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Honda noob, confused on k20a2 manifold talk RRC, Skunk fitment

7K views 24 replies 5 participants last post by  tinman5 
#1 ·
Hey guys,
I really tried to look, but I saw a lot of talk of manifold fitment and cutting but
not directly for my motor and throwing 400-600 for a manifold, I would like to be sure I am getting the right one from members that are selling.

I have a k20a2 swap in my EP3,
I would like to get either a RRC or the Skunk2 pro series.
A member locally was selling their pro series for a really good price but it was for the 06-11 Si's and not the one based on the skunk website
- K-Series (non-Civic Si) Pro Series Intake Manifold (Black)
307-05-0315

The seller mentioned I could just cut for the modification, is that true? and really is it worth it and just wait until I can find someone selling me an RRC or one for my car at a better price?

I would rather not mess around with making something work like that, I had already a lot of issues trying to get my skunk2 headers to be installed and would like something to just drop in like they say on their websites.

Thanks for any info
 
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#2 ·
Okay, heres the deal, IF you have access to some quality air tools or a band saw, you can do the required cutting yourself. The water outlet on the older heads is plumbed differently. On the old heads the water outlet is independent from the intake manifold whereas on the newer heads the outlet is incorporated into the manifold.
That is the unfortunate crux of working with an older engine. What I can say from personal experience, an upgraded manifold is worth the effort. Mate a standard issue RBC with a Max Bore throttle body (at the very least) and a home made 3" cold air intake to take full advantage of your exhaust upgrade. Unfortunately messing around with these K's is not cheap and as such, not for the timid. Fortunately the foundation is just so much...better...than the B series and to an extent the H series engines.



Thats the RBC on my EP. You will need to trim up the T-bar for clearance. Be advised.
 
#3 ·
And just to be clear, when shopping the classifieds, you are looking for a cut manifold. The only manifolds I see breaking $400 will be a Skunk2, RSP/RRC. You can pick up a brand new RBC for about $200'ish all day and modify it yourself. Add $70 for a Karcepts adapter to bolt up your throttle body and maybe some snazzy thermal gaskets.
The only snag you will run into will be getting your intake piping to mate to the new angle these manifolds point the throttle body. Knowing this will help you at install.
If you dont mind my asking, did you ultimately get your exhaust sorted out?
 
#4 ·
Hello again tinman,
funny you responded, I was actually thinking of Pm'ing you but thought I would try the forum first.

A local member is selling the k -series black pro manifold Skunk2, for a really good price, but it is for the 06-11 which is a different part number then the one I listed in my OP which apparently is the one that is a perfect fit.
I am a little worried about cutting a brand new manifold, as if I screw it up, I am stuck which is why I wanted to be sure the RRC would fit ok.

I may be able to get an RRC one for a decent price and am in the WTB section atm looking for a someone willing to part with their setup (manifold, injectors, rail, TB etc....) and try and save a few dollars. I have been going a little crazy buying stuff trying to sort my exhaust issue ( thanks to you) which is PERFECT NOW! So thankful to your help!
 
#6 ·
yes , the exhaust was sorted out,
I have been meaning to take the pictures to post when the car is in the air next. So I can better explain what I did thanks to your advice.

The final touch was those torque solution bushings, they made the exhaust so solid, it barley moves and now does not rub or bounce anywhere.

RRC requires cutting? oh that is new, I was going to buy one, lucky I did not.
So bang for buck, the RBC is choice, but if I can find a skunk2 one with that part number for my a2 then I will be ok?
http://store.skunk2.com/engine-tuni...anifolds/pro-series-intake-manifold-3488.html.
But I guess no one really sells stuff like that off their builds, and that is quite a bit to buy new.
 
#7 ·
All these manifolds are a bit pricey. Be advised, the RBC also requires cutting... But they are more readily available modified. Of all the options it is by far the better value checking in at $200'ish brand new. Is it the best manifold available? No, but it will perform better than the PRC you currently have, costs half as much as the nearest alternative, and with port work down the line will perform compareably to an RRC.
A machine shop can make quick work of the cutting assuming you can find an adventerous machinist. But honestly, you modify the manifold yourself in a couple of hours depending on tools available. A dremel *might* be adequate, but a proper cut off wheel and grinder will be the best most appropriate tools for the job.
 
#8 ·
i have those tools available at in the shop I work at, it's just the task of actually doing it without error.
The fact that I can't undo an error kind of intimidates me, hopefully I can grab one that has already been modified.

I saw your picture of the trimming and a local tuning shop had told me I would have to do the same, but other then that , isn't the PRB and skunk a drop in? The only reason I was thinking about the Skunk2 and the RRC was because they have already the improved inside and would have to worry less about porting it out when I get a TB which I would do anyway before the install
 
#9 ·
One more suggestion, order up a couple more intake manifold bolts from the dealership. In order to remove the manifold you will need to remove the 2 studs from the head. Replace these studs with bolts. Should you have a need to remove the manifold in the future you can do so in about 15-20 minutes.
Might seem trivial, but I have pulled my manifold twice this year.
 
#11 ·
You are not curing cancer, you are just cutting a manifold. Just do it, and you will be happy you did. There is still a large market for it even though you cut it. Because there are claims that the k20a2 head is one of the best. It isnt too difficult, nor hard to do. Work slowly, and i am sure you can get the job done.
 
#14 ·
do you know of places that sell the pre-cut thermal gaskets to?

I bought a users RBC manifold that has been modified but I have not test fit it yet as I would like to get a rail setup before doing the work. But I have heard I need to drill new holes in the gasket to get the water ports right.
 
#16 ·
I am going to post pictures of the cut, so I can show the veterans if it is a good cut and I am ok using this setup before I start ripping stuff apart.

I got burned a little last time on the header install as I did not expect to hit the roadblocks I hit during the install and was lucky I did not break any of the cat bolts during removal as I had to put it back together and order more parts before trying again.

I was fortunate to have members here help me source everything properly which is why I am asking for this install before I start it.
 
#21 ·
This is the RRC manifold that I bought from a user that was modified for my a2.
I just need to get the rest of the components for the install. He had already did the cutting but the only issue is underneath it.


I will have to figure out how to plug these nitrous threads. I went to a local hardware store to try and find small enough pipe fittings but I could not find small enough ones to fit inside. The closest things I found that would fit were grease fittings but they of course are not sealed and I would rather not weld it.
 
#22 ·
Damn nitrous ports...
But being nitrous ports they are based on certain sizes, more than likely 1/16" NPT or 1/8". Give the guys at Summit Racing or Jegs a call and they can set you up with the proper dash fittings in short order.
That being said, I would opt for welding over.
 
#24 ·
A proper weld is the equivalent of "re-casting" the alloy. The weld (when done correctly) will be stronger than the original surface. Kinda like when a broken bone heals. There will never be an instance in which the welded plug will loosen or vibrate itself free.
Now that being said, a well sealed dash fitting will seal the ports. There should be no cause for concern HOWEVER the plugs become something that may in time fail. Again, the probability is slim, but given the option I would choose I less thing to fret over. A random stall at a light, degraded performance, oh no, did one of the plugs come out?
Then there is the issue of a plug not simply falling out but getting sucked IN. Yeah, that would be a bad thing.
In my age I have noticed my tastes have changed, even my views and methods of attack on a new toy have changed. It is a better thing to eliminate issues before they arise, whenever possible.
More of my random old guy speak...
 
#25 ·
Also, I love the polished look, but when I saw that picture of the under side...I said dammit...
Almost felt bad about pointing you in that direction. But honestly, the ports are not a deal breaker. You got yourself a fine piece of OEM hardware. I may in time pick up at least one RRC myself. I recently (foolishy I might add) picked up an RSX S, so I may be tinkering with a 20 again instead of chunking it outright for a K24.
 
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