Jump to content
SAU Community

NISMO Plenum for GTR

Roy

By Roy,
in Engines & Forced Induction

 Share

Recommended Posts

  • Replies 78
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

RH9
RH9

Guys sorry to reply so late, I see there have been a few comments re this plenum. As far as my boost goes, the issue only occurred after going from the previous turbo's to the 2530 Kai's and installi

OYEAHA
OYEAHA

Ah unlucky was worth a try ! Only thing I can hide from the mrs is credit/PayPal account lol

bigmikespec Veteran

bigmikespec

Posted
Posted

I don't think there will be much in the way of results... the only way to do it properly would be to have O2 sensors in each exhaust runner and test back to back to the stock RB26 plenum. The aim of the plenum is to achieve equal flow distribution, there will be a small power gain because of the increased volume.

  • 9 months later...
RH9 Rookie

RH9

Posted
Posted

Hi guys,

Just digging up this thread for the benefit of anyone who is considering using one of these.

I aquired one from a mate who is parting out his race motor - never intended to buy one due to the price but I got a sweet deal.

I was expecting more low end torque and a significant power increase.

Very hard to compare todays dyno result to last time as the air temp between winter and summer is so different along with air density.

Anyway; basic motor spec:

RB26 bored 0.5mm

Ported cylinder head

Tomei 270/260 Pro cams (I think)

HKS GT2530 Kai's

Factory cast iron manifolds.

1.7 bar boost.

No other changes other than the Nismo plenum and the weather conditions.

Previously made 620nms at 5,100rpm and 467kws @ wheels at 7,200rpm (DIN).

Today made 610nms @ 5,100rpm and 473kws @ wheels at 7,800rpm (DIN).

Power used to drop off sharply after 7,200rpm but now its flat all the way to 8,000rpm.

Boost curve is around 100rpm slower to build but still peaks at approx 5,000rpm. It has less "spool" from 3,000 to 4,000rpm but climbs much more steeply from there. Boost curve is more stable than before as it used to dip down slightly between 5,500rpm and 6,000rpm. Now it sits flat to redline.

We tried more boost but the EBC couldnt control the boost steadily over 1.7 bar so we stayed at this level.

My conclusion is that its a worthwhile mod but perhaps not so useful on this particular spec engine.

Pro's: wider power band, more stable boost, more even cylinder temps at #6.

Con's: price unless you get a good deal.

Just bare in mind the plenum may work better or worse depending on your engine spec. Happy with the stronger top end but somewhat dissapointed I didnt get the torque increase - maybe just the weather??

Cheers

Andy

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Thanks for the results Andy - fits perfectly with the 2% quoted by Nismo, given its pretty much what the results show there :thumbsup:

Boost stability should'nt change with a properly sealed plenum.working EBC be it Nismo/Greddy or stock - so it sounds like the EBC (or whatever method), something has changed there. Perhaps a slight leak with the old plenum.

Piggaz Grand Master

Piggaz

Posted
Posted

It's funny that in RH9's case the peak torque was slightly less at the same RPM when the runners are longer and 2 mm smaller.

I know years ago, Yavuz spun mine to 9000 RPM and power held flat. It didn't really "nose over" as such. Hmm..

Lithium Grand Master

Lithium

Posted
Posted

Very very solid power for the old RB26 on low mounts, gotta be happy with that.

Thanks for the results Andy - fits perfectly with the 2% quoted by Nismo, given its pretty much what the results show there :thumbsup:

Boost stability should'nt change with a properly sealed plenum.working EBC be it Nismo/Greddy or stock - so it sounds like the EBC (or whatever method), something has changed there. Perhaps a slight leak with the old plenum.

It's funny that in RH9's case the peak torque was slightly less at the same RPM when the runners are longer and 2 mm smaller.
I know years ago, Yavuz spun mine to 9000 RPM and power held flat. It didn't really "nose over" as such. Hmm..

Yep - and with this whole 2% difference thing the results are so close that there any range of minor variables could result in those changes, as said... a tiny boost leak, some other random thing that may have changed, even the way the tuner set up the boost control or conditions on the day. You can see that difference between a cold and hot run even, so it is a bit hard to jump to any major conclusions on - as Andy indicated.

Was it previously running a factory plenum?

bigmikespec Veteran

bigmikespec

Posted
Posted

It is easy to write off the results as insignificant... the increase in power and extended power band until later in rev range is more than likely due to increase plenum volume compared to anything else. You would see this with any larger plenum.

There is no mention of actual cylinder temps, if someone was serious they would have an O2 sensor in each runner, that would tell a story. Until then people can continue to scoff at the results so far which dont really say anything.

Lithium Grand Master

Lithium

Posted
Posted

Can't really scoff at the dyno results - or otherwise, its so close.

If there is definitely a noticeable improvement in temperature across the 6 cylinders then it HAS to be a good thing. I'm a firm believer in making the engine happy first, and power gains being a result of that is a nice bonus - but the same power with a less stressed motor is brilliant.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
2530s @ 24psi falling over @ 7200rpm on a 2.6ltr...
Boost control wasn't consistent from 5-6k...
Obvious something, albeit minor, was up beforehand.


(and again, not discounting the #6 reaffirmed etc, its all good and useful information).

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Nismo GT Pro LSD configurations

      By GTSBoy · Posted

      Well, the trouble with that ^^ is: The configuration shown is absolutely a 1-way, not a 1.5-way. There is no way that a 1.5-way can be said to offer LSD action only on acceleration. If Nismo cannot get that right, then it is impossible to believe their documentation. That ^ is not a 1.5 way setup. That is a 1-way.   And so now I have allowed all doubts to flourish and have gone back to look at the MotoIQ video. I originally made the mistake of believing him when he said "this is a 1.5-way" at the ~6:10 mark. Because what he did was take the gear assembly out of the 2-way opening and just rotate it one place to the left to drop it into the 1-way opening. When he dropped it in there, the cam was "backwards" compared to the correct orientation shown in all other photos of that config. The flat shold have been facing the 1° ramp side of the opening, not the 55° ramp side. And I thought, "gee that's cute", but I was concerned at the time, when he put the other ring back on, that the gap between the rings looked like it was wider then in the 2-way config. And then I said a lot of things in my long post on Tuesday that could only make sense if the guy from MotoIQ was correct about what he'd done. BUT... I have now done my homework. I grabbed a frame of the video with the 2-way config, and then grabbed another with the "1.5-way" config, snipped out the cam and opening of that frame and just pasted it direct on top of the 2-way config. I scaled it so that the triangular opening was almost exactly the same height in both. AND.... the gap between the plates is wider with the cam installed in the triangualr opening backwards. That is.... it cannot go together that way. There would be massive force on the plates all the time, if you could even reassemble it.  So, My statement on the matter? The Nismo diff is actually only a 2-way and 1-way. There is no 1.5-way option in it, regardless of what they say. Here's a photo of a real 1.5-way ramp opening from Cusco (along with the 1 way option). And the full set of 1 through 2 way options from their racing diff, which is not same-same as what we'd typically be using, but...the cams work the same. A little blurry, but it comes from this Cusco doc, which is quite helpful. AND.... Cusco do in fact do what I suggested would be sensible, which is to have rings that do 1 and 1.5, and 1.5 and 2. Separately.  
    • PranK
      Hello sau 👋

      By PranK · Posted

      Welcome Adam. Car looks great!
    • Kinkstaah
      Nismo GT Pro LSD configurations

      By Kinkstaah · Posted

      "With a 1.5-WAY, the LSD is effective only during acceleration."
    • TurboTapin
      Nismo GT Pro LSD configurations

      By TurboTapin · Posted

      Well it wasn't as easy as I thought.... and it also wasn't in my original manual which I did end up finding. They discuss the process in the Nismo catalogue though and it requires slight machining. Page 145.  NISMO PARTS CATALOGUE 2020
    • TurboTapin
      Why am I hitting a power wall with my stroked RB25?

      By TurboTapin · Posted

      I'm an idiot, my intercooler is rated for 1000hp. I had clicked on the wrong product. Knowing the delta P would be nice, but I'm doubtful I'll do it. Now as for an EMAP, that would be great and I'll get around to it eventually but from my findings in my last post, I'm considering a turbo swap now. 
×
×
  • Create New...