Nice! Not as much gains as I expected up top, but the midrange is nice. What are your header measurements? Looks like you could benefit a lot from ITB along with cams... the air going into to the engine is not as much volume as the air coming out.

 

My goal is to produce a nice fat usable reliable power band for a reasonable cost and minimum hassle so I can power out of corners better. iTBs don't fit that bill and they are way loud. I'd rather spend that money on tires where it counts the most. The most I'll do from here is the SoS throttle body and the cams. The mugen header may not produce much up top but the adds more down low where I think our cars need it the most...plus I got it for pretty cheap used so it's not likely going anywhere soon.

 

Your goals are exactly the same as mine. One of the tracks I frequent has three different turns where I apex in second gear at 4500-5k revs, this tune would help a lot.

Given that, do the BC cams improve the midrange much or at all?

 

I'm not sure. Evans said it would but he couldn't say for sure how much. I'll probably get it done right after the new year unless snow grounds my car and I'll report back.

 

i believe the mugen header has a 60 mm collector. that's what is holding back from more gains across the powerband imo. i think the k&n intake compliments the stock throttle body well. with a larger throttle body the setup can benefit from a larger diameter intake pipe.

 

Yep. The itb may be loud by itself, but the sound mainly comes from the exhaust so its prob not marginally louder than the stock tb, esp with a box. Very similar to the difference between a stock airbox and a short ram intake. Many engines come factory with itb and sound good to driven on the street, i dont see this as impossible to do on a s2. Being that its a track car, sound shouldnt be an issue. A car with the potential of a s2000 should be treated stock (quiet), or as loud as it pleases to be and nowhere in between. IMO the larger throttle body is not gonna be much difference either but more of a halfway crook method. Depending on choosing the right horn specs on the itb and the box to cover it, it will show significant gain because the air will cater as the cylinder demands, and not as a engine as a whole. When the engine speed gets higher and higher, being that its a small motor, the cylinders can only combust the amount of air they can suck in the 0.001 ms (or whatever) time frame its given. The stock tb cannot meet this demand as the revs climb. My main point is that the stock tb was created, engineered, and tuned, to work with stock header and exhaust. If you wanna free up flow, the stock tb has to go; especially with a all motor setup. I would never run open itb in my car, thats only for race cars where the motors open, but with a box i think it can work wonders on track and dd. Only thing holding me back on the itb is the cost.

 

As for steve, modding is an addiction man. Your gonna say cams and tb is your last mods, but when your next season comes your gonna convince yourself to get motor work, injectors, itb, diff, and a million more things that can break the bank, to give a tiny little edge, especially with the new haltech toy we just got. We all know how guys get when it comes to our cars.

I cant wait to get my tune, I think Im gonna get similar results, but maybe a little more up top because I have a bigger header, but using you as a bench mark I would consider a different header/exhaust combo also. Im def gonna consider itb next year not as much for power but more for response, just seeing how the response feels on my 1000rr (I know its not the same as a s2k), theres nothing like it.

 

i agree. the stock throttle body on the f20c and the 04-05 f22c is the same exact size as that on the b18c5 found in the integra type-r. the same size throttle body on a motor that is 200cc larger lol.

i was able to pick up 10 whp peak and power everywhere else between ~6500 rpm and redline when i switched to a larger throttle body and a larger intake pipe. i never lost any power anywhere in the powerband by swtiching to a larger throttle body and a larger intake pipe.

bigger is better on this motor. how big is too big, that i don't know. i just know that these heads are amazing even in stock form and can respond well to bolt on modifications once tuned.

 

Modding is an addiction but for me power isn't. I'd buy $10,000 shock before getting itbs. Once you start going to the track you'll realize there will always be more powerful cars no matter what you do. The fun part is lapping them with half the horsepower.

 

Very true, although I think Honda used the tb from the b18c5 because the itr is a monster, so I would say the ITR tb is big for the b18 but not necesarily too small for the s2k. 195hp is a lot for a b18 which goes to show how important it is, esp because the b series doesnt have the coil pack and ecu technology the f and k have. I think stock tb is very good on a s2k stock, but once modding and tuning starts itb is a must. But with so much breathing, bigger is def better, and is amplified by any time of ram air effect. Stock tb cant cope with ram air. The main issue isnt with the primaries, but the end where the 4 connect and receive air from the single throttle. There is too much turbulence here, and too much mess. This matters a lot when the only force sucking air in in a N/a setup is the vacum pressure. When you have vaccum pressure it should be able to breath 100% free as it pleases, not 1 throttle controlling 4 cylinders. I am not sure if itb will add that much power, even though it should on paper, but response is VERY important on a racetrack, and the response is unparalleled with itb. It only makes sense.


For example take a look at the tb on a k24 (tsx), one on a k20 rsx-s, and one on a newer civic si, and a base rsx. They are all different, and they each act in a different way. On my rsx-s i had a stock tb, and my friend with a same MY rsx with a same setup upgraded to the larger better shaped (straighter more like a s2000 tb) si manifold (RBC) i believe its called and saw much better gains with the same injen cai we both had. We were both untuned and he showed strong gains. This goes to show how air acts matters esp at high revs.