blacktop 20V vvt rpm

[cooter]

hey guys
i didnt want to hijack the thread about 7age with blacktop and vvt so i thouht i start another one.
ive just finished wiring a microtech lt10s on my blacktop 20v and am wondering at what rpm i should be getting the vvt to turn on??
cheers
craig

[Mooro]

Can't answer your question but I think with the silvertop it is activated at around 4400 rpm, whereas with the blacktop there are more factors other than rpm that activate it. From what I have read it chooses the optimal point to activate it anywhere between 1800rpm and 6800rpm based on a number of factors.

[cooter]

crap. cause i think the microtech can only switch on and off.

[Mr Revhead]

VVT is not RPM switched.
for an on off application, switch on at 2000 rpm and off at 6200
dyno testing of the off point is prob a good idea

VVT ona stock 20v is pretty much on all the time
once the engine is half warm, anything over 1/4 throttle switchs it on

[cooter]

for an on off application, switch on at 2000 rpm and off at 6200

why would it be like this??

i cant see why it would switch back to the low revs timing setting at 6000. wouldnt you want that timing setting to continue to redline?

[Mr Revhead]

nope, it turns off there,
my skillz arent sweet enough to explain the theory behind it though!

[cooter]

hmm ok. i still dont think im gonna be able to get the micro to do this anyways. is there any harm in letting it stay till redline?
craig

[The Real Roadrunner]

dude this is the easiest answer
tune the car with it off save map to laptop
tune with it on
then lay the graphs over each other one will give better bottom end, the other better top end
set the switch point where the lines cross over and your done

if your talking about 3d mapping it then it become hard but the above is the only way to do it properly on a microwreck.

hope that helps

[cooter]

great thanks for that roadrunner and everyone else. so ill get the tuner to set it when i get the car tuned. its still runing on base microtech tune.
its set at 3000 atm
cheers
craig

[Mooro]

dude this is the easiest answer
tune the car with it off save map to laptop
tune with it on
then lay the graphs over each other one will give better bottom end, the other better top end
set the switch point where the lines cross over and your done

if your talking about 3d mapping it then it become hard but the above is the only way to do it properly on a microwreck.

hope that helps

I like this theory and I think this is basically what a silvertop does...the only thing is that I think the optimum changeover point may change depending on other factors. For instance, as a guess, the dyno will essentially be run at WOT, but the optimum changeover point maybe different at half throttle etc...I think this is where the blacktop has an improved verison of vvt.

[japlish]

i had mine set at 4200rpm

[The Real Roadrunner]

as stated 3d mapping is hard as you set rpm vs load and then set p/w to suit but if its switch only, the only way you should to it is wot as thats when you want it to work best.

[Mr Revhead]

im pretty sure the black top doesnt have a "better" vvt system.... it just switchs by a different amount.
the change over point is pretty low, and didnt really seem to alter with half throttle or full....
as soon as the engine is over 1/2 warm anything over 1/4 throttle switchs it.
i had a light hooked up to the vvt solenoid, and you can sit on idle and stab the throttle and th light came on instantly. which would mean its TPS switched

[FMS01]

as soon as the engine is over 1/2 warm anything over 1/4 throttle switchs it.
i had a light hooked up to the vvt solenoid, and you can sit on idle and stab the throttle and th light came on instantly. which would mean its TPS switched

Ditto for my Silvertop with std ECU

Cheers,
Julian

[fixeruperer]

you can also tell the microtech to switch at a certain vacuum and rev.
e.g 4000rpm at 3" vac