POM HB

Hi all,

Yeah, my car failed emission last month and I'm trying to find the way to get it to pass by using my PFC.

I know the safe under boost afr would be under 11.5:1. For cruising, we might be able to do 14.7 or even a bit leaner.

How can I do just that and not destroy my engine????

I know how to lean the hell out of a cell, but what would happen if it's too lean? Stall? Kaboom? Stall and then kaboom? BTW, the cell is not under any boost.

I didn't really know how much I should go, so I went down some. And, I don't have a wideband o2 installed. Any suggestion? The cell is x4, y6 or the other way around (6 to the right and 4 down). It's second gear at ~2700.

I'm pretty much thinking I could just go really low on fuel before the car stalls. But, I thought that might destroy my engine or damage it somehow.

And, if I could accomplish just that, should I leave the settings there or return the settings back to where it was just to be safe?

Some more info on PFC.
PFC w/ commander (no dataloggin) from rotoryextreme GB 2 years ago.
Untuned by professional or WBo2 (so, still w/ pretty much base map)
Had only been reduced some fuel in idel and emission related cells.
Ign maps are untouch.

My set up
Stock turbo
Air pump is there
DP and Intake
stock cat
cat back


BTW, what is the afr for emission purpose?

POM HB

Man....no one have any idea???

Cummon guys. Throw it out here!

POM HB

Wargasm

I wrote up some stuff to cover this exact question

http://www.zeroglabs.com/rx7/emissions.htm

Matt Hey

Leaning out too far in vacuum will just cause stuttering and rougness. Going much leaner than stoich may start to make your emissions worse. It's kind of a shot in the dark without a wideband O2.

Here is some info by Chuck and Kyle (PFC tuning GURUs) about how lean you can go...

In previous posts this year, Kyle and I have mentioned about adjusting transistion areas. In fact if you were to read all of our posts, you would have volume two and know all we know.

(1) cruise should be set for best smoothness plus mileage. This is P5 to P6 normally. Set high 15AFRs to low 16AFRs.

(2) P10 is 0 vacuum/boost, go for 14.7AFR, stoich.

(3) For P7 - P9, taper between (1) value and 14.7AFR, or set all the same as cruise. If you look at your boost gauge, when you floor the throttle from cruise, your boost gauge goes instantly from vacuum to 0 + boost, So in reality, P7 - P9
are useless unless you find a place where you can cruise at 100+ mph. Yes in Germany you would use these.

(4) Your P16 and P17 are way too rich. Go about 11.5AFR for P17 if you have a large IC.

(5) For P11 - P16 taper the AFR from 14.7 to 11.5AFRs. I'll do these using simple logic. Since stoich (14.7) is about ideal for normal driving and power, we will set 0psi at that then richen up linerally until we hit our first tuned boost area of P17.
P10 14.7
P11 14.5
P12 14.0
P13 13.5
P14 13.0
P15 12.5
P16 12.0
P17 11.5

(6) idle ~14 AFR

Unless you can afford to dyno power tune all P rows, this is your best bet.
__________________
Chuck

POM HB

WOW,

Thank you both very very much! I'll have to re-read the stuff again before taking any action. Ohhhhh, those advices are big helps

POM HB