lowering VTEC engagment

[EK4R]

How bad is this for your car or would you even recommend it?

Ofcourse the car will be tuned to spec but just wondering if it will cause excessive wear over time.

Vtec window would probably be at 4000 on WOT and 5000 with partial throttle. (this is for a jdm k20)

let me know your thoughts people

[scheung]

If it was good...honda would have done it ages ago

[Vincikwan]

unless your cams are changed...maybe

[m0nty]

If it was good...honda would have done it ages ago

Is this another one of those "VTEC is bad for your engine" threads?

The reason why the manufacturer does not do it is to conserve fuel. No other reason.

[kookie]

I have my vtec point sitting at 4300 on wot and 5800 on partial.
I have had my car tuned and its perfectly safe as long as your car is tuned for it.
If you have a look at the stock cal's on k-manager you will see that most of them have the vtec point much lower. Honda don't do it because they released a crappy tune for the dc5r not sure about jdm thou.

[EK4R]

Is this another one of those "VTEC is bad for your engine" threads?

The reason why the manufacturer does not do it is to conserve fuel. No other reason.

no its not one of those threads. i hope it doesnt turn to one anyways...

what will you have your engine tuned at?

im thinking 4k for WOT and 5k for Partial similiar to kookies

how long have you had your car tuned for kookies and have you been to track etc (hard driving)

[EK4R]

ok just a few read on clubrsx. and it seems lower vtec is fine as long the tune is suited for it and the cam switch over from low to high is set at vtec point so you dont stay in low cam for too long or hit high cam too early.

anything else i should be concerned with? air/fuel ratio is set at 0.9 and its basically a flat line throughout the rev range up to 8800rpm

[Elwood]

I really want some photoes and specs of your EK4.

Always seem to be doing something to it :P

[EK4R]

well you might see it in person sometimes. cos i sold it to a syd buyer. looks like a panda with a spoon wing .

anyways this is for a different project

[3r1k]

Every car has different vtec point hence tune it according to your engine, your tuner should know which vtec point best for your car.

Kookie's case is different, he is special for some odd reasons :P

[mugsee]

To tune the vtec point properly, your tuner should find out the intersection where the high cam starts making more power than the low cam and then define that as the vtec point. This should be done for partial throttle (upper boundary) and full throttle (lower boundary).

Most tuners set their vtec point to 4300 because thats the standard number accross all kpro tunes and most tuners are too lazy to tune both low and high cams for you. I doubt that the optimal vtec point occurs at 4300 on-the-dot.

[kookie]

Well mine does due to my custom 2-1 design.
Mine was tuned for using the crossover in the vtec intersection using part and full throttle.

To be exact my vtec comes on at 4313 (according to kmanager).


As Mugsee has said you need your tuner to sort this out for you as he will be able to determine at which point your car's vtec point is optimal at. Its all to do with the setup of your headers that determine where the vtec will sit. i know stock headers you can have vtec set as low as 3800 because of the way it's designed.

[Vincikwan]

dont know how come u guys can get it so low..my tuner (chasers) tried to bring my vtec down (i lost power) he tried to bring my vtec later (a sudden rush in power). So he ended up leaving it as it was as my car was mostly stock at that time. So i guess unless you did some mods, dont bother lowering the vtec.

[kookie]

dont know how come u guys can get it so low..my tuner (chasers) tried to bring my vtec down (i lost power) he tried to bring my vtec later (a sudden rush in power). So he ended up leaving it as it was as my car was mostly stock at that time. So i guess unless you did some mods, dont bother lowering the vtec.

What ecu do you have? If its vfac then don't bother. The only way you can really lower the vtec engagement without the loss of power is to have an ecu that can tune for cam angles and ignition timings. Vfac i think only does air/fuel which does sweet nothing for the DC5.

I only tuned for af and the power difference was nothing. DC5's make there power by tuning the ignition and cam angles.

[Vincikwan]

The vafc is really under estimated.