http://hcoc.2u.com.my/vtecpoint.htm

Basically he says that using a vtec controller (V-AFC, Fields, etc) to move the crossover up or down, even with fuel adjustment, that the ignition maps are still the same. Meaning that if you lowered the VTEC point, the ignition map is still running for low cams while you're actually in high cams... and vice versa.
While it does make sense, is there any truth to this... and is it "bad" for the car to be in this state?

 

Yes, it is true.

It's not exactly bad for the motor, but you aren't getting the best out of it this way.

With a Hondata ECU the fuel and ignition timing maps change with the VTEC X-over, just like they should.

 

Yeah I thought so. It's basically like:
If you made XXX more power with moving the Vtec crossover, you could have made a lot more with a complete setup (Hondata).

 

my vtec controller allows custom ignition maps.. its called a HONDATA

 

Ok, so on my gsr motor I moved vtec xover up to 5500. So ignition is overfiring from 4800(stock) up until the x-over. It may be good for power but could it cause detonation? Too much spark, not enough fuel?

 

ditto

 

best article of the month award oes to you man. Good info

 

well you can get a apexi timing controller. sucks that they are discountinued. i am sure you can find one used though.
they go hand in hand






[Modified by eviltwin, 3:07 AM 10/5/2002]

 

Could this be an alternative to going all out with a hondata? Thanks for the interesting topic!

http://www.inlinefour.com/datsysconvte.html

 

whats the crossover for a b16a sirII right now mines set at 5400in and 5500 out i want to set it to stock crossover so i dont have problems

 

Very interesting. The article makes sense.

but honestly after the money of both a VTEC and ignition timming device you are almost at a basic Hondata unit. I paid about $400 for the V-AFC setup (harness included so no cutting factory wires). Figure another $400 for the other unit.

I dunno; so what should I do?

 

hmmm and only 395!!!
anybody have this and how does it perform for you?


[Modified by TheRedSkoolingBus, 8:32 PM 10/4/2002]

 

I would go Hondata if you can afford it.

 

well i got both of my apexi units for 600. since then i have sold them and bought a hondata, but they are not that close in price at all. i bought my stage 3 hondata for na for about 475. now i nedd a p28 which will prbably cost me another 150. then to find someone to do the soldering of what is needed to get all the bells and whistles working could be what another 150 or so. i havent gotten that far yet in my hondata project so i wouldnt know.

 

And if you make any additional mods then you will need a new chip and re-tuning and if .....

Almost makes sense to get the AEM EMS at this point. That is what I did.

 

If you look at an ignition timing map, you'll see there's no real big change in ignition timing on and off VTEC. The whole purpose of that article was supposedly to say there's some dramatic change in ignition timing at VTEC and that things will be messed up if you change it and just tune the fuel. But looking at this B18C map from Hondata, I don't see any sort of big change.



edit: Of course a Hondata rules a VAFC anyday and tuning for better ignition timing will net more power but I just fail to see where this article was getting it's facts about ignition timing changes.


[Modified by SurferX, 11:00 PM 10/4/2002]

 

good info. i think the article basically says don't mess with the vtec crossover if you havn't done like basic internal and ecu upgrades. i mean...i wouldn't touch my vtec crossover if my motor is stock. i'm currently running my vafc with a mugen ecu. i havn't done any dyno tuning so my vafc as of right now is pretty much an "eye catcher". what i need to do next is the dyno and then the vafc will be at work.

great article BTW.

 

2 's up yo!

 

So you read one article and you have already decided to change everything back? Why would you do this? If everyone told you to jump off a bridge, would you do it?

 

thats y if u dont have the tunning capabilities or resources to get a hondata get a chipped p28 the use a vafc on that

 

let me fix this for you...
if you don't have anyone to tune your hondata get a vafc and chip your ecu...