when the hell does my vtec engage??????
Junior Member
Joined: Nov 2007
Posts: 32
Likes: 0
From: Bloomington, MN
Re: when the hell does my vtec engage?????? (Dogginator)
I had always thought this was the other way around....So I did some research. I went to Honda's corporate website and searched in there. Google and other search engines just pull up opinions it seems. On this page:
http://corporate.honda.com/pre...=4096
I found this info on how VTEC works on the S2000:
Variable Valve Timing and Lift Electronic Control (VTEC)
The S2000 engine uses a performance version of Honda's innovative variable valve-timing system on both the intake and exhaust valves. VTEC maximizes the S2000 engine's volumetric efficiency - packing the maximum amount of air and fuel into the combustion chamber on each intake stroke and expelling the maximum amount of exhaust gases on the exhaust stroke. VTEC works by varying valve timing and lift to compensate for the time delay and out-of-phase arrival of the air-fuel charge at the intake valve. Ideally, the valves should remain open for a short duration at low engine speeds and for a longer duration at high engine speeds- and that is precisely how VTEC works. In the S2000 VTEC engine, each intake and exhaust valve uses two different cam-lobe profiles: one for low engine speeds and a second for high engine speeds. From idle to around 6000 rpm, the two intake and exhaust valve cam followers at each cylinder are actuated by low-rpm cam lobes. Their short duration and low lift ensures good cylinder-filling at low engine speeds. At around 6000 rpm (depending on throttle position), an electronic control unit commands a spool valve to open and send oil pressure to pins in the cam followers. Under pressure, the pins lock the two intake-valve followers and the two exhaust-valve followers to a third follower. Until this moment, this third follower has been independently following the contour of a separate high-lift, long-duration cam lobe. Now the valves are actuated by the third follower and more closely match the induction and exhaust timing required for optimum torque at high engine speeds.
It's my limited understanding that VTEC in the S2000 works the same as other hp DOHC VTEC systems. So, according to the people that made VTEC, the cams change over around 6K rpms. I'm gonna keep looking......
slim
http://corporate.honda.com/pre...=4096
I found this info on how VTEC works on the S2000:
Variable Valve Timing and Lift Electronic Control (VTEC)
The S2000 engine uses a performance version of Honda's innovative variable valve-timing system on both the intake and exhaust valves. VTEC maximizes the S2000 engine's volumetric efficiency - packing the maximum amount of air and fuel into the combustion chamber on each intake stroke and expelling the maximum amount of exhaust gases on the exhaust stroke. VTEC works by varying valve timing and lift to compensate for the time delay and out-of-phase arrival of the air-fuel charge at the intake valve. Ideally, the valves should remain open for a short duration at low engine speeds and for a longer duration at high engine speeds- and that is precisely how VTEC works. In the S2000 VTEC engine, each intake and exhaust valve uses two different cam-lobe profiles: one for low engine speeds and a second for high engine speeds. From idle to around 6000 rpm, the two intake and exhaust valve cam followers at each cylinder are actuated by low-rpm cam lobes. Their short duration and low lift ensures good cylinder-filling at low engine speeds. At around 6000 rpm (depending on throttle position), an electronic control unit commands a spool valve to open and send oil pressure to pins in the cam followers. Under pressure, the pins lock the two intake-valve followers and the two exhaust-valve followers to a third follower. Until this moment, this third follower has been independently following the contour of a separate high-lift, long-duration cam lobe. Now the valves are actuated by the third follower and more closely match the induction and exhaust timing required for optimum torque at high engine speeds.
It's my limited understanding that VTEC in the S2000 works the same as other hp DOHC VTEC systems. So, according to the people that made VTEC, the cams change over around 6K rpms. I'm gonna keep looking......
slim
Junior Member
Joined: Nov 2007
Posts: 32
Likes: 0
From: Bloomington, MN
Re: when the hell does my vtec engage?????? (slimgsr)
You'll find the info repeated on the TSX. Or is this because the TSX has a single stage intake? Either way here's the link:
http://corporate.honda.com/pre...=3783
I really find it hard to believe that VTEC occurs before the 2 stage manifold does. The change in the engine tone at 5800 is from a cam profile change, not an intake change. An easier example of this would be to compare a stock V-8 to a same but cammed V-8. The engine tone is quite different. That won't happen with an intake manifold change. And it isn't because it's a V-8 either. Also, look at the dyno sheets. Cams make the power, not the intake. That's why at approx 6K, you see the curve jump.
Besides, the frickin' people that invented VTEC, say the cam cross over is approx 6K rpms. So unless anyone can show something from Honda saying different, I don't see any reason to think otherwise...
slim
http://corporate.honda.com/pre...=3783
I really find it hard to believe that VTEC occurs before the 2 stage manifold does. The change in the engine tone at 5800 is from a cam profile change, not an intake change. An easier example of this would be to compare a stock V-8 to a same but cammed V-8. The engine tone is quite different. That won't happen with an intake manifold change. And it isn't because it's a V-8 either. Also, look at the dyno sheets. Cams make the power, not the intake. That's why at approx 6K, you see the curve jump.
Besides, the frickin' people that invented VTEC, say the cam cross over is approx 6K rpms. So unless anyone can show something from Honda saying different, I don't see any reason to think otherwise...
slim
Daisy... Daisy...
Joined: Jun 2004
Posts: 16,580
Likes: 4
From: 24601
Re: when the hell does my vtec engage?????? (slimgsr)
Originally Posted by slimgsr
I had always thought this was the other way around....So I did some research. I went to Honda's corporate website and searched in there. Google and other search engines just pull up opinions it seems. On this page:
http://corporate.honda.com/pre...=4096
I found this info on how VTEC works on the S2000:
Variable Valve Timing and Lift Electronic Control (VTEC)
The S2000 engine uses a performance version of Honda's innovative variable valve-timing system on both the intake and exhaust valves. VTEC maximizes the S2000 engine's volumetric efficiency - packing the maximum amount of air and fuel into the combustion chamber on each intake stroke and expelling the maximum amount of exhaust gases on the exhaust stroke. VTEC works by varying valve timing and lift to compensate for the time delay and out-of-phase arrival of the air-fuel charge at the intake valve. Ideally, the valves should remain open for a short duration at low engine speeds and for a longer duration at high engine speeds- and that is precisely how VTEC works. In the S2000 VTEC engine, each intake and exhaust valve uses two different cam-lobe profiles: one for low engine speeds and a second for high engine speeds. From idle to around 6000 rpm, the two intake and exhaust valve cam followers at each cylinder are actuated by low-rpm cam lobes. Their short duration and low lift ensures good cylinder-filling at low engine speeds. At around 6000 rpm (depending on throttle position), an electronic control unit commands a spool valve to open and send oil pressure to pins in the cam followers. Under pressure, the pins lock the two intake-valve followers and the two exhaust-valve followers to a third follower. Until this moment, this third follower has been independently following the contour of a separate high-lift, long-duration cam lobe. Now the valves are actuated by the third follower and more closely match the induction and exhaust timing required for optimum torque at high engine speeds.
It's my limited understanding that VTEC in the S2000 works the same as other hp DOHC VTEC systems. So, according to the people that made VTEC, the cams change over around 6K rpms. I'm gonna keep looking......
slim
http://corporate.honda.com/pre...=4096
I found this info on how VTEC works on the S2000:
Variable Valve Timing and Lift Electronic Control (VTEC)
The S2000 engine uses a performance version of Honda's innovative variable valve-timing system on both the intake and exhaust valves. VTEC maximizes the S2000 engine's volumetric efficiency - packing the maximum amount of air and fuel into the combustion chamber on each intake stroke and expelling the maximum amount of exhaust gases on the exhaust stroke. VTEC works by varying valve timing and lift to compensate for the time delay and out-of-phase arrival of the air-fuel charge at the intake valve. Ideally, the valves should remain open for a short duration at low engine speeds and for a longer duration at high engine speeds- and that is precisely how VTEC works. In the S2000 VTEC engine, each intake and exhaust valve uses two different cam-lobe profiles: one for low engine speeds and a second for high engine speeds. From idle to around 6000 rpm, the two intake and exhaust valve cam followers at each cylinder are actuated by low-rpm cam lobes. Their short duration and low lift ensures good cylinder-filling at low engine speeds. At around 6000 rpm (depending on throttle position), an electronic control unit commands a spool valve to open and send oil pressure to pins in the cam followers. Under pressure, the pins lock the two intake-valve followers and the two exhaust-valve followers to a third follower. Until this moment, this third follower has been independently following the contour of a separate high-lift, long-duration cam lobe. Now the valves are actuated by the third follower and more closely match the induction and exhaust timing required for optimum torque at high engine speeds.
It's my limited understanding that VTEC in the S2000 works the same as other hp DOHC VTEC systems. So, according to the people that made VTEC, the cams change over around 6K rpms. I'm gonna keep looking......
slim
Originally Posted by slimgsr
You'll find the info repeated on the TSX. Or is this because the TSX has a single stage intake? Either way here's the link:
http://corporate.honda.com/pre...=3783
I really find it hard to believe that VTEC occurs before the 2 stage manifold does. The change in the engine tone at 5800 is from a cam profile change, not an intake change. An easier example of this would be to compare a stock V-8 to a same but cammed V-8. The engine tone is quite different. That won't happen with an intake manifold change. And it isn't because it's a V-8 either. Also, look at the dyno sheets. Cams make the power, not the intake. That's why at approx 6K, you see the curve jump.
Besides, the frickin' people that invented VTEC, say the cam cross over is approx 6K rpms. So unless anyone can show something from Honda saying different, I don't see any reason to think otherwise...
slim
http://corporate.honda.com/pre...=3783
I really find it hard to believe that VTEC occurs before the 2 stage manifold does. The change in the engine tone at 5800 is from a cam profile change, not an intake change. An easier example of this would be to compare a stock V-8 to a same but cammed V-8. The engine tone is quite different. That won't happen with an intake manifold change. And it isn't because it's a V-8 either. Also, look at the dyno sheets. Cams make the power, not the intake. That's why at approx 6K, you see the curve jump.
Besides, the frickin' people that invented VTEC, say the cam cross over is approx 6K rpms. So unless anyone can show something from Honda saying different, I don't see any reason to think otherwise...
slim
The 4400 RPM VTEC engagment for a B18C1 GSR at WOT is a well known fact. The two-stage intake manifold is what leads to this and the torque curve is seamless at the transition like it should be.
Daisy... Daisy...
Joined: Jun 2004
Posts: 16,580
Likes: 4
From: 24601
Re: when the hell does my vtec engage?????? (mesonerz)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mesonerz »</TD></TR><TR><TD CLASS="quote">and the saga continues..... 
</TD></TR></TABLE>
There is no saga here.
</TD></TR></TABLE>There is no saga here.
Thread Starter
Honda-Tech Member
Joined: Oct 2004
Posts: 396
Likes: 1
From: 7th chamber of hell.
Re: when the hell does my vtec engage?????? (Dogginator)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dogginator »</TD></TR><TR><TD CLASS="quote">
There is no saga here. </TD></TR></TABLE>
yeah i know i was only joking....
There is no saga here.
</TD></TR></TABLE>yeah i know i was only joking....
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