SOHC FAKE VTEC
11-10-2003, 05:44 PM
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SOHC FAKE VTEC
I recently read in a honda/acura performance modifications book that the 96-00 Civic EX, or D16Y8's with VTEC isnt really real VTEC
I read that the "VTEC" that is on my engine (98 Civic EX D16Y8) just advances the timing of the cam gears and therefore makes the VTEC noise and improves performance a little bit. But, it does not have a second set of cam lobes like the B16A or the B18C series engines which make it a lot less powerful.
I just wanted to confirm or deny this piece of material, because if its true, I am definatly swaping... my vtec just doesnt feel the same as when I thought it was real
I read that the "VTEC" that is on my engine (98 Civic EX D16Y8) just advances the timing of the cam gears and therefore makes the VTEC noise and improves performance a little bit. But, it does not have a second set of cam lobes like the B16A or the B18C series engines which make it a lot less powerful.
I just wanted to confirm or deny this piece of material, because if its true, I am definatly swaping... my vtec just doesnt feel the same as when I thought it was real
11-10-2003, 05:48 PM
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Re: SOHC FAKE VTEC (uranazo)
Jesus H Christ. You have no idea how your car works. SOHC Vtec applications only adjust one cam (the intake cam I do believe). DOHC VTEC applications adjust both cams. You have "real" vtec and I don't know what's worse; that they would print this or that you would believe it.
11-10-2003, 05:51 PM
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Re: SOHC FAKE VTEC (Ricey McRicerton)
yes whoever wrote that needs to lay off the crack. sohc vtec works just like dohc vtec except it only vaires the intake valve timing.
http://www.howstuffworks.com look up vtec
Modified by jwn7 at 10:50 PM 11/10/2003
http://www.howstuffworks.com look up vtec
Modified by jwn7 at 10:50 PM 11/10/2003
11-10-2003, 05:51 PM
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Re: SOHC FAKE VTEC (Ricey McRicerton)
Agreed, look at a frickin camshaft from a D16y8, you would see that extra set of lobes there bud. Its funny that you believed that stuff though 
11-10-2003, 06:02 PM
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ive looked up vtec before on that website, the difference btw them is that the DOHC setup has 2 different set of cam lobes whereas the SOHC setup just has one and all it does is change the cam gears...
QUOTE FROM THE BOOK:
The best way of exploiting a changing cam spec is the Honda/Acura VTEC system as found on th B16A and the B18C. This revolutionary, amazing system uses two different cam lobes. At low speed, a short duration, low lift, wide lobe separation angle cam lobe is used. At a predetermined point, the engine's computer activates the high rpm cam which is at near race car specs. The high rpm lobe on an Acura Integra B18C5 motor has a nearly full-race duration of about 290 degrees! (or about 242 degrees @ 1mm) This is the best of both worlds ... ect ...
The VTEC system on the D-series motors found on Civics is not as sophisticated, it merely advances and retards the cam to widen the powerband, and it does not have all of the advantages of having two different sets of cam lobes as the B16A and B18C does.
HPBooks, Honda/Acura Engine Performance by Mike Kojima
QUOTE FROM THE BOOK:
The best way of exploiting a changing cam spec is the Honda/Acura VTEC system as found on th B16A and the B18C. This revolutionary, amazing system uses two different cam lobes. At low speed, a short duration, low lift, wide lobe separation angle cam lobe is used. At a predetermined point, the engine's computer activates the high rpm cam which is at near race car specs. The high rpm lobe on an Acura Integra B18C5 motor has a nearly full-race duration of about 290 degrees! (or about 242 degrees @ 1mm) This is the best of both worlds ... ect ...
The VTEC system on the D-series motors found on Civics is not as sophisticated, it merely advances and retards the cam to widen the powerband, and it does not have all of the advantages of having two different sets of cam lobes as the B16A and B18C does.
HPBooks, Honda/Acura Engine Performance by Mike Kojima
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11-10-2003, 06:07 PM
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Re: (uranazo)
That is in part true, but also BS. Take your valvecover off, and crank your car. You will see two sets of lobes working, the intake and exhaust lobes. There is a 3rd lobe that isnt doing anything, that is because youre not at 5700rpms. That lobe is activated by the VTEC solenoid, and that one is run instead. Reading is the right way to go, but do some hands on research also.
11-10-2003, 06:11 PM
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Re: (uranazo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by uranazo »</TD></TR><TR><TD CLASS="quote">ive looked up vtec before on that website, the difference btw them is that the DOHC setup has 2 different set of cam lobes whereas the SOHC setup just has one and all it does is change the cam gears...
QUOTE FROM THE BOOK:
The best way of exploiting a changing cam spec is the Honda/Acura VTEC system as found on th B16A and the B18C. This revolutionary, amazing system uses two different cam lobes. At low speed, a short duration, low lift, wide lobe separation angle cam lobe is used. At a predetermined point, the engine's computer activates the high rpm cam which is at near race car specs. The high rpm lobe on an Acura Integra B18C5 motor has a nearly full-race duration of about 290 degrees! (or about 242 degrees @ 1mm) This is the best of both worlds ... ect ...
The VTEC system on the D-series motors found on Civics is not as sophisticated, it merely advances and retards the cam to widen the powerband, and it does not have all of the advantages of having two different sets of cam lobes as the B16A and B18C does.
HPBooks, Honda/Acura Engine Performance by Mike Kojima</TD></TR></TABLE>
Mike Kojima can jump off of a ******* cliff.
http://www.leecao.com/honda/vtec/sohcvtec.html
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Someone who isn't Mike Kojima »</TD></TR><TR><TD CLASS="quote">
In a SOHC engine, there is a single camshaft per bank of cylinders. So both the exhaust and intake cam lobes are on the same camshaft. The figure to the right illustrates this design. The three cam lobes in the middle are the intake cam lobes. The two low RPM lobes actuate two valve rockers, which in turn pushes the intake valves open. The high RPM lobe actuates a follower, which is shaped like a valve rocker, but doesn't actuate any valves. While there are different intake cam lobes for high and low RPM operation, the same two exhaust cam lobes are used for all RPMs. The lack of cam profile changing for exhaust valves is the primary difference between DOHC VTEC and SOHC VTEC engines. Since the exhaust valves in a SOHC VTEC engine behaves just like a non VTEC engine, only the intake valves will be discussed below.
During low RPM operations, the two outer intake cam lobes directly actuates the two valve rockers. These low PRM intake lobes are optimized for smooth operation and low fuel consumption. The high RPM intake lobe actuates the follower. But since the follower isn't connected to anything, it doesn't cause anything to happen. This procss is illustrated by the figure to the right.
At high RPMs, oil pressure pushes a metal pin through the valve rockers and the follower, effectively binding the three pieces into one. And since the high RPM lobe pushes out further than the low RPM lobes, the two valve rockers now follow the the profile of the high RPM lobe. The high RPM lobe's profile is designed to open the valves open wider, and for a longer duration of time, thus allowing more fuel/air mixture to enter the cylinder. The improved breathing allows the engine to sustain its torque output as RPM rises, thus resulting in higher power output
The SOHC VTEC is a system that achieves mild power gains. Usually, SOHC VTEC engines gives about as much power as DOHC non-VTEC engines of similar displacement. Whether or not the added complexity of the VTEC mechanism off-sets the simplicity of SOHC (versus DOHC) is up for debate. SOHC VTEC is currently found on the Civic EX, Accord LX/EX/V6, Odyssey LX/EX, Acura TL, CL, and CL Type-S.
</TD></TR></TABLE>
QUOTE FROM THE BOOK:
The best way of exploiting a changing cam spec is the Honda/Acura VTEC system as found on th B16A and the B18C. This revolutionary, amazing system uses two different cam lobes. At low speed, a short duration, low lift, wide lobe separation angle cam lobe is used. At a predetermined point, the engine's computer activates the high rpm cam which is at near race car specs. The high rpm lobe on an Acura Integra B18C5 motor has a nearly full-race duration of about 290 degrees! (or about 242 degrees @ 1mm) This is the best of both worlds ... ect ...
The VTEC system on the D-series motors found on Civics is not as sophisticated, it merely advances and retards the cam to widen the powerband, and it does not have all of the advantages of having two different sets of cam lobes as the B16A and B18C does.
HPBooks, Honda/Acura Engine Performance by Mike Kojima</TD></TR></TABLE>
Mike Kojima can jump off of a ******* cliff.
http://www.leecao.com/honda/vtec/sohcvtec.html
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Someone who isn't Mike Kojima »</TD></TR><TR><TD CLASS="quote">
In a SOHC engine, there is a single camshaft per bank of cylinders. So both the exhaust and intake cam lobes are on the same camshaft. The figure to the right illustrates this design. The three cam lobes in the middle are the intake cam lobes. The two low RPM lobes actuate two valve rockers, which in turn pushes the intake valves open. The high RPM lobe actuates a follower, which is shaped like a valve rocker, but doesn't actuate any valves. While there are different intake cam lobes for high and low RPM operation, the same two exhaust cam lobes are used for all RPMs. The lack of cam profile changing for exhaust valves is the primary difference between DOHC VTEC and SOHC VTEC engines. Since the exhaust valves in a SOHC VTEC engine behaves just like a non VTEC engine, only the intake valves will be discussed below.
During low RPM operations, the two outer intake cam lobes directly actuates the two valve rockers. These low PRM intake lobes are optimized for smooth operation and low fuel consumption. The high RPM intake lobe actuates the follower. But since the follower isn't connected to anything, it doesn't cause anything to happen. This procss is illustrated by the figure to the right.
At high RPMs, oil pressure pushes a metal pin through the valve rockers and the follower, effectively binding the three pieces into one. And since the high RPM lobe pushes out further than the low RPM lobes, the two valve rockers now follow the the profile of the high RPM lobe. The high RPM lobe's profile is designed to open the valves open wider, and for a longer duration of time, thus allowing more fuel/air mixture to enter the cylinder. The improved breathing allows the engine to sustain its torque output as RPM rises, thus resulting in higher power output
The SOHC VTEC is a system that achieves mild power gains. Usually, SOHC VTEC engines gives about as much power as DOHC non-VTEC engines of similar displacement. Whether or not the added complexity of the VTEC mechanism off-sets the simplicity of SOHC (versus DOHC) is up for debate. SOHC VTEC is currently found on the Civic EX, Accord LX/EX/V6, Odyssey LX/EX, Acura TL, CL, and CL Type-S.
</TD></TR></TABLE>
11-10-2003, 06:17 PM
#10
*sigh* man pull off your valve cover, and look at how it works.
the D16Z6 and the D16Y8's cams have 5 lobes per cylinder. the far outside lobes operate the exhaust valves, the inner next 2 operate the low cam profile of the intake valves, and the center lobe operates the high cam profile of the intake valves (vtec lobe).
when the vtec solenoid opens up, oil pressure is released into the cam follower (rocker arm) assembly, locking the 3 intake cam followers together, causing them to run off of the center lobe. the intake side of the head is just like a b-series vtec, and the exhaust side is just like a b-series non-vtec.
i think that honda would've made sohc vtecs have exhaust side vtec too, but 6 lobes per cylinder just wasn't fitting on the cam.
hope this helps you understand.
-Shawn
the D16Z6 and the D16Y8's cams have 5 lobes per cylinder. the far outside lobes operate the exhaust valves, the inner next 2 operate the low cam profile of the intake valves, and the center lobe operates the high cam profile of the intake valves (vtec lobe).
when the vtec solenoid opens up, oil pressure is released into the cam follower (rocker arm) assembly, locking the 3 intake cam followers together, causing them to run off of the center lobe. the intake side of the head is just like a b-series vtec, and the exhaust side is just like a b-series non-vtec.
i think that honda would've made sohc vtecs have exhaust side vtec too, but 6 lobes per cylinder just wasn't fitting on the cam.
hope this helps you understand.
-Shawn
11-10-2003, 06:27 PM
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Thanks Shawn!
that really helped me, i still think later on i wanna do a swap bc i like the dohc setup better but besides that ... it kinda sux that the exhaust doesnt have vtec... why do you think they would misprint this? kinda makes me wonder about everything else in this book... he seems to really know a lot about modifying honda engines and ive learned a lot about other kinda things but is it a bad idea to keep reading and risk learning more false information?
that really helped me, i still think later on i wanna do a swap bc i like the dohc setup better but besides that ... it kinda sux that the exhaust doesnt have vtec... why do you think they would misprint this? kinda makes me wonder about everything else in this book... he seems to really know a lot about modifying honda engines and ive learned a lot about other kinda things but is it a bad idea to keep reading and risk learning more false information?
11-10-2003, 06:39 PM
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Re: SOHC FAKE VTEC (Ricey McRicerton)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton »</TD></TR><TR><TD CLASS="quote">Jesus H Christ. You have no idea how your car works. SOHC Vtec applications only adjust one cam ( the intake cam I do believe ). DOHC VTEC applications adjust both cams. You have "real" vtec and I don't know what's worse; that they would print this or that you would believe it.</TD></TR></TABLE>
If it's SOHC.... then obviously.... there is only one cam. Did you mean Valves?
If it's SOHC.... then obviously.... there is only one cam. Did you mean Valves?
11-10-2003, 06:41 PM
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Re: (uranazo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by uranazo »</TD></TR><TR><TD CLASS="quote">Thanks Shawn!
but is it a bad idea to keep reading and risk learning more false information?</TD></TR></TABLE>
Yes
Modified by BauleyCivic at 10:52 PM 11/10/2003
but is it a bad idea to keep reading and risk learning more false information?</TD></TR></TABLE>
Yes
Modified by BauleyCivic at 10:52 PM 11/10/2003
11-10-2003, 06:42 PM
#16
yeah, he meant one set of valves (intake or exhaust).
i hope what i said ---^ up there helped some people out in understanding this ish. i don't know who the hell mike kojima is, i think he might be an editor for an import mag or something, but you can trust what i said, as i have built gobs of hondas.
i hope what i said ---^ up there helped some people out in understanding this ish. i don't know who the hell mike kojima is, i think he might be an editor for an import mag or something, but you can trust what i said, as i have built gobs of hondas.
11-10-2003, 06:45 PM
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Re: SOHC FAKE VTEC (EG2 SiR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG2 SiR »</TD></TR><TR><TD CLASS="quote">
If it's SOHC.... then obviously.... there is only one cam. Did you mean Valves?</TD></TR></TABLE>
Yes sir. Thanks for clearing that up. I meant one set of cams.
If it's SOHC.... then obviously.... there is only one cam. Did you mean Valves?</TD></TR></TABLE>
Yes sir. Thanks for clearing that up. I meant one set of cams.
11-10-2003, 06:47 PM
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Re: SOHC FAKE VTEC (Ricey McRicerton)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton »</TD></TR><TR><TD CLASS="quote">
Yes sir. Thanks for clearing that up. I meant one set of cams .</TD></TR></TABLE>
ha ha, you said it again
Yes sir. Thanks for clearing that up. I meant one set of cams .</TD></TR></TABLE>
ha ha, you said it again
11-10-2003, 06:48 PM
#19
Re: SOHC FAKE VTEC (Ricey McRicerton)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton »</TD></TR><TR><TD CLASS="quote">
Yes sir. Thanks for clearing that up. I meant one set of cams.</TD></TR></TABLE>
bwahahahahahahaa... you did it again ricey here---->
edit- damnit, beat me to it
Yes sir. Thanks for clearing that up. I meant one set of cams.</TD></TR></TABLE>
bwahahahahahahaa... you did it again ricey here---->
edit- damnit, beat me to it
11-10-2003, 06:50 PM
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Re: SOHC FAKE VTEC (ShadyED9)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ShadyED9 »</TD></TR><TR><TD CLASS="quote">
bwahahahahahahaa... you did it again ricey here---->
edit- damnit, beat me to it</TD></TR></TABLE>
Dammit..I think I need to slow down on the . That's why I keep saying CAMS instead of VALVES! 
bwahahahahahahaa... you did it again ricey here---->
edit- damnit, beat me to it
</TD></TR></TABLE>Dammit..I think I need to slow down on the
. That's why I keep saying CAMS instead of VALVES!
11-10-2003, 07:16 PM
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Re: (ShadyED9)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ShadyED9 »</TD></TR><TR><TD CLASS="quote">i think you're too worried about that 2.0 d-series </TD></TR></TABLE>
That was from probobally 6 months ago and Im back to FI on my good ol y7. Maybe one day I'll end up doing it, but right now it's not real high on my priority list.
</TD></TR></TABLE>That was from probobally 6 months ago and Im back to FI on my good ol y7. Maybe one day I'll end up doing it, but right now it's not real high on my priority list.
11-10-2003, 07:37 PM
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Re: (MrIllegalX)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MrIllegalX »</TD></TR><TR><TD CLASS="quote"> to honda-tech! </TD></TR></TABLE>
i second that
funny *** thread
to honda-tech! </TD></TR></TABLE>i second that
funny *** thread
11-10-2003, 07:39 PM
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Re: (shepworldwide)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shepworldwide »</TD></TR><TR><TD CLASS="quote">
i second that
funny *** thread </TD></TR></TABLE>
hahahaha werd
i second that
funny *** thread
</TD></TR></TABLE>hahahaha werd
