Split-Second AFC N/A Thread

[ProtoType5]

So it's come to pass, that there are a few of us somewhat insane, somewhat hopeful, Naturally Aspirated Proteges out there that are currently pushing themselves into the tuning game. Personally, I'm getting into it, just for the fun and learning experience of actually tuning...and with further mods, be able to squeeze them for everything they are worth...If they are really worth anything. I'll be posting updates and pictures of my process and hope to get FunkyBuddha's experience posted up as well....So stay tuned...

 

[jeg0024]

Sounds good, let me know if you want any of my input as well Oh, and do you want this moved to the N/A forum or left here? Let me know!

 

[Maxx Mazda]

PM Glen (FunkyBuddha) this thread. He's got quite a bit of N/A knowledge aside from tuning that would be good to discuss here.

 

[Chief7925]

subbin

 

[FunkyBuddha]

Well..when Nick and I do the install ..i'm waiting for my mp3 ecu to come in still. I'll post some data and feedback.

So far..
I/H/E and cams, the cam gears are set to 3/3 retard so the powerband is a bit after 4000rpm. Feels like a vtec motor actually LOL. I'll have to post a baseline dyno w/ the cams/cam gears.

116whp/120tq = I/H/E/Cams

 

[jamesk]

um..... if there is good gains from just tunning the af, count me in! i am very interested in this tunning process (as you all know, I've been posting everywhere about it, lol).

ive been thinking about the greddy system because it does timming as well. but i have the mp3 ecu, so maybe i dont have to. if anybody accomplishes a good gain from the mp3 ecu with a afc, then ill buy a afc immediately.

our cars do run rich, so there should be a gain. my wide band goes as low as 10.0!

 

[ProtoType5]

Well, I'm installing my W/B soon as well, and was very interested in the A/F readings I'd be getting. If it is dipping to around 10, then there is some serious room for improvement....I'm planning a road tune, then dyno tune, with a stock MP3 dyno, then my road tune, then the shop's tune...So hopefully will get some kind of decent data to collect and look at...I'm not really expecting a night and day kind of change. I'll be happy with 3-4 to the wheels...I'm more interested in the process and the experience of tuning...Make going turbo that much easier.

 

[ProtoType5]

OK, According to my knowledge...On the tuning program an input of 10, means no change to the O2 sensor input correct...So with the AFC installed and the maps filled to a value of 10 in all areas, would that be running a stock map????

 

[jamesk]

what happens with my sideband readings, at WOT, the readings will go back and forth between 14.4 to 15.2 and around 4000 rpms, the readings will be a solid number in low 11's, and slower go drop down all the way to 10.0 to redline.

this reading tellls me that the car is running way to rich. at NA, the ratio should be around 13.1:1 at full throttle. i also think that the ratio drop doesnt start untill late. it should start around 3500k i think.

 

[ProtoType5]

The drop is probably the switch to Closed Loop in the ECU...That's when it stops trying to "trim" the fuel ratios, and just goes straight to the pre-programmed map..

 

[jamesk]

yea it is closed loop, that is the point where it stops going back and forth. the problem is that i want it to be closed loop all the time. is there a way to make it on closed loop all the time?

 

[Maxx Mazda]

Ya, basically the AFC has a clamp that forces the ECU into colsed loop all the time. (Tuning off of O2 sensor and MAF.) Now you can modify the signal fro mthe MAF (that's what the AFC does) to get the AFR's you want. I've never done it on an N/A car before, but Glen talked to John at airflow logistics and he says it can be done. I tuned it on my car when I was boosting, and it's very easy to tune indeed. I would think it is best when paired with the MP3 ECU as you will have the best and smoothest timing maps available.

 

[ProtoType5]

In closed loop the ECU is still in charge of the Trimming values correct??? So from what I've read you are trying to minimize the amount of trimming involved to maximize the time you're driving in the correct A/F ratio...

So the largest gains will be found after the ECU would regularly switch to Open Loop, when there was absolutely nothing controlling or reading the A/F ratio..

Plus with this setup, I can always switch back to the P5 ECU and go TURBO...and I'll have the experience of tuning before-hand...

 

[WRCprotege]

i just got the MPI tuner, and was wondering if it does the same.. or is the AFC the only thing that will tune NA cars in open loop.. i havent put it on, so tell me more about this AFC controller.. i already have the mp3 ecu in the car now.. and this controls fuel only??

 

[ProtoType5]

I'm not the expert, but I am pretty sure you'll need a voltage clamp with the MPI, then you'll be running nearly the same setup as the AFC...I've got no experience with the MPI tho...

 

[Maxx Mazda]

In closed loop the ECU is still in charge of the Trimming values correct??? So from what I've read you are trying to minimize the amount of trimming involved to maximize the time you're driving in the correct A/F ratio...

So the largest gains will be found after the ECU would regularly switch to Open Loop, when there was absolutely nothing controlling or reading the A/F ratio..

Plus with this setup, I can always switch back to the P5 ECU and go TURBO...and I'll have the experience of tuning before-hand...

Yep. In closed loop the ECU controls how much fuel / timing based on inputs from various sensors.

Your thinking on wanting the ECU to go into open loop is wrong. You can't change the map that comes with the ECU, so you want to keep it in close loop and modify the values comign fro mthe sensots in order to get it to do what you want.

 

[jamesk]

what do you guys think i should do. ive been having such a delima with this.

should i keep my MP3 ecu and buy a afc, or should i sell my mp3 ecu and by the greddy emanage?

here are some key facts that i hear which are making this hard to decide. is there room for improvement for the mp3 ecu? can it get any more advanced without knocking or is it the best map for our cars? it would be much easier if i just kept it, the tuned the air fuel ratio. plus the timming map for the greddy system is only 16x16, so idk if it can get any better.

whats the best option????

 

[Maxx Mazda]

The MP3 ECU will be the best setup for an N/A monster. THe Greddy is not worth it.

 

[jamesk]

The MP3 ECU will be the best setup for an N/A monster. THe Greddy is not worth it.

THANKS MAXX MAZDA! im glad that is cleared up. should i order the spilt second afc now? lol i mean im ready to buy it and have the money, but i mean if i should wait for someone else to do it? should i just order it and expeirement with it?

i also have a wideband, is it worth getting the second verison?

 

[Maxx Mazda]

Get the Ver 2, yes. It makes tuning SO much easier.

I would go ahead and order it if you feel comfortable taking the risk. In theory it should work no problem, but once again no one knows for sure. There may be some wierd quirks etc that need to be ironed out.