Freddy Plenum vs Genuine options RB25

[BuiltNotBought]

Looking for a plenum for rb25 de+t neo 

Not looking to push much power maybe 300kw at the wheels, is there much difference in flow for Freddy “Greddy style” compared to original Greddy or options like Proflow or Otaku garage? 
 

I won’t be porting the de Neo head for now as I think it’ll be fine 280-300rwkw but appreciate the help and any experiences anyone has between them and any advice. Thanks 

Looking at this plenum for now below 

[Dose Pipe Sutututu]

The one in your post is fine, if it's a Dim Sum copy, just spend a bit of time cleaning up the casting marks inside and getting the mating surface machined/belt sanded so it's flat.

[GTSBoy]

And be prepared to surrender low/midrange torque.

[Dose Pipe Sutututu]

15 minutes ago, GTSBoy said:

And be prepared to surrender low/midrange torque.

This too

[BuiltNotBought]

Really, low/midrange torque goes really bad??

I want decent acceleration, maybe I use a stock rb25det neo manifold?

57 minutes ago, Dose Pipe Sutututu said:

This too

 

1 hour ago, GTSBoy said:

And be prepared to surrender low/midrange torque.

 

[GTSBoy]

3 minutes ago, BuiltNotBought said:

Really, low/midrange torque goes really bad??

I want decent acceleration, maybe I use a stock rb25det neo manifold?

Short inlet runners cost quite a bit. Dulls off the off-boost torque, and delays boost onset, because arrival of boost is driven by gas flow is a product of the ability to flow air which is torque. This is the reason that the stock manifolds have longer runners.

On a 3L, or bigger, you can usually accept the compromise of giving away some torque because the extra capacity gives you a little extra to waste. But on a smaller motor, there's not a lot there to start with. Example, I swapped RB20 out of my R32, 25NeoDET in its place. The "wall of torque" that I experienced afterwards made it all worthwhile. That's because I came from RB20 land where torque is not a thing. But I would not do anything, anything at all, to reduce the low/mid torque I have now, because I remember what it is like to not have it!

[BuiltNotBought]

So how much difference does it make you think? Like 1 second in the 0-100? 
I was have smaller turbo so hopefully that spools quick GTX2871. 
currently it’s NA so you can imagine pretty slow, but I do want fast accusation a little as there’s not many places I’ll be driving where I go over 80 even near me. So 0-60 and 0-80 targets 

5 minutes ago, GTSBoy said:

Short inlet runners cost quite a bit. Dulls off the off-boost torque, and delays boost onset, because arrival of boost is driven by gas flow is a product of the ability to flow air which is torque. This is the reason that the stock manifolds have longer runners.

On a 3L, or bigger, you can usually accept the compromise of giving away some torque because the extra capacity gives you a little extra to waste. But on a smaller motor, there's not a lot there to start with. Example, I swapped RB20 out of my R32, 25NeoDET in its place. The "wall of torque" that I experienced afterwards made it all worthwhile. That's because I came from RB20 land where torque is not a thing. But I would not do anything, anything at all, to reduce the low/mid torque I have now, because I remember what it is like to not have it!

 

[GTSBoy]

9 minutes ago, BuiltNotBought said:

So how much difference does it make you think? Like 1 second in the 0-100? 
I was have smaller turbo so hopefully that spools quick GTX2871. 
currently it’s NA so you can imagine pretty slow, but I do want fast accusation a little as there’s not many places I’ll be driving where I go over 80 even near me. So 0-60 and 0-80 targets 

 

Not easy to quantify wrt something like how many fractions of a second slower it would be over 0-100. But given that a 250-300rwkW car is able to do that launch sprint in 5-6 sec (and faster with appropriate tyres, and surface)..... giving up as much as a second would feel like torture.

A ~450HP capable turbo is not going to make lots of boost in the 2000-3000 rpm range. So, whilst with some boost on hand it will be faster accelerating in that rev range than your engine currently is NA, it will not feel like a fast car until the boost is solidly in. You know what your car feels like right now when you open it up at 2000rpm. if you've ever been in an actual fast car, you will appreciate that the NARB25 is.... not exciting. Well, add some boost and it will be better. But shorten the intake runners and it might not be better at all. It might come out better, but it could end up feeling the same.

For me, it's not the 0-X km/h sprints that matter. It is easy to fry the tyres with anything over 200 rwkW. You can't use all the power available in 1st and 2nd anyway, you have to modulate the throttle. What matters is how the car reacts when you're driving in traffic in 4th or 5th and have maybe 2000 rpm on board, and you want/need to add some speed quickly, and don't have time for the downshift. It won't make boost, it will be all NA (at the speeds we're talking about - remember how fast you're going at 2000 in 4th! and don't plan on breaking the limit by too much.) So giving away NA torque is not what I would consider practical for a street car. And retaining that NA torque builds boost faster which makes the car faster. The flashy plenum is not actually better, unless you're looking at a track car where you can keep it on the boil all the time.

 

[BuiltNotBought]

8 minutes ago, GTSBoy said:

Not easy to quantify wrt something like how many fractions of a second slower it would be over 0-100. But given that a 250-300rwkW car is able to do that launch sprint in 5-6 sec (and faster with appropriate tyres, and surface)..... giving up as much as a second would feel like torture.

A ~450HP capable turbo is not going to make lots of boost in the 2000-3000 rpm range. So, whilst with some boost on hand it will be faster accelerating in that rev range than your engine currently is NA, it will not feel like a fast car until the boost is solidly in. You know what your car feels like right now when you open it up at 2000rpm. if you've ever been in an actual fast car, you will appreciate that the NARB25 is.... not exciting. Well, add some boost and it will be better. But shorten the intake runners and it might not be better at all. It might come out better, but it could end up feeling the same.

For me, it's not the 0-X km/h sprints that matter. It is easy to fry the tyres with anything over 200 rwkW. You can't use all the power available in 1st and 2nd anyway, you have to modulate the throttle. What matters is how the car reacts when you're driving in traffic in 4th or 5th and have maybe 2000 rpm on board, and you want/need to add some speed quickly, and don't have time for the downshift. It won't make boost, it will be all NA (at the speeds we're talking about - remember how fast you're going at 2000 in 4th! and don't plan on breaking the limit by too much.) So giving away NA torque is not what I would consider practical for a street car. And retaining that NA torque builds boost faster which makes the car faster. The flashy plenum is not actually better, unless you're looking at a track car where you can keep it on the boil all the time.

 

I see, honestly I’m not too fussed about the looks. The only reason to go plenum is to make the piping easier instead of the classic over the rad etc. 

[GTSBoy]

7 minutes ago, BuiltNotBought said:

The only reason to go plenum is to make the piping easier instead of the classic over the rad etc

As I've said elsewhere, I am using the stock intercooler piping path in the engine bay, and a return flow cooler, and making ~250 rwkW (without any effort put into trying to turn it up past there just yet) and expect to be able to make some more, and frankly, I would be perfectly happy with 260-270rwKW. This is peak road Skyline usability territory. You go past there and, sure, the car will snap necks more when it's on boost, but it will also break shit all the time, cost a (even larger) fortune in tyres, etc etc.

Anyway, I also do not like the over-the-fan pipe path, and you don't have to do it.

[robbo_rb180]

Torque will suffer greatly, will try and find dyno difference on r34 with gt30 between stock and plazmaman short runner.
like 2000-3000rpm power rdip at least.

EDIT
Green line is stock manifold, others is plazmaman short runner

I also had a rb25 with greddy and q45 TB back in the day and was shit daily driving. Plazmaman top plenum with stock runner and DBW made it so much nicer.

Edited 14 hours ago by robbo_rb180
added pic

[Dose Pipe Sutututu]

I do like the look of these things (minus the ugly flat top surface with the text)

https://rajabracing.com.au/product/nissan-rb25det-neo-intake/

Retains the OEM bottom runners, for that phat low range.

If you want response king, maybe go with the Plazmaman pipe work, here's my old setup from a decade ago

[Kinkstaah]

28 minutes ago, robbo_rb180 said:

Torque will suffer greatly, will try and find dyno difference on r34 with gt30 between stock and plazmaman short runner.
like 2000-3000rpm power rdip at least.

EDIT
Green line is stock manifold, others is plazmaman short runner

I also had a rb25 with greddy and q45 TB back in the day and was shit daily driving. Plazmaman top plenum with stock runner and DBW made it so much nicer.

This should be the nail in every FFP coffin everywhere. What an absolute downgrade. Suprised RB26 people didn't get a better intake manifold with longer runners seeing stuff like this.

[MBS206]

1 hour ago, Dose Pipe Sutututu said:

I do like the look of these things (minus the ugly flat top surface with the text)

https://rajabracing.com.au/product/nissan-rb25det-neo-intake/

Retains the OEM bottom runners, for that phat low range.

If you want response king, maybe go with the Plazmaman pipe work, here's my old setup from a decade ago

The Plazmaman setup is what I originally had on my RB25 too. Worked really well. In fact,I think I still have it in the garage.

Then I went over radiator when I went to the RB30 as it wouldn't clear the bonnet otherwise.

[Kapr]

@BuiltNotBought Just as GTSboy said.
 

If you want driveabilty and more low down torque..keep the stock runners.
They are VERY good from a factory.

I have them too on my RB25DET NEO and as a GTSboy i have fmic but with stock piping route(i have Blitz intercooler)
Iam making around 320 BHP and the car pulls "hard" from like 2,5k all the way to 7k.
I have it dyno tuned to mimic N/A power curve and making little less max torque due to the smallbox tranny.
But driveability is very great.
I had 350Nm below 3k so car feels very quick.

 

EDIT: 

Not my channel but i saw this and i know that is what i want (and i have exactly this)  

Edited 7 hours ago by Kapr

[GTSBoy]

My return flow is custom and puts the return behind the reo, instead of at the bottom. All my core is in the air flow, rather than losing some of it up behind the reo.

I realise that the core really acts more as a spiky heatsink than as a constant rate heat exchanger, and that therefore size is important.... but mine fits everything I needed and wanted without having to cut anything, and that's worth something too. And there won't be a hot patch of core up behind the reo after every hit, releasing heat back into the intake air.