My engine is finally broken in so I decided to do a couple of second and third gear pulls. I have a wideband o2 sensor (innovate LM-1) hooked up to I could read the afrs. And what I saw was from around 3k-5000 afrs were in the low twelves to high elevens (descending as rpms increased) range, then from 5k-5500 afrs read from high elevens to high tens (again descending) then from 5500 plus it read between 10.4-10.1:1.

Correct me if I am wrong, but shouldn't those numbers be higher with stock fuel system and 2.5/3" no cat exhaust? Max boost hung around the .6kg/cm2 or 8.5 psi. I thought that with a full exhaust you run leaner....

ALso as the rpms increase the cars seems to slow down, to my understanding is that since my AFRS are pretty low its bogging down because of running rich. Along with that, when I reve the engine slowly (no boost) to redline I get flames when shifting, but when underload/boost and shifting I do not get any flames, and that is with the AFRS reading richer, what gives?

What is a good recomendation for AFRS? I have heard low 12's and high 11's.... which is better?

 

leaner = more power

leaner = more danger

there is really not a "better"

but a nice compramise is about mid 11's

your car is rich. It will only lean out if the injectors cannot keep up with the air (boost). Other wise the comptuer is able to use the correct maps.

Stock runs really rich

try some higher boost levels like 10psi and see if it leans out (should)

 

what is your setup other than your exhaust?
cause i am going to be getting the lm-1 too and wanted to use 1 of the outputs to my stock ECU and 1 to my autometer AFR Guage.

ideal is 14.7:1

 

ummm no

it won't run lean if you are only running 8.5psi... if you have a 3" catless exaust and you are only running 8.5psi then you must have a stock air box, or a ported waste gate. or a screwed turbo.

 

hehe that's stoich

great for cruising but not for under load.

 

LOL! Yeah I forgot to add that I had ported my wastegate, which I wish it was enough to keep it boost levels stock, and I never put my HKS intake back in....

Besides that I have a SAFC II and Blitz Boost controller (still needs installed). When you get the rpm convertor, log atleast boost and rpm....

Bust still even adding an extra 3 psi really makes the 10:1 still really rich....

 

Do you have the trottle signal to the safc hookd up to the throttle signal or the boost signal?????

if you hook the throttle input on the safc to the boost pressure signal from the sensor, you can then program the safc to add or remove fuel by boost/vac which is way more useful than doing it by throttle.

You just have to remember that the SAFC is now displaying %of max boost range (lowest vac to highest boost it has seen) in the throttle readout instead of the tps signal. It would be nice if you could reset the names of the parameters on the display, but, oh well!

 

Its hooked up by the boost before the FCD. I had it wired after the FCD and I was getting a reading of 100% at 0psi, now its alot better...

 

there ya go.... no just start takin a bit of fuel out when the car is on boost ...

at 8 psi, my car was running rich too... but at 12, it was gettin a bit lean!!

you may want to check your wideband just to be sure.. you can check it by turning it on and hitting the probe with a propane torch... it should read 14.7 dead on while exposed to the flame.

 

Yeah I want to recalibrate the LM-1 just to be sure before I start taking fuel out, and I guess I will give the torch a shot as well...

ANother question, should I add more fuel in the mid rpm range? or is the low 12's good?

 

This is a common misconception, and results in people doing silly things like throwing in bigger injectors unnecessarily. Those are the mixtures programmed by the factory, and at only 8.5psi boost you're nowhere near the limits of the stock fuel system.
Depends what you mean by "bogging". Like I said, those are normal mixtures for factory tuning, and they don't make stock cars bog. Yes you can free up some power by leaning them out a bit, but if your performance is dropping off noticeably, you have issues elsewhere.

 

I understand that the stock maps are made to run rich, I just not thought that they were made to run THAT rich. The power really drops off from the 6200 ish to 7k range like someone put the brakes on. I really was not paying that much attention to the mid range, if anything it may have been a flat power band.

BTW does the peak power point change when adding a full exhaust? Because I can say for sure that 6500 (where stock peak power is) is way off right now. I am going to try and watch the boost guage again to see if I am loosing boost pressures when running that high, if not that then the only other thing I can think of is that I have some sort of grounding issue when revs reach the top end....

 

fd's run even richer, its supposed to be that way

 

Not in my experience. My 12AT made ~50% more power than stock from intake, exhaust and turbo mods, but still made peak power at 6500rpm like stock.