Rep Power: 318

So you spent how much for 1.5 hp? That's some expensive hp. And you went from stock to I/H, pulleys, 2 degree advanced (on what exactly?) with VAFC-II and only got 2.7, then corrected it for a grand total of 4.2 hp gain. Lets see I/H cost about what 500? VAFC-II about 250, so for 750 bucks you got 4.2 hp.

 
Rep Power: 318

That's not a big deal for N/A cars. Sure the air is more dense and all that at lower temperatures, but a 30 degree difference might equate to 1 hp, maybe 1.5 on our cars. If you have a car with an intercooler, then that makes a huge difference becasue the intercooler can't do as good of a job at high temps.

 
Rep Power: 811

For every 10F drop in temp, you gain 1% increase in power.

 
Rep Power: 318

Actually, if you look at the ideal gas equation and saturation tables aviable in any advanced thermodymaics book, you'll find that the humidity plays a much more important role. That saying is a VERY general idea. And that theory comes from the old fashion carburator days. Today, if you're intake temperautre changes, our cars have various controls to compinsate and run in the most favorable condistions for any temperature. IF you don't beileve me on that, look at a turbo car and run it, it will have closer to 1.5% per 10 degree change in weather. Our car is around 0.5%, and if you average that, it's about 1% change which makes for a rule of thumb that has became less and less true if the advancement of technology.

 
Rep Power: 811

So what does humidity do to performance. It seems my car runs like crap most of the time cause it's always humid here.

 
Rep Power: 0

So basically my I/H pulley camgear doesn't do any good at all, except that my 110hp comes at 5500rpm....
Anyway........~~
Injen CAI-200
DC header-200
AEM tru-power-145
AEM tru-time-125
VAFC2-299

 
Rep Power: 318

Humidty is water vapor, if water gets in the engine it does two things: (i) it takes the place of what could other wise be air (or oxygen) thus lowwering the total amount of air being sucked in (less air, less fuel, less power) and (ii) water is a inhibtor of the combution reaction. It actually slow the reaction between the fuel and the air down thus making it seem like you have really crapy gas, even if you don't.

 
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If temp is higher, the water vapor that is contained within the air is much more than in colder air. Comparing 100deg with 70deg, the same 70% relative humidity is much more humid in 100deg situation. Take the word RELATIVE.....the ability of water vapor that can be held within 100deg is much higher at 100% than in 70deg......The installer suggests me to do dyno below 80deg on a ralatively dry day....

 
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I have one and it works great. obviously somebody hooked it up wrong on your car.

 
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does anyone have the answer to the vtec3 compared to the vtec1?

Our civic here is equiped with a d16w8 engine it is claimed to have 3 stages of vtec.

Wonder if this has got anything to do with the vtec 3 and vtec1 setting? Since the b16 and older models of d series engines have only 1 stage of vtec.

 
Rep Power: 811

I'm 100% sure vtec=3 for the 2001-2002 civic. I looked it up in the book, and someone even did a dyno comparing them. Again, the vtec3 performed better.

 
Rep Power: 318

Actually the difference between 100F and 70F is about 9%. The 100F air can hold about 9% more water than the 70F at 99.9% humidity. (Note that if you have 100% humidity it will be raining.) The reason is becasue you haven't hit the boiling point temperaure of water, once you hit that, then you can put alot more water in the air. Playing around with 30 degree F won't make that much difference if you are talking about a high humidty. A dry day (low humidty) will make a big difference over a wet day (high humidty)though. Believe me, I know what humidty is, I'm getting my PhD in Chemical Engineering and the abilty to hold water in air (or any liquid in a gas phase) is a big thing in chemical reaction kinetics, so my guess is that I know a little more than your installer about equilibrium constants and the ideal gas law.

Sorry for the slow dealy, I just got back from Vegas.

 
Rep Power: 0

Pretty much stock I wouldn't expect major gains from just a VAFC.

 
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I am not into chemical engineering but I am rocket engineer so that I have some basic for that.

 
Rep Power: 811

Someone got 5.5whp with just a race hheader and intake.

 
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So does anyone know what the vtec3 stands for? is it 3 stages of vtec or just another term for new vtec but same old system?

 
Rep Power: 811

It's just a set of conditions for the vafcII. It's in the instructions as a little chart that shows rpms and stuff. Just set it to 3 for the civic ex.

 
Rep Power: 0

If somebody still reads this thread.....
VTEC Type is the range that you can adjust the VTEC changover point. VTEC-1 is high rpm changeover(3000-7000), VTEC-2 is mid rpm(3000-6000), VTEC-3 is low rpm(2000-6000)....
That means, our VTEC is low rpm VTEC changeover, means....it's basically a VTEC-E design....
Even older SOHC VTEC are VTEC-1, except those Hybrid VTEC, such as J30A V6, are VTEC-2......
Looking at the camshaft, that's the point to select 1, 2 or 3.
VTEC-1: 3 intake lobes per cylinder, 2 of them are SAME height, and 1 high lift.
VTEC-2: 3 intake lobes, 1 is low profile, 1 is normal(with respect to VTEC-1 car) profile, and 1 is high lift.
VTEC-3: 2 intake lobes, 1 low profile, 1 high lift(with respect to normal profile).....

That's the end of the story.....

 
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The VTEC Type does NOT affect performance as far as technical concern. It is just the range. Somebody feel that it doesn't work that well, it does not make any sense.

 
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If somebody can make a bypass for the igition timing correction to my ECU, then that will be a different story(as far as I know).
I checked igition timing on some cars using OBD-II reader when the car is at IDLE....
Here's the result......
Stock TSX, 93 octane, 6.8 deg advance
Stock Civic EX, 87 octane, 2.4 deg adv
My Civic, with I/H+pulley+2 deg valve advance on 93 octane(no fuel tuning).....26.5deg adv(or retartd, forgot, but still)!! WTF!!!!!!.......

 
Rep Power: 264

So a vafc2 and some dyno time with really nothing done to the car will get 12 whp?

 
Rep Power: 811

lol. I tuned my car after header, pnp head, and a few other small mods and only got 2whp from the vafcII. The a/f is pretty good already. Someone here with alot of mods did get up to 10whp tho in a manual after tuning the wide throttle. With nothing done to the car you may get a few hp but that's it since our cars run a bit rich from the factory.

 
Rep Power: 0

First priority, get rid of the factory intake manifold first....

 
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In the future I plan on doing p&p, i/h/e, mild cam, full balance, and I'm sure I'll have to do sumthin with the valves... haven't quite learned about that yet But with all that, the VAFC-II should give a good boost when tuned correctly, no?

 
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p&p, i/h/e, mild cam, full balance? It will do nothing good for the engine until you get rid of the stock intake manifold

 
Rep Power: 811

There's always something that's restricting performance. Once you do everything, I'm sure it will give more of a difference. I have oversized "race" valves with my pnp but I've heard the extra flow doesn't really help unless you get a turbo.

 
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True that pnp is more a set-up mod than performance, but it's gonna make the car run a little more efficient (as far as air in and out). But I forgot to say that I want to do the Y8 conversion as well... I really want to learn more about the fabrication of putting in on tho, but no one has done a DIY and I know like 3 people who've done it so far.

 
Rep Power: 811

my pnp and valves = around 10whp with only header. I'm gonna start getting more stuff tho and see what happens. Intake, exhaust, bored tb maybe...

 
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Well I'm just lookin to get about 150 whp but at lower RPM. But just today I really started thinkin about the K20... get's like 200hp and I'll have the i-VTEC. But would I just go to Acura and say, "I need everything under the hood for an RSX-S" or are there places where I can get a new motor and everything for cheaper. I'd rather get a new motor than a rebuilt or a used. How much would EVERYTHING cost me and let's say that I'm doing all the work myself?

 
Rep Power: 288

10k or more if u buy from dealer, just buy a type-s if you spending that much