Rb custom plenums

[Rb20_4valve]

has any1 modded or purchesed a custom plemun or modded there existing plenum that actually looks anygood

i have seen modded and custom plenums but im not happy with the look of em.

i would like to mod the existing 1 preferably.

any 1 that has done it or no anything good and bad bout it, info would be much appreciated

[T0nyGTSt]

Go to the Forced Induction forum.

Out of all the intakes I've seen, only the Mood and Subzero ones were passable.

The one in a friend's r33 looked good but it was a one off design.

In light of all these hassles, I'm going Japanese and that's the Trust/Greddy plenum.

T.

[PSIKO]

Originally posted by Rb20_4valve

i would like to mod the existing 1 preferably.

that's bad news

they're designed the way they are in order to capture/disperse the air equally

when you move the inlet to the front (I take it this is what you mean?) then you aren't getting equal quantities of air into each cylinder

best way to go if you have to mod your plenum is get some engineered plenum (with the scoops etc) like a sub zero one, or get a brand name one as they've done the work already and have proven results (as far as I'm aware anyway!)

I'd jsut stay with the stock one and increase the tb size, as I read somewhere the other day they have better torque producing figures than the gtr plenum at high revs/boost

Although at the same time I could be talking bs, but that's what I remember

[GTS-t VSPEC]

My mate can make a custom plenum on the existing intake runners. Looks very nice, and some of the cars running them have made 400rwhp+, so they work aswell. If you want details then PM me.

I agree that the cut and shut plenums seem like a bad idea, but I have seen a few that still seem to make good power.

[Gradenko]

Originally posted by PSIKO

that's bad news

they're designed the way they are in order to capture/disperse the air equally

when you move the inlet to the front (I take it this is what you mean?) then you aren't getting equal quantities of air into each cylinder

The stock plenum has had sweet bugger all engineering into dispersing air evenly. It may do, somewhat, but thats more a matter orf course than design. Nissan's target was to lower the cost of ic piping and shorten its route. That they suceeded at, at the cost of an undersized 'cooler, but even air disperstion was not at the top of their list.

I should take pictures of the stock one I have lying around here. The throttle body is positioned such that it blasts air right down the neck of cylinder 3 and 4. No deflectors or trick engineering gone into it at all. I'd be willing to wager that cylinder 3 and 4 running lean is the cause for a substantional number of rebuilds.

Properly done, a cut'n'shut should have no problems out doing the stock plenums job, just have to take it to someone who has experience with it. If you're still sceptical, consider the number of oem plenums that are front facing log-on-top-of-runner styles: ca18det, sr20det, 4g63, 1jz and 2jz. All very similar to what a cut'n'shut ends up being (especially the last two).

The proof is in the works though and Steve-SST has given mine a thumbs up, so it'll interesting to see how it'll fair.

[summoner]

I have a Phil Matra custom plenum for RB20's which i havent installed yet, mite get some pics of it today me thinks. Looks nice although i probably need to polish it up to get full effect

[T0nyGTSt]

The Tilbrook one looks good. But it ain't Jap

T.

[GTS-t VSPEC]

Summoner, How much did it cost?

[summoner]

$600

pics are here:

http://www.hotperthcars.net/summoner/image.../cefiro/plenum/

[GTS-t VSPEC]

Cool, so it uses the stock intake runners. Nice, going on the Cefiro:D

[summoner]

yep will be going on it, goto get off my butt and fine an XF TB for it too

[GTS-t VSPEC]

I have an RB25DET throttle body if it's any use:D

[Gradenko]

Interesting plenum, summoner. I remember Phil selling them on pf for rb30's. With the throttle body, a 60mm rb25det one won't be much of a restriction up to 400hp (at the engine). I have an extra one for sale too .

[DCIEVE]

how much for the rb25 tb's? will need one soon for a custom plenum, making it myself with the help of a fabricator so will see how it goes, shoudl save me the 600 he normally charges for this sorta work

also does using a larger tb require aftermarket manangemnt or can i use the safc to clean up the mixtures...

[Gradenko]

DCIEVE, I was going to sell it for $60 on another forum but you can have a SAU discount . $50. Pic here.

As long as you can mate your current throttle position sensor onto the new throttle body, you shouldn't have many problems with the ecu recognizing the tb. Fueling might be an issue though and a s-afc won't be as good as a remap.

[Gradenko]

Originally posted by Gradenko

I should take pictures of the stock one I have lying around here.

In reply to myself, I finally got a pic taken. Not all that clear though. I was holding the plenum "steady" and the half a dozen beers I had before hand had some say in that.

Thats looking down the throttle mounting plate. The light you can see through there is coming in the through the entrance for runner 3 & 4, which is just off the top of the frame. So what happens to air thats blasting in there at 1-odd bar? Some of it hits the runner divider and scatters, but the rest, the majority, takes the path of least resistance to low pressure goodness and ends up in cylinder 3 and 4.

Horrible design.

[R31 POWER]

I heard that v6 ecotech commahores throttle bodies are alittle bit bigger than xf and they are more compact.

[DCIEVE]

what sort of numbers can the rb20 tb flow, is it worthwhile going to the 25 tb?