O2 target from Scanmaster for 93 oct.

[grocerygetter]

93 octane...
hot outside...
egt is probed couple inches off the head in #3...
Full Exhaust...

With my boost controller set at 17psi...I'm seeing 790s in first and second gear with 1600 deg F egts, 740s-750s at @ 1700ish on egts deep into third. Note the mods in my sig...Also blm's at idle are 123. Fuel psi is @44 after the car is warmed up.

With the dump open, third gear is richer and the egt's in 1 and 2 are a little warmer.

How is this? A tad rich? I ask becuase when I lift the car pops quite a bit like fuel burning down the runners. It only pops after the headers get hot...that's why I was thinking it's a tad rich.

 

[TurboDave]

Not so rich really, sincy you're only pushing 17# of boost, and the egt being mounted so close to the exhaust port things dont' sound too bad really. Actually, if I had to put a label on it, I might tend to lean in the direction of you running a tad lean.

 

[grocerygetter]

I'm going to pull a plug Saturday and take a look...thanks for the input!
Also, no more than .9 deg of KR.

 

[bruce]

93 octane...
With my boost controller set at 17psi...I'm seeing 790s in first and second gear with 1600 deg F egts, 740s-750s at @ 1700ish on egts deep into third. Note the mods in my sig...Also blm's at idle are 123. Fuel psi is @44 after the car is warmed up.

Using the stock O2 sensor is really playing russian roulette, IMO. Even a new one can easily degrade, to the point of being questionable, for WOT tuning.

In back to back runs, I've had 820mv (on a stock O2 senosr), indicate 11.8 -> 12.5:1 (on a WB).

You're at the stage of trying to see, if the EGTs are high from being lean, or the O2 is reading lean from higher EGTs.
If you're burning your own chips, you might try adding a little fuel with the time in PE correction, and see what that gets you.

BTW, what's sort of injector duty cycle are you running?.
3rd Gear Boost reduction setting?.

More info. at:
http://www.t6p.com/forums/showthread.php?t=7454

 

[grocerygetter]

I was told the Scanmaster read lower than Direct Scan etc. You've read 820 on a Scanmaster and got that number off a wideband?
I'm using one of Eric's chips for the 30# Tomco's. Stock Turbo. The headers on the car flow though.

 

[TurboDave]

I was told the Scanmaster read lower than Direct Scan etc.

Nope, not really. OTC will read higher than the other scan tools, but scanmaster and most others use the same O2 reference voltage.

You've read 820 on a Scanmaster and got that number off a wideband?
I'm using one of Eric's chips for the 30# Tomco's. Stock Turbo. The headers on the car flow though.

 

[grocerygetter]

I pulled the #1 plug (lazy here...easy to get to.), looks awesome, perfectly clean not white. So that would lead me to believe that the back to cylinders are running a hair lean. My static fuel pressure was set at 46 before. I raised it to 47. I have an RJC power plate to put on the car...just waiting for my vac. block gasket so I can redo that as well. I figure that may let me back the fuel pressure back down to 46 or 45...is that right? I know the pp doens't make hp...it just evens out airflow. The headers are what throws in this tuning variable that isn't normal...LOL.

 

[DCVING 6]

You've read 820 on a Scanmaster and got that number off a wideband? QUOTE]

I believe what bruce was saying is that while the stock (narrow band) sensor read a *constant* 820ml, the wideband actually showed the A/F fluctuating from 11.8 to 12.5. This shows how in-accurate the stock narrow band sensor is in closed loop.

 

[grocerygetter]

I put a wideband bung in the downpipe a few inches post turbo...I guess I should breakdown and buy a wb now.

 

[DCVING 6]

I guess I should breakdown and buy a wb now.

Worth its weight in gold.

 

[grocerygetter]

I got the powerplate on...looking forward to driving it at lunch. It idles richer but not too bad...blm 117. I'm curious to see the numbers at WOT. I set the fuel psi at 45 atmosphere.

 

[bruce]

I put a wideband bung in the downpipe a few inches post turbo...I guess I should breakdown and buy a wb now.

That might be too close for a Bosch WB.

I have mine (Bosch or NTK depending on my mood) down by where the cat., used to be.

 

[bruce]

I was told the Scanmaster read lower than Direct Scan etc. You've read 820 on a Scanmaster and got that number off a wideband?

I can run several different exhaust gas sensors at a time.

I saw a 820, while tuning, and while tuning, I had changed the AFR, and the stock O2 sensor read the same voltage. ie the stockers just aren't designed for WOT work, and shouldn't be used as such. But, since a few people had good luck doing that (if you ignore all the blown headgaskets), it's become folklore, that you can rely on a stock O2 for tuning, when in fact you're just guessing that things are OK.

 

[grocerygetter]

alright...Innovative LM1 sitting in my truck...ready to go home and drive the GN...I'm not changing anything...I'll post here with my AF#s.
Ya'll suck...talking a brotha into buying a WB...LOL.

 

[grocerygetter]

OK...boost surging is a bad thing...that's where my knock is coming from (duh) but you should see the AF curve while that's going on. The car is pretty solid at mid to high 11s in first and second until it starts to boost surge (16psi-19psi)...it's that freakin puck matching thing that I haven't done yet (arggh). When the boost surges up the AF hits high 10s from what I can tell reading the datalogs. I need the rpm trigger for this thing...it would help when looking back.
So, as you said, the SM was rock solid and just barely getting leaner as it went through gears...but in reality there was quite a bit of fuel curve change during boost spikes.
Now for the question, yes...I know...fix the puck matching issue. But, my question is why am I having to kick this thing to 48 psi to pull this off? It honestly makes me think the chip still needs more fuel...but it's rich at idle (10s-low 12s) with blms at 117. At 55 + mph cruise speeds the AFR is stoich or within a hair of it (14.2-15)