A/F ratio adjustment for WOT

[01Z]

I'm looking for information and advice on how to tune my LS1.

At the dynojet my car produced decent hp and tq but my a/fr was 14 pounds of air. I need to drop it about 10% or a little less. It is likely creating knock that pulls the timing and fuel from the low octane tables. I'm losing the potential advantage of 10-20 hp and torque.

What is causing the lean condition - is it my maf? How would I determine the command process? I would rather fix the parts than tune around the problem.

thanks

[Chris 96 WS6]

13.1:1 AFR is ideal for HP on a naturally aspirated car. I like to recommend 12.8:1 on the dyno because on the street/track with higher loads it will lean out some.

Its hard to say what could be making your lean. Usually the OEM tune is pig rich, not lean. Is the MAF modified in any way? Has it been cleaned recently?

[01Z]

Thanks & thanks for a suggestion! When I bought the car I jumped on the SLP loudmouth purchase before the price hike. I immediately did the free ram air thing and bought a used K&N filter. I cleaned the filter and oiled it up. I'm thinking I may have dowsed it in my enthusiasm. Can you give me some advice on how to safely clean the MAF?

thanks

[CamTom12]

13.1 is a good post-cat reading. Equivalent to 12.6.

probably what's causing your problem is your headers + hypertech. Now you can move more air and I've seen hypertech's lean-out looking for more power. The solution I'd suggest is to reset to stock tune and sell the hypertech. Then buy a tuning suit and DIY or take it to a tuner :)

also, maf isn't used at WOT, but you'll be able to tell if it's crapped out with oil

[01Z]

13.1 is a good post-cat reading. Equivalent to 12.6.

probably what's causing your problem is your headers + hypertech. Now you can move more air and I've seen hypertech's lean-out looking for more power. The solution I'd suggest is to reset to stock tune and sell the hypertech. Then buy a tuning suit and DIY or take it to a tuner :)

also, maf isn't used at WOT, but you'll be able to tell if it's crapped out with oil
More good advice here. BTW, no headers and the hypertech wasn't in the equation on the last pull so it actually had no effect unless there were remnants of its effect left over. I'm back to square one if the MAF isn't involved at WOT. Like said, I would prefer to fix whatever is making the car lean than to tune around it. I have a tuner on hold but have been told it's not a good idea. I'm still not in the mood to lay out the $500 for dyno tune or buy the self tune software plus the huge learning curve involved. Maybe that will have to change but I'm still hoping to find mechanical solution.

thanks mucho!

[Moparnos (The SLP Guy)]

if you want to tune you have to get tuning software like ls1edit or hptuners. there no way to tell you whats wrong with it. get the tuner, log some runs and from that you can see what is happening.

[CamTom12]

sorry, read the wrong part of your sig. (working on my buddy's phone in the back of a flight simulator haha) no headers should run pretty rich... unless you fully reset the hypertech to stock it's tune will still be there. Hypertech's also add too much timing which could be exacerbating your problem.

The one car I helped tune that came in with a hypertech made more power in stock trim, haha!

[01Z]

I'm really back to the beginning again then. Once more, the hypertech wasn't in the equation. It was removed entirely on the last pull. I'm in a place where I can adjust the a/f with a tune or buy a "maf-a-matic" from granatelli.

The dyno guy tells me a send-away-pcm tune will be worthless as will the granatelli unit. Obviously he wants to tune my car on his dyno but doesn't yet have the software to do it. I understand that the dyno tune is the best route but it is so expensive as is hp tuner or efilive not to mention the learning curve. I think a cheapskate like myself may be in the wrong hobby. I sure appreciate the feedback though.

thanks

[Chris 96 WS6]

I was assuming we were talking about the LS1 car, because the sig says his Hypertech is on the LT1.

Either way I would ditch that hypertech as they are complete garbage. I actually lost 2hp with a hypertech on my stock car. They are good for fan temps and gear changes but do not expect one-size-fits-all programming to actually gain any hp. Hypertech does lean things out too.

The best way to clean the maf is to go to Autozone and get a can of Electronic Parts Cleaner. You just spray down the little electrodes and wires with it and let it dry. You don't want to touch it with anything as you can break the tiny wires. Do not use carb or brake cleaner as they are too harsh and can leave a residue.

[Chris 96 WS6]

I'm back to square one if the MAF isn't involved at WOT.
Whoah.....Cam is 100% wrong about that. The MAF is definitely involved at WOT. The 02's are not, which means there is not feedback loop to adjust fueling, but w/o the MAF the PCM would have no clue how much fuel to add.

Well, I'll just say the car will run part or WOT w/o the maf but only in speed density mode, meaning the PCM is guessing at the airflow based on MAP readings....a proper running car does use the MAF at WOT, which is why you can scan for your grams/sec MAF airflow at WOT...

MAF is definitely in play at WOT.

[CamTom12]

shit, you're right.

I'll bet the MAF is just dirty... sorry guys, friggin brain fart of all century. I had just been fixing my damn tune that morning too...

Too many approach charts have my head spinning...

Another option would be to unplug the maf and it'll drop into speed density mode. This will also throw you into the low-octane timing tables, but you'll be rich again until you clean out your maf. (you'll also get an SES light that will extinguish when you plug the maf back in again)

[01Z]

MAF is definitely in play at WOT.
Good enough, thanks.

Another question if nobody minds: How about my injectors - the car idles just a little rough but smooths out the moment the throttle changes. With 65k on the clock, I'm not too opposed to replacing them. I'm guessing that I want to stay with the 28.8 lb. Does anyone have a part number so I can cross reference and do you have any suggestions on brands?

thanks

[Chris 96 WS6]

I doubt they are a problem as that's not honestly very many miles. When's the last time you changed your fuel filter? What about spark plugs?

[01Z]

I was assuming we were talking about the LS1 car, because the sig says his Hypertech is on the LT1.

Either way I would ditch that hypertech as they are complete garbage. I actually lost 2hp with a hypertech on my stock car. They are good for fan temps and gear changes but do not expect one-size-fits-all programming to actually gain any hp. Hypertech does lean things out too.

Chris, yes I did have a hypertech tune on the LS1 and removed it for the last dyno pull. I still have it on the LT1. I'm going to create another thread to discuss this so as to not mix this thread up into it.

I'm really appreciative of everyone's help here!

Glen

[01Z]

hehe, this is coming at me fast....
Fuel filter is brand new. Plugs are probably original and I have 8 new NGK TR55s sitting on the table. I was going to put them in my LT1 (rusty looking origs @ 100k) but maybe I should do the LS1 first.

thanks

[Chris 96 WS6]

Change those plugs out and I bet the idle smooths out..

That might change the dyno numbers too.

[01Z]

What gap do you suggest - .055?

thanks