LNF Adventure ^_^

[The_Saj]

So you guys might laugh at me for this... first off let me list what i'm working with when it comes to the vehicle etc...

2007 Saturn Sky Redline
2.5" exhaust no muffler (it's still pretty quiet)
fabbed intake pip with k&n filter
fabbed charge pipe (turbo side) with recirc hks ssqv3
Maf relocated to about 1" from what i believe is an IAT for the charge side
Factory bov hooked to boost to keep it shut (damn thing leaks)
the hks is hooked to the manifold to allow fast enough response time (solenoid from ecu is looped and doesn't throw code)

Alright now with all that said... VCM Suite of course (otherwise i'd be posting in some other forum...) The tune i'm running is a much more aggressive tune than what i've seen some others run for cam timing (works like a charm and always has) and i finally relocated the maf... that's where the issues have come in... i WAS running around 22psi with this tune and was having issues of it going lean during the summer and super rich in the winter (this being while i finally relocated the maf)

I'm attempting the standard method for LTFT+STFT for calibrating the maf... while this is making a difference... it only seems to be making a difference until i hit boost... once i hit boost the ecu freaks and enters limp mode... now with this being said... it's hitting the right afr... stft are bouncing between -10 and +6%... it started out pegging at -20% for both... i'm going to make another cruise around and get it a bit closer... but i can't get any load readings above 120% because it kills boost. it's getting -1 degree of knock retard (which happens when it starts to miss under boost)... i'm thinking about yanking my spark plugs and giving them an inspection just to eliminate that from a possible issue. commanded afr is .87... misfire happens when afr drops under .92... i can hold 1-2psi without it freaking out but you can feel the misfires...

Any info as to what maybe a cause is welcomed... spark timing is running stock atm (i put it back to stock to eliminate that as a risk or problem)

[codename Bil Doe]

What octane? What plug gap are you running? Post your tune.

[The_Saj]

a little later tonight (when i get back to my laptop) i'll go ahead and post the last log and tune... current it seems to be getting closer and the misfires are going down... knock is following the same trend just increasing as i get the maf calibrated... (that probably didn't make sense the way i meant it... i can't run the full power range so i tune what it'll let me... then it'll let me move a little higher in the boost range... then i calibrate again... then i get a little higher... it's sad really)

i don't remember what gap... factory spec gap last time i changed plugs... and 93 octane... all i ever run really

[cobaltssoverbooster]

.034

[codename Bil Doe]

Go a step colder than stock on the plugs and gap them .028-.030. Post that tune when you get a chance.

[MikeM173]

I'm currious on your setup. Can you post pictures? I feel like the issues at hand are more from something done vs tune, and that your trying to tune around it. I could be way off and just guessing while I'm at work. I would also like to see the tune you are working with especially when you say it is more aggressive.

[codename Bil Doe]

That's why I wanted to see the tune. Hockeyman was having a lot of issues but it's a definitely a hardware issue (most likely new sensors) not tune. Sounds like it may be similar situation of hardware issue here.

[cobaltssoverbooster]

if the charge pipe contacts the intercooler or the tb flanges it can cause maf errors. make sure the tube is spaced our 1/8" from flange contact and see if the signal clears up some.

there is other possibilities so don't disregard bill or mike's suggestions

[MikeM173]

No offense but most people don't FAB stuff up correctly, and just throw stuff together to save a dollar. I am not saying you did a crappy job because I honestly have no clue. I just know what "most" people do. That is my first concern. My second concern is the tune because I've seen some people do some weird crap but again without seeing it I'm just basing it off of the majority. Next I would look at some mechanical issues like what Bill and CSSOB had mentioned. Lastly I just don't like the idea of the MAF moved to the charge piping but that is just my preference. I would rather go MAFless then tune it there but to each there own.

[codename Bil Doe]

^this sums it up.

[oldskool]

The intake is probably the problem - flow through the MAF is very very important, and from the sounds of your trims, that's likely a big part of the problem.

Also, I'm very interested why everyone is so quick to suggest colder plugs with a tighter gap. My LNF is approaching 32k miles, and i've never changed spark plugs as a matter of diagnosing a tune or hardware problem. They'll get changed in due time when maintenance demands. And the car has been on 21-22 psi early in it's life, and more recently (5k miles or so) up to 27-28 psi from the EFR. Spark blow out is really a myth on these cars if everything else (tune as well!) is working properly.

[The_Saj]

i completely understand the comment about fab'ing things being done badly... i won't lie on the amount of effort put in... specifically materials were an issue (don't have any extra pipe laying around anymore like i need. I believe the issue is the maf placement... specifically it's too far in the pipe (obstructing flow enough that it's cause turbulence etc) specifically it's about 1/8" from touching the opposite side of the pipe... so i'm gonna add another 1/2"-3/4" on the mounting plate and see if that helps resolve it...

i'm gonna go ahead and upload the tune file and the log from the last trip... these are 15 minute trips (i know that's not really enough to properly calibrate) i waited for it to hit at least 150 on the dash before pulling out most of the time. first couple times i didn't think to let it warm up and was tuning virtually from cold start (my memory isn't the best)

i appreciate the comments and i can take constructive criticism so feel free to tell me if there is anything obvious with the tune that is wrong or w.e just remember this is an old tune i'm trying to reuse... the cam timing hasn't really been modified much of any from what i pulled off the ecu to begin with... and the timing is stock atm till i figure out this maf issue... the dal's are still set high just because i'm not gonna punch it till i know everything is the way it needs to be

[|V3nom|]

sounds like you need to do this mod with your maf...

[codename Bil Doe]

I thought you were busy playing in Mustang world like me now?

[|V3nom|]

almost, i have a 04 f150 with a 2v 4.6 thats a MAJOR dog lol. just waiting on the new scanner to come out so i can log knock and make timing adjustments. you any good at tuning fords?

[codename Bil Doe]

I haven't taken a look at the 4.6 yet, but I'm getting a feel for fjord. Just started playing with them. 2012 Boss Laguna Seca & a 2007 4.6 spec Mustang. People would make their lives a lot easier making all the mapping points identical. Save yourself a lot of hassle tuning and eliminating unnecessary variables. Didn't want to post that over there yet because I didn't want people's panties catching fire. Direct me to a file and I'll check it out.

I dig the MAF mod. First thing I thought was poor charge tube. It's so confused!

[|V3nom|]

that pic is from a guy on the sky forum. gmtech also did the same mod to his ic pipe. he claimed it was better than stock or any aftermarket intake on the market as it resulted in the smoothest maf freq. i think he also said blow through is easier/better to tune than pull through, at least on the kappa, but dont quote me. blow through is definitely better for people running atmospheric bovs.

[The_Saj]

lol see that's the problem is that i relocated the maf... specifically it's obstructing flow too much because it's too far in the pipe... i'm going to make a spacer block and see if that helps... if it doesn't i may just simply put it back on the pull in side... i would really like to get rid of having to recirc the bov...

[gmtech16450yz]

Switching to a blow through MAF on an LNF will give you the absolute smoothest and quickest responding airflow readings, but like anything else it has to be done correctly. Think about it, does it make sense to get airflow readings in an air cleaner that's about 10 feet of tubing, an intercooler and a turbo away from the actual intake? On quick transients the readings are so far behind what's actually happening in the intake that it will cause surging and poor mixture control.

Here's some pics of mine if you need an idea on how to build yours properly. Yes, if it's too deep in the pipe it will cause issues.

http://s841.photobucket.com/user/j16...?sort=3&page=1

BTW oldskool, DEAD ON with what you said about spark blowout. On the LNF's specifically, I'd say 99% of the guys that say they have "spark blowout" actually have injection window misfires. I made my ~500whp/500wtq on stock plugs at stock gap in my LNF.

[codename Bil Doe]

Good knowledge!