Ported stock intake manifold vs. Skunk 2

[fowler.j.12]

I have read a couple threads on here and the one on Team Integra.(Which is a damn good writeup)

Looking to get a 68mm TB. That on a GSR head and stock Intake mani.

At about 11:1 compression. ITR headers Full 2.5 inch exhaust

Would I be better off just cleaning up and porting my Stock mani or go to a Skunk2 pro series? I don't want an Edelbrock since they list gains at high end and I'm not turning past 8k rpms.

 

[fowler.j.12]

Bump. Help please

 

[9TechN9ne9]

Correct me if im wrong, but the stock GSR IM is a 2 step and the S2 is 1 step. Sounds like a no brainer to me.

 

[fowler.j.12]

I do not know what the 2 step and 1 step are? That is what i'm looking for though. Pros cons gains?

 

[Samurai_Blue]

its a double edged sword. I think the gsr manifold is just shit in general. You can lose power if you take out the secondaries. with the skunk manifold you will lose some power unless you tune but you will receive more in gains

 

[9TechN9ne9]

The stock GSR intake manifold looks like this

It has 2 sets of runners and 2 sets of butterflys making it a 2 step. S2 uses a 1 step design with shorter runners to get a better throttle response and shifts the powerband into lower rpms.
I would start with this first
http://www.team-integra.net/forum/14-performance/118942-new-article-intake-manifold-measurements.html

 

[9TechN9ne9]

photo doesnt look like its working.. and im way too lazy to fix that.

 

[Local]

See this thread over on HT if you havent already. He ports out a GSR mani which see's some pretty great numbers up against a performer X & the skunk2. I've personally used all 3 within the past couple of months.. im happiest with the skunk2 piece. It is all really build specific tho-- what works best for others may not work as good for you. My compression is right around 11:1 as well & im running Pro1's. My tuner actually suggested keeping the GSR manifold at one point, its got loads of torque.

the steps in question are actually butterflies, which open up at a cerain RPM. The GSR was designed with 2 to increase low-mid range torque, where as most other OEM + the skunk2 piece are single butterfly designs. The GSR manifold was a great innovation for increasing torque on these motors & holds its weignt against the aftermarket options. I'd be really interested to see a ported GSR mani in action.

 

[fowler.j.12]

Thanks for the help.

 

[9TechN9ne9]

To go back to the original question, its up to you whether its worth your investment in time and money on either product. You know the pros/cons so the decision is left to you.

 

[fowler.j.12]

Would porting the intake side of stock manifold and output side to a larger tb help a little in the gains department?

 

[NemesisCBR]

Cant say for sure but if it does help it wont be much. Those kinds of details are very minor and are usually final touchs to a setup or min/max in race builds. Even the tuners/racers have to dyno it to see if theres a gain or not.

I dont know what these 'steps' are.. seems like people have a dozen different names to call things. Theres one butterfly in the stock gsr manifold. Its called a secondary butterfly because the tb is considered the first. (im going with logic on that one :mrgreen Since Local already mentioned the thread from HT i dont have to say much about it but you definately dont want to get into modifying the stock manifold unless you know what you need to do and have the time/resources to do so. It was a fantastic project and im glad the HT member went through with it.

Manifold choice. Theres a design purpose to every part made and so many ways to frankenstein your build. Its very important that you know how each part works and how it might apply to your build. Thats the min/max race mentality. For most people this doesnt apply as strictly because well.. you arent really tryin to win races with ur s***. The stock manifold is a well tuned piece of work but parts have their limits. I can give this one example for choosing between those two manifolds. Stock will have more midrange, the pro series will be more beneficial top end but will highly depend on the build. The pro series might have potential to make up the difference in midrange but ill have to see it tuned first to confirm. I definately wouldnt call the choice a no brainer.

My recommendation.. for a fairly stock build if you are just swapping the manifold with no cams, dont bother. When you start making more power through improved breathing, the pro series will probably start to outshine the stock manifold. Builds with similar but different parts will not guarantee to yield the same results.

And the almighty question.. what is your goal/intent?

 

[fowler.j.12]

Goal is a fun daily driver. Hopefully track car on the weekends if I want to. Me and my friends have talked about it for a while.
Maybe 200 HP probably won't make that but I'm going to try.

 

[NemesisCBR]

Well the general info you need has been provided by previous posters. You should be able to make a decision.

 

[Screech]

I had the same idea a month or two ago, was hoping to see what your intentions were. Guess it was just an inquiry.

The secondaries removal in very common, not limiting to just the gsr either. Look at the sn95 cobra's, also k series you have the rbb intake and a couple oem others. They had imrc's which are the same as a gsr iab setup.
In general conscientious when you remove the iab's/ imrc's you will loose low end torque and gain in high end hp.

This is the lower part of the intake manifold looking at the iab's straight on.

This is the top end

What I was thinking before pulling these apart is to actually cut the intakes barriers so it was just a hollow plenum area. Such as the k20a2/z1 intake manifolds.
Then port match the intake runners to the head.

But it would take a long boring time of hacking stuff up on the runner side to achieve what I would want. There was another problem with that, I cant really remember at this time what it was though.

Anyways, just wanted to share all this info.
The edelbrock performer x intake is something I really am in search of. I have jdm itr pistons, and going with aftermarket cams. The long runners of the performer x will generously help you.
Cams is where you find the most power once you start messing with a engine, allowing a engine to breath is essential. Its a large pump.
Longer runners were found on the ctr intake manifolds when compared to the usdm itr intakes. see if I can find a picture of my old ctr intake.