Stock IM vs RBC IM

Squiggy weighed in, and he has it.
I also have the swap and did make a lot of hp gain, but I don't have a torque graph, so I might have lost torque at the expense of top end hp
 
webby said:
You've tuned a ton of people with the rbc manifold, and some with the zdx throttle body as well. Are those dynos all looking like this? Because I recall quite a few users in the 220's-230's to the wheels with those setups. I just don't know what their dyno charts looked like.
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And I guess tuners don't dissuade users from doing RBC, even though it's wasting huge chunks of time and money. And they tune the dukie anyway? And what about the dynos/edynos with 220, 230 whp numbers. they are dukie too? I'm confused. Hope I've got it all wrong in this post. Help me out.
 
323 said:
Squiggy weighed in, and he has it.
I also have the swap and did make a lot of hp gain, but I don't have a torque graph, so I might have lost torque at the expense of top end hp
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Squiggy said: "I would like to know what impact the zdx has on the setup and if it benefits from the rbc or vice versa."

That's not quite what I had in mind as weighing in. I know that Vit works like a fiend for his customers, so I'm confused. Does he have upset RBC-swap customers (I doubt it) complaining about his etune, when the problem is the RBC? Did he see RBC swap etunes that revealed a pattern of poor results, drop-outs in the power band, etc., so he decided in good conscience, "I'd better let folks know about this." This is probably what's happened. He saw a pattern emerging, he's an honest guy, so he's telling people, in effect, "Don't bother with this mod."

Rats. I guess that you go balls out with a supercharger or turbo, or just leave the car alone. I don't want to dick around with $300 here, $400 there, with no real gains. So for now, I'll leave the car alone.
 
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So it seems Honda did a great job on the intake side of things with this car, and almost all bolt-on power increases will have to be made on the exhaust side (and with tuning). The PRL intake possibly being the exception.
 
Seems like what's going on is the RBC is optimized for high rpm flow (since the k20 redlined much higher), so you'll see high rpm gains start to creep in near redline on the k24. When you're talking about peak hp, it's almost always at the top rpm range, so you'll still see peak gains, but that drop in midrange torque is not insignificant.
 
Yeah im researching a little and see where the loss in midrange has been mentioned before. Like last year lol. I guess im just disappointed that there really isnt a way to get over 200 whp NA without using the rbc amd losing all your midrange. We definitely need companies to start working on intake manifolds for our engines....
 
As much as people think the stock intake resonator chamber is just for sound control, it might also have something to do with performance. The intake manifold is just one piece of the puzzle when you're talking about standing waves and the charging effect they have. Since the resonator chamber does such a good job of reducing sound, that could be a direct result of the resonator also affecting the standing waves. Less sound out the intake tube = less energy lost out the intake tube. Could be why intakes are such a crapshoot when it comes to midrange.
 
I think theres a difference between an intake and intake manifold. I removed the resonator from my intake and noticed better throttle response and it seems to breathe easier. Pretty sure I didnt lose anything. People with aftermarket intakes only seem to lose just slightly when not tuned, after loading even a reflash tune they do gain a little. Unless im wrong, which is very possible, the only piece ive seen actually lose any power even after tuning is this rbc manifold. So pretty much the only thing i can do for good gains is forced induction. I guess ill just save for a supercharger then...
 
From an engineering standpoint, when calculating airflow, the two have to be considered together. While you can design them and calculate flow separately, the flow of one will still ultimately be dictated by the other.
 
Just stumbled on a product. Its a p2r ported intake runners. Keeps the stock manifold. Wonder if this would gain the power of a rbc (or close) and not drop everything else? @VitViper have you messed with any of these yet?
 
Glad I saw this thread also. The RBC,ZDX with a cold air were my last pieces to the puzzle. Guess and intake is my only option now. I'd rather have mid-range/ throttle response then top end power.
 
hey_mikey said:
As much as people think the stock intake resonator chamber is just for sound control, it might also have something to do with performance. The intake manifold is just one piece of the puzzle when you're talking about standing waves and the charging effect they have. Since the resonator chamber does such a good job of reducing sound, that could be a direct result of the resonator also affecting the standing waves. Less sound out the intake tube = less energy lost out the intake tube. Could be why intakes are such a crapshoot when it comes to midrange.
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Idk im completely stock besides a k&n drop in with resonator deleted and i feel enough to say theres an improvement
 
PASCIAK said:
Idk im completely stock besides a k&n drop in with resonator deleted and i feel enough to say theres an improvement
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That's fine. Unless someone dynos their before and after resonator delete there's no way to know for sure. Besides, I was speaking more hypothetically (which is why I said it "might" help performance, not that it absolutely does). People say they feel the 5hp peak improvement from intakes too when they'd be really hard pressed to show an improvement on the clock. But I bet if you rode shotgun in a car that ran to 60 in 6 seconds vs one that did it in 6.1 seconds, you would have a hard time telling which is faster.

Less restriction is great for high rpm breathing and therefore top end power, but longer tuned runners are better for midrange torque. I haven't done any flow analysis on honda's manifold and intake resonator on the Si, so I won't claim one is better than the other. Just saying that to properly take advantage of the charging effect that improves midrange, you gotta take both the manifold and intake into consideration.

The fact that it's so hard to see large meaningful increases in power (staying NA) from this motor shows that it's pretty efficient to begin with.
 
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