qtiger

I'm sorry but you're wrong. VTEC isn't a magical power adder... it switches cam lobes to a high lift lobe. At low RPMs you simply aren't flowing enough air to make horsepower on the high lobes.

99DCtwo

were talking 4000-4500 and up and with an intake and header only you are flowing more than enough air otherwise all those people from jun and hondata must be blwin smoke up are ass when they reprogram your vtec point 1000 rpm sooner for increased power, but they just spend countless hours of r&d to tell us some b.s. and make some money. right?

kfar09

im looking at my dyno plot right now and my hp and torque drop right at 4000 rpm. and then they start to go back up a little at 4300. so wouldn't i want to change my vtec engagement to 4000 rpm so my powerband doesn't drop

qtiger

The new Hondata flashes drop the VTEC engagement point on modified K series, but not on B series.

99DCtwo

you are still going to have a little bit of a drop in power wherever vtec engages just because of the slight time it take to switch between lobes. you want to get your vtec engagement wherever you do your slowest high speed driving you could call it. You don't want your vtec on at highway speeds for gas mileage reasons, but go any faster open it up and let her give you all she got!!!

99DCtwo

hondata you actally get to adjust yourself, thats a serious system, that was a bad reference, talk to any of their guys on the phone they will tell you to use a vtec killer cam and run it wide open all the time, try passing emmisions with that!!!!!!!

99DCtwo

besides vtec is vtec on any engine. k or b.

Epoch

Umm... the reason you have the drop in power isn't the lag between switching cams... it's nearly instantaneous... The reason is because it's best for a daily driver (like the stock GS-R profiles) to have a nicely tuned low range cam profile for gas mileage and low end torque, and the second profile is put there to let the engine to make it's maximum safe and warranty-able power, as well as making use of that second intake valve...


I have no idea what you're trying to say

:slap: there are several major differences between the VTEC and i-VTEC system, and the K series is seriously superior (in terms of making NA power... harder to put a good turbo into those engine bays) B series.

Though... this raises a question that I wondered about... does the VTEC system _only_ allow an increase in the cam lift and duration, or can it offer a decrease? Kinda curious if you can set up the VTEC cams in a turbo'd system to reduce the overlap when in the upper RPMs, allowing the turbo system to effectively pressurize the cylinders better with less blowby? Yet, in the lower RPMs, allow the right amount of overlap to purge the exhaust gas and (maybe?) speed up the spooling or the turbo? *fantasy*

99DCtwo

there will balways be a power drop when you engage vtec, take a look at your dynos always see a slight power drop and then it raises no matter when you turn on the pay check, your car doesn't say right at 4000 rpms exactly like the the very microsecond that the 1st cyl. hits v tec starts its lags the entire drive train down a bit to start moving the secondaries!!!!!!!!!

99DCtwo

I meant valve train, sorry!!