Rb25 Bottom End Query

[fattox33]

Hey all,

Will be building up my RB25 R33 for approx. 500rwhp around April 2011, and need to know a few things before I start..

Background - the motor currently has stage 1 HKS cams and exhaust cam gear (adjustable), however I am unsure of the timing as the motor was bought secondhand.. i assume around 262-264 possibly? also has ACL forged standard bore pistons, and race bearings all round. running on standard conrods at the moment.

New parts - Will be upgrading with the following: Garrett GT3582R .67 rear (700hp capable), 750CC injectors, Sard fuel rail, Malpassi rising rate FPR, walbro intank pump, high mount manifold, plazmaman front facing plenum, and Link G4 plug-in ECU.

I'm shooting for 500hp, so using the rate of approximately 20% loss through a manual drivetrain that puts engine/flywheel power at 600hp...

I want to know if anyone here has ever run an RB25 on this sort of power, I assume it'll need to be running between 22-30 psi of boost, but this will only be for a dyno run to prove capability, the engine will be down-tuned to around 300rwkw or approx. 400rwhp for daily use.

Also if anyone knows, what is the approximate breaking/failure point of standard Nissan conrods in an RB25? I know I'll probably need to upgrade them in the near future anyway, but I understand that dyno-runs at 500hp and daily driving at 400hp exert different stresses on the motor (dyno offers a lot less friction so bigger numbers are easier to obtain without overly much damage to the motor).

TL:DR; will 500hp dynoed and 400hp daily tune kill my standard RB25 rods? pistons are forged.

[NYTSKY]

Look in my build thread.

[r33_racer]

Rods will be fine, just dont go past factory rev limit.

For piece of mind you can get a set of spool rods. Affordable and will shit it in for the power you are looking at.

[TiTAN]

Garrett GT3582R .67 rear (700hp capable) - i wasnt aware garrett made any other than .63 .82 1.06 genuine T3 housings of which the .63 will be hard pressed to make more than 350kw @ the rears, if you want the power go the .82 or 1.06

walbro intank pump - i would be looking at a bosch 044 instead they are proven time and again that they can pull the numbers

I'm shooting for 500hp, so using the rate of approximately 20% loss through a manual drivetrain that puts engine/flywheel power at 600hp... - at the best of times guessing these figures is akin to picking the lotto numbers, if you want to know what it has at the fly get it on an engine dyno.

I want to know if anyone here has ever run an RB25 on this sort of power, I assume it'll need to be running between 22-30 psi of boost, but this will only be for a dyno run to prove capability, the engine will be down-tuned to around 300rwkw or approx. 400rwhp for daily use. - nytsky has 400kw with a built 25, you build the engine to take this power, with the lag of a turbo that will make the power, why wind down the boost like a girly man

Also if anyone knows, what is the approximate breaking/failure point of standard Nissan conrods in an RB25? I know I'll probably need to upgrade them in the near future anyway, but I understand that dyno-runs at 500hp and daily driving at 400hp exert different stresses on the motor (dyno offers a lot less friction so bigger numbers are easier to obtain without overly much damage to the motor). - Rod bolts are the weakest link more so than the rods, if you can just open it up and get some spool rods fitted $600 + fitting, a small price to pay for security seeing as the rest of it is already done.

TL:DR; will 500hp dynoed and 400hp daily tune kill my standard RB25 rods? pistons are forged. - TL:DR maybe, it may last for years or it may not, you may win lotto tomorrow or you may not end of the day its luck and tuning

[R31Nismoid]

I think you'll find a legitimate 500rwhp a bit hard with a .67 rear... you sure that is correct?

The only other thing is the factory rods - Totally depends on what rod bolts were used.

If for some reason factory items were installed - you would want to think twice about it all TBH and settle for a bit less power/smaller turbo to be in the safe side

Otherwise mirror what Titan has said, especially the fuel pump part.

[r33_racer]

lol I missed all the other questions in there....haha pays to read the whole post properly instead of just skimming and then reading the last line.

[fattox33]

thanks for all the help guys, sorry I did actualy get the A/R wrong on the rear I had a different turbo in mind (or had a fk up, either or it's my bad!)

I was talking to a mate, and for the sake of an extra $1500-$2000 it may well be worth looking into getting some decent forged I-beams and fitting them up, a friend in town is a qualified mechanic who's doing weekend cashies, has built an RB25 and a 25/30 from the ground up with pretty high power so I figure i'll talk to him to get some forged rods and ARP rod bolts, all the bearings are ACL bearings, the motor is pretty well nearly built for that sort of power as it is, the only weak link would be the rods and possibly it would be worth looking into flowing the head a bit better, i mean im spending close to $10k as it is on just parts and tuning so why not spend a few hundred extra for some head goodies while the head is off?

i figure with an AVC-R and a decent cam duration it wouldn't have too much trouble building boost, especially when i get bored and turn on antilag =P

[fattox33]

NB: current parts list, edit and add others if you see the need or if i've missed something =D

Garrett GT3582 - 0.82 rear

Wastegate - Tial Sport 38mm

Turbo Manifold (high mount)

Plazmaman intake manifold kit (piping/plenum/silicone/bigger tb)

Fuel System Upgrade - Bosch 044/750CC injectors/Sard rail/Malpassi FPR)

APEXI AVC-R boost controller

Link G4 Plug-In ECU

Spool Conrods

ARP Rod Bolts

I figure if I go with forged conrods it probably means I can crank maximum recommended boost out of that turbo and aim for over 500rwhp, as I said it'll be getting down-tuned for street duties (cops are arseholes in Toowoomba/i'm a poor uni student and need something reliable-ish)

All help is immensely appreciated

[KiwiRS4T]

NB: current parts list, edit and add others if you see the need or if i've missed something =D

Garrett GT3582 - 0.82 rear

Wastegate - Tial Sport 38mm

Turbo Manifold (high mount)

Plazmaman intake manifold kit (piping/plenum/silicone/bigger tb)

Fuel System Upgrade - Bosch 044/750CC injectors/Sard rail/Malpassi FPR)

APEXI AVC-R boost controller

Link G4 Plug-In ECU

Spool Conrods

ARP Rod Bolts

I figure if I go with forged conrods it probably means I can crank maximum recommended boost out of that turbo and aim for over 500rwhp, as I said it'll be getting down-tuned for street duties (cops are arseholes in Toowoomba/i'm a poor uni student and need something reliable-ish)

All help is immensely appreciated

Intank Bosch is 040. Shouldn't need fpr or new fuel rail (unless you're getting some odd-ball injectors).

[Guilt-Toy]

make sure you have a 044 pump and your turbo has the 1.06 rear housing for that horse power. as well as the rods issue and no more then 7500rpm it will live a long time

[TiTAN]

i figure with an AVC-R and a decent cam duration it wouldn't have too much trouble building boost, especially when i get bored and turn on antilag =P

you could sell off the AVC-R and use the built in boost control with the ECU, with a wired in switch you can have dual boost settings, but with a motor built like that the power isnt going to hurt it.

Just leave the boost up and dont put your foot down as far you get the same result.

[tridentt150v]

wastegate will be too small for that set up

[r33cruiser]

make sure you have a 044 pump and your turbo has the 1.06 rear housing for that horse power. as well as the rods issue and no more then 7500rpm it will live a long time

I was always led to believe that the .84/86 was the one to go for for 500-550hp? I thought 1.06 was only if you wanted 600+? and had the luxury of more displacement.

P.s what would the lag of a 1.06 be like on a 2.5ltr considering the .84/86 wont be on full song till the early (if your lucky) to late 4000rpms?

[R31Nismoid]

The GT35 is a 700hp rated item in the .82 IIRC

I know my GT3040 was 600hp in a .82 with the largest GT comp wheel on offer (and was well and truly on song by 4k rpm)

Given it was what, 17psi for 270rwkw with a crap exhaust, so give it 20-22psi 300-320 is what you'd expect from the 600hp variant without much of a worry (in theory)

I cannot see why a GT35 with a 82 couldn't see 350-360rwkw with 22psi or so given it's a proper external setup and if the motor is build right.

With a Garret-IW you might have problems however but that's not something to deal with in this scenario

[TiTAN]

the 0.82 will do 500hp, pushing it over 400kw is where its a little hit and miss the 1.06 far more reliably pulls the 400+ numbers (on standard 98 pump fuel).

[fattox33]

Intank Bosch is 040. Shouldn't need fpr or new fuel rail (unless you're getting some odd-ball injectors).

it's going from side feed standard injectors to top feed 750cc's so i thought i'd need a rail?

would a TR44 wheel from that mob in brissy be even worth looking at out of curiosity? and i'd rather the 0.86, ill talk to a friend down here who made 472rwhp with the gt3582 and see what housing he had..

i don't want an overly large lag, like i understand im gonna have to expect some going from a highflowed standard turbo being on full by around 2000rpm lol... i'd honestly be happy with 480rwhp (360rwkw), it's still a pretty decent power figure, in the end of the day like i said, will be tuned for daily driving, the dyno sheet will basically just be a wank sheet when i do sell it (trust me, I will eventually!)

[fattox33]

QUOTE (KiwiRS4T @ 9 Jul 2010, 03:53 AM) *

Intank Bosch is 040. Shouldn't need fpr or new fuel rail (unless you're getting some odd-ball injectors).

it's going from side feed standard injectors to top feed 750cc's so i thought i'd need a rail?

would a TR44 wheel from that mob in brissy be even worth looking at out of curiosity? and i'd rather the 0.86, ill talk to a friend down here who made 472rwhp with the gt3582 and see what housing he had..

i don't want an overly large lag, like i understand im gonna have to expect some going from a highflowed standard turbo being on full by around 2000rpm lol... i'd honestly be happy with 480rwhp (360rwkw), it's still a pretty decent power figure, in the end of the day like i said, will be tuned for daily driving, the dyno sheet will basically just be a wank sheet when i do sell it (trust me, I will eventually!)

another thing i'm curious about is cam timing, i know i have got some form of cam replacing the standard but i have no clue what size, like i said the engine has been replaced and it came as is, the mechanic who built it doesn't know the timing as the cams were done with tuning, im guessing 256deg... i was thinking of up-rating the entire valvetrain anyway, tomei all through so valve spring seat shims, solid lifters and a big lift/big duration cam (270deg).. would 270 degrees be too long on the exhaust timing as well as intake timing?

Edited July 9, 2010 by fattox33

[fattox33]

still up for questions here, see previous!