This is my first post on Honda-Tech. I'm relatively new to the world of import tuning and had a question. I'm not sure if it is true or not, but I've been hearing that turbochargers somehow interfere with VTEC and that it is better to supercharge. Is this true? If you have any information about this or can explain exactly what the conflict is between turbos and VTEC, I'd like to hear it.

-Ziggy

 

hey im not really into turbos right now but iv never ever heard that. you might want to try the forced induction forum. all about turbos and superchargers there.

 

No VTEC actually is great for turbo's. VTEC especially, becuase the big lobe that VTEC uses would not be that great at low RPM's for forced induction due to the extended overlap and lift, but it works out great at the higher RPM.

The only issue about a VTEC motor such as the Interga Type-R would be the high compression, which would be good (relativly) with no forced induction of any kind.

 

That is actually incorrect. VTEC is good for turbo, overlap is bad, not good. The whole point of valve overlap on a NA setup is to create a vacum within the combustion chamber to increase the amount of air within that space. On an FI setup, sucking the air into the chamber isn't needed becuase it is being forced in there already. In that case, you want no overlap at all, becuase if both the intake and exhaust sides are open simultaneously, you are actually losing pressure within the chamber. If only the intake side is open, you are increasing the overall pressure within the system.

Now to be even more correct, VTEC is only good for FI setups becuase of the larger cam lobes involved. Because of this, if the non-VTEC lobe were never engaged the impact on the motor would probably be positive rather than negative. This is why you see a lot of FI people eliminating VTEC from the system (on a highly tuned car) becuase it isn't really necessary. Big cams in a non-VTEC motor could just as easily yield similar numbers.

 

that is a rumor, but its wrong...