This will explain vtec better than i could type it out

http://www.autozine.org/technical_sc...vvt_2.htm#VTEC

 

http://www.hotrocker.com/ What about this?

 

Thats a relatively new vtec I believe I'm not sure thats even in the us yet

 

Actually Honda's VTEC uses two cam profiles, and a funky hydraulic actuator to choose the lobe. There is an actual switch over from the small lobes to the big which is audible. That goes back to at least the '99 Civic Si, and I think the Preludes had them before then.

EDIT: I have been hoping solenoid technology would advance to a point that constantly variable everything as far as valve timing is concerned for years now.

 

Then I am way behind on VTEC because the VTEC I read about was just advancing or retarding the cam.

 

VTEC has never just advanced or retarded the cam. There have always been two cam profiles with the VTEC system, dating back to the early 90s when it first debuted with in the NSX. At a specific rpm an solenoid locks the rockers that follow the smaller profile together with a rocker that follows the more radical lobe together using oil pressure I believe, and the valves are opened and shut by the more radical profile. The change is an audible difference. It is a pretty trick system.

Honda has the VTEC listed as meaning Variable Valve Timing and Electronic Lift Control. Yeah, I know, the acronym is horrible, but that is taken straight from a brochure about the system when it was first introduced.

 

Does anyone know how the VVT on the L92 works? I've seen next to nothing on it still. I think I'll search ls1tech and see if they have anything for me to cross post here.

 

http://gm.wieck.com/forms/gm/previewpage?026545

Looks like it is an advance/retard system.

 

Perhaps thats why I was confused about VTEC I appologize, I need to stay more current on my reading apparently.

 

vtec on honda/acura started back with the NSX. it was the first VTEC motor. the vtec that we're all familiar with comes on a variety of 4 cyl engines (b series, H series, D series, etc). even single cam motors can be vtec. my beater civic is a 97, 1.6L SOHC VTEC automatic with 210k miles on it.

two intake valves per cylinder, but three cam lobes. (the DOHC models have the same thing on the exhaust side, but the SOHC models only have 1 exhaust valve) an oil pressure solenoid that locks the three follower/rocker arms together to ride on the middle cam lobe which has a higher lift/duration than the "low lobe"


the newest versions of vtec, like found on the RSX and basically any K-series motor, is the same 3 lobe for 2 valve design, but it incorporates an advance and retard feature to increase mpg, and decrease the "vtec hit", making a smoother transition from the low lift to the high lift lobes



my old roommate showed hotrocker to me, and i have always wondered if anyone had it on their car. it seems like a good idea, but i would imagine it being a complete PITA to tune it.