rb26 OEM v Greddy v Nismo plenums

[RB335]

Hi Guys.

So in pursuit of making my RB26 a well even and smooth running engine I've done a lot to it, putting all the best bits on it

I'd like to know some more information on the Nismo and Greddy manifolds.

The question is do they make the engine run smoother and respond better.

The theory is these try to get the airflow to each cylinder as even as possible, especially fixing the 6th lean condition.

Speaking to many tuners about it and a lot are in disagreement, most say with modern ECU's you can adjust the individual injector to ensure a proper A/F mixture so these manifolds won't help.

My theory still is though if one cylinder is getting less airflow, for that power stroke it makes it is making less power and pushing down with less power down the crank, and the engine won't ran as smooth.

So my first question is, while the theory exists, in practice how much of a difference does it make - I don't mind spending the money if it makes some improvement in your guys experience if you've ever done back to back.  I know a lot of SR guys notice improvements when they put aftermarket OEM replacement plenums on but have not heard so much talk with RB26's

Much reading I done mentions that this helps get the twin turbos working more evently, I'm running a single though.


The 2nd question is, Greddy or Nismo, big price difference.  And which ones can or can't be replaced with the engine in, apparently the engine needs to come out for these to be fitted.

The Greddy one i wonder why is a 2 Piece.

I'm also considering, the Hypertune multi TB plenum

Edited May 27, 2018 by RB335

[WantGTR]

theres people making 900+hp on a stock plenum. not much point in changing it unless youre chasing four figures plus.

[Leroy Peterson]

theres people making 900+hp on a stock plenum. not much point in changing it unless youre chasing four figures plus.

... or want to tidy up the engine bay and make it less of a headache to work on. On the downside, youre changing oem stuff that works just fine and increases possibility of failure

[GTSBoy]

The theory of uneven power strokes making the engine less smooth doesn't really hold water.

And the idea of tuning out lean cylinders only works if you put 6x TCs or 6x O2 sensors on the runners to see the effect otherwise you're "fixing" something with no evidence.

[sneakey pete]

From what i've seen with my egt's the 6th cylinder leaner thing is pretty much a matter of a few extra % fuel into the injector, as most base maps for rb26's do anyway and its then a non issue.

 

[WantGTR]

5 minutes ago, Leroy Peterson said:

16 minutes ago, WantGTR said:

theres people making 900+hp on a stock plenum. not much point in changing it unless youre chasing four figures plus.

... or want to tidy up the engine bay and make it less of a headache to work on. On the downside, youre changing oem stuff that works just fine and increases possibility of failure

nothing fits better than or fits like oem. theres larger plenums take up more room and are harder to work on. not to mention they change the angle or position of the outlet so you need to change cooler piping as well. aftermarket is not always better. and GTSBoy is right.

[Torque Curve]

Just “Power-Port” the oem inlet. 

Specialised power porting in Mt.Helen have done them in the past. 

[TXSquirrel]

Since you are running single turbo, have you considered single throttle plenum?

https://plazmaman.com/product/nissan-rb26-single-throttle-body-billet-inlet-manifold/

 

[sneakey pete]

Not sure how single turbo is relevant to that? ?