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SOHC VTEC Explained

 
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Old Dec 23, 2004
  #31  
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hey i got a noob question. we here at the phillipines post a 3 stage vtec 2k1 model civic. engine model is d16w8. u guys have an idea this is true or bull? i mean we even got stickers placed on the back side of the car saying 3 stage. although we have the same chasis, we only got the 1.6 variant available here and not the 1.7l so m thinking did we here just got lied too?

heres the official honda philippines site
stating that we have a vtec3 engine. and a 2.0l k20

http://www.hondaphil.com/indexFlash.htm

Last edited by wez20011; Dec 23, 2004 at 01:27 AM.
Old Dec 23, 2004
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great info
Old Dec 23, 2004
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I heard there isn't much you could do on our engines, in terms of boring and and all. Its pretty much maxed out from the factory. How do you know when boring an engine makes a diff? and what is boring th engine?
Old Dec 23, 2004
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Boring an engine means making the cylinders bigger, thus increasing the displacement. Most stock sleeves in hondas can take .5mm oversize with no problem.

wez,
To see if your car has 3 stage VTEC, look for 2 VTEC solenoids by the valve cover.
Old Dec 27, 2004
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You forgot to say how SOHC VTEC sucks lollll

Great post
Old Jan 20, 2005
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thanks

great vtech info!! thanks
Old Jan 31, 2005
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Cam specs are wrong, basically were measured wrong.
Old Feb 9, 2005
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Those are from a Honda Tech book. I included the copies of the pages also.
Old Feb 24, 2005
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so does this mean that the D17A2 engine is just worthless even if you port and polish the head and block and add retainers, rings, valves, piston and rods, cams ect ect, ?.. can an attempt to sleeve out the D17A2 all motor make a beast out of it.?? plus maybe addinga turbo afterwards..

what do yall think.?
Old Feb 24, 2005
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Originally Posted by wez20011
hey i got a noob question. we here at the phillipines post a 3 stage vtec 2k1 model civic. engine model is d16w8. u guys have an idea this is true or bull? i mean we even got stickers placed on the back side of the car saying 3 stage. although we have the same chasis, we only got the 1.6 variant available here and not the 1.7l so m thinking did we here just got lied too?

heres the official honda philippines site
stating that we have a vtec3 engine. and a 2.0l k20

http://www.hondaphil.com/indexFlash.htm

3 stage is interesting becasue it combines VTEC-E and a regular SOHC VTEC into one engine. It is correct. You have a very lean slow mode for Philippine traffic, a mild mode for highway and super highway use, and the last one for accelerating like a bat out of hell Honda style. The reason that a 1.6 L engine is used in the Philippines is because there are taxes on larger engines, which is why the K20 is also available because the Corolla has a 1.8L optional engine (here, it comes standard)

here is some info on the 3-stage, which is the version we should get if Honda keeps the Civic SOHC. 3- stage VTEC info for my pare in the Philippines.
Old Feb 25, 2005
  #41  
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Here is the proof that only one valve opens until VTEC engagement. I tore apart my entire F****** motor to prove you wrong 4drcivic2k1 (and I was doing some other stuff too but you will see that in the DIY section soon). This is at top dead center.
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Last edited by caorndorff; Feb 25, 2005 at 12:37 PM.
Old Feb 25, 2005
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4drcivic2k1 you just got owned. I remember you saying there was no way only one valve could open up on the intake side. You even made a big fuss over it, saying you knew everything about Honda’s. Nice job caorndorff, looks like a lot of work.
Old Feb 25, 2005
  #43  
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Yup that exactly how mine looked when we swapped the head. We thought something was wrong cause of that one valve sticking out
Old Feb 25, 2005
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and it seems like the lx would be faster having both valves open instead of 1 when vtec is in low cam profile. Does that mean the extra power from the ex only comes from vtec, which nobody ever even uses if you have to floor the car and take it to high rpms. I don't think any average civic owner does that.
Old Feb 25, 2005
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You said 2 valves open total. Rotate it to the exhaust lobe, both of those will be open. That other intake valve is open as well, pour some water on it and see.

Last edited by 4drcivic2k1; Feb 25, 2005 at 09:27 AM.
Old Feb 25, 2005
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Originally Posted by caorndorff
Here is the proof that only one valve opens until VTEC engagement. I tore apart my entire F****** motor to prove you wrong 4drcivic2k1 (and I was doing some other stuff too but you will see that in the DIY section soon). This is at top dead center for cylinder 3.

BTW, why would an intake valve be open at top dead center? That wouldn't run very well now would it?
Old Feb 25, 2005
  #47  
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Originally Posted by gearbox
and it seems like the lx would be faster having both valves open instead of 1 when vtec is in low cam profile. Does that mean the extra power from the ex only comes from vtec, which nobody ever even uses if you have to floor the car and take it to high rpms. I don't think any average civic owner does that.
but the LX has smaller valves and the cam profiles are not that aggresive. On the EX (VTEC) motor, the non vtec lobe is more aggresive than the Lx simply because it has to the job of both smaller valves do in the non Vetc motors. But yes, almost all of the power gianed by Vtec is in higher RPMs. I made use of it all the time when I had my Civic EX 5 speed. Now that I have an auto though, I take it easy. Every time I floor the car, I imagine the tranny cruching away. Even though I know it won't becasue the tranny for the 4 cylinder Accord is internally the same as the V6 Accord, so if it can handle the 212 ft-lb V6, the 161 ft-lb from my K24 is nothing. But back to my point, I just don't seem to hit those higher rpms with an auto, guess it makes me a "better" driver.
Old Feb 25, 2005
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Originally Posted by Jrfish007
but the LX has smaller valves and the cam profiles are not that aggresive. On the EX (VTEC) motor, the non vtec lobe is more aggresive than the Lx simply because it has to the job of both smaller valves do in the non Vetc motors. But yes, almost all of the power gianed by Vtec is in higher RPMs. I made use of it all the time when I had my Civic EX 5 speed. Now that I have an auto though, I take it easy. Every time I floor the car, I imagine the tranny cruching away. Even though I know it won't becasue the tranny for the 4 cylinder Accord is internally the same as the V6 Accord, so if it can handle the 212 ft-lb V6, the 161 ft-lb from my K24 is nothing. But back to my point, I just don't seem to hit those higher rpms with an auto, guess it makes me a "better" driver.

On the EX, there are only 2 lobes. One per valve. One is bigger than the other. The big one, or "vtec lobe" ALWAYS has one valve riding on it, no matter what. The other lobe, which simply cracks the other intake valve open to keep fuel from puddling behind it ALWAYS has one valve on it. When VTEC engages, both valves follow the single larger lobe.
Old Feb 25, 2005
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Originally Posted by 4drcivic2k1
On the EX, there are only 2 lobes. One per valve. One is bigger than the other. The big one, or "vtec lobe" ALWAYS has one valve riding on it, no matter what. The other lobe, which simply cracks the other intake valve open to keep fuel from puddling behind it ALWAYS has one valve on it. When VTEC engages, both valves follow the single larger lobe.

Yeah Iknow both valves opens, but in non-VTEC mode, more than 80% of the air flow comes from the smaller valve. So my point is that the single smaller valve (with a little help from the bigger valve <- that's the part I left out last time) has to do what both valves in the non-VTEC motor do.
Old Feb 25, 2005
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Both valves are the same size. One just opens more.
Old Feb 25, 2005
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These aren't stock valves are they? I think valve size doesn't really come into play unless you have a turbo.

Old Feb 25, 2005
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Valve size always comes into play. A larger valve will flow more air, wether NA or boosted.
Old Feb 25, 2005
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Originally Posted by 4drcivic2k1
Both valves are the same size. One just opens more.
I'm using my adjectives wrong. by smaller I mean the cam lobe is smaller. Yeah, both valves are the same. Sorry, it's one of those things I know what I'm saying, but I just can't say it correct.
Old Feb 25, 2005
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You mean what i know
Old Feb 25, 2005
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Originally Posted by 4drcivic2k1
BTW, why would an intake valve be open at top dead center? That wouldn't run very well now would it?
You just don't get cars do you? Top dead center dose not mean that all 4 cylinders are at the top. Two are at the top and two are at the bottom. At to dead center cylinder two and three are at the bottom, one and four are at the top. And I never said anything about the exhaust valves being closed ever. You just hate to admit you were wrong.
Old Feb 25, 2005
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Originally Posted by 4drcivic2k1
On the EX, there are only 2 lobes. One per valve. One is bigger than the other. The big one, or "vtec lobe" ALWAYS has one valve riding on it, no matter what. The other lobe, which simply cracks the other intake valve open to keep fuel from puddling behind it ALWAYS has one valve on it. When VTEC engages, both valves follow the single larger lobe.
Now your starting to get it
Old Feb 25, 2005
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You stated that it was the top dead center for CYLINDER 3. THAT WOULD IMPLY THAT THE PISTON IS AT THE TOP OF ITS STROKE. THAT WOULD MEAN THAT THE VALVE SHOULD BE CLOSED COMPLETELY OR JUST STARTING TO OPEN, depending on if it is compression or intake stroke. If you have a valve completely open at TDC you will have bigger problems than VTEC engaging.
Old Feb 25, 2005
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Originally Posted by caorndorff
Now your starting to get it

I've got it since the beginning.
Old Feb 25, 2005
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Originally Posted by 4drcivic2k1
I've got it since the beginning.
No you haven’t.
Old Feb 25, 2005
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I explained this whole thing in the last thread, to the exact same extent that he is now.



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