instant VTEC

[Phat_ciVic]

just out of curiousity i was wonderring if you could change the programming of ur vtec motor, to make vtec come on instantly. and turn off after a certain rpm. with a turbo it would be like removing the lag.
is this just a stupid idea?

[Kit]

it wouldnt be desirable, cos from the factory, the vtec crossover point is the optimal rpm to change cam lobes.
altering the vtec crossover point on an otherwise stock engine will decrease performance rather than increase it, which is why, with a standard engine, vtec controllers are pointless

with a turbo, its impossible to remove the lag... the turbo relies on exhaust gases to make boost. At a low rpm, the engine isn't pumping out enough gases to spin the turbo fast enough to create boost.

unless of course if you had an anti lag system :P

Chris

[VTEC16]

you could do that! would be awesome!

You would acheive the low down responsiveness of a racing camshaft, with the high revving characteristics of a street cam!!!

Why didnt honda think of that?

[Phat_ciVic]

was kit right tho, would changing the rpm that vtec comes on have a negative effect on perfomance

[Kit]

you could do that! would be awesome!

You would acheive the low down responsiveness of a racing camshaft, with the high revving characteristics of a street cam!!!

Why didnt honda think of that?

isnt that exactly what vtec does? responsiveness of a street cam, with high revving characteristics of a racing camshaft??????

[Phat_ciVic]

i think wot he ment was
instant vtec would be the low down responsiveness
and the turbo would be the high revving characteristics of a street cam

[2ds]

was kit right tho, would changing the rpm that vtec comes on have a negative effect on perfomance

Yes, honda are spot on with their cross over point. if you actually go to the trouble of doing two dyno runs, one all the way through the rev range with the low profile and one with the high you will see that changing the cross over point will only lose power.

As for turbo lag, hook an injector up to your exhaust manifold and dump fuel straight in there, should get rid of some of the lag :p

[carbine]

I believe he was taking the piss.

[Kit]

was kit right tho, would changing the rpm that vtec comes on have a negative effect on perfomance

yes it is correct: if you read up about it and understand how a vtec engine works, and why it changes cam lobes, you'll realise that it is right.

essentially in a 2 stage vtec engine (like the b16a). you have 2 cam profiles, one that runs from 0-5800rpm (we'll call this the mild cam for now), and a hotter cam that runs from 5800-8000pm (lets call this the wild cam for now).

if you run the engine on the dyno with the mild cam only (you can do this by intecepting the vtec solenoid), you will find power drops off dramatically above 5000rpm.

if you run the engine on the dyno with the wild cam only, you'll see it makes really poor power until about 6000rpm when it "comes on cam".

put the two power curves together, and where the power curves crossover is where the factory vtec crossover is. if you alter it, you'll have less power cos the other cam is making less power

[2ds]

you could do that! would be awesome!

You would acheive the low down responsiveness of a racing camshaft, with the high revving characteristics of a street cam!!!

Why didnt honda think of that?

isnt that exactly what vtec does? responsiveness of a street cam, with high revving characteristics of a racing camshaft??????

he's taking the piss....

you have just been trolled ;)

[Phat_ciVic]

i don't have turbo lag, i was just askin out of curiousity

[2ds]

so many people posting

[Kit]

As for turbo lag, hook an injector up to your exhaust manifold and dump fuel straight in there, should get rid of some of the lag :p

yep, an anti lag system used on rally cars (but its a bit more sophisticated than that)
it pumps fuel through the system and keeps the turbo spinning so that you get instant boost, causes a LOT of backfire hehe

[SIKCVC]

You would acheive the low down responsiveness of a racing camshaft, hahahaha biggest contradictive sentance EVER!

is there any other decent way of reducing lag? I've been racking my brain trying to think of another way... maybe supercharger? dual stage turbos (bit hard on a 4) the only real way would be to launch in boost wouldn't it? I have no idea :P as with most topics :P

[VTEC16]

he's taking the piss....

you have just been trolled ;)

[Phat_ciVic]

yeah i got that
thanx

[SIKCVC]

sorry if it sounded like i was laughing at anyone I was laughing at your joke :P

[Setanta]

he's taking the piss....

you have just been trolled ;)