A new way to check vtec engaging???
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From: Milwaukee, Wisconsin, US
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Ah ok so you are referring to I believe the civic HX which has VTEC-E.
The honda Civic EX, does NOT incorporate VTEC-E. The Honda Civic EX uses SOHC VTEC, where the Honda Civic HX uses VTEC-E, also known as "lean burn" VTEC.
This clears things up.
VTEC
http://automobiles.honda.com/models/...pe&Category=EX
VTEC-E (lean burn technology)
http://automobiles.honda.com/models/...pe&Category=HX
The honda Civic EX, does NOT incorporate VTEC-E. The Honda Civic EX uses SOHC VTEC, where the Honda Civic HX uses VTEC-E, also known as "lean burn" VTEC.
This clears things up.
VTEC
http://automobiles.honda.com/models/...pe&Category=EX
VTEC-E (lean burn technology)
http://automobiles.honda.com/models/...pe&Category=HX
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From: Austin, TX
Rep Power: 0 How many times on this forum have we confirmed that D17A2, so called SOHC VTEC engine in Civic EX, is a VTEC-E(concept, but not really the design. However mechanically they are the same.)!? Do I need to reconfirm this? And I forgot how many times we proved that, for a VTEC-E engine in HX, switch it to regular burn(vs. lean burn), it will just perform like SOHC VTEC, with even better mid range because of low VTEC engagement point. Just search.
A good proof of the 7th gen D17 EX is SOHC VTEC-E design is, if you go to search for rocker, it gives you the same part number on the intake rocker, which VTEC implements. If you still don't believe, open up your valve cover. If you have 5 lobes per cylinder on D17A2, I pay you $1000 for it.
This was the thread I started with to clear up what we so called SOHC VTEC in D17 Civic EX and D16 Civic EX.
http://www.7thgencivic.com/forums/sh...d.php?t=142384
And here's the spec of camshafts for both, A6 HX, A2 EX and D16. Note the absense of mid lobe on 7th gen VTEC.
7th gen
End Play: 0.05-0.15mm
Camshaft-to-holder oil clearance: 0.050-0.089mm
Total Runout: 0.03mm
::: D17A2 Lobe Height :::
VTEC intake primary: 38.604mm
VTEC intake secondary: 32.848mm
VTEC exhaust: 38.784mm
::: D17A6 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D17A1 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
6th gen
::: D16Y8 Lobe Height :::
VTEC intake primary: 36.778mm
VTEC intake secondary: 37.065mm
VTEC mid: 38.274mm
VTEC exhaust: 38.008mm
::: D16Y5 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D16Y7 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
A good proof of the 7th gen D17 EX is SOHC VTEC-E design is, if you go to search for rocker, it gives you the same part number on the intake rocker, which VTEC implements. If you still don't believe, open up your valve cover. If you have 5 lobes per cylinder on D17A2, I pay you $1000 for it.
This was the thread I started with to clear up what we so called SOHC VTEC in D17 Civic EX and D16 Civic EX.
http://www.7thgencivic.com/forums/sh...d.php?t=142384
And here's the spec of camshafts for both, A6 HX, A2 EX and D16. Note the absense of mid lobe on 7th gen VTEC.
7th gen
End Play: 0.05-0.15mm
Camshaft-to-holder oil clearance: 0.050-0.089mm
Total Runout: 0.03mm
::: D17A2 Lobe Height :::
VTEC intake primary: 38.604mm
VTEC intake secondary: 32.848mm
VTEC exhaust: 38.784mm
::: D17A6 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D17A1 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
6th gen
::: D16Y8 Lobe Height :::
VTEC intake primary: 36.778mm
VTEC intake secondary: 37.065mm
VTEC mid: 38.274mm
VTEC exhaust: 38.008mm
::: D16Y5 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D16Y7 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
Last edited by 82801BA; Feb 2, 2005 at 09:14 PM.
Joined: Dec 2001
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From: Milwaukee, Wisconsin, US
Rep Power: 400 Right, the parts are all the same, however, the difference is in what is going on inside the engine. VTEC-E leaves one of the 4 valves per cylinder closed in low rpm operation. The valve is not operating in any way whatsoever.
The Civic EX does NOT DO THIS. The civic EX has ALL FOUR VALVES OPERATING AT ALL TIMES.
THAT is the difference between the two. Though the parts are the same, the difference is in what is actually happening inside the engine.
If the VTEC in the HX using 3 valves during low rpm operation, then 4 during mid, then hi-cam during high is the same thing that is going on in the VTEC in the EX, and the EX is doing the same thing, and the parts are the same, then how do you explain the very different dyno plots?
The Civic EX does NOT DO THIS. The civic EX has ALL FOUR VALVES OPERATING AT ALL TIMES.
THAT is the difference between the two. Though the parts are the same, the difference is in what is actually happening inside the engine.
If the VTEC in the HX using 3 valves during low rpm operation, then 4 during mid, then hi-cam during high is the same thing that is going on in the VTEC in the EX, and the EX is doing the same thing, and the parts are the same, then how do you explain the very different dyno plots?
Joined: Dec 2001
Posts: 10,031
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From: Milwaukee, Wisconsin, US
Rep Power: 400 Here... straight from honda's website.
1996-2000 Honda Civic EX coupe and sedan: 1.6L SOHC VTEC I4
2001-Current Honda Civic EX coupe and sedan: 1.7L SOHC VTEC I4
1996-2000 Honda Civic HX: 1.6L SOHC VTEC-E I4
2001-Current Honda Civic HX: 1.7L SOHC VTEC-E I4
1996-2000 Honda Civic EX coupe and sedan: 1.6L SOHC VTEC I4
2001-Current Honda Civic EX coupe and sedan: 1.7L SOHC VTEC I4
1996-2000 Honda Civic HX: 1.6L SOHC VTEC-E I4
2001-Current Honda Civic HX: 1.7L SOHC VTEC-E I4
Joined: Dec 2001
Posts: 10,031
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From: Milwaukee, Wisconsin, US
Rep Power: 400 the "hybrid" vtec you are talking about is the fact that while there are only 2 lobes for each set of valves, however, there is no closing of a valve at low rpm operation.
So it's the same as VTEC-E in the sense that there are only 2 lobes per each set of valves instead of 3 lobes like normal VTEC. However, that's where the similarity ends. Again, on the civic EX, all 4 valves operate at all times at all rpm ranges.
The vtec engagement points you are referring to are ONLY on the HX engine/ecu/vtec control unit. At 2500rpm the 4th valve opens up, and at 3300rpm, the cam profile changes over to a hi-cam profile.
The VTEC-E results in a bit higher power rpm vs a civic with non-vtec. This is evident by comparing the Civic DX and Civic HX engine. The two engines are essentially the same except for the VTEC-E in the Civic HX. But the Civic HX's VTEC-E mechanism results in 115hp, versus 106hp from the Civic DX. So the Civic HX has more power in addition to better fuel economy.
So it's the same as VTEC-E in the sense that there are only 2 lobes per each set of valves instead of 3 lobes like normal VTEC. However, that's where the similarity ends. Again, on the civic EX, all 4 valves operate at all times at all rpm ranges.
The vtec engagement points you are referring to are ONLY on the HX engine/ecu/vtec control unit. At 2500rpm the 4th valve opens up, and at 3300rpm, the cam profile changes over to a hi-cam profile.
The VTEC-E results in a bit higher power rpm vs a civic with non-vtec. This is evident by comparing the Civic DX and Civic HX engine. The two engines are essentially the same except for the VTEC-E in the Civic HX. But the Civic HX's VTEC-E mechanism results in 115hp, versus 106hp from the Civic DX. So the Civic HX has more power in addition to better fuel economy.
Last edited by S2000man01; Feb 2, 2005 at 09:36 PM.
Registered!!
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From: Austin, TX
Rep Power: 0 S2000man01,
I hope you don't skim thru the post. Read it.
Hybrid VTEC has 3, SOHC VTEC has 3, and VTEC-E has 2, valves per cylinder.
SOHC VTEC has 2 almost same profile lobes+1 mid high lobe, denoted by VTEC I, the orignial VTEC.
VTEC-E has 1 high lobe and 1 almost flat lobe, but it's just a variation of VTEC, has nothing to do with the -E IF and ONLY IF several things happens:
1. Not a lean burn vehicle
2. Have the catalytic coverter down to the underside of the car, not in the engine bay.
EX has one of the intake valve closed also.
Hybrid VTEC is not a name for it(of course, not the one use in Gasoline-Electric Hybrid), but just a term for clearification. Hybrid VTEC has both VTEC-E and VTEC characteristics. With 1 almost flat lobe, 1 normal lobe and 1 mid lobe, uses in ALL 6 Cylinder SOHC VTEC. Simple, because studies have shown that opening only 1 intake valve at low rpm generates more torque. It's thermal dynamics, it works this way.
Don't trust company's names. In another word, go to your computer, look for Intel Prescott, it can either be Celeron 4 or Pentium 4. Prescott is just the core name, same analogy of engine name. But everything around it is different. Same concept(core), putting different things inside is different.
Do a research, try put a CAI/SRI on your car, go outside and step fully on the fuel, note the different of sound coming back from the engine bay right at 2500rpm. You will hear a different, and you will definately feel it.
Do not argue on this topic, because I did it before, just like you, and many ppl did it before too. I was thinking the same thing as you DO NOW and didn't realize the truth until I drop in VTEC controller, open up the valve cover, and do the DIY VTEC light. All agree that it happens at 2500rpm. Dyno proved also, if I don't leave the VTEC engagement around 2500 rpm, I get a complete flat curve(no hp gain, worse than stock!!) from 2500-3500 rpm, where I set my VTEC point at 3500 at that time. I don't need to lie to you, and I actually did a lot of research on this topic, because I was just like you.
By the way, for a TRUE 12 valve operation, it only happens on i-VTEC only, both SOHC and DOHC, except K20A2 uses in type-s. The 12 valve operation is at low rpm, where the intake lobe also has 2 lobes only, but instead of a very low profile lobe, one of the lobe is absent.
And your point is true, VTEC-E results in a bit higher power. However, VTEC-E can also be tuned to perform just like regular VTEC. If I am to take out the lean burn, I can get what I wait for, 127hp. Same thing happens for DOHC VTEC, cam profile different, exhaust system different, anything different can have an effect on the engine. The VTEC system on D17 EX VTEC compare to VTEC system in HX is that, the cam profile is a little taller, EX doesn't use lean burn, and the exhaust system is different to guarantee smooth flow vs. HX. It creates a different also.
If you have the brochure with you, look at how Honda describe VTEC on Civic EX and HX. It should say "Engine uses in HX and EX....feature VTEC engine, which creates a swirl effect at low rpm, ......" It doesn't specify whether it's a EX and HX, but it does include both. However, the swirl effect only happens when one valve is closed**(well, just fluid dynamics, my field of study). What do you think about it? I am happy to discuss this topic with you.
I hope you don't skim thru the post. Read it.
Hybrid VTEC has 3, SOHC VTEC has 3, and VTEC-E has 2, valves per cylinder.
SOHC VTEC has 2 almost same profile lobes+1 mid high lobe, denoted by VTEC I, the orignial VTEC.
VTEC-E has 1 high lobe and 1 almost flat lobe, but it's just a variation of VTEC, has nothing to do with the -E IF and ONLY IF several things happens:
1. Not a lean burn vehicle
2. Have the catalytic coverter down to the underside of the car, not in the engine bay.
EX has one of the intake valve closed also.
Hybrid VTEC is not a name for it(of course, not the one use in Gasoline-Electric Hybrid), but just a term for clearification. Hybrid VTEC has both VTEC-E and VTEC characteristics. With 1 almost flat lobe, 1 normal lobe and 1 mid lobe, uses in ALL 6 Cylinder SOHC VTEC. Simple, because studies have shown that opening only 1 intake valve at low rpm generates more torque. It's thermal dynamics, it works this way.
Don't trust company's names. In another word, go to your computer, look for Intel Prescott, it can either be Celeron 4 or Pentium 4. Prescott is just the core name, same analogy of engine name. But everything around it is different. Same concept(core), putting different things inside is different.
Do a research, try put a CAI/SRI on your car, go outside and step fully on the fuel, note the different of sound coming back from the engine bay right at 2500rpm. You will hear a different, and you will definately feel it.
Do not argue on this topic, because I did it before, just like you, and many ppl did it before too. I was thinking the same thing as you DO NOW and didn't realize the truth until I drop in VTEC controller, open up the valve cover, and do the DIY VTEC light. All agree that it happens at 2500rpm. Dyno proved also, if I don't leave the VTEC engagement around 2500 rpm, I get a complete flat curve(no hp gain, worse than stock!!) from 2500-3500 rpm, where I set my VTEC point at 3500 at that time. I don't need to lie to you, and I actually did a lot of research on this topic, because I was just like you.
By the way, for a TRUE 12 valve operation, it only happens on i-VTEC only, both SOHC and DOHC, except K20A2 uses in type-s. The 12 valve operation is at low rpm, where the intake lobe also has 2 lobes only, but instead of a very low profile lobe, one of the lobe is absent.
And your point is true, VTEC-E results in a bit higher power. However, VTEC-E can also be tuned to perform just like regular VTEC. If I am to take out the lean burn, I can get what I wait for, 127hp. Same thing happens for DOHC VTEC, cam profile different, exhaust system different, anything different can have an effect on the engine. The VTEC system on D17 EX VTEC compare to VTEC system in HX is that, the cam profile is a little taller, EX doesn't use lean burn, and the exhaust system is different to guarantee smooth flow vs. HX. It creates a different also.
If you have the brochure with you, look at how Honda describe VTEC on Civic EX and HX. It should say "Engine uses in HX and EX....feature VTEC engine, which creates a swirl effect at low rpm, ......" It doesn't specify whether it's a EX and HX, but it does include both. However, the swirl effect only happens when one valve is closed**(well, just fluid dynamics, my field of study). What do you think about it? I am happy to discuss this topic with you.
Last edited by 82801BA; Feb 2, 2005 at 10:25 PM.
StAyInG StOcK aNd MarRiEd
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Just to throw my 2 pennies into the pot, from personal experience, my vtec on my 2004 Sedan kicks in in the low 4 grand, you can hear and feel when it kicks in. So no matter what everyone says about their cars kicking in at low numbers and stuuf, mine engages at 4,000 - 4,300 rpms.
Joined: Dec 2001
Posts: 10,031
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From: Milwaukee, Wisconsin, US
Rep Power: 400 I understand everything you have said in your post, but honda's website itself, says that the VTEC-E (also known as lean burn) utilizes the 3 valve method for low rpm. At 2500 rpm the 4th valve opens up. However, even honda's website says this is ONLY ON THE HX CIVIC.
We seem to be arguing back and forth repeating ourselves over and over. And no, the swirl effect is not only created in engines that use the 3 valve system. Even the S2000 is engineered in such a way as to take advantage of a swirl effect of the intake charge into the combustion chamber.
I guess the bottom line is, I'm being told by a tech as well as the owner of the dyno shop where Hondata does their R&D (also happens to be an S2000 owner, and a nation wide renowned expert on engines) that the Honda civic EX DOES NOT use the 3 valve system, and that ALL FOUR VALVES operate at all times and all rpm ranges on the D17 honda civic EX. Pardon if I take their knowledge and expertise on honda engines over yours. (by the way, he was also involved in tuning a D17 engine for Hondata in an attempt at initial development for a Hondata Flash for the D17 civic EX) So nothing personal, but when it comes to getting reliable information, he has never steered us wrong.
We seem to be arguing back and forth repeating ourselves over and over. And no, the swirl effect is not only created in engines that use the 3 valve system. Even the S2000 is engineered in such a way as to take advantage of a swirl effect of the intake charge into the combustion chamber.
I guess the bottom line is, I'm being told by a tech as well as the owner of the dyno shop where Hondata does their R&D (also happens to be an S2000 owner, and a nation wide renowned expert on engines) that the Honda civic EX DOES NOT use the 3 valve system, and that ALL FOUR VALVES operate at all times and all rpm ranges on the D17 honda civic EX. Pardon if I take their knowledge and expertise on honda engines over yours. (by the way, he was also involved in tuning a D17 engine for Hondata in an attempt at initial development for a Hondata Flash for the D17 civic EX) So nothing personal, but when it comes to getting reliable information, he has never steered us wrong.
Last edited by S2000man01; Feb 2, 2005 at 11:12 PM.
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From: Milwaukee, Wisconsin, US
Rep Power: 400 By the way, another little tidbit he mentioned to me. The 2005 RSX-S is NOT flashable by hondata at the moment, as the new 2005 RSX uses a completely different ECU architecture.
Joined: Dec 2001
Posts: 10,031
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From: Milwaukee, Wisconsin, US
Rep Power: 400 I guess bottom line is that I take his word over yours, which again, is nothing personal. He just kinda happens to know what he's talking about.
I remember a while back there were a few people arguing in a thread as to whether or not Hondata was making an ECU flash for the S2000. One guy posted that he said Hondata was making an ECU flash for the S2000 cuz he called them and asked and if anyone didn't believe him to call Hondata themselves.
Instead, in the next post, was a reponse from this dyno shop owner that was a typed text from words directly from the mouth of Doug Macmillan, co-founder of Hondata, who happened to be standing right next to him. His response was that the S2000 would NOT be getting an ECU flash from Hondata and that the S2000 is the only ECU in Honda's range that is not programmable . (notice this means the D17 IS....
)
So again, sorry if I take his word from posts I've searched over yours in what actually goes on inside the engine of a D17 Honda civic EX.
I remember a while back there were a few people arguing in a thread as to whether or not Hondata was making an ECU flash for the S2000. One guy posted that he said Hondata was making an ECU flash for the S2000 cuz he called them and asked and if anyone didn't believe him to call Hondata themselves.
Instead, in the next post, was a reponse from this dyno shop owner that was a typed text from words directly from the mouth of Doug Macmillan, co-founder of Hondata, who happened to be standing right next to him. His response was that the S2000 would NOT be getting an ECU flash from Hondata and that the S2000 is the only ECU in Honda's range that is not programmable . (notice this means the D17 IS....
)So again, sorry if I take his word from posts I've searched over yours in what actually goes on inside the engine of a D17 Honda civic EX.
Last edited by S2000man01; Feb 3, 2005 at 01:04 AM.
Once boosted now i-VTEC
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Originally Posted by 82801BA
How many times on this forum have we confirmed that D17A2, so called SOHC VTEC engine in Civic EX, is a VTEC-E(concept, but not really the design. However mechanically they are the same.)!? Do I need to reconfirm this? And I forgot how many times we proved that, for a VTEC-E engine in HX, switch it to regular burn(vs. lean burn), it will just perform like SOHC VTEC, with even better mid range because of low VTEC engagement point. Just search.
A good proof of the 7th gen D17 EX is SOHC VTEC-E design is, if you go to search for rocker, it gives you the same part number on the intake rocker, which VTEC implements. If you still don't believe, open up your valve cover. If you have 5 lobes per cylinder on D17A2, I pay you $1000 for it.
This was the thread I started with to clear up what we so called SOHC VTEC in D17 Civic EX and D16 Civic EX.
http://www.7thgencivic.com/forums/sh...d.php?t=142384
And here's the spec of camshafts for both, A6 HX, A2 EX and D16. Note the absense of mid lobe on 7th gen VTEC.
7th gen
End Play: 0.05-0.15mm
Camshaft-to-holder oil clearance: 0.050-0.089mm
Total Runout: 0.03mm
::: D17A2 Lobe Height :::
VTEC intake primary: 38.604mm
VTEC intake secondary: 32.848mm
VTEC exhaust: 38.784mm
::: D17A6 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D17A1 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
6th gen
::: D16Y8 Lobe Height :::
VTEC intake primary: 36.778mm
VTEC intake secondary: 37.065mm
VTEC mid: 38.274mm
VTEC exhaust: 38.008mm
::: D16Y5 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D16Y7 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
A good proof of the 7th gen D17 EX is SOHC VTEC-E design is, if you go to search for rocker, it gives you the same part number on the intake rocker, which VTEC implements. If you still don't believe, open up your valve cover. If you have 5 lobes per cylinder on D17A2, I pay you $1000 for it.
This was the thread I started with to clear up what we so called SOHC VTEC in D17 Civic EX and D16 Civic EX.
http://www.7thgencivic.com/forums/sh...d.php?t=142384
And here's the spec of camshafts for both, A6 HX, A2 EX and D16. Note the absense of mid lobe on 7th gen VTEC.
7th gen
End Play: 0.05-0.15mm
Camshaft-to-holder oil clearance: 0.050-0.089mm
Total Runout: 0.03mm
::: D17A2 Lobe Height :::
VTEC intake primary: 38.604mm
VTEC intake secondary: 32.848mm
VTEC exhaust: 38.784mm
::: D17A6 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D17A1 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
6th gen
::: D16Y8 Lobe Height :::
VTEC intake primary: 36.778mm
VTEC intake secondary: 37.065mm
VTEC mid: 38.274mm
VTEC exhaust: 38.008mm
::: D16Y5 Lobe Height :::
VTEC intake primary: 38.427mm
VTEC intake secondary: 32.193mm
VTEC exhaust: 38.784mm
::: D16Y7 Lobe Height :::
Intake: 35.299mm
Exhaust: 37.281mm
Did you get this from my VTEC post about 2 months back ?
Once boosted now i-VTEC
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Registered!!
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From: 4o8, California
Rep Power: 311 Okay, I've read through all the posts, but am still a little confused. Can someone bottom line it for me? If the EX and HX are VTEC-E, when does VTEC kick in? 2500 rpms? 4300?
Thanks
Thanks
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From: Milwaukee, Wisconsin, US
Rep Power: 400 it's already been answered by greater minds than anyone here. unless of course someone wants to argue with the man who was one of the original developers of a test ECU for hondata for the D17.
let it die.
let it die.
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