This, is VTEC explained.

[TN90accord]

But in boilmakers post it appears as if the D17A2's valvetrain is designed to switch between 12 valve and 16 valve operation.

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[Miracle]

I do believe Boilermaker was talking about the K20A3... I may be wrong though. He did not mention the D seires in his post, but I may have missed it.

[TN90accord]

Originally Posted by Boilermaker1

how it works in this piece.... with the real parts
This is an A2 cam


2 outers are the exhaust lobes
there 1 intake lobe and a circular lobe

This is the intake rocker assy


the one on the left has a roller on it and the other one has nothing.
At low RPM, it runs 1 intake valve. At high RPMs, a pin locks the rockers together and both open.

It was this post.

[Miracle]

There were only 4 engines available with the 7th Gen, non-Si Civic's:

D17A1

* Found in:
o 2001-2005 Honda Civic DX/LX
+ Displacement : 1668 cm3
+ Bore and Stroke : 75 mm X 94.4 mm
+ Compression : 9.5:1
+ Power : 115 hp @ 6100 rpm & 110 ft·lbf @ 4500 rpm
+ Valvetrain : SOHC
+ Fuel Control : OBD-2 MPFI

D17A2

* VTEC
* Found in:
o 2001-2005 Honda Civic EX
+ Displacement : 1668 cm3
+ Bore and Stroke : 75 mm X 94.4 mm
+ Compression : 9.9:1
+ Power : 127 hp @ 6300 rpm & 114 ft·lbf @ 4400 rpm
+ Valvetrain : SOHC VTEC
+ Fuel Control : OBD-2 MPFI

D17A6

* VTEC-E
* Found in:
o 2001-2005 Honda Civic HX
+ Displacement : 1668 cm3
+ Bore and Stroke : 75 mm X 94.4 mm
+ Compression : 9.9:1
+ Power : 117 hp @ 6100 rpm & 111 ft·lbf @ 4500 rpm
+ Valvetrain : SOHC VTEC-E
+ Fuel Control : OBD-2 MPFI

D17A7

* Found in:
o 2004-2005 Honda Civic GX
o Uses CNG (Compressed Natural Gas)
+ Displacement : 1668 cm3
+ Bore and Stroke : 75 mm X 94.4 mm
+ Compression : 12.5:1
+ Power : 100 @ 6100 rpm & 98 ft·lbf @ 4000 rpm
+ Valvetrain : SOHC
+ Fuel Control : OBD-2 MPFI

I do not see how it could do that though.... I really don't. Nothing has made me believe that the D17A2 is VTEC-E, and I may just have to take my VC off and find out for myself.

[TN90accord]

One reason I believe it is probably VTEC E is because of the low engagement of VTEC. If it were SOHC VTEC wouldn't the crossover be at atleast 3500 rpms if not like 4500?

[Miracle]

I don't "feel" My VTEC activate until 4200 or so.... anybody done programming on the D17A2 to pull the stock activation point?

I am about to show you guys what I am talking about... I am uploading a video right now...

[Miracle]

Judge for yourself.........

[fventura03]

IN FOR LATER

[civ05se]

Originally Posted by .Red.EM2

I don't "feel" My VTEC activate until 4200 or so.... anybody done programming on the D17A2 to pull the stock activation point?

I am about to show you guys what I am talking about... I am uploading a video right now...

I also believe our Ex gotta be VTEC not VTEC-E. I hear my engine go extra loud "screaming" starting from 4800rpm to redline. BTW, 4000rpm or more, I feel a lot of power/torque.

[Boilermaker1]

Well, I just pulled out the Honda Manual, the rocker assy for the A6 and A2 are the same. I didn't look at all the tables and crap to check and see if the lift on the cam, etc... were all the same, but the mechanism is.

[YeahIknow]

With my boosted d17a2 my vtec seems to kick in at 3000 rpm. and I'm not sure if i like at or not because sometimes the car will stutter right before vtec. Its not bad but I do notice it some times.

I'm thinking the reason for the early engagement is because of my turbo spooling between 2500-3000 rpm and the map hit 0 hg and you know the rest. but I maybe wrong.

Does this happen to anyone else?

[TN90accord]

I really don't know when the vtec crossover is. When turning I can feel torque steer at about 3000 rpms, but the car is slow until about 4000 rpms. Maybe the stock cams start making better power higher up in the powerband. I'd say there has to be more lift/duration on the A2 when compared to the A6 because they have the same compression but the A2 makes more power. Maybe it's VTEC-E with more lift and/or duration than the A6.

[civ05se]

Originally Posted by TN90accord

Maybe it's VTEC-E with more lift and/or duration than the A6.

So it's gotta be straight up VTEC since there is no such thing as VTEC-E with more lift and/or duration.

[toyomatt84]

Originally Posted by .Red.EM2

Judge for yourself.........

I heard it kick in at the normal RPM mark (2700rpms). I did a search through Honda's specifications of the D17's that have VTEC, and it definitely is 2700rpms.

Here's a direct quote from Honda's personal site:
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">HX and EX models feature Honda's VTEC® technology for greatly reduced emissions and higher fuel economy. Employing many refinements in the interest of cleaner combustion, VTEC®-E* technology is based on Honda's VTEC variable-valve-timing system, which promotes efficient, lean combustion at mid- and high rpm.

*VTEC-E is available on HX only.</TD></TR></TABLE>

http://automobiles.honda.com/c...=2001
http://automobiles.honda.com/c...=2002
http://automobiles.honda.com/c...=2003
http://automobiles.honda.com/c...=2004
http://automobiles.honda.com/c...=2005

[civ05se]

Originally Posted by toyomatt84

I heard it kick in at the normal RPM mark (2700rpms). I did a search through Honda's specifications of the D17's that have VTEC, and it definitely is 2700rpms.

Here's a direct quote from Honda's personal site:


http://automobiles.honda.com/c...=2001
http://automobiles.honda.com/c...=2002
http://automobiles.honda.com/c...=2003
http://automobiles.honda.com/c...=2004
http://automobiles.honda.com/c...=2005

reading through those links...something funny, I never associated my A2 to be high performance but I guess it is compared to the other trims. But I still don't get is why does my engine "scream" when I hit 4800rpm or more? Is it just how the engine is or is the high rpm intake lobe activating?

[toyomatt84]

It might be noisier at 4800rpms, due to a resonant frequency at that rpm, but I do not know for sure. It's definitely not your VTEC kick-in point, so that's ruled out.

[YeahIknow]

So I guess my vtec is kicking in when it supposed to.

[toyomatt84]

Originally Posted by YeahIknow

So I guess my vtec is kicking in when it supposed to.

Should be. There's no reason for it not to.

[vbkapousidis]

So if i were to swap A1 head with an A2 head on my D17 i could just is the V-AFC and avoid searching for an ECU?

[i-VTEC_DOHC]

wow this thread confused so many people

ahahahaha just like a bunch of asians trying to read english for the first time

im not being racist. im asian myself. half actually

and the answer to vbkapousidis is yes.

im glad i know when my vtec kicks. 5800 =]

[toyomatt84]

Originally Posted by vbkapousidis

So if i were to swap A1 head with an A2 head on my D17 i could just is the V-AFC and avoid searching for an ECU?

Wrong thread.
http://honda-tech.com/zerothread?id=1628016

[mexxem2]

i KNEW the d17a2 has vtec lol
my friends thought i was a complete idiot when i told them it does.
basically cause you dont feel it kick in..i mean you can
but its kinda hard to pin point when and where it kicks in
this is good info
me learned something