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Rb25 Neo Manifold Advice

sonnyQ

By sonnyQ,
in Engines & Forced Induction

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sonnyQ Mentor

sonnyQ

Posted
Posted

Hi all, I appear to have a cracked manifold or a shagged gasket as the car sounds like a grain truck on the exhaust side of the engine. As there is a fair bit of labour involved with replacing whatever the problem is, be it manifold or gasket, I am tossing up my options should I need a new manifold.

I am not completely averse to the idea of upgrading/hiflowing the turbo down the track (has 85thou on the odometer). However, before this happened I was days off getting a nistune and boost controller installed. With that in mind I am wondering what the best bang for buck manifold is that would suit a wide variety of suitable turbo's?

If I were to stay with the stock turbo for a while, would an upgraded manifold be a waste of time? Would I need a tune or anything else?

any help appreciated...

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GTScotT Grand Master

GTScotT

Posted
Posted

The above is irrelevant as plazmaman is an intake manifold, not exhaust.

Sonny I highly doubt your manifold is cracked, its likely to be the gasket from turbo to manifold which is just T3.

As it wont be a single day job for an ameture anyway, I recommend you take the turbo and manifold off and inspect for the damaged gasket. You can then also inspect for cracks in the manifold if the gaskets are fine.

stock RB manifolds are very easy to come by as are the gaskets, so dont be afraid to take it apart first and work it out from there.

LANDSCRIBBLE Mentor

LANDSCRIBBLE

Posted
Posted

They say the stock manifolds flow well enough for 300rwkw. So yea for a stock turbo its not really worth upgrading. Not sure if it would need a retune from only upgrading the mani, the gains would be very minimal on that power level

34GeeTeeTee Grand Master

34GeeTeeTee

Posted
Posted

The above is irrelevant as plazmaman is an intake manifold, not exhaust.

Sonny I highly doubt your manifold is cracked, its likely to be the gasket from turbo to manifold which is just T3.

As it wont be a single day job for an ameture anyway, I recommend you take the turbo and manifold off and inspect for the damaged gasket. You can then also inspect for cracks in the manifold if the gaskets are fine.

stock RB manifolds are very easy to come by as are the gaskets, so dont be afraid to take it apart first and work it out from there.

Fark, at work and completely misread the post! Sorry Clint!

IF your exhaust manifold is stuffed and you decide to stay with the stock one let me know as i have a spare in my shed! :)

sonnyQ Mentor

sonnyQ

Posted
  • Author
Posted

Sweet, thanks Ray. Bit disappointed I missed your pre-edit post...

My mechanic is trying to con me into getting a 6boost one made up as they are local and the 'best', but having just bought a house I think this would just open a big can of worms for me :( Particularly if the stock mani can flow to 300rwkw I don't think I would bother changing it. Would there be any gains AT ALL with a 6boost/hottie manifold running the stock turbo? Surely a bit more flow? I think my money would be better off going into nistune/boost controller/clutch first up...

Lastly, does anyone know if the T3 gasket is something that does commonly needs replacing on the NEO's/RB's?

34GeeTeeTee Grand Master

34GeeTeeTee

Posted
Posted

Sweet, thanks Ray. Bit disappointed I missed your pre-edit post...

My mechanic is trying to con me into getting a 6boost one made up as they are local and the 'best', but having just bought a house I think this would just open a big can of worms for me :( Particularly if the stock mani can flow to 300rwkw I don't think I would bother changing it. Would there be any gains AT ALL with a 6boost/hottie manifold running the stock turbo? Surely a bit more flow? I think my money would be better off going into nistune/boost controller/clutch first up...

Lastly, does anyone know if the T3 gasket is something that does commonly needs replacing on the NEO's/RB's?

Its Mat ;)

6Boost manifolds are brilliant, i am repping one at the moment and love it BUT you pretty much answered your own question when you mentioned the house :)

The stock manifolds CAN flow 300 as it has been proven heaps on this forum alone, check the RB25 dyno thread mate :yes: The nistune/boost controller/clutch will do a lot more for you than an exhaust manifold!

Oh, and the edited post was somehow me reading it as inlet manifold, i don't know how but i was having a blonde moment :P

sonnyQ Mentor

sonnyQ

Posted
  • Author
Posted

Ok, so i'm going to at least pull some of the heat shields and other rubbish off to make it easier for the mechanic, and enable me to have a peep myself. Will check studs, manifold for cracks and gaskets...

And sif 'Raymond Terrace' isn't a name...sounds like a serial killer

34GeeTeeTee Grand Master

34GeeTeeTee

Posted
Posted

Ok, so i'm going to at least pull some of the heat shields and other rubbish off to make it easier for the mechanic, and enable me to have a peep myself. Will check studs, manifold for cracks and gaskets...

And sif 'Raymond Terrace' isn't a name...sounds like a serial killer

If you lived there you wouldn't laugh.......................... Cus its probably true :ph34r:

You should be able to see black witness marks if its been leaking for a while, i know when i pulled my manifold off to replace it with the 6 boost i found #6 was leaking but must have only been under boost as i never heard it.....

GTScotT Grand Master

GTScotT

Posted
Posted

Sweet, thanks Ray. Bit disappointed I missed your pre-edit post...

My mechanic is trying to con me into getting a 6boost one made up as they are local and the 'best', but having just bought a house I think this would just open a big can of worms for me :( Particularly if the stock mani can flow to 300rwkw I don't think I would bother changing it. Would there be any gains AT ALL with a 6boost/hottie manifold running the stock turbo? Surely a bit more flow? I think my money would be better off going into nistune/boost controller/clutch first up...

Lastly, does anyone know if the T3 gasket is something that does commonly needs replacing on the NEO's/RB's?

Blowing the gasket is common on all turbo cars mate :) they just die after a period of time and yours is probably 15yo stock.

IMHO Your mechanic is seriously sucking cash out of you for nothing. There is surely a negligable benefit to upgrading the manifold on a stock turbo, and its going to incur more heartache than not as its sure not to fit the same.

Only consider this option if you WANT to stay lowmount in the long run and DO intend to upgrade the turbo. If you dont mind the idea of a highmount then this is a useless exercise as its a lot easier and less labour intensive to mount and make the required changes to accomodate than if the low mount isnt a Perfect Fit.

I hope Ive been clear enough, Im a little pressed for time.

And I interpreted Ray as Ray charles (blind) rather than OP blind error on name vs location LMAO.

sonnyQ Mentor

sonnyQ

Posted
  • Author
Posted

Blowing the gasket is common on all turbo cars mate :) they just die after a period of time and yours is probably 15yo stock.

IMHO Your mechanic is seriously sucking cash out of you for nothing. There is surely a negligable benefit to upgrading the manifold on a stock turbo, and its going to incur more heartache than not as its sure not to fit the same.

Only consider this option if you WANT to stay lowmount in the long run and DO intend to upgrade the turbo. If you dont mind the idea of a highmount then this is a useless exercise as its a lot easier and less labour intensive to mount and make the required changes to accomodate than if the low mount isnt a Perfect Fit.

Haha, my mechanic is actually a good mate that I have know for years....I think he just wants me to build a hottie (and work on something fun). Hopefully its just a gasket and I can change it myself....never pulled a turbo or anything off before though :/

so the long and short of it is: If I upgrade the turbo move towards a high mount? If hiflow a worthwhile exercise? what about sticking with the stock mani and getting one of the hypergear etc straight bold on jobs? I will have a dig around on the dyno thread.

Cheers everyone for the advice, very helpful :thumbsup:

GTScotT Grand Master

GTScotT

Posted
Posted

Rule of thumb for modding a basic skyline:

300+ rwkw = quality highmount and external gate turbo

250-300rwkw = Stock Manifold + Hypergear SS2/G3, GT30 IWG OR external gate plumbed off manifold and can use any option for this one like HG, Kando, Garrett, Precision.

250kwish = Stock manifold + highflow or HG SS1PU (highflow for stock appearance, SS1PU for a more unrestricted outcome at the expense of a slightly more obvious upgrade)

FYI most of the sub 300kw options from Hypergear will not require a substantial amount of work to have them fit as he machined the rear housing to fit the stock dump pattern. Most cost effective fast skyline would sport a hypergear SS2 and mostly off the shelf parts, my personal opinion.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

If you only ever want to get a hi-flow - don't move away from the stock manifold, it''l cost you another $2000 by the time it's done and wont really give you a decent performance gain. Stocker 300rwkw under is the best bang for buck.

You've likely just done a gasket as people are saying. It's pretty common in RBs over 10 years.

sonnyQ Mentor

sonnyQ

Posted
  • Author
Posted

Thanks everyone for their input. Going by advice, I think the plan will be to replace all the gaskets on the turbo side, hopefully that's all the problem is. From there i'll stick with the orig plan of nistune and dial in some extra boost then go NPC organic clutch when that fails. I think i'll go for a high flow job ultimately, and then injectors and fuel pump and re-tune (mortgage allowing :P)

Looking at the dyno thread I think the first step will bring teh lulz, and then i'll move on from there....any chance I will hit 200 with 10/11psi, nistune, fmic and exhaust? others seemed to go close.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Make sure you also change all the manifold studs. The reason the gasket has blown out is probably due to 1-2 of them breaking... And a couple more will probably break during manifold removal. So have all the studs changed out and never worry about it again :)

msports180 Mentor

msports180

Posted
Posted

Mine had done 170k's and never broke one stud, only 2 came out instead of the nut coming off. I soaked the shite outa em with CRC, drove it, soaked em again then left it a few days and all came out no probs.

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