I prefer powerplant as opposed to motor or engine. j/k

 

one cam = more power so its simpler i like it more already now would you get more horse power with mivec and mods than the standerd head and the same mods???????

 

Thanks for that! This may be one of the 1st companies to offer this with FI as a production car???

 

Just curious, the Evo MIVEC is not supposed to have the variable lift feature. In fact, it looks more like the early BMW intake only VANOS, just adjusting intake cam phasing rather than duration - this would be like a hydraulically operated adjustable timing gear to maximize engine power depending at which rpm it is operating. This would mean that power could still be gained by changing the intake cam -

 

The later model MKIV Supras had variable valve timing and I believe the USDM STi comes with it as well.

 

Yea the USDM sti do have their AVCS.

 

You have a good point there! I was wondering about that when I was going thru these write-ups in mags. Maybe a MIVEC compatible intake cam(s) are being developed by various big players in Japan as we speak. It will only get better from here! I can't wait!

Cal

 

so u guys think these evos are gonna jus as good as the evos now?? or better?

 

its not called an evolution for kicks now is it?

 

gotta point

 

Ok the record needs to be set straight. Mitsubishi's MIVEC and Subaru's AVCS are not like VTEC in any way. MIVEC and AVCS are the same generic variable valve timing mechanisms as Toyota's VVTi and BMW's VANOS and Double VANOS systems. In terms of Honda Engines, MIVEC and the like are the "i" in i-VTEC. The "i" stands for intelligent and is a reference to the variable valve timing control system that works inconjunction with the VTEC system. MIVEC is a variable valve timing system with fixed cam lobe profiles.

MIVEC only changes the relative alignment between the camshaft and its driving sprocket. This changes the relative timing between the intake and exhaust cams and thus their valve opening cycles or the intake and exhaust valve opening overlaps. No other valve timing parameters, including the amount of valve lift or valve opening duration are varied. The only thing that MIVEC varies is the valve opening overlaps. Also, MIVEC only varies the relative timing on the intake cam. AVCS, VVTi, and VANOS work the same way.

Think of it as a constantly adjusting, adjustable cam gear on the intake cam that retards timing based on engine RPM. The higher the RPM, the more valve closure timing is retarded. This allows the combustion chamber fill with more A/F, an obvious performance improvement. At low RPM, valve opening timing is retarded to improve combustion effieciency for low emissions and improved fuel consumption.

VTEC varies the amount of valve lift and valve opening duration using different, selectable cam lobe profiles on the same cam. The different profiles are selected and utilized hydraulically based on engine RPM. DOHC VTEC engines have variable intake and exhaust cam lobe profiles. SOHC VTEC engines have only varying intake lobe profiles.

Back on topic... it may be only a rumor but i have heard that HKS already has MIVEC cams in the works. They might really only have to redesign the intake cam. The exhaust cam should be very similar to the non-MIVEC cam considering the actual head and block specs have not been drastically changed in any way. The only internal change i have heard of is the new piston ring combo. Regardless, even if the development takes a while, i think it will be worth the wait!

 

if your tuner is scared of tuning MIVEC, then it's probably not the right tuner to go to.

 

Hey AWDDrift, thanks for that explanation. I really needed that whole thing you said. Now I must go home and show off the newly acquired knowledge.

 

Theoretically, based on my limited knowledge of cams, couldn't the intake cam even be the same as the exsisting cams offered?

If all that is being adjusted by MIVEC is the cam timing through a continuously adjustable cam gear, there shouldn't be any need to change any aspect of the actual cam itself.

Again, I don't know anything for sure. This is only an assumption

 

good point..