s2000Junky

Back on the old Comptech kits before they included your FVM/black piggy back box, we would suffer from very rich afr in that 3-6krpm range before stock vtec would kick in, and we addressed this buy using a vafc to trim the fuel in that area wile also lowering vtec, so this is no longer an issue with current kits it seems, which is a good thing. Also with vtec lowered, you should not notice it kick in anymore, that is the point. When you feel it kick in like stock, its because the power is flat lined prior to that, with the motor wanting more cam. My vtec is set to 3600rpm. I think the FVM box in your kit lowers it to 4k. You might be able to hear the vtec change over rather then feel it, if you can key in on that over the sound of the SC and exhaust. My guess is its working, or the motor would not pull to redline willingly and afr would be really lean across the band.

Adding 1psi more would put you in the sweet spot on your afr/fuel curve. Right now your running lean best down low but too rich in the top end. Running the next pulley size smaller will require you to add just a little more pressure, but put you in a good place down low wile leaning out to a more favorable 12.5 up top so you have a flatter fuel curve. With 1psi more and 1 point leaner up top from 11.5 to 12.5, you will likely see 25whp more peak which is a hell of a return. Your blower efficiency level goes up as well. At 5psi, its barely yielding enough to offset the parasitic losses. 6-9psi is the highest efficiency range for a 1220. At 5psi peak rpm with 11.5afr your making 270-280whp dynojet right now. Just leaning out the top end to 12.5 will give you another 8-10whp, but you cant safely do that as is because you would be too lean down low. So stick with what you have for now, as its the best compromise for safety.

s2konroids

I remember those days well, the old vafc2 and rrfpr

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s2000Junky

Yeah, ive graduated to a NEO now, living on the high horse

s2konroids

Haha

jdmz

With more testing today I think the fvm may be defective. I was able to hear vtec kick in at around 5800 rpm. Before I was doing 2nd gear pulls and it was mostly fine but doing 3rd and 4th gear pulls showed that I had a lean spike to 14 at 6k rpm. I'm going to contact SOS to see if they can replace the unit.

I also bought the 7psi pulley but gotta work these issues out first before I install that.

s2000Junky

Bummer if thats the case. I wonder what the deal is with these units, if there is a manufacturing defect or some kind of initial programming oversight? Anyway, good lesson in street tuning, with using 3-4 gears to help isolate a potential problem in tune. The lower gears just wiz by too quick to get a bearing on anything, certainly when it comes to afr and vtec engagement point.

jdmz

What is your current setup? I saw that you are running the NEO. Is that working well for you? If a new fvm doesn't fix things I may need to look into a different solution.

s2000Junky

The neo is a good alternative if you get to that point, as it does everything the fvm does short of adding injector duty in lowered vtec (which I assume fvm does) but is programmable so there will be a small learning curve for you, but is interface adjustable without a laptop (most simplistic programmable piggy back available). I would stick to the fvm though if you can get a working unit. NEO are not that common used, and you will spend $500+ to get a new one with the optional pnp harness, which is really a must in my book.

MorngWoodStewie

I understand both engine and compressor rpms are identical through the gears, but isn't actual air movement speed and ultimately more air; increase?
Like weighing in that a turbo won't spool in neutral; so no matter the rpm etc. other things come into play like faster speeds create ram air and overlap efficiency increases etc. (Including -probably the most important- timing)
Soo would tuning the higher gears like 3-4 like on a dyno which usually use; make all the gears as a whole better, because 3-4th are usually the closest to the 1:1 ratio?

So like junky said 1-2 go by to quick anyways but targeting afr's in the higher gears 3-4 will actually work them all because of the ratio?

s2000Junky

Im not sure if im clear on what your asking/getting at, but there is more load over time in the higher gears on the motor in regard to the last discussion, and with the lengthened time in each point of the motors ingestion of air and tune you are looking at, you will give the examiner a finer more accurate view of those points in question. The motor also behaves differently under more load conditions than less, so its always best to tune around the higher gears/load to get not only a more accurate tune, but a safer one.