you can recommend? 

Car will be for street duties tbh this is really what my budget allows but can always stretch if I have to. 

 

Cheers,

[Murray_Calavera]

If that's what the budget is, I'd think about not spending $ on cams and the inlet manifold, and instead spend the money on a Nitto oil pump and bigger/baffled sump. 

[32pwwr]

6 minutes ago, Murray_Calavera said:

If that's what the budget is, I'd think about not spending $ on cams and the inlet manifold, and instead spend the money on a Nitto oil pump and bigger/baffled sump. 

The baffled sump was one I forgot to add and was going to go nitto but told billet gears would do the job if I didn’t want to to the collar. 

[Dose Pipe Sutututu]

I've used billet gears, I don't recommend it.

Just get a Nitto pump from the get go, a big sump, don't get Bosch 2000/2200cc (they're CNG junk), convert to DBW.
 

Also 400kW rear wheel won't last too long with a R33 RB25DET motor, I would aim about 350kW for longevity. 

[32pwwr]

1 minute ago, Dose Pipe Sutututu said:

I've used billet gears, I don't recommend it.

Just get a Nitto pump from the get go, a big sump, don't get Bosch 2000/2200cc (they're CNG junk), convert to DBW.
 

Also 400kW rear wheel won't last too long with a R33 RB25DET motor, I would aim about 350kW for longevity. 

Okay sweet, with the nitto pump I don’t have to do the crank collar ? don’t wanna take it apart tbh lol for longevity over 400kw would be looking at machining ? And forged ?

[Dose Pipe Sutututu]

If you want that kind of power and a working oiling system, that crank needs to come out and a collar put on

[32pwwr]

2 minutes ago, Dose Pipe Sutututu said:

If you want that kind of power and a working oiling system, that crank needs to come out and a collar put on

And at that point I’m probably best then doing the lot lol
 

thanks for the input man, I’ll call around and see if I can get away with doing the crank and Just keeping stock rods and pistons do new bearings and piston rings etc 

Edited November 22, 2022 by 32pwwr

[Dose Pipe Sutututu]

11 minutes ago, 32pwwr said:

I’ll call around and see if I can get away with doing the crank and Just keeping stock rods and pistons do new bearings and piston rings etc 

at that point you might as well just go for a basic rebuild, with H beams & pistons  

What's the car's intent? street duties or drags/roll/circuit?

[32pwwr]

Just now, Dose Pipe Sutututu said:

at that point you might as well just go for a basic rebuild, with H beams & pistons  

What's the car's intent? street duties or drags/roll/circuit?

Street duties tbh man, just don’t got the budget for the machining and the wait time is ridiculous… I did consider if I could get away with balancing it all and slapping it in, not having to hone and bore it etc 

[Dose Pipe Sutututu]

My suggestion is to leave the motor as is, but at least get an extended sump. Aeroflow do decent ones with a 10AN return already welded on.

Fit ARP studs in, slap your turbo setup on and send it. Keep power in the 350kW region and it will live.

Once you open up Pandora's box, shit goes south.

[32pwwr]

5 minutes ago, Dose Pipe Sutututu said:

My suggestion is to leave the motor as is, but at least get an extended sump. Aeroflow do decent ones with a 10AN return already welded on.

Fit ARP studs in, slap your turbo setup on and send it. Keep power in the 350kW region and it will live.

Once you open up Pandora's box, shit goes south.

Awesome thanks bro, I did snap up a complete bottom end for peanuts I considered do a slow build on and later slap that in but that’s just an idea haha and 350rwkw-400kw would be a handful with a 32 gtst on the street

was making 270kw on the 20 and had an absolute blast with it so can see an extra 100kw being even more fun especially with more displacement 

I was quoted a decent price with not much of a wait time for porting the head and doing a clean etc on it would it be worth it for what I’m looking for ?

Edited November 22, 2022 by 32pwwr

[Dose Pipe Sutututu]

11 minutes ago, 32pwwr said:

I was quoted a decent price with not much of a wait time for porting the head and doing a clean etc on it would it be worth it for what I’m looking for ?

Don't bother with this unless you want over 500kW

[Murray_Calavera]

3 hours ago, 32pwwr said:

And at that point I’m probably best then doing the lot lol
 

thanks for the input man, I’ll call around and see if I can get away with doing the crank and Just keeping stock rods and pistons do new bearings and piston rings etc 

Are you doing the engine build yourself? The cost to fit a crank collar is nothing in the grand scheme of things. 

[32pwwr]

16 minutes ago, Murray_Calavera said:

Are you doing the engine build yourself? The cost to fit a crank collar is nothing in the grand scheme of things. 

Pulling the engine apart yes, re-assembly will be done by and expert. just need to weight it up there’s no way of really doing it unless I pull it out and at that point I’m better off just doing a rebuild of the motor. 

[Murray_Calavera]

8 minutes ago, 32pwwr said:

Pulling the engine apart yes, re-assembly will be done by and expert. just need to weight it up there’s no way of really doing it unless I pull it out and at that point I’m better off just doing a rebuild of the motor. 

Put it back together yourself

[32pwwr]

Just now, Murray_Calavera said:

Put it back together yourself

I was going to but with the money about to be spent don’t wanna blow it up, mechanic is awesome enough to let me watch and learn as he does it.

[Murray_Calavera]

1 minute ago, 32pwwr said:

I was going to but with the money about to be spent don’t wanna blow it up, mechanic is awesome enough to let me watch and learn as he does it.

The money your spending on your mechanic to build one motor, you could use on educational material (say https://www.hpacademy.com/courses/learn-how-to-build-engines/) and tools to build X motors in the future. 

I don't think you should be worried about 'blowing up' a motor from incorrect assembly. If everything is going well during assembly, turns over perfectly by hand, what is it that you are worried about? 

I'm not saying you won't run into speed bumps along the way, but they should be apparent at the time and then you can address them as you encounter them. 

The blowing up part is usually reserved for tuning issues lol. Speaking of which, are you going to tune it yourself? 

[Dose Pipe Sutututu]

and also a regular OEM mechanic shouldn't build performance engines...

One of my mates did that for his S15, it died after 3x track days. He learnt his lesson, albeit an expensive lesson. 

[32pwwr]

23 hours ago, Dose Pipe Sutututu said:

and also a regular OEM mechanic shouldn't build performance engines...

One of my mates did that for his S15, it died after 3x track days. He learnt his lesson, albeit an expensive lesson. 

My mate just works on rbs mainly 25-26, so rather pay him “mates rates” to do it in his off time hahha

[32pwwr]

23 hours ago, Murray_Calavera said:

The money your spending on your mechanic to build one motor, you could use on educational material (say https://www.hpacademy.com/courses/learn-how-to-build-engines/) and tools to build X motors in the future. 

I don't think you should be worried about 'blowing up' a motor from incorrect assembly. If everything is going well during assembly, turns over perfectly by hand, what is it that you are worried about? 

I'm not saying you won't run into speed bumps along the way, but they should be apparent at the time and then you can address them as you encounter them. 

The blowing up part is usually reserved for tuning issues lol. Speaking of which, are you going to tune it yourself? 

I’m pretty good with the fabrication, painting and wiring. Get it how I like it but when trying to learn how to build a motor I just can’t get myself to by myself, I’d love to reason Ill do it along with him and mainly I’ll be doing it he’ll just guide me on it. 

reason I learnt how to paint, fabricate and some basic wiring skills is Because my father and learnt step by step from him hahah