Rb20det 25 intake manifold

[vitaminD]

So I was wanted to have a custom upper intake plenum made for my Rb20det. I had the fabricator who did my turbo manifold and piping make one and it turned out like this:

It kinda looked like ♥♥♥♥...It was built off of the original flange from the stock upper and built outwards. The throttle body would not fit without pounding down the upper water pipe. Not ok...

So I decided I would give it a shot. Let me know what you guys think:She is one of a kind!!

I started with a 1/2" plate and shaped it to the correct position.(the shape follows the fender well in my s30)

Next I made the throttle body plate and attached it at the appropriate angle to allow the factory throttle body fit (without pounding anything)All of the alluminum work was done by hand, working from wooden templates and hand routering the alluminum (you need a really strong router!!)

I then constructed a chamber from carbon fiber (its is real!!) I had to use a special resin do deal with the heat. Rated for up to 280 degrees without heat deformation.

And here is the finished product:

The vacume ports come out the bottom (like the plazaman) to keep a clean look. what do you guys think???

I was thinking about offering these for sale but I don't know if anybody will be interested...I would like to get a couple out there first...

If anyone is interested send me a message I would like to do one for a rb25 as well. If someone is near MN I would be willing to do it for basically just materials to get the templates made...

I will post up a in car picture tonight...Peace!

[imotion s14]

looks very nice

[silviasgp06]

looks nice but will the CF hold it's seal with the metal part of the intake? seems to me that the temp change expansion/contraction might cause a boost leak in the future, if not i might try making something similar.

[vitaminD]

looks nice but will the CF hold it's seal with the metal part of the intake? seems to me that the temp change expansion/contraction might cause a boost leak in the future, if not i might try making something similar.

At first I was worried about that as well, but the carbon is not actually resin'ed to the alluminum I am using a 3m bonding agent they use on aircraft. The 3M rep told me that it will deal with the thermal expansion no problem, although I am debating puting a few machine screws around the base. Just in case...

[Darius]

I'm just wondering what will happen to it when it sees 20psi?

The manifold looks immaculate and has decent port inlet design! How much does it run you to buy/shape the materials and recoup the costs for the mold production, etc.? Just wondering what it will approximately cost to buy one.

btw, I have a stripped down RB25 intake manifold I will sell ya for dirt cheap if you want to start in on production for that?

[l0nestar]

I would consider something like that. looks pretty trick!

The only questions I have are, Would you have been better off using velocity stacks, instead of routering the holes and polishing them?

Also, the number 1 port (nearest TB on 3rd pic) looks rather close to the edge - was there any way to extend for more 'meat' or surface area on the outer surface? I'll MS-Paint my idea here in a sec...

What do the ports look like from inside the air chamber?

What is the diameter of the TB flange?

[vitaminD]

The carbon is about 3/16" thick through out and Due to the arch, is very strong. I could build one of these for any throttle body as long as I had it to build from. The #1 runner was close to the edge due to fitting the factory throttle body to clear. Although this is still more than the factory. I could defininately make one with A LOT more volume. But I felt it was uneccessary for MY application. If someone wants a one off I can still make it. I did not have the velocity stacks at my disposal, and if I added them on the inside this would create a right angle covering some of the factory port (since the lower half of the manifold's ports are not perfectly round). The round over on the inside and port matching to the lower half was easier and I think should flow better. I do not have access to a flow bench, but it was my best guess.

[matafied]

man that looks sexy!!!! nice work ( humping monitor )

[mello88]

Looks amazing, IMO it blows the 'greddy' and polished malyasian manifolds away in terms of looks. How well it performs against them, we'll have to wait until your future dyno thread...

I'm sure many 20 guys would be interested in something like this! Although I'm sure this ends up costing a lot more than the existing manifolds due to all the manual labor and quality materials you're putting into it.

PS are you thinking of selling the other custom manifold you had made?

edit: Let me say it again: it looks awesome!

[vitaminD]

[QUOTE=mello88]

PS are you thinking of selling the other custom manifold you had made?

QUOTE]

I will sell it but it does need a little bit of work...Needs vac ports still and a little elbow grease.I paid 500 bucks for it.Sell it for 200 if anybody wants it...

Well if someone wanted the exact one that I made, I would sell one for probably around 550.00. Only because I kept all of my templates and I can test fit on my own motor since it does not yet run anyway. (Megasquirt in the works)i know the cheapest one I have seen was 450, and the plasaman is ridiculous, around 1100. Mine is very very similar to the plasaman.

[l0nestar]

No prob bro! I hope you do not think I was knocking you at all.

I think it looks awesome and I would consider being a Guinea Pig for a 25 manifold I think it would also help 'spice up' my engine compartment :-D

I am somewhat concerned about how well it would stay sealed (and for how long) at higher pressure rates (20-30) PSI. I could easily build a set of seals to pressure test it. But then I would not be sure about how it would handle with heat, and over time.

Do you have any internal pictures or pictures of the inside contours of the carbon fiber plenum?

Again, not knocking you.

[vitaminD]

I was trying to figure out a way to pressure test it. Any help would be greatly appricated!!!The carbon is 6 layers thick. But it would be easy to go another 3 if needed. Like I said this is the Version 1.0. There are definately things I would change on the next one. Like the 1/2" plate, 3/8" would have been PLENTY!!! The 1/2" was over kill and is really difficult to work with.Lets try to figure out how I can pressure test this thing...

[mello88]

I would pressure check like this... Bolt it to the motor, use RTV and/or your gaskets for the manifolds and your TB. Plug all the vac ports, and seal the TB using a 2.25/2.5" silicone coupler with a aerosol can clamped in (or skip the TB and make a TB blockoff plate, see next paragraph). Use one of your vac ports and your air compressor and a modified leakdown tester/regulator/etc to pressurize the manifold. Use soapy water to spray down all the sealing points and watch for bubbles. Alternatively, make a quick blockoff plate with holes for the lower manifold bolts, that way you can pressure check it off the motor. I would test to ~1.5-2 times the boost you anticipate running, 25-35psi.

When I pressure checked my oem 20 manifold I bolted everything up except the TB. I made a blockoff plate out of 1/2" MDF with a thick RTV ring on it where it touches the mani... I let the RTV cure then bolted it on where the TB would usually go. Made sure everything was plugged off except one of the vac ports, and pressurized with my compressor + leak down tester to ~30psi. Used soapy water to find leaks/bubbles, all I found was the stock (porus) paper gasket leaks slightly under boost (used RTV instead, now it holds 30psi with 0 leaks).

GO!

edit: ps please send me an email about the other mani. (jo el me ll o at gm ail d ot c om)

[rb hilux]

hi mate nice work i would be keen to get one please get back to me asap

[nizmo zilvia]

Really nice. Any updates?

[ANVIL]

would this just replace the top plenum and bolt to the stock intake manifold?

[nizmo zilvia]

I'm sure that's what you would do. There isn't any other way I would think.

[MATTs14]

We need some updates. I really would want to buy one of these. I wanna see some results or something

[DriftsideRacing.com]

wow that's cool

[yotik]

nice im keeping an eye on this. test results for rb20det please

[RBSilvia]

MN in the house! I'm from the next town west of Waconia.

Looks really nice. I'll probably be in the market for an I.M. next summer. I'll definitely look you up then.

btw...what chassis is that RB in? Thats a huge engine bay compared to my s13 lol

edit: i see it's a '73 Z....awesome car
Modified by RBSilvia at 6:19 PM 9/18/2008

[BoostFab]

looks pretty good; i think it's better if you do the plenum in aluminum then overlay it w/ CFnot sure how much pressure your way will hold...

[onepuff]

Damn how did i miiss this thread. I was thinking of doing the exact same thing a few months ago. Too lazy though. Look forward to updates.