hey guys this is my first post but i have been reading this forum on and off for the past 8 years or more. i am planning on getting some one piece cast aluminium forward facing plenums made up as this option isnt available like it is with all the rb25 and 2jz's and im sick of people trying to sell me a top half of a n.a manifold with $10 of tube welded on and wanting $500. they will just be based on the rb30 street version but i just wanted your opinion on what size throttle body i should have them made for? or just the intake size without holes tapped . i was thinking of just going an 80mm inlet hole with out threads tapped. Just looking for what you guy think trying to keep it as universal as possible so it will suit most peoples set ups. thanks in advance matt

ill be interested to see what these manifolds end up looking like .... and 80mm tb would be a good size there are many available to suit it

yeah i was thinking an 80mm i was going to run a 90mm on my set up but i know alot of people hate the idea of the larger size for throttle response and practicality . i was thinking maybe just a 70mm inlet hole with no screw holes for mounting that way you could still squeeze a stock tb over it just and if you wanted a bigger size you could bore it out to your own prefered size? the factory recieved the plenum yesterday so i need to sort this out quick. then hopefully ill have some pictures to upload in the following weeks

I would leave the mounting face for the throttle body bare so that people can drill there own mounting holes and put what ever throttle body they like on. the mounting face would have to of been machined flat first obviously so that a seal between the casting and the throttle body can occur. The ford throttle bodies are still popular on many set ups due to there availability and price. i think there off XF Falcons and are around 75mm which i think is a fairly common intercooler pipe size. 75mm is just smaller than 3". Another problem you may find is that the people making the cast may want a minimum order. I do not know how much casting things cost but i would assume it is not cheap process and making a one off would not be cost effective for them, that is unless your happy to cover all their costs. JPC performance have made a complete cast intake for the RB30. maybe its worth investigating that. if you still go ahead with it post up some pics when its finished. would be great to see something other than bolt on top halves.

yeah leaving the mounting face bare was what i was trying to say . getting the cast made up will be no problem ive got a factory who have made up other stuff for me and are happy to help out. hopefully a few people like the idea and i will get a fair few made up. i didnt no jpc still existed? ---------- Post added 17-09-15 at 16:58 ---------- i just checked out the jpc manifolds for $1200 haha wow that is alot for a piece of cast. these ones i am getting made up should be roughly around the $400 mark still sorting out finer details before they get made up

Sounds pretty sweet to me

ok so ive talked with suppliers they are able to make it up and say it should take about 2 months. i was kind of hoping they would be a bit faster but what can you do . we have agreed on $190 U.S so that with exchange rate and postage to get them over here the $450 dollar mark should be basically what they cost and it will be the full plenum with runners and factory fuel rail fitment. i will try to get photos as progress is made hopefully. will be going with the 70mm intake hole and bare faced mount

Id be interested to see what these look like. What did you ask of them in terms of design? is this like a normal NA plenum with the front cut out and converted to a TB intake? but cast? Although in your first post you mention you are sick of people just welding up the port and moving it, but .... will these look much different ? are these guys flow people? or just going to cast up somthing ? I know people have been saying stuff like the design needs the trumpet stuff to work nicely.... im not trying to be a downer here, just interested...

Rajab style

Are you making a whole intake that will bolt on to the engine or are you just having a top section cast that will bolt onto the factory n/a runners.

Hey guys thanks for the interest, i have sent over the street version of a cpc plenum for them to get a rough idea and make some changes for them to be able to cast it.So it will be a hole plenum and runners combined in one piece. It is basically one of those chinese factorys that will have a go at anything so i doubt there will be any air flow tests . Ill have one done myself when they arrive. Ill ask about the trumpets ---------- Post added 21-09-15 at 18:52 ---------- Keep the feedback and opinions coming everylittle bit helps if i can get it done

Seems like a lot of effort to go to when there are already plenty of options on the market - proven ones, expensive ones, popular ones and everything in between. Good luck though, be keen to see the outcome...

Always good to see new products but for me a rajab was so easy xf throttle been done 1000 times ect, For me looks r key for me most of the time if looks good in the bay people will want them

it was just something i wanted to add to my own product range as budget yet still half decent and good looking option . it will be half the price of most of the options that have been mentioned so far also which is the main goal . i spoke with the suppliers they havnt started any moulds yet but i asked about the trumpets /v stacks inside and they say it may be difficult but they should be able to cast them .

Whats with everyone copying Ariels (CPC) intake manifolds.first protig ..now you.. cheers darren

I have a protig plenum not the same as a cpc one mate

it is more of a guide /basic idea of what im wanting as it is good looking, fairly simple and keeps the factory fuel rail and injector mounts. it wont be an exact replica and it wont take any business away from him as people will still want his polished up aluminium with a row off pennys all the way round plenums . mine is more for the working class man

yer $4000 for a billit cpc plenum isnt really for the everyday joe

I think GH proves the point that modding the factory one for $150 shows that it's not a restriction of flow at a good 180+mph. Don't need to reinvent the wheel, and why spend money on something that looks pretty but doesn't work as well.

Quote: Originally Posted by Wkd_Vl [View Post] yer $4000 for a billit cpc plenum isnt really for the everyday joe 990 for a street version. The billet plenums are not for everyone, but not everyone wants to go 200+mph