Jump to content
SAU Community

Recommended Posts

Just looking to see some feedback and opinions on changing from a stock intake to a forward facing style.

It seems like a fairly pricey thing to change and would take some labour and adjustments under the hood.

It seems very logical to run a forward facing plenum for many reasons. I would like to know what effect you felt it had on your car.

Link to comment
https://www.sau.com.au/forums/topic/467997-rb25det-forward-facing-plenum/
Share on other sites

Look 100x better, 100000x easier to change/upgrade injectors, easier to change spark plugs... little bit of stuffing around to convert but nothing major. Much shorter inlet path.

Would be interesting to see if someone has done a back to back comparison on a near stock motor with no changes other then the intake... When I did it I changed injectors and turbo at the same time so cant really compare

Look 100x better, 100000x easier to change/upgrade injectors, easier to change spark plugs... little bit of stuffing around to convert but nothing major. Much shorter inlet path.

Would be interesting to see if someone has done a back to back comparison on a near stock motor with no changes other then the intake... When I did it I changed injectors and turbo at the same time so cant really compare


I asked for back to back results on the same tune a few years ago. From memory someone did post results and they were in line with what everyone else says. The theory and results behind the plenum is almost the same as na, which is surprising.

Yeah they look good and you can clean up all wiring and coolant and fuel lines to fit below it. But it's still around $400 for a useless thing.
Have around $400 spare and want something to do? Go for it

I have talked myself out of non standard RB25 manifolds and plenum chambers so many times it isn't funny .

Just yesterday I was looking at a pretty blue Freddy going onto a GTS25T and asked again the shop owner does this cost torque and drivability right where cars are driven most of the time .  Quick answer , yep more top end but costs down low . 

It is also very obvious that things like the thermostats housing and oil filter are considerably harder to get at . No crossover pipe but that's not real hard to remove once you've done it once or twice .

I think the reality is that the J pipe or whatever is the way to go or if being real stealthy you're stuck with return flow type intercoolers .

The factory alternatives are the RB26 setup or the Y pipe and plenum like some R34 RB20/25 DEs use .   

I've got one on my motor,why? For bonnet clearance when my 25 was in my 180, now I still have it on my 32 as bonnet clearance with an rb30 and because top feed standard hight injectors.
More top end? Barly noticeable at 300kw, however there was a noticeable loss of low-end/midrange power on the rb25 can't comment on the difference with the 30 thou

  • Like 2

i have back to backs with 320rwkw greddy and plazmaman vs std and in both cases there was very little difference and there was zero difference between std throttle and q45 on the greddy at 350rwkw.

That said the extra accessibility was worth it on both cars as they see lots of track work.

  • Like 2

I have talked myself out of non standard RB25 manifolds and plenum chambers so many times it isn't funny .

Just yesterday I was looking at a pretty blue Freddy going onto a GTS25T and asked again the shop owner does this cost torque and drivability right where cars are driven most of the time .  Quick answer , yep more top end but costs down low . 

It is also very obvious that things like the thermostats housing and oil filter are considerably harder to get at . No crossover pipe but that's not real hard to remove once you've done it once or twice .

I think the reality is that the J pipe or whatever is the way to go or if being real stealthy you're stuck with return flow type intercoolers .

The factory alternatives are the RB26 setup or the Y pipe and plenum like some R34 RB20/25 DEs use .   

I have talked myself out of non standard RB25 manifolds and plenum chambers so many times it isn't funny .
Just yesterday I was looking at a pretty blue Freddy going onto a GTS25T and asked again the shop owner does this cost torque and drivability right where cars are driven most of the time .  Quick answer , yep more top end but costs down low . 
It is also very obvious that things like the thermostats housing and oil filter are considerably harder to get at . No crossover pipe but that's not real hard to remove once you've done it once or twice .
I think the reality is that the J pipe or whatever is the way to go or if being real stealthy you're stuck with return flow type intercoolers .
The factory alternatives are the RB26 setup or the Y pipe and plenum like some R34 RB20/25 DEs use .   

I have talked myself out of non standard RB25 manifolds and plenum chambers so many times it isn't funny .
Just yesterday I was looking at a pretty blue Freddy going onto a GTS25T and asked again the shop owner does this cost torque and drivability right where cars are driven most of the time .  Quick answer , yep more top end but costs down low . 
It is also very obvious that things like the thermostats housing and oil filter are considerably harder to get at . No crossover pipe but that's not real hard to remove once you've done it once or twice .
I think the reality is that the J pipe or whatever is the way to go or if being real stealthy you're stuck with return flow type intercoolers .
The factory alternatives are the RB26 setup or the Y pipe and plenum like some R34 RB20/25 DEs use .   


Groundhog day?

I've never regretted mine, but it was part payment for some wheels. Car has always driven fine
  • Like 1

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

    • Bit of a pity we don't have good images of the back/front of the PCB ~ that said, I found a YT vid of a teardown to replace dicky clock switches, and got enough of a glimpse to realize this PCB is the front-end to a connected to what I'll call PCBA, and as such this is all digital on this PCB..ergo, battery voltage probably doesn't make an appearance here ; that is, I'd expect them to do something on PCBA wrt power conditioning for the adjustment/display/switch PCB.... ....given what's transpired..ie; some permutation of 12vdc on a 5vdc with or without correct polarity...would explain why the zener said "no" and exploded. The transistor Q5 (M33) is likely to be a digital switching transistor...that is, package has builtin bias resistors to ensure it saturates as soon as base threshold voltage is reached (minimal rise/fall time)....and wrt the question 'what else could've fried?' ....well, I know there's an MCU on this board (display, I/O at a guess), and you hope they isolated it from this scenario...I got my crayons out, it looks a bit like this...   ...not a lot to see, or rather, everything you'd like to see disappears down a via to the other side...base drive for the transistor comes from somewhere else, what this transistor is switching is somewhere else...but the zener circuit is exclusive to all this ~ it's providing a set voltage (current limited by the 1K3 resistor R19)...and disappears somewhere else down the via I marked V out ; if the errant voltage 'jumped' the diode in the millisecond before it exploded, whatever that V out via feeds may have seen a spike... ....I'll just imagine that Q5 was switched off at the time, thus no damage should've been done....but whatever that zener feeds has to be checked... HTH
    • I think Fitmit had some, have a look on there (theyre Australian as well)
    • Hah, fair enough! But if you learn with this one you can drive any other OEM manual. No modern luxury features like auto rev-matching or hillstart assist to give you a false sense of confidence. And a heavy car with not that much torque so it stalls easily. 
    • Actually, I'd say all three are the automatic option. Just the different trim levels. The manual would be RSFS, no? 
×
×
  • Create New...