Unlimitation

Hey I just want to know the differences in the older GSR and Prelude VTEC compare to all the newer ones. Other than I-VTEC, is there any changes in VTEC?

So a 94 GSR VTEC is same as the newer VTEC right?

dom93hatch

Old and new VTEC? It's always been the same system, except for I-VTEC. Maybe you're thinking of the differences between the SOHC and DOHC motors, or even VTEC-E.

TheOtherDave™

The mechanics of the DOHC VTEC valvetrain in the B18C* and H22* are fundametally identical. On VTEC valvetrains, oil pressure is used to drive locking pins out from the center rocker arm, which locks it to the two rocker arms that acutally bear down on the valve/ spring assembly. As a result, the valves are now opened as dictated by the center cam lobe, which is ground for high-rpm performance (higher lift, longer duration). This switch takes place at around 5500rpm, though it depends on engine load, throttle position, knock sensor activity, etc.

Starting with the K-Series, the new i-VTEC systems introduce a hydraulically controlled system to vary the camshaft position relative to the cam sprocket (Honda calls is VTC if memory serves). This is an independent system that complements the VTEC valvetrain system mentioned above.

One application of this technology is to leave the exhaust valves open a scoshe during the intake cycle, thereby eliminating the need for a conventional EGR (Exhaust Gas Recirculation) valve. Depending on application, VTC will also advance the intake cam (at low-rpm, I think) to aid cylinder filling on the intake stroke.

Those are the major differences as I remember them.

Oh, and moved to Engine Tech. h:

Unlimitation

Thx for the replys. Sorry for postin on wrong section.
The reason I asked this is because someone mention that the older VTEC (like the one in 94 Integra GSR ) is not as "strong" as the one in newer cars with VTEC.

So just please answer this question for me:

Does the VTEC in 94 GSR perform the same as the newer VTEC Honda has right now?

Thank in advance.

bluetwo

I think they are just different... the power and torque come on at different rpms.
Fuel effiency and power are probably a little better, but some people will have different opinions.

TheOtherDave™

Don't worry 'bout it. I moved it here since it focused more on motors and less on specific issues for the Teg. h:

Since there were no drastic changes to the head design during the 94-01 build of the B18C1 (the motor under the hood of DC2/DB8 Integra GSR) , the powerband is virtually identical for all model years.

The K-series motors are of an entirely different design than the B-series.

Their "i-VTEC" valvetrain has the advantage of that VTC camshaft timing system (which I mentioned earlier) in addition to the VTEC valvetrain. The addition of VTC is part of what aids mid-range torque in the K20A2 (for example). But then again, so does the K20A2's higher compression and greater displacement...

So while the K-series motors make more flywheel horsepower, there is IMO no real point in comparing them to their B-series predecessors.

sherwood

the vtec system has not fundamentally changed at all.

like the others said it's just the addition of the new systems to aid vtec in making the powerband more solid that have changed the denotation on the engine (ie, i-VTEC)

to compare the engines is just stupid because they are just different types of engines altogether
::edit:: sorta.. lol

Unlimitation

So the way I see it is that the engine is pretty much the same except with the "Intelligence" in i-VTEC. The powerband are more considerable with better low and mid-range torque and power all around.

I think NorCalDC4 really explain it well. Thx guys.