So is it not even worth it to get a vtec controller? And i thouhgt some of the new honda vtec's where vtec all the time. is this true or did someone tell me some bull****??

 

I could research what happens when vtec engages and maybe come up with an explanation as to why it increases your HP earlier, but I'm not that smart. I did a real life trial with it for that reason and the results showed an increase in power earlier in the powerband. I would estimate a .2 drop in ET times when switching the vtec Xover point to around 4k rpms, as long as you can increase you fuel flow to account for the cam difference in the lower rpms. Sorry Nail but honda's don't have any power below 5k so that doesn't make any sense. Its for highway passes so you don't get creamed, and so that when a normal person drives a civic they don't waste gas.

 

You guys have it all wrong, all vtec does put simply is open your valves more. Say we are talking about a none vtec car for a second. If you hadd a cam or cams to make more power at higher rpm's it will do so without a problem but in the other rpm ranges it will suffer. If you add a cam aimed at mid range power it will do that good but it will suffer in the higher ranges. It is allways a give/take thing, there is no magic cam that will make power all over. Allthoug DOHC VTEC engine's do ok at attempting to make power in a wide rpm range they still fail when the lower rpm range is concerned like from off idle to say 4000rpm. VTEC engines and I mean all of them are aimed at making peak power up top, the vtec is there to aid that. Another point is how vtec works, a dowel pin is opened from oil pressure, the oil pressure is allowed to open this dowel pin through far more than just the engines rpm's. It takes the corect oil pressure, engine temp, and map sensor readings. On a dead stock vtec car say like a 99/00 SI, if you go out and crank it up after it has set all night in temps of the 20's/30's then take off with it. The car will not allow vtec to "kick in" untill the engine is warmed all the way.

Putting a VTEC Controller on your car allows you to by-pass all of these safty measures which IMHO for one is never good. Also the butt dyno lies alot and does not justify any changing of anything major on a car. I am not calling anyone a liar so please do not get that idea. You may have made more mid range power than you were before but and this is a big but it does not mean you were making more power in general. I would also bet that gas milage went down as a result of this.

There is IMO no justifying changing the vtec cross over with out new cam/cams, fuel maps, a dyno session, and no doubt you are pulling more power. Also when tuners and I mean people that do it for a living do change the vtec cross over they 98% of the time go no further than around 200 to 500rpm off the original setting from the factory to simply smooth out the tq band.

You guys can do what you want, I am not saying it will be bad or anything like that but I have been into cars for over 15 years and into Honda's for around 10 years and not untill lately did the whole "change your vtec cross over" start being oh so popular