Jump to content
SAU Community

Recommended Posts

RB26 N1 Manifolds, any better?

Hi Guys.

So in the upgrade path of my GTR, i've had lots of conflicting information, one of them is about Manifolds.

I had been told by one person, he put TOMEI expremes on, and it made the car very laggy.
So I'm wondering, is there any improvements to be felt either low down, mid or top with GT-SS Sized turbos at high boost.

Most say just port match the manifold to the turbo inlet and to the head and don't touch anything, however I have seen some online shops selling
N1 Manifolds, which still appear to be cast, but higher flowing.  I'm wondering surely Nissan would have modified these for a purpose for the N1 models
if they give some sort of improvements.

Has anybody tried the N1 manifolds themselves and noticed any sort of improvement, or could offer any advice.
I don't simply want to hear "stock ones are OK" comment, but some more info and personal experiences.
I remember various articles on Autospeed on porting stock manifolds on RB engines, but did not cover RB26.

Thanks guys.

Link to comment
https://www.sau.com.au/forums/topic/467095-rb26-n1-manifolds-any-better/
Share on other sites

 

Tomei shows the difference in ports here - https://www.tomeiusa.com/_2003web-catalogue/000_expreme/each-product/rb26_exhaust-manifold_en.htm

manifold.JPG

The N1 manifolds are reportedly a 'higher quality' cast with slightly larger ports as standard designed for N1 turbos (old version of Garrett 2860-7s)

Standard RB26 manifolds ported to match the turbine outlets will level out any advantages to be had with N1s or Tomeis.

The one drawback to note with the Tomei manifolds is quite a few owners have had them develop cracks due to being made from a thinner 2.5mm stainless steel rather than cast iron.  This is particularly exasperated when heat wrap is used to dissipate the heat, using exhaust wrap crystallizes the metal ( especially stainless ) and halves its life causing cracks.

Given the difficulty to get to the manifold should they fail, porting N1 or standard manifolds is a much more proven/cost effective method to improve flow.  The money would be better spent on a set of BNR34 dump pipes or Tomei dump pipes if you have the cash.

 

Some good threads to look at;

 

Edited by squareznboxez

I'm currently making 350kw at the wheels with factory untouched manifolds with -7s, basically with a -7/-9 the turbo will run out of flow before the factory casting of the manifolds.

-5 I'd say is when it's time to open them up

  • Like 1

If I was given N1 manifolds I would use them, but I would not pay for them since the difference is so minor and can be done with about 30 mins and a die grinder.

If you go larger in I.D generally you will loose port speed and incur lag. Sometimes with no appreciable top end gain. You can make up some of it with collector design but with low mounts you are limited.

 

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Brooooo Please send ABS control unit schematic Please! R33 gts25t ABS (Its two plug ecu, black and white) wire colors possible? [email protected]
    • Don't even try to run it on the stock ECU if you're going to have the boost controller bring boost above ~10 psi. I've already told you that. If you use the Nistune ECU, you will need to CAREFULLY read the available documentation for Neo tuning, and read some threads on the Nistune forums, to discover the various things you have to do to prevent the ECU from going bananas when the boost is too high. The is a table associated with th boost sensor that must be modified to prevent it from shitting the bed. This is just one of the things that you will need to do to the tune in Nistune, because the Neo turbo ECU will be expecting to see a number of things (such as the TCS) that are not there, and you have to block the DTCs on those. It is totally not surprising to me that you are having the problems that you are, but the solutions to these problems have been known for >15 years. So just get it done.
    • Hi. Sry iam not a mechanic and iam not at the car atm so i dont know 100% but they told they measure those and even try to change those. AFM they have two. Coils are new a they have my old one too. Plugs too. ECU...we have 25 NEO stock and Nistune 25 NEO.   But i dont know if any one those could be the problem and why/if/what can cause this, Only thing they did not check is fuel...but that walbro 255 is new(like 1,5 years)... That fuel pressure gauge idk...but i let them know Any suggestions?   EDIT: how can they know if it is like you say he ECU pull power when it reaches a specific boost level that is too high? Tha car has boost controler
    • Can you clarify what you mean by boost cut, do you mean it misfires both when under load (driving) and when stationary and out of gear? Or does the ECU pull power when it reaches a specific boost level that is too high (boost control issue)? Does it occur at idle with no throttle? When you say "the ECU is OK", what ECU is it and why do you think it is OK? Have you used the NEO ECU, and if so do you have a MAP sensor attached? Same for the AFM, why do you think it is OK? Do you have any way to put a fuel pressure gauge on it (even just a mechanical one between the fuel filter and fuel rail)?
×
×
  • Create New...