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Ok, so I have been doing some research to try to find out why our cars don't respond well to modifications like other previous generation civics have. I might be off on some, or maybe all of this, so feel free to correct me. Don't flame if I'm wrong though because I'm just making an attempt to solve a problem. I have only owned a Honda for 3 months and know close to nothing about the previous generations of Civics. I owned an did my own work on my old Altima though so I have a basis on which to understand the basics of cars. This is only theoretical. So here I go...
A difference between the 7th generation civic and the previous, aside from the most obvious, is that the 7th gen is a ULEV. If you look at several aspects of the other SOHC engines you will find displacement and bore & stroke to be roughly about the same, not exactly though. You will also find the compression ratios nearly equal. How does ULEV work? Our catalytic converters play a big part in the decomposition of exhaust components, but that however, does not significantly restrict the potential of our engines. When creating a ULEV engine... what would be the most obvious things to do? Like previously stated, build a catalytic converter that can handle a larger amount of the exhaust components and break them down to less harmful gases to be released into the atmosphere. Using different catalysts will have the ability to reduce them even more and faster. But a greater process is put to work than just a catalytic converter.
This is where a great difference takes place between the way the seperate generations work. a 7th generation Civic runs leaner than the previous generations. By running leaner we create less harmful exhaust gases, making it possible for the catalysts to break them down faster, and maintain a fairly high gas mileage. Engines that run lean are known to burn hotter and produce more horsepower. However, when we have an engine that runs exceptionally lean, we have an engine running cooler, which in turn produces less combustion, and therefore produces less power. This may very well be the case with this generation Civic. Assuming it is the case... there are ways around this. But let me further my discussion on the basic fuel system first.
As air comes into the engine, the amount and velocity of that air is read by an Mass Air Flow sensor (MAF). The vehicle's Engine Control Module (ECM) takes this reading, processes it, and makes the proper adjustment for an optimal Air:Fuel mixture. After this mixture combusts it is passed through the exhaust manifold, catalytic converter, and over the oxygen sensor which then in turn also is sent to the ECM to change the Air:Fuel mixture again. So the oxygen sensor and MAF are coinciding with each other to form a stabilization of this mixture. When I say optimal mixture this is for the daily driver who wants high gas mileage and could care less if he was running the slightest bit more horsepower.
So, assuming that the D17A is running exceptionally lean to make the ULEV and not LEV, then we have to look at how to get them to run a little richer but still lean, possibly like an LEV. If I am correct, the Apex'i S-AFC or the V-AFC allows one to raise the fuel curve for the amount of air that is being pulled into the engine. This will create a richer mix for the engine, allowing it to run hot enough to produce more horsepower. With the addition of induction using an SRI or a CAI, we can then again boost the amount of air pulled into the engine. This will in turn allow for a better mixture than stock, and produce more horsepower. A larger diameter MAF than stock could also allow for a greater mixture even producing more horsepower.
A more expensive route is the AEM Engine Management System (EMS). While this is capable of producing the same effects as the AFC, it has others as well which are more suitable for performance. To go further on what we could do with an EMS which can better our Air:Fuel mixture to run at a better ratio and keep that ratio consistent throughout different operating extremes is to add on an Exhaust Gas Temperature sensor (EGT). This will inform the EMS of more precise temperature changes that affect performance.
So, in theory, by using various fuel controllers, and adjusting this mixture, it would seem that the motor would be more responsive to bolt-ons. This is only a theory though based on this engine running leaner than the previous. Sure, it may be wrong, partially or totally, but I'm just offering it as a theoretical possibility. I already know that there are a lot of others on this forum that know more about engines, and I'll open up the door to them to prove me wrong, but please don't flame... at least I'm trying to help.

 
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Lots of good thought into that....I see where you are coming from, and I agree with a lot of what you are saying...unfortunately I am at work and cant write a whole long response....but I will.

 
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the previous gen civics didnt respond well to mods either right?
i/h/e on previous gens is almost the same as 7th gen minus 1 or 2 hp.
thats just from my expierence.

 
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Nice discertation! you get an "A"

 
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hey, honda is not a marketing company. They put out products and tune them well. When it leaves the factory is meets US standards and performs to that. We would have to alter everything in the car to get it to perform the way we want it, faster and more powerful. But in being students and average people, people do not want to spend the money and they get what they pay for. Jusy my thought. If you are going to work on you handling, just lowering your car only constitutes for looks. A true tuner would have have spent $2500(minus the rims) on lowering his car.

 
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If they were a marketing company the Type-R and Si would of come out with the 2k1.

 
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I thought I read a bunch of threads asking why the 7th gen doesn't respond to bolt-ons like previous. Damn... I wrote all of that based on that as a fact. But like I said in the beginning, I don't know that much about the previous generations so I could only go on what I have heard.

 
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I totally agree with what you are saying. But your point is somewhat of the same point I'm getting at... You have to put a lot more into getting a Civic to respond better than just a simple bolt-on. But, what I'm thinking is... look at the other cars out there that may respond better with the same size engine. Most do not get as good gas mileage, and most are not ULEV. That is the kind of idea that came to my mind that it is very possible that it was in the scope of the fuel system that can allow you to grab the extra few ponies off of those modifications.

 
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Good stuff - this is my take. The engine is 1.7 L (kinda small) It is already well tuned for power, emissions, mileage, and reliabililty. There are some areas that can be improved on, but expecting to get alot more power from simple performance parts isn't realistic. Alot of the limiting factors are in the basic engineering of the engine itself. For example, its SOHC and this somewhat limits it. Thats why most engines in performance cars today are DOHC. SOHC is lighter and simpler and the civic (excluding the Si) and thats why its in our cars - they aren't for performance. So without using nitrous or forced induction the power potential for this engine isn't alot. High amounts of N/A horsepower can be had from this engine, but it takes alot of modification (the KMS civic). Plus driveablilty can become an issue. It all comes down to an issue of what is considered 'responding well to modifications'. The intake/header/exhaust route doesn't cut it anymore. To get this engine to respond its gonna take a couple thousand dollars at least. I'm talkin intake, header, exhaust, chip, pulleys, cam, flywheel... thats about 2 grand at least right there. Putting that on a V8 of course will make a much bigger difference. People mention that the d17 needs to be cracked to find where the real gains are. I don't think the engine will be 'cracked'. This is just the sad truth about it.

Bottom line - expect to spend alot of money to get power. Its been said many times before.

My own plan for the civic (if I decide to keep it - Gen 3 Integras or 6th Gen civic Si's are lookin better and better) would maybe be for a K24 swap. This engine has some sweet torque and in a few years If I could get this engine for maybe 3 grand, I would swap it. Or I might go turbo if the price comes down to around 3g's. Thats my sweet spot - 3 thousand. I'd rather get one thing that will add a bunch of power than to get a bunch of components for the D17 and have much less power. Unless you use forced induction there isn't much potential for the D17 in my opinion. Its just too costly.

 
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We can't really say that it is well tuned for power. We can probably say that it is well tuned to get maximum power while satisfying emissions, getting good mileage, and staying reliable. What I am trying to say is that the idea of the fuel system should enhance these modifications with no regard to mileage and emissions. Everybody is right... obviously if you want power your gonna have to drop a couple g into it.
Did you really mean a K24? The torque falls off mid range

 
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i'm waiting for the labor part of swaps to be cheaper, then i'll swap in either a k20a2 (SI/base RSX) or a k24.

 
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Smokie2k2LX, ya you're right about tuned for power while keeping mileage, driveability, etc in mind. Ya, the K24 is what I meant. I just think it'll be a much cheaper engine eventually and even though the torque falls off in the mid range, thats where I drive most. I'll bet the new JRSC would even fit on it with slight modding too. Then theres the possibilty of a type-s head on it. Mmmm now that sounds fun! Ahh, more money once again!