Freshdot

So I have an s2000 with a few bolt on's that I'd like to have running a bit more optimized. Now before we get into why VAFC's "suck" and what I "should do," I'm fully aware of it's limitations. I'm also fully aware that this sort of light tuning has been done for many years now with great success.

I'm pretty clear on most of the functions except for two: which are LVT/HVT, along with the VTEC UNMT.

Regarding the LVT/HVT: I get that LVT is before VTEC and HVT is after VTEC, however I don't understand how these RPM values can overlap. Looking at this example:

WIDE THROTTLE:
LVT - 1000 RPM = -3 HVT - 4000 RPM = -3
LVT - 2000 RPM = -3 HVT - 4500 RPM = -3
LVT - 3000 RPM = -3 HVT - 5000 RPM = -3
LVT - 3500 RPM = -3 HVT - 5500 RPM = -3
LVT - 4000 RPM = -3 HVT - 5700 RPM = -3
LVT - 4500 RPM = -3 HVT - 6000 RPM = -3
LVT - 5000 RPM = -4 HVT - 6500 RPM = -2
LVT - 5500 RPM = -5 HVT - 7000 RPM = -0
LVT - 5700 RPM = -5 HVT - 7500 RPM = -2
LVT - 6000 RPM = -6 HVT - 8000 RPM = -4
LVT - 6200 RPM = -6 HVT - 8500 RPM = -6
LVT - 6500 RPM = -6 HVT - 9000 RPM = -10


V/T CONTR: L-H = 6000 / H-L = 5500

V/T UNMT: Hi/Lo +2%
Lo/Hi 0%


What I don't understand is why both LVT and HVT are tuned differently from 4000-6500rpm if this a WOT setting? Shouldn't there be values for LVT up to 6000rpm (VTEC crossover) and then the HVT values take over?? Or is my understanding of what lo/hi cam means a bit screwed up here?

Next is the V/T UNMT: Is this as simple as recording my AFR's and making the necessary adjustments at the VTEC crossover point?? The other thing I don't get about this feature, is why would the Lo/Hi need to be touched?

spAdam

iTrader: (1)

The LVT/HVT settings you would tune as you tune anything else with vtec. It's a different trim for each cam. Set the swtichover to 6600 so it stays on the low cam and tune up to that point. Then set the switchover to 3900 or so and tune the high cam. set the crossover wherever the torque lines cross.


Regarding the vtec control, it's called hysteresis. The vtec engages at one value but doesn't disengage until it falls to a lower value. That's normal and is in your factory calibration.


The unmatch is for when the ecu says high cam but the vafc says low cam and vice versa.


Regardless of whether you want to hear it or not, this is a **** way to tune a car... especially one with cam phasers. It doesn't even allow you to adjust ignition, which is where the power is made. In the past, people used to wipe their asses with their hands with "great success" but then they came up with better ways to do it after they realized they were walking around with **** all over their hands.


Please delete your duplicate posts.

Freshdot

Your shitty hand analogy was the right amount of push I needed to just get a Haltech and see Mr. Evans.

spAdam

iTrader: (1)

I'm glad my sense of humor didn't offend you. Haltech has some awesome products, you won't be disappointed. The new elite systems even have obd2 functionality.

bspeed

spam you got pm.

Freshdot

A large part of me wanted to give it a shot myself being that I have access to a dyno and a VAFC isn't too in depth. But yea man, just gonna shell out for a platinum pro and tuning. The whole hi/lo throttle thing is what bothers me most about the VAFC.

spAdam

iTrader: (1)

I honestly haven't used Haltech since I finished college but I was super happy with the PS1000/2000 then. I found out about the Elite from a coworker who is putting one on his Miata and read up on it. It's on my short list for if/when I give up on NepTune for my personal car.

bspeed

Platinum pro is pretty good, but the new Elite boxes are way more capable. Add the fact that you can run your harness and then designate what wire is what afterwards instead of the usual build harness then match to corresponding pin.
There is an Elite 750 coming out this year that is priced in line with the Platinum but is more capable, especially for a daily or weekend car.

I have a 1500 myself sitting in the closet with the rest of my parts to finish up the build.