ivtec

[GYPO2C]

hi all,

i know that the ivtec is a very mild form of the vtec apparent in cars like type s tegs and s2000's etc, but i was just wondering if anyone could tell me where the ivtec actually kicks in with the euro? I was trying to judge it by feel, but the only time i feel a little more kick without anything gradual is at 6000rpm.

[Banana]

issert vtec'd?

[madjace]

i was wndering the same , with my old dc5 i could feel it but with the euro i cant quite tell where it is either , mine is an auto though so that might even things out to the point where i just cant feel it

[Ferrarista]

5800rpm ( i think )

[SiReal]

Is iVtec the 3 stage VTEC? or is it the continous VTEC? u might not be able to feel it at all.

[aaronng]

The Euro has the same i-VTEC system as the DC5R. The difference is that the high cam lobe is smaller. The mild i-VTEC that you are thinking about is the one in the CRV. The CRV's has VTEC only on the intake camshaft. The Euro has VTEC on both the intake and exhaust camshafts. the "i" part is cam phasing which is on the intake cam only for CRV, Euro and DC5R.

The reason why Euro's i-VTEC cannot be felt is because the high cam is not as aggressive. On a DC5R, the 2nd cam profile comes on at 6000rpm and goes til 8400rpm. That's 2400rpm. In the S2000, it's 6000 to 9000rpm, a wider range of 3000rpm. So the 2nd profile has to be aggressive to maintain torque in that range. For the Euro, 2nd cam comes on at 6000rpm and goes til 7300rpm. That's only 1300rpm, so the 2nd profile is relatively mild compared to the DC5R and S2000.

There are people in the US putting in K20a cams into the k24a by doing a head transplant, that makes the cam profile changeover become apparent again.

[aaronng]

Is iVtec the 3 stage VTEC? or is it the continous VTEC? u might not be able to feel it at all.
It's 2 stage DOHC VTEC, with added cam phasing on the intake shaft.

3 stage VTEC was used in D16 engines in the Civic sedan. I can't remember the exact engine model though. And there is no continuous VTEC. VTEC changes the cam profile, so it is a step change.

[SiReal]

Aaronng, you are a wealth of knowledge and interesting to read as well!!!!

[GYPO2C]

The Euro has the same i-VTEC system as the DC5R. The difference is that the high cam lobe is smaller. The mild i-VTEC that you are thinking about is the one in the CRV. The CRV's has VTEC only on the intake camshaft. The Euro has VTEC on both the intake and exhaust camshafts. the "i" part is cam phasing which is on the intake cam only for CRV, Euro and DC5R.

The reason why Euro's i-VTEC cannot be felt is because the high cam is not as aggressive. On a DC5R, the 2nd cam profile comes on at 6000rpm and goes til 8400rpm. That's 2400rpm. In the S2000, it's 6000 to 9000rpm, a wider range of 3000rpm. So the 2nd profile has to be aggressive to maintain torque in that range. For the Euro, 2nd cam comes on at 6000rpm and goes til 7300rpm. That's only 1300rpm, so the 2nd profile is relatively mild compared to the DC5R and S2000.

There are people in the US putting in K20a cams into the k24a by doing a head transplant, that makes the cam profile changeover become apparent again.

thanks for the explanation... brilliant. One more question though... when you say its 2 stage...and your saying the second profile on the euro kicks in at 6000rpm, when does the first stage kick in? Or when you say two stage, is it just the one extra step which is that at 6000rpm?

[EuroAccord13]

*Moved*



This goes in the Technical Section...... :)

[twing]

vtec falls into two main category. All engine here is AUDM.
economy type: a 12v to 16v configuration on intake. This is made for low fuel consumption in mind. They can be SOHC or DOHC. Example: jazz vti, civic vi, normal teg/lux teg, accord vti, crv. At low RPM it uses 12v, at high RPM it uses 16v with a bigger cam profile on intake.

medium performance: a SOHC with 16v configuration. D16y1 and D16y8 are the example.

high performance: teg Type R, Type S. 16valve all time. DOHC. On high RPM, it uses bigger cam lobes for intake and exhaust. Euro may be in this category. What is Euro engine code? K24A2 is the one that fall into this category. http://www.theksource.com/news/04/k-series-vtec-breakdown/

Hope that helps.