Is there anyway that I can turn off my VTEC on my h22a? Kinda a strange question, but is there?

 

because at the current moment, my turbo pulls nice until VTEC and then it doesn't pull any harder...I think the ecu might be dumping in too much fuel and I don't have an sfc or vafc to tune down the fuel...running an fmu, so I simply want to see if it pulls as hard as it does while not in VTEC

 

well there are two things to my knowledge that control VTEC. oil pressure and a 12 volt signal from the ecu. theoretically if you were to cut the 12v signal then it would not engauge. the ecu wouldnt recognize it was there.

 

Yah, my buddy was telling me that I could unplug a harness that goes into the tranny or something like that but then I'd throw a CEL, I was also thinking about disconnecting the oil pressure unit since VTEC runs off of oil pressure but I'm not exactly sure how to do this.

 

it dosent pull any harder than what... the normal lobe? well the turbo is going to outweigh the VTEC "mad pull". you will still need it to get the proper lobe engauged. if you were to run it all on the primary lobe then it wouldnt get the proper power at all. now about tuning down the fuel. jack with your fpr. dont lean it out. unless its REALLY REALLY TOO RICH. lean + turbo = detonation = bye bye motor. screw that. get it tuned on a dyno. spend hours fine tuning it.

 

Lots of people have this problem.

The stock VTEC lobes have a lot of overlap, which tends to hurt some turbo applications. (Some, not all, it's very odd.) Although, overlap is GREAT for N/A. This is why most turbo H22A guys run custom turbo cams that have the VTEC lobes highly modified for boost instead of N/A.

The easiest way to disengage VTEC is how I do it. There is a wire off your ECU (you'll have to check the helms for which one, I've already forgotten what color it is) and you just hook an on/off toggle switch into it. All it is is basically a 12 volt power signal.

You can turn VTEC on and off at will with the flip of a switch. I have heard of plenty of turbo H22A guys running with VTEC off. I myself will be trying it both ways. I bought an LED just to remind me when I have VTEC switched on and off. Gehy, yeah, but I don't want to forget which is which. lol Plus, it helps when trouble shooting. With the turbo, you don't "feel" VTEC nearly as much.

 

od... mine pulls hard as ***** when VTEC comes on

 

turbo + overlap=not good...

 

alright guys but what about what i was talking about with the lobes. its to my understanding that the lobes are designed to switch at a set point. yes you can change that set point but still it does switch over. whouldnt running on the smaller lobes decrease the higher end power? same as running the secondary lobes on the low end. too much or too little lift for the power range. guide me in the correct direction.

 

forget it, i am runnign crower turbo cams soon, so not like i care

 

Geeze, sounds like an non vtec block is more cost effective to build on than a vtec block when pertaining to turbos. . .

 

FI + vtec is perfectly fine. It's all about tuning. I'm not surprised you are having issues with running an FMU without having some way of fine tuning, like with an afc. Tuning is key. FI makes vtec better.

 

Cam tuning is also your friend. VERY good friend.

 

So very true.

 

would have to agree with you any dya of the week... No need for an h22 if your going turbo from the sound of it... Plus, a h23 is much cheaper to get a new one with everyone doing the swap. I guess someone will either set us straight or inform us about how we really dont have a clue what we are talking about...

 

yeah you still would be best having the lift of the VTEC cam to jam more air in there, if anything you want to advance the intake cam and retard the exhaust cam to get rid of the overlap...and then you'll run smoother. get cam gears

I think just running the idle lobes is a bad idea, they just don't have enough lift.


[Modified by satan_srv, 10:46 AM 4/1/2003]

 

just get your car tuned and you will be golden.

 

can't do much in terms of tuning...all I have is an fmu!!! hahaha

 

Hey guys...I own a EH2 but I saw the thread. Anywhooo....You could buy the Ferrera VTEC roller-rockers that eliminate the on-off VTEC function...it is permanently on but you could prob. tune it easier, I would think. Just a thought...

 

im too lazy to read all the posts but if you want to turn off vtec just unplug the green wire going into the vtec selinoid by the distributor... its the only wire going it to it.

 

On my teg (dunno if it's same for prelude) there's a "john deere" wire that's green and yellow that goes to the ecu. You can put a simple toggle switch on that and it will keep the vtec from engaging if you want. From what I have understood from several reliable sources (again this is for my teg so I dunno about the prelude) if you disable the vtec you throw some other things off and have a good chance of damaging your motor. I didn't fully understand it, I just took their word for it.

The simple thinking that vtec is good, so vtec+turbo must be better is false. Stock cams are designed for NA and not for FI. Turbo cams are very different in lift and duration. The only thing that gives a vtec motor more power when boosted than a non-vtec motor is the higher compression.

Generally speaking a non-vtec motor is easier to boost whereas the vtec motors are harder but put out more power. You can usually run more boost on a non-vtec but I have consistently seen the properly built vtec motors put out more hp on a little less boost. It takes a lot more tuning, knowledge, and planning to boost a vtec motor but you can usually get more hp.