[Rb30/25 max hp on stock head bolts]

Good Evening Gents thanks for the input. I will hopefully know soon had a call from a supplier. 

Will hold on and do the right thing? 

[Rb30/25 max hp on stock head bolts]

Good Evening everyone hope you all well and keeping safe.

I am busy with a rb30/25 build and would like to finalize my build in the next 2 months however I am sitting with a little problem hopefully you guys can advise.

My questions is what is the max hp the stock Rb25det head bolts can handle?

I have been trying to source Arp head studs same as Rb25det  but Unfortunately none of the suppliers in Sount Africa have stock and are all waiting for containers to come in. Been about 4 months and i would like to start driving the car.

I have googled and came across a discussion that says they sitting at around 600hp on stock Rb25det head bolts. Not sure if this can be confirmed and if anyone has done something like this.

Build breakdown as follows:

Rb30 block

Stock 86.5mm pistons with Hastings rings

Stock rods but shot peened and Arp rod bolts

Rotating assembly balanced

Oil galleries drilled

Rb25det cosmetic head gasket

Acl main and big end bearings

Rb25det oil pump and flowed 

New water pump

Rb25det damper pulley

1.5mm oil restrictors

Stock crank 

Rb25det head ported and flowed intake and exhaust

Port matched intake

Rb26 valves,  quarters , retainers, valve springs, Lifters, cams cut 270

So the head is solid lifters and solid cams

Top mount branch pic attached built by Marius Fullboost South Africa 

38mm waste gate

Greddy blow off valves 

Stainless boost pipes

HKS Fuel rail

Lucas 1200cc injectors 

2 x bosch 044

Turbonetics Hurricane 7868 aka Benita 

Spitronics Mercury Fuel Management

That about where I am at the moment.

Any input as usual is appreciated and thanking you in advance for all the help and guidance so far with this build?

Thanks Brian Chev R

 

 

 

 

 

[Rb30/25 Greddy Style Intake]

Hi KiwiRS4T don't have the stock anymore have the 76mm. So you reckon I can make some power with it?

What would you say should be the limit before the intake needs changing again?‍♂️

Sorry about all the questions I am stuck with it now so trying to see what are the limits and if any good.

Valuable input?

[Rb30/25 Greddy Style Intake]

Hi KiwiRS4T appreciate your response will probably need to take my intake with to check for mating. Currently use a Hks fuel rail would that fit? My throttle body is a 76mm atm. Some guys say I should go 80-90mm.

So gathering from your response it's a bi go. Will have to research other options.

Thanks appreciate your input?

[Rb30/25 Greddy Style Intake]

Good Day Guys Chev R here hope you all doing well and keeping safe.

I would like to please ask again for your expert advice and assistance please.

I have fitted my Rb30/25 into my car everything looking good however with the added deck height of the Rb30 sub I am have to make a few changes.

What I am after is input on the Greddy Style cast intakes. I can get the intake similar to the plazmaman intake manifolds too but they are ridiculously expensive in South Africa. My current intake i used the stock Rb25 bottom half with runners and built a plenum on top. Unfortunately this now stops my bonnet from closing. My Turbo has the same issue but will be dropping the turbo flange lower to get the clearance. Please see pics attached of fitment. 

Also attached is the cast greddy style intake. Not sure if any have used it and can advise if they any good? Any opinions will be highly appreciated. Would have preferred to have a custom plenum built on the old runners but too expensive as well.

Sorry for long write up. Any honest input will be appreciated.

Thanks

Chev R (Brian)

[Turbo Advice]

Hi GTSBoy intake not of all the info and really appreciate all the guidelines. Very detailed.

Will have to decide where I would like to be. 

Just had a thought I can possibly also upgrade my turbo to a 62mm inducer and 84mm exducer on the compressor wheel to a billet 7 blade or 11 blade. Will have to machine my compressor housing to fit.

And leave the turbine as is as it measures about 64mm inducer and 74mm exducer with Ar68 housing.

Once again thanks for the responses helps to have a clearer path of where I want to go.

Will also research some other turbo options on the Garrett range.?

[Turbo Advice]

Hi GTSBoy the idea is to start of with 500hp and gradually increase. Car will be used on the street.

Sub assembly is freshly built but not with forged internals.

If I may ask what do you mean by 84mm? Is this 84mm on the compressor side or exhaust side?

The Turbonetics measures 78mm on the top of the wheel and about 90mm at the bottom .

Exhaust measures 68mm on the top of the wheel and 78mm at the bottom of the wheel.

Comes std with a Ar96 exhaust housing T4

So the intent is still for the car to be responsive and not to have too much lag.

Maybe to start boosting at 3-3500rpm.

Hope this helps

Sorry if I did not understand your response too well.

Murray thanks for your response I gather what you mean

[Turbo Advice Rb30/25]

Hello Everyone Chev R here from South Africa.

I am in need of advice from some of the guys that have done this before. I have checked a few threads on turbos that guys suggested and has been been covered.

My need currently is this I am building a Rb30/25 and have got my current turbo specs as follows:

Ar 70 compressor housing

Compressor wheel 58mm

Exhaust housing Ar68

Exhaust wheel 64mm

Now some of the guys I know in the drag seen here advise that the turbo will be perfect down low but will probably choke towards limiter maybe 6000rpm. What is your take on this please need some guidance?

I will be limiting rev range to 7000.

One of the guys I know offered me a turbonetics 7868. I will attach specs as per my research.

What I am after is is my turbo going to run out of steam higher in the rev range. If someone has had a similar turbo set up?

If so would the turbonetics be a good second option as this is being offered to me at a good price. 

Car will be used for street and once the covid pandemic passes at the race track from time to time.

Apologies posting again because I may have posted In the wrong forum. 

Would the turbonetics be a good set up for street mostly occasionally quarter mile track?

Basic breakdown of my build

Rb25det head a little work done to it.

Solid lifter ,solid cams, ported and flowed with Rb26 valves ,quarter's, retainers and lifters

Solid cams solid lifters , cams cut 270

Rb30 sub

86.5mm pistons , hastings rings

Oil restricted 1.5mm

Rods short peened , and arp rod bolts 

Rb25det oil pump

Rotating assembly balanced 

Appreciate all the help and assistance 

Brian ( Chev R)

 

[Turbo Advice]

Hello Everyone Chev R here from South Africa.

I am in need from some of the guys that have done this before. I have checked a few threads on turbo that guys suggested and has been been covered.

My need currently is this I am building a Rb30/25 and have got my current turbo specs as follows:

Ar 70 compressor housing

Compressor wheel 58mm

Exhaust housing Ar68

Exhaust wheel 64mm

Now some of the guys I know in the drag seen here advise that the turbo will be perfect down low but will probably choke towards limiter maybe 6000rpm. What is your take on this please need some guidance?

I will be limiting rev range to 7000.

One of the guys I know offered me a turbonetics 7868. I will attach specs as per my research.

What I am after is is my turbo going to.run out of steam higher in the rev range. If someone has had a similar turbo set up?

If so would the turbonetics be a good second option as this is being offered to me at a good price. 

Car will be used for street and once the covid pandemic passes as the race track from time to time.

I would appreciate your honest inputs on this please?

Thank you kindly Brian ( Chev R)

[Rb30/25 with Zd30 gearbox]

Thanks Gts boy appreciate it. Guess I will have to send it back than?

[Rb30/25 with Zd30 gearbox]

Good Morning Guys hope you all doing well.

Have not posting in a while been busy getting my build together.

Just a brief I took the rb30 dohc and used that as a build guideline.

Build a Rb30/25 with a series 2 sub.

Stock pistons 86.5mm as the sleeves were oval.

Drilled oil return galleries

1.5mm restrictor

Rods short peened with arp rod bolts

Rb25det oil pump

New water pump

Used my Rb25det head. Ported and flowed with Rb26 valvels, quarters , retainers, solid lifters and original cams cut 270. Just refreshed everything. 

Currently using rb30 gearbox but was grinding a little bit. 

So I opted to get a new gearbox seeing that everything is now being put back together.

I had a call from a guy that imports engine etc. He said he had a Rb25det fat boy box. So I obviously jumped at the opportunity to get the box based on reviews.

Got the box at home now and just checked fitment etc and started seeing some differences. 

My starter does not fit seems to be smaller. So I am worried I would have to change flywheel, clutch etc

The bolt pattern seems to line up with backing plate but not starter bolts

So it seems I would need to change the starter.

Upon some research on google this gearbox seems to be from a Nissan bakkie the zd30 diesels gearbox.

Basically my gripe is should I try and use this gearbox I probably need to change flywheel, starter and pressure plate. I don't like the Idea because i had my complete rotating assembly balanced. And with the covid pandemic not all engineering shops are operating.

What I am after and if I can get your input please guys is?

Has anyone ever used this gearbox or attempted to and what were you findings?

Looks similar to pictures I see of the fatboy box. Also found this code not sure if this is rb though FS5R30A.

Confused as I am doubting my decision as the guy assured.me it is a Rb25det fatboy gearbox and do not want to go through all the hassles as I wanted something straight fit that can  handle more power. My clutch seems to fit though.

I am attaching some pictures for review.

I would really appreciate your input guys as you have been doing this and have the experience.

Thanking you in advance Chev R based in South Africa 

 

[RB 30 /25 BUILD]

11 hours ago, PLYNX said:

Found em ! 

Here what can be done with a linisher, die grinder, sanding discs, etc etc.

Note the difference where excess metal is removed.

You'll also need a set of fairly accurate scales to weigh each rod to get them all the same weight towards the end of the process.

The finished rod is now ready for shot peening :

 

 

Hey Plynx

You can actually see substantial difference's. Will have to get someone experienced to do this for me. Shot peening have confirmed with Fulrace collecting them today from my engine builder to drop off will find out if they can do it there maybe.

Thanks for all the hassle in showing me this

I have one more question if I may and this is with regard to the sump/oil pan and oil pick up? Here goes:

The series 2 sub assembly I bought did not have an oil pick up so I have been searching on whether I can just use my Rb 25 det oil pick up and sump/ oil pan.

I have come across some reading where guys say the Rb25 det sump needs to be modified and some fins cut but no real detail explanation.

Is there any one that may have more info on this mod and maybe pic's if available?

And is it necessary for me to have sump baffles fitted as this will be mostly a road car and from time to time on the track?

Thanks in advance everyone any responses will be appreciated

 

[RB 30 /25 BUILD]

9 hours ago, KiwiRS4T said:

Large duration cams is the 270 deg cf stock around 240. VCT would help with making car more streetable and is definitely worth doing.

The sump plugs I suggested were so that if it became necessary you could run a breather to a catch can and a drain back. Polish up your stock rods as you have suggested and just get the forged pistons.

Hi Kiwi

Sorry I am not so technically knowledgeable but I will have a chat to our Skyline Guru this side and try and have this done.

I do currently have a catch can but pipes run from cam covers. Will have this done aswell.

Rods will be taken In on Monday to have the shot peen done.

I attached just some pic's of how the setup looked.

Thanks for all the valuable info from everyone so far it is appreciated?

[RB 30 /25 BUILD]

3 hours ago, GTSBoy said:

Is that because of large duration? Because otherwise they're not mutually exclusive, and VCT is worth a LOT of cam.

Hi GtsBoy

Not sure what you mean by large duration can you elaborate? Please excuse my ignorance I am not really a engine builder.

Something I will need to look into I guess

[RB 30 /25 BUILD]

1 hour ago, GeeDog said:

Are you planning on using the VCT? You'll need to get head mods done for the oil supply, and also to allow a bit more meat where the RB30 block is different to the RB25 (if I remember correctly a coolant gallery in the block isn't really covered by the head. I might be totally wrong, it's been a few years & I'm not as young as I used to be. I used a machine shop who has done quite a few RB25/30 setups, and was going to recommend him to you, until I realised South Africa.

Hey GeeDog

No I won't be using the VCT my head is solid cams and solid lifters.

Sorry also did not realize but makes sense. Your input is valued 

[RB 30 /25 BUILD]

25 minutes ago, PLYNX said:

GTSboy Ive done the same over the years as well running the old Holden inline red motor 6 up to 7000rpm on preped star fire rods and just over 8000rpm on preped VW Passat rods so it can be done.

You just need to get rid of the excess casting slag and weight from the rod then prep them the rest of the way.

I Ive got a set of RB30 rods half preped some where which I stopped cause here in AUS the after market rods worked out better.

Have you looked into maybe a set of after market 6 inch Chev rods ?

They can made to fit with a small amount of work !

Research Research Research !

Hey Plynx 

Will be taking the rods to Fullrace here in South Africa a engineering shop.

To be honest I have not looked at the v8 rods but I have seen a few topics that made mention of it.

True and everything I have done is through reading and research on what guys like you have done.

Still researching thanks

[RB 30 /25 BUILD]

24 minutes ago, GeeDog said:

 

South Africa then - SA on an Australian forum is usually taken as being South Australia.

Hey GeeDog

Noted will make proper reference ?

[RB 30 /25 BUILD]

9 minutes ago, GTSBoy said:

You can spend the hours on the rods instead of Rand. Back in the bad old days, I spent many hours polishing ALFA rods and other things that it wasn't worth spending cubic $$ on new billet stuff for. And in those days, pre-Chinese manufacturing, anything aftermarket cost waaay too much anyway.

Thanks GTSboy will be having rods done?

[RB 30 /25 BUILD]

7 hours ago, KiwiRS4T said:

Don't know anything about your turbo or ECU but you look to be set for north of 400KW

Re oil control  consider putting a couple of half inch plugs in the sump (above the oil level ) in case you need them later.

Also people will suggest say 1200 injectors (do it once).

Why two blow off valves?

Should be great when done!

 

And what Plynx said - head work looks like overkill but if you have already done it....

And yes forged pistons but rods will be fine if treated as per above.

Hey KiwiRS4t

Thank for your reply

The Turbo is a hybrid if I can call it that Garret 60-1. Are 70 Compressor and Ar 68 Exhaust side and T4. Similar to Gt35. Management is one of the brands we have here. 400kw much than I ever imagined but noted.

Are you able to elaborate a little more on the half inch plugs in the sump please?‍♂️

One seized at some point bougt a new one and managed to fix the other so just fitted both?‍♂️

THanks and noted all info will surely speak to my engine builder?

[RB 30 /25 BUILD]

7 hours ago, PLYNX said:

Hey Man;

That all looks pretty good

Just a few things I've spotted in your build;

-Do some research on how much power has been made with stock cams on the RB25 head ! I think you might be over investing for the power you want to make. Some drop in cams for the on the hydrolic set up will save you a bunch of money here

-O-ring the block - if your going to run a cometic head gasket that should be fine.- the alternative is to run a copper head gasket with the o-ringing. Coupled with this, save your little lunch money and get head studs for better clamp pressure.

-As to the rods crack testing, shot peening and magnafulxing them will increase their strength and has been a tried and true method for stock rods since Noah was a boy.

-And lastly, again save your lunch money and drop in a set of forged pistons,  don't do it twice ( the money you will save on the head set up may even allow the rods you are after )

Hope this helps

 

 

 

Hey Plynx 

Thanks for the response.

I have invested in having the head done while the motor was still the Rb25det so not spending on it at the moment has been done.

Noted on the o ring of the block as I have a cosmetic currently will probably look at the Head studs instead.

Rod testing etc will have done not alot of guys have done this just confirms for me?

As for the Forge pistons and Rods I have gotten pricing on it. Unfortunately the SA rand is f....... if can say that think at this point Rand to Dollar is 15. So guys that import charge a fair bit. Rods and Pistons should cost me about R30k SA rand. I need to save up a little to get there.But in my plans for sure.

Thus is valuable input thank you very much.?

 

[RB 30 /25 BUILD]

Good Day Guys

Chev R here from SA have not posted for a while since my car was down. Started an Rb 30 build and need some input and guidance on how to make this budget build work and bullet proof if i can say that please

I had Rb 25det in my car but unfortunately detonated number piston ringlands and spun number 6 big end bearing. So i have been reading up on a substantial amount of info regarding the Rb 30/25 build. I have also down loaded the Rb 30 Dohc guide.

I have started the process of my build and this is what i have done and bought so far"

Cylinder Head:

• Rb 25 det Vvt 
• Ported and flowed 
• Rb 26 valves , quarters , retainers , valve springs and solid lifters 
• Rb 25 det cams cut 270
• Head is solid lifters and solid cams

Block / Sub Assembly:

• Rb 30 series 2
• Drilled to 86.5 due to sleeves not measuring same size through
• Oil Galleries Drilled to size of my Cometic head gasket
• Block has been decked 
• Tension er being drilled and moved 
• New Rod bushes 
• Complete rotating assembly balanced
• Acl Mains and Big Ends
• Rod Bolts Arp 202-6007 for Rb 26 taken. Was going to take Sr20 Arp 202-6005 but when i went to buy we measured both bolts and they measured the same only difference was the length of the bolt rb 26 being slightly longer. Opted for 26 as it comes with 12 as apposed to 16.
• Block will be o ringed 
• Rb 25 det 1.2mm cometic head gasket 
• Extended Crank Collar fitted 
• New Timing Belt
• Using Rb 25 Det Oil pump that will be flowed
• New Stock pistons with Hastings Rings

Other Parts :

• 60-1 T4 Turbo 
• Bosch 750 cc Injectors 
• 40mm Waste gate 
• 76mm exhaust 
• Full Boost SA turbo branch 
• x 2 Greddy blow off valves 
• 3 button clutch 
• Spitronics Mercury 2 Engine Management 
• 76mm throttle body 
• Catch Can 
• Vacuum Block 

 

What i am after is with what i have so far what do you guys think would be a good Hp number i can aim for? I have read some guys doing 500hp and others in access of 600hp. Please share your experiences?

Also i have read about rods being short peened and polished to make them stronger. My question is is this worth wile doing and will it assist to make them stronger? If so i will have it done while the motor is apart.

I am a skyline guy and here in SA everything is almost 2jz and i guess with reason but i guess i wanna prove a point that RB'S also make power you know. I will be saving for forge pistons and rods abit later will be getting CP's.

I would appreciate your expert advise and guidance please.

Should there be anything i may have left out please make mention and all input is appreciated

Thanks 

 

[Rb 25 Det Head on Rb 26 Bottom end]

Hi Guys.

Hope I can get some help here. I have searched to try and see if I can get any info but could not get much.

If I could possibly get some info on the conversion I am considering doing please.

I currently have and Rb 25 Det engine. These are some of the Mods that were done.

Cylinder Head: Ported and Flowed

Cams cut 270

All rb 26 internals: Valves , Lifters , Retainers , Valve Springs etc

So the head is complete solid lifters solid cams not using vvt anymore.

Sub Assembly is stripped due to detonation: 1 piston in the ringlands , no 6 big end bearing spun.

So this is what I need help with please

A friend of mine offered me a rb 26 bottom end that I can fit the Rb 25 det Head too.

So some of the info that I have managed to get says it can be done. The Rb 26 uses 12 mm bolts.

But are there any other mods that need to be done in terms of water galleries and oil?

Can I use my rb 25 cometic head gasket of the block?

Or is this a straight fit?

Any input will be appreciated

Chev R

[Advice / Input]

Hi Kiwi plugs are gapped 0.8mm. I have a set of Bmw M3 coils that I will be using. Just will try and see what happens once this is done. Thanks for all the input I really appreciate it.

[Advice / Input]

Thought I'd add a video to show rev's clean only breaks up under load

VID-20170422-WA0003.mp4

[Advice / Input]

Hi Kiwi I've been busy with converting a set of coils but came across another thread discussing some of the issues other guys are having. After reading through It seems to me that I may have a similar problem. So I removed all the coils including the aluminum portion that is bolted in the middle of the cylinder head. Low and behold the hole bottom of the aluminum casing is black seems that the coils have been earthing against it when ever it spark breaks. So my car starts normal idles normal and rev up to limit when stationery also is not missing like a dead plug or coil. Only time it spark breaks it under load. So I got some liquid electrical tape with a brush and also bought some plastidip spray also for electrical insulation. I will be spraying the aluminum cover with that to insulate it so the coils does not spark against it. Also will do the coils and suppressors with the other. Worth the try I guess. I unfortunately cannot have the aluminum portion cnc'd out of plastic as the other guys did. So I will be doing that tonight possibly with put everything back tomorrow and go and test. Hopefully resolves my issue if not I have been busy with a set of other coils. Don't know if you've seen any of the threads speaking about spark break issues.