Wanting A New Plenum On Rb20Det

[luvboost]

hey guys i am just wondering what you guys have put on your rb20s. ive read about using a rb26 plenum, does that work? or where could i get one? im after a forward facing

cheers

[Kaido_RR]

rb26 plenum is not bolt on and requires alot of work and custom work done.

Its pretty much an engine out job

[luvboost]

do you no who does the work to make it fit?

Edited February 10, 2011 by luvboost

[Boss-zilla]

find an adaptor plate (they do pop up every now and then on ebay/sau and other site) once you have that it a matter of taking off the old and putting on the new. May not be as simple as it sounds.

What power/mods do you have now?

If you look half way down this page you will see all the parts together with the adaptor plate i was talking about.

Edited February 10, 2011 by Boss-zilla

[bubba]

rb26 plenum is not bolt on and requires alot of work and custom work done.

Its pretty much an engine out job

It's not an engine out job if you have the right tools and small enough hands to get to the bolts that hold the top half of the plenum on.

But yes, RB26 plenum to RB20 isn't bolt on, there are adapter plates available for a pretty penny. I made my own out of stock runners and an RB26 plenum chamber but you can also buy some on ebay, I know people using a KU Engineering plenum with success.

[Wogan]

i once bought an rb26 plenum with an adapter which had been made by cutting an rb20 plenum... i don't know how well it works because i never ended up fitting it.. you can buy it off me if you like.

[TTT]

luvboost - have a look in the "projects, overhauls and builds" section of the forum and find the thread that ROY started "a boy and his love for his RB20"

if you can't be bothered reading it... the short version is that his 270rwkw RB20 using stock plenum etc was replaced with a fancy front facing plenum from plazmaman..

end result was worse than stock and eventually retuned to be almost as good.

for many MANY thousands of dollars.

even shorter version - don't bother changing the plenum.

[bubba]

We have proven a stock RB20 plenum and throttlebody are good for 365rwkw and that was on a 3L bottom end.

Edited February 11, 2011 by bubba

[Boss-zilla]

Thats why i was wondering what power/mods he had. After seeing Roy's results i wouldnt bother myself with after market however the gtr ITB set up has proven to be a little better.

[bubba]

Slightly better response wise maybe but shortening the runners on an RB20 isn't a top idea.. they already suffer a lack of torque. Shorter runners mean less low down torque but better cylinder filling at high rpm so, it will be laggy but scream like hell to redline

I only did mine because it's a 3L so has an abundance of torque already and I needed the height clearance.

Edited February 11, 2011 by bubba

[bcozican]

as above, shortening runners on rb20's not a good idea

i have put on plazaman plenum (same as roy in build thread mentioned above) my car is rb22 specifically tuned for high rppm for drift... i got 200 rpm more response and a decent more power held for longer at higher rpm... and a neater engine bay

but.... i have everything already and it was the last thing i did and wouldnt say it dramatically increased performance... unless you want a nicer engine bay or really really want to do it... leave it as is

[Kaido_RR]

It's not an engine out job if you have the right tools and small enough hands to get to the bolts that hold the top half of the plenum on.

But yes, RB26 plenum to RB20 isn't bolt on, there are adapter plates available for a pretty penny. I made my own out of stock runners and an RB26 plenum chamber but you can also buy some on ebay, I know people using a KU Engineering plenum with success.

its not abut removing the std plenum that is the issue. When you add the a adapter plates the extra length pushes the plenum outwards further and the gap between the plenum and body is very small. Due to the 1st section of te plenum having long studs on it and the size of the plenum itself it becomes very hard to split the plenum onto the stud due to the space.

Also it is alot asier to hookup all the vacuum and heater hoses which go underneath when the engine is out.

[luvboost]

hey guys ive got exhaust, front mount, bosch 040, z32 airflow, gtr injetors, apexi avcr, apexi afc neo, apexi pod filter and just the stock turbo but the turbos getting changed soon! i want to put it in also to clean the engine bay up. i hate the side facing plenum look

[Kaido_RR]

hey guys ive got exhaust, front mount, bosch 040, z32 airflow, gtr injetors, apexi avcr, apexi afc neo, apexi pod filter and just the stock turbo but the turbos getting changed soon! i want to put it in also to clean the engine bay up. i hate the side facing plenum look

its a big job for very little gain.

i'm not sure if they make the greddy plenum for rb20, but even that will cost you around $900-$1000 for a real greddy plenum or $300-$500 for a china copy then you have the install cost.

If i was you i would sell the afc neo and get yourself a rom tune done you will get alot better results and the car will run alot better also (think its call niztune or something for the rb20, i know hyperdrive can do them)

Edited February 11, 2011 by Kaido_RR

[bubba]

GReddy do not make an RB20 plenum, the only off the shelf complete replacement (not just the top half like Plasmaman) solutions are ebay jobs such as the KU Engineering plenum.

That being said, Plasmaman is probably the best bet as you retain the longer runners.

[luvboost]

so its not really going to work then what about if i put a different head on like 25 26 would that change the plenum i could use or not. i dont no much just asking

[masTers]

For the cost of an aftermarket plenum, you better off spending the money on a RB25 conversion.

[Kaido_RR]

so its not really going to work then what about if i put a different head on like 25 26 would that change the plenum i could use or not. i dont no much just asking

not really worth the coin and im not sure if a 25 or 26 head would fit and there would be alot of stuffing around and at the end of the day what it would cost you would be cheaper to just do a 25 swap and put a greddy plenum on that when the engine is out

[luvboost]

so with the rb26 plenum it has shorter runners and the rb20 has longer ones? what if i could get a plate made up for the rb26 that makes the runners that same size? would this work or still lose power

cheers for the help so far

[masTers]

No it wouldn't work.

If you really want to spend some money, get a plazaman or hypertune RB20 plenum that sits on the factory RB20 runners.

The RB26 plenum conversion from the results I've seen on a mates RB25 was horribly expensive and not many gains.

Also dont forget to factor in the cost of making up new piping to the intercooler on the intake side.