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Thank you for going to the trouble of looking up the original thread that had the entire dyno chart rather than just the top end.
I don't usually even look at the HP curve since its just a function of the torque curve, and in this case the shape of the curves are pretty close to the same except right at the very top end. What's really significant here is that in both tests the torque has been falling off since around 6,000 RPM, and by 7,800 to 8,000 RPM the torque is falling off at such a rapid rate that the HP curves are falling off too. That paints an extremely clear picture showing how grossly inefficient the manifolds being tested really are in the upper RPM range.
So now take a look at the dyno chart I've attached. This shows the difference between an RBC manifold and my 9.0 manifold. Notice how the RBC torque curve stays relatively flat up to 7,500 RPM? This is unusual for a Honda manifold and its all due to the massive amount of header testing I've done on these engines. But even with that header advantage the torque curve is falling off at such a rapid rate above 7,500 that the HP curve is barely rising at all. Falling like a stone is the term I use to describe this. I'm not interested in falling HP curves, so that's the reason that test was truncated at 8,500.
Now look at the shape of the torque curve from the 9.0 manifold. The dip in torque curve centered at 6,100 RPM is due to the primary length of the header, and by lengthening them by 2" that dip disappears completely, but this was a back to back test on the same 2,188cc (90 x 86mm) engine so there couldn't be any adjustment made to the header and still call it a valid test. See how the torque curve continues relatively flat all the way to 8,200 RPM? That's because I designed the intake manifold to do just exactly that, and the shape of the torque curve above that point is designed specifically to make the HP peak happen at 9,000 RPM.
So polish away on stock Honda manifolds as much as you want, but you're not going to change them into something they were never designed to be no matter how much money you spend on them. How much they flow during a flow bench test is absolutely meaningless. That's just a bogus sales tool the guy who's porting the intake manifold uses to get you to buy his work. The dyno is the real test, and countless dyno tests have shown that its a complete waste of money modifying Honda intake manifolds or bolting bigger throttle bodies onto them. You'd be just as good off flushing the money down the toilet.
 

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USDM > *
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I've been preaching this same message for awhile as well. The only thing I would bother grinding or porting on an OEM manifold is the tb inlet. Lots of people have paid $$$ over the years and yet no one has posted a back to back dyno graph after porting:hmmmm:
 

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I've been preaching this same message for awhile as well. The only thing I would bother grinding or porting on an OEM manifold is the tb inlet. Lots of people have paid $$$ over the years and yet no one has posted a back to back dyno graph after porting:hmmmm:
I have seen some test, sorry can't publish them. Difference isn't worth the money which you pay for cutting and porting whole OEM manifold ;)
 

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BlackNDecker,
If you're sharing a hotel room with my sister you're a necrophiliac, and I hope you have a good time with whatever's left.
On topic: I think the problem here is just ignorance, and maybe some wishful thinking thrown into the cauldron for good measure.
Does a hogged out manifold flow more air by itself than a stock one? Sure! And that's as far as any rational thinking goes. Is there any direct correlation between intake manifold airflow and HP production? Nope! But lots of people don't know that already so the wishful thinking takes the place of logic and dyno testing, and they throw good money away on something that simply can't work except in their dreams.
Just as soon as the RBC manifold appeared in Japan we bought one and dyno tested it against the PRC. Up to about 6,000 it was roughly the same but above 6,000 it was better, so it became the standard Honda manifold to use.
Same thing happened years ago when the RRC first appeared, and since there wasn't any significant difference between them on the dyno we didn't buy another one. That weird Euro-spec RSP manifold with the internal expansion chamber to reduce noise was something we went a little farther on because one guy thought it showed promise. He even paid me to change the position of the injectors (into what we call the "lawn sprinkler" position) and adjust the length of the velocity stacks. We put it on the dyno and instantly knew that doing all of that had been a complete waste of time and money, so not one more RSP manifold has been seen here since.
In conjunction with Hondata's Bonneville program I've turned an RBC manifold into and equal sided center-feed with 3 stages of Nitrous, and I've done more with Kinsler ITB's than anyone, so it'd be a really good idea for people to listen to what I say but that's certainly not always the case, is it?
I hate to see guys throwing good money down the toilet like this, but they seem to enjoy learning their lessons the hard way so what more can we do?
 

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Its actually a mental condition, look it up.
No, I understand what necrophilia means. Maybe you didn't realize that you created a euphemism?

Regardless, I don't understand what necrophilia (or your sister) has to do with the futility of porting OEM manifolds? The only thing I can imagine is you were equating "beating a dead horse" (also a euphemism) to "fucking your dead sister". Amirite??
 

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I had just noticed the bit of insulting Spanish you show as your "location" and was warning you of the danger involved in assuming everyone's sister is alive.
The "On topic:" separated that comment from the main body of the discussion.
We communicate euphemistically on a fairly regular basis in my experience, which one were you in question about?
 

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I had just noticed the bit of insulting Spanish you show as your "location" and was warning you of the danger involved in assuming everyone's sister is alive.
The "On topic:" separated that comment from the main body of the discussion.
We communicate euphemistically on a fairly regular basis in my experience, which one were you in question about?
Ahhhh si. Now I get it:p
 

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So which intake is the best bang for the buck.. OEM seems to work, but center feed rape's them, so to conclude the topic, where should be money spent?

It was brought up so take the time to answer..
 

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So which intake is the best bang for the buck.. OEM seems to work, but center feed rape's them, so to conclude the topic, where should be money spent?

It was brought up so take the time to answer..
This is an unanswerable question and would be different depending on an individual's set up. Also, you would need to know exactly how each of the aftermarket manifolds stack up against each other (Xcessive vs IpS vs 9.0/8.5 vs other?) on your exact build and then divide the additive price of each by the horsepower difference. But...you probably realized this was an unanswerable question before you even finished typing it.

The best "bang for the buck" per hp is probably a used RBC. The ~$900 saved could buy alot of additional go fast parts.
 

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This is an unanswerable question and would be different depending on an individual's set up. Also, you would need to know exactly how each of the aftermarket manifolds stack up against each other (Xcessive vs IpS vs 9.0/8.5 vs other?) on your exact build and then divide the additive price of each by the horsepower difference. But...you probably realized this was an unanswerable question before you even finished typing it.

The best "bang for the buck" per hp is probably a used RBC. The ~$900 saved could buy alot of additional go fast parts.
I have my own info from dyno testing so I use that... But, I just dont see that people are making 320+ with a RBC, or even a skunk2 because even the cheaper xecessive kills that intake manifold..

I guess if you want answers it's best to test side by side, but I can't see myself installing a RBC.. Ekk!
 

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I have my own info from dyno testing so I use that...
Then why'd you even ask???:thud:
1civic said:
But, I just dont see that people are making 320+ with a RBC, or even a skunk2 because even the cheaper xecessive kills that intake manifold..

I guess if you want answers it's best to test side by side, but I can't see myself installing a RBC.. Ekk!
Now you are confusing yourself. You asked what is the best "bang for the buck manifold" not "which manifolds will make 320+ hp". This is why these types of questions are mental masturbation.

AFAIK, Xcessive manifold will not work with OEM tb...so you have to factor the cost of the new manifold + cost of a new tb + cost of new intake (center feed likely won't work with side mount setup) into the equation. At some point, the added cost will negate the "bang for the buck" approach.
 

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If you want help making an informed decision you first need to state what you have currently and what your ballpark budget is to get where you want to be. From your own statement, "ekk", an RBC isn't even on your list of possibilities, so maybe a new thread?
 

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If you want help making an informed decision you first need to state what you have currently and what your ballpark budget is to get where you want to be. From your own statement, "ekk", an RBC isn't even on your list of possibilities, so maybe a new thread?
Well as you know not everyone has the money for custom parts, you guys were having a debate... I have my own info which helped me, but is it the best, maybe not, will a RBC beat it, no...


I have a pro156 port by 4 piston in a rbc casted head, and kelford 179-c cams on a 99x87.5 k24 block with off the self 12.5:1 advertised CP pistons..

Most common of the builds people do...
 
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