Hey guys, i'm pretty knew at this forum stuff. but i was just wondering what is the difference between the old vtec and the new ivtec. I have 2004 si and i cant feel when the ivtec kicks in. And one more question.... is the a ivtec controller out there.

 

It is meant to increase economy and lower emissions instead of increase power. Plus it is only on the intake side.

 

the EP3 iVTEC is meant for economy, it is very similar to the VTEC-E found on the Civic EXs. Basically, any rpm before 2200, the engine basically operates on 12 valves, above that rpm, all 16 valves work. 2 lobe cam design...

iVTEC on the CL7 and DC5-S are different though. There is actually a 3 Lobe cam design for VTEC on both Exhaust and Intake sides, so there's the "kick" and audible difference. The I part of this VTEC is because it works in conjunction with VTC -- adjusting cam position to either retard or advance the timing to offer torque and power at lower rpm ranges.

 

Hmmm I didn't know the new si ivtec was meant for fuel economy... shows how much I know..

 

damn that sucks. will getting a vtec controller do anything?

 

Nope, it won't do anything. Just get a K20A swap, that will do something.

 

oh hell yeah that would!!! but too expensive. i think i'll just reflash my ecu. hey do you know of any good exhaust systems out there that are not too loud. Cops are going crazy lately with the exhaust tickets. planning to spend under $700

 

HKS or Greddy evo 2

 

Magnaflow makes good stuff.

 

The K20A3 does not have a standard DOHC VTEC valvetrain as we know it from the B-series engines - the K20A3 should actually be called a "DOHC i-VTEC-E" engine, because it uses a VTEC-E cam setup. The K20A2 is the "real" DOHC i-VTEC engine, utilizing the standard DOHC VTEC cam setup we're all familiar with. To help you understand the differences between the K20A2 and K20A3 engines, I've included the following information from a post I made elsewhere:

Allow me to evaluate. Let's start out by defining some terms:

VTEC - Variable valve Timing and lift Electronic Control. At low RPM, a VTEC engine uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. The VTEC mechanism engages a high-lift, long-duration "race" cam profile at a set RPM value (i.e., ~5500RPM on the B16A) to increase high-end power delivery.

VTEC-E - Variable valve Timing and lift Electronic Control for Efficiency. This system isn't really VTEC as we know it. At low RPM, the VTEC-E mechanism effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At a set RPM value (i.e., ~2500RPM in the D16Y5), the VTEC-E mechanism engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?

VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs.

i-VTEC - intelligent Variable valve Timing and lift Electronic Control. This is a combination of both the VTEC and the VTC technologies - in other words, i-VTEC = VTEC + VTC. Currently, the only engines that use the i-VTEC system are the DOHC K-series engines.

Now this is where things get tricky - Honda uses the term "DOHC i-VTEC" for two different systems: The first system is used in the K20A2 engine of the RSX Type-S. The second system is used in the K20A3 engine of the Civic Si.

The First System (K20A2):

This system is pretty close to the older DOHC VTEC engines. At low RPM, the K20A2 uses a normal cam profile to retain a smooth idle, good fuel economy, and good low-end power delivery. At 5800RPM, its VTEC mechanism engages a high-lift, long-duration "race" cam profile to increase high-end power delivery. The only difference between this i-VTEC engine and the older VTEC engines is the addition of the VTC system. The intake camshaft has the automatic self-adjusting cam gear which continuously optimizes valve overlap for all RPM ranges.

Here we see an image of the intake cam lobes of the K20A2. Notice there are 3 lobes; the two side lobes are the low-RPM profiles, and the center lobe is the high-lift, long-duration profile which engages at 5800RPM. Basically the same setup as the old VTEC engines we are familiar with.

Now here we see the VTC mechanism - the gear on the end of the intake cam that adjusts valve timing (overlap) automatically on the fly.

This system is used in engines powering the JDM Honda Integra Type-R, Civic Type-R, Accord Euro-R, and the USDM Acura RSX Type-S and TSX.

The Second System (K20A3):

This system does not really conform to the "DOHC i-VTEC" nomenclature, as Honda would like us to believe. As I mentioned in my previous post, it actually should be called "i-VTEC-E," because it uses a VTEC-E mechanism rather than a standard VTEC mechanism. At low RPM, the VTEC-E system effectively forces the engine to operate as a 12-valve engine - one of the intake valves does not open fully, thus decreasing fuel consumption. At 2200RPM, the VTEC-E system engages the 2nd intake valve, effectively resuming operation as a normal 16-valve engine. There are no high-RPM performance cam profiles; this engine is tuned to balance fuel economy and power, rather than provide pure performance. On the intake cam, there is the VTC mechanism which basically is an automatic self-adjusting cam gear used to continuously optimize the valve overlap for all RPM ranges. This being a VTEC-E system - and not a true DOHC VTEC system - is the reason the K20A3 redlines at a measly 6800RPM, while the K20A2 is able to rev all the way to 7900RPM.

Here we see an image of the intake cam lobes of the K20A3. Notice there are only 2 lobes - there is a nearly round one used only for the low-RPM disabled intake valve, and then there is the regular lobe used by the other valve at low-RPM and by both valves at high-RPM:

This system is used in engines powering the USDM Acura RSX base, Honda Civic Si, Accord 4-cylinder, CRV, and Element.

Special note: The K20A3 engine used in the Acura RSX base has a slightly different intake manifold design from the K20A3 engine used in the Civic Si. The RSX engine uses a dual-stage manifold, similar in concept to the manifold of the B18C1 in the old Integra GSR. It uses long intake runners at low-RPM to retain low end power, and switches at 4700RPM to a set of shorter intake runners to enhance high-end torque. This accounts for the extra 9 ft-lb of torque in the RSX (141 ft-lb, vs. 132 ft-lb in the Civic Si).

Here is an image showing just how this dual-stage manifold works. On the top, you can see the low-RPM (long) runners are in use, and on the bottom, you can see the high-RPM (short) runners in use.

Myths:

1. The i-VTEC engine engages VTEC gradually, and not suddenly like in the old VTEC engines.

Wrong. The i-VTEC engine "engages VTEC" at a single set RPM, like always. Whoever started this rumor is a fucktard. Read the definitions above.

2. VTC engages at a set RPM.

Wrong. VTC is always activated. Read under "VTC" above.

3. The K20A3 engages VTEC at 5000+ RPM.

Wrong. Technically, there is no "VTEC" (as we think of it) in the K20A3 engine - it uses a VTEC-E technology, which engages at 2200RPM. Read under "The Second Sytem" above.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kal &raquo;</TD></TR><TR><TD CLASS="quote">HKS or Greddy evo 2</TD></TR></TABLE>

HKS is good stuff

 

Listen to Nikos guys.

He is the Zeus of all the K series gods on H-T.

 

f/s bc exhaust. used for 6 months.

 

Holy ****... thanks for all the info. Kinda disappointing but now i know. fucken car dealers dont know what the **** their talking about. He even told me that the vtec kicks in at 5500 rpm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by funkyjiffy &raquo;</TD></TR><TR><TD CLASS="quote">Holy ****... thanks for all the info. Kinda disappointing but now i know. fucken car dealers dont know what the **** their talking about. He even told me that the vtec kicks in at 5500 rpm. </TD></TR></TABLE>

Well it doesn't really matter man. An engine is an engine, and a redline is a redline.

Just because you car doesn't have real variable valve timing VTEC, doesn't mean it's a bad engine.

It still has the powerband in the upper RPM levels like other hondas, and still drives similarly.

It's not really necessary to have variable valve timing to determine a higher RPM power range, some engines don't have it (I.e. the 4AGE, specifically the one used in the AE86 corolla), and produce power in the same RPM range as honda DOHC VTEC motors.

It's still has a lot of potential and similarities to its big brother K20A2 and there are still options to improve its performance up to par,
cams (will definitely help with that "puny" redline), K20 Intake manifold to add some more torque + power, etc..

Have fun with your car man.

 

i have a 04si also and im just gonna do the a2 head swap.

 

just to do a little addendum to nikos' post.

Myth 1. The i-VTEC engine engages VTEC gradually, and not suddenly like in the old VTEC engines.

VTEC is either on or off. there is no half VTEC. nikos is dead on there.

however, the ecu can determine when and how the vtec is engaged. with some tunes, under WOT, vtec is at 4300, while if partial throttle, it's still at 5xxx. hondata's ecu reflash puts vtec at 5200-5800. under WOT, it engages at 5200. the lightest feather throttle, vtec engages at 5800. anywhere in between it's a linear interpolation what rpm the vtec hits.

 

hum.... k20a2 head swap. that sounds good. how much is that costing you?

 

Get Mugen Exhaust...Thats where its at...

UnlimitedEK9

 

mugen is hella nice, but too costly for me. thinking bout getting the borla cause it looks clean and looks stock so cops wont bitch. but dont know how loud it is. if its too loud i'm ganna but a bigger resonator in it.

 

Thanks for that info. My friend just bought a ep3 a few months ago
and we were both really disapointed in it. It just didn't have that quality
vtec sound. I always thought if it was ivtec it would be just as good as
the rsx type s, just tuned down a bit. All this time I thought ivtec sucks dick,
but I guess it is just his car that has an engine in it similar to my 93 vx with
vtec-e.

 

I hope the guy didn't buy the car just because of the VTEC sound. Think of it this way, it makes the same hp as the older Si but it doesn't have to rev as high in order to do so. It also has twice as much torque and the chassis is stiffened up a bit.

 

I guess dissapointed is the wrong word to use. I just thought that if it is ivtec
it should have valvetrain as the rsx, not a economy type ivtec. He didn't get it
for the sound, he just wanted a reliable daily driver car. What I meant to say
is that I think that the ivtec engine in the 02+ Si is really ******* misleading.

 

I thought of the same thing until I read about the K20A3. I bought the car for the same reason. I needed something that was peppy but also reliable to get me from point a to point b.

 

hey . thanks for info .
i would rather get a turbo upgrade than motor swap . the turbo i want is 4100.00 . its a rev hard . dyno tested to give 260 hp at the wheels . the motor swap is more expensive i belive . someone here put a rsx type-s motor inthere si . cost 6500.00 wwith labor . i dont know abot the type-r motor . the turbo i think give's way more hp for money . thats me lol . so far i have only a cold air intake on now . i want to get reflased ecu also .

my question now is with our motor has redline at 6800 . that reflashing is supposed to let our car redline at like 7700 . can the motor handle it . besides turbo how far can you go with blowing up motor .