Newbie MAF q's
 

:bang: I know that you guys are gurus in this area and this is my first LS motor/car. Im also kinda sorta new to the whole OBD II system. So this is what (I read the thread about the LS1/LS6 book a month afterward) I did: followed the directions for porting the MAF-cut out the center air foil, punched out the screen and smoothed out the inside. Not all of these effects happened immediatly. In fact, everything happened over a long period of time (2 mos and 2k mi) and it is baffling me. Here are my symptoms: Rough idle (sporatic miss), Loss of top end, High speed pinging, Tranny (A4) not kicking down properly. I got the car dyno'd last week and the #s are 289 hp and 329 tq. It stopped producing pwr at about 53k revs. The guy that dyno'd it said Im down about 30 hp.
This is what else is done to the car: SLP whisper lid, Ported MAF and screen removed, Ported throttle body, Oil sep in pcv line, TR55s and MSD wires.

I am totally mystified by all of this. Like I said all of the problems didnt happen all at the same time. It was all pretty gradual and slow.
Any suggestions? :confused:

go back to stock.


D. Maf:


What they are: http://ourworld.cs.com/jrpws6/mod+guide/GMSMAF.jpg


What they do: "...Aftermarket mafs, don't make power, due to larger size, they make power, by tricking the computer into seeing less air, therefore the computer gives more timing, and less fuel..." (Ryan 'slow')

What to look for: PORT/SWAP/DE-SCREEN AT YOUR OWN RISK. The stock maf is good for 500hp. If by chance your maxing out your MAF contact your tuner and see what he/she recommends.

How to install: http://www.installuniversity.com/ins.../mafh_swap.htm

I knew that book was going to get people into trouble
(see my book review in the New section).

If you can't edit your way out of the problem then you
want another stock MAF. Best bet? get a junkyard one
and just use its ends, you can tell by inspection if there's
any damage.

Used you'll find them for $50-$60 in the classifieds so a
junkyard should be less, and quicker. All years ('98-'02)
of F-body 4th gen are the same MAF. But a newer one
might be cleaner.

Jimmyblue, youre right about it getting me in trouble. I thought it would be good reading like the how to make hp book by David Vizard. Little did I know. I thought that getting a new MAF sensor would be the way to go and so Ive been investigating one from SLP.
JRP, so the stock one in stock condition is good up to 500??!? I havent done any equations on airflow and power but I didnt think that the stock one would be good after headers and rockers.
Im currently in the process of trying to map out a solid way to 410 hp or more at the wheels without nitrous. I also want it to be a reliable daily driver and not go with a lot of expensive (relative term I know) parts. Since an SLP MAF is cheaper and my local parts house has it in stock should I pick it up and go that way or definatly go with a stock one?
Any recommendations on the power figure Im looking for? I was thinking 1.8 full roller rockers, headers and high flow cats, LS6 intake and tuning. Missing anything?

P.S. Is this normal for it to take this long to change the characteristics of my car and how do I reset once I get a new MAF? Just drive it a while and it will correct its self?

as i stated in my post, if you want an aftermarket MAF contact whoever is going to tune your car. the stock one will definately handle your 410rwhp requirement in its unported and screened setup. and with those mods listed you wont hit 410rwhp, you'll need a 224+ cam or small cam and heads.

do a search for SLP MAF and Granatelli MAF, you'll find the good majority of people end up having problems and return back to stock.

mosts PCM stuff is learned and re-learned in about 100 miles.

I guess stock on this stuff is THE way to go. Ive really been checking the threads and they seem to go to and fro back and forth. The learning and re learning is really good to know. Im used to put it on, adjust it, go faaaster of the days of old. :drive: Ive also really been shopping around for LS6 heads but have been seeing used bare LS1 heads for really cheap. As I understand these things are really good flowing out of the box. The only thing that really has me hesitant about swapping heads is that its a b*#$& changing plugs. Heads can only be worse I imagine.
The reason Im looking for that figure is because Im going Z06 :guns: hunting. There is this guy that beats the crap out of his Z06 and I think that beating him might humble him enough to take it easy on that precious car.
What kind of figures are you looking at?

ls1howto.com

all the installs you want/need.

a h/c install isnt that hard.

:hail: For me its not the difficulty level but the time involved.

Out of your combo, what are you pulling?

havent dyno'd any of my setups, and its been changed a few times. currently looking at a new cam. if i had to bench race i'd say 380-385rwhp as of now.

If you aren't going to tune the PCM then the only 85mm
MAF you can get away with is the SLP '01-'02 version.
This runs real close to stock cal. It's also out there on
the aftermarket at not too much worse than the price of
an unmolested stocker. But you have to be sure you don't
get the earlier version for '98-'00 because that one has
more of a lean cal. In any case you can adjust the SLP
yourself if need be. But if you go back to stock on this
one piece you will have that much less to figure out
when trying to tune for the rest.

Well guys, I tried the new MAF last night. No joy. Still a miss at throttle. I was beginning to think maybe plugs or an injector. It only misses when sitting at idle. As soon as I apply some gas it doesnt seem to miss. Its even more pronounced while in gear. Ive changed out the fuel filter thinking that might be part of it but no joy there. Last night part of the trouble shooting I did was to put a timing light on each wire to see if I could have a misfire at the plug however either this method is not accurate for the LS motor or its not a plug. Before the dyno I changed out to the TR55's and Im wondering if a plug might not be up to par. I have no idea what it could be. I also had the ride up to a top end run and I seem to have lost some mph on the top end. Im baffled and have no idea of WTF!!! :bang: :punch: I have a friend that runs a diagnostic on it and he says it checks out. Should I take it to the dealer and have them diagnose it and do the work myself? Im losssssstt.
And to think, I was really looking forward to heads and cam swap, headers, LS6 intake, full roller rockers, double row timing chain, porting my oil pump, ya know the normal stuff. Really getting into this new stuff. Now Im really having second thoughts.

HELP PLEASE!

The miss can be an air leak or you might have killed the plugs when modifying the MA.

I really wish those books put out the facts like "Porting and descreening a MA,expecially in a A4 car is no good!!"

I'd give it a week to get done learning first. If your
buddy can look at misfire counts then see if it points
to anything isolated. The top end may be affected by
some of the "bad learning" that was accumulated with
the old MAF and have to unlearn that from the LTFTs
before it will quit over-enriching WOT. Some cells that
you don't spend much time in, take a lot more driving
time to get flushed out.

Whats the possability that its an O2 sensor? One of the things I did was spray some Brakleen into the intake when I did the pcv mod. I could have waited longer to fire it back up however I was anxious. Wanting to solve the pinging problem and find out why I was 30 hp down on the dyno. Im kinda worried about a burned valve however I havent known or even heard of Brakleen doing that. Hard on sensors is one thing. The miss is so sporatic though. There is nothing consistant about it. sometimes it misses then hits.
I tried tracking down an air leak by spray (one would think Ive had enough of that) and that yielded nothing. I also changed the plugs well after I modded the MAF. I did notice that I am running pretty rich though. Even on the new plugs.
Jimmyblue, could you please explain the LTFTs for me so I can grasp the concept and understand what it does and how it works? I messed around and returned the new MAF because it didnt seem to be the problem. I take it I shouldnt have done that? I was going to return the SLP one and opt for the 01-02 MAF for a better compatability than the "proper" one.
Any one else feel free to chime on in!!

Any one at all???

ANY ONE??? :confused:

Can anyone tell me the effect that my ported MAF has on my A4 shift points and down shift points??

Ported MAF reports less than true airflow.
Airflow is one component of the engine "load"
calculation. Load is used to decide how much
transmission line pressure to apply (PWM)
and when to shift and how firmly. When you
fake out the load calc you can put out more
power than the clutches (misdirected) can
hold, upshift early and downshift late.