Desired Airflow {B4307}

[minytrker]

Is this right? I logged this and then added this to 4307 and logged it again and came up with the same number so I dont think something is right.
http://www.ls1powertuning.com/tuning/RAFIG2.JPG

http://www.ls1powertuning.com/tuning/RAFIG.JPG

[Tordne]

How long did you leave the car running? Could it be added airflow from startup tables?

You could also check something like the GM.DYNAIR PID to see what value it actually has.

[minytrker]

The first pic it was at idle for about 10 min and in the 2nd pic that was idle and driving for awhile. I just noticed that I kept getting .26 in the same block so i firgured I have something set wrong.

[SSpdDmon]

"0.26" is well within the operating ranges of the PCM. What's all done to the car? If the IAC counts are close to 50~70 when warm, I'd leave it alone. You're in a good spot.

**If it's an M6, make sure you were logging without the clutch pressed down and the gear selector in neutral. If I recall correctly, the PCM assumes the car is in gear except for when the clutch is depressed. Also, make sure the tables in the tuner are displaying enough decimal places.**

[minytrker]

02 Electon Blue Z06 430hp/390tq (before CNC heads)
237/242 .603/.609|CNC ported heads|Halltech CAI|SVO 42 injectors|NX TB150 wet shot|Powerbond UD Pulley|LG Pro headers|Borla Stingers|DTE Transmission Brace|Harden Output Shaft|Ram HD Clutch| B&M Ripper Shifter|Slotted & drilled rotors|Tuned by LS1 Power Tuning

[minytrker]

After the heads being done I have a horrible cam surge now. Thats why I am lookin ginto everything.

[SSpdDmon]

Your cam surge is most likely due to timing and fueling. If that's an accurate log of your idle trims, then you're ok there. Where are you seeing the surge? What is the timing doing in your logs during the surge?

[minytrker]

It surges with or without the a/c on. Its worse when it hot outside vs when its cooler. The timing it staying the same. I have been playing with latly have went from about 22-29 at idle.

[TAQuickness]

minytrucker - Lemme tell you what I learned about surging. Fuel.

I had a Gillies style low load low rpm bucking and surging problem. Could never find the culprit until I started running dual widebands. She only bucks when the AFR's between the two banks varried more than 3%.

I got the car into a nasty bucking state, set cruis control, then used BIDI to add fuel until it stopped. Like wise, I tinkered with timing with little noticable results.

[TAQuickness]

I see this may just be an idle surge, check around the manifold with some carb cleaner or starter fluid.

[minytrker]

I havent had time to mess with it yet but I have noticed it surges alot less when its cool outside vs hot.

[Darkness]

I havent had time to mess with it yet but I have noticed it surges alot less when its cool outside vs hot.
Must be CL vs OL then.

[minytrker]

Must be CL vs OL then.


No its in CL when it does it. It surges when the temps are around 100 outside, at night when its maybe in the 80s it surges less.

[VYSSLS1]

the most common cause of surging is fuel, timing would have to be fluctuating near 20 degrees to cause a major surge.

if its in closed loope, when u have the problem, look at short & long term fuel trims.

or send log file, and ill have a look.

[SSpdDmon]

the most common cause of surging is fuel, timing would have to be fluctuating near 20 degrees to cause a major surge.

if its in closed loope, when u have the problem, look at short & long term fuel trims.

or send log file, and ill have a look.
Not true. When tuning an A4 LS1 w/ 232/234 595/598 112 cam, the timing was the surge culprit and it wasn't jumping more than +/- 5 degrees while the torque converter was locked. At 1600 rpms in 4th gear, it felt like your neck was going to snap in half. I set the timing to a single number from ~2000 rpm to ~1200rpm and 90% of the surging went away. Fueling was in closed loop maintaining a stoich AFR with the NBO2 sensors.

[VYSSLS1]

Not true. When tuning an A4 LS1 w/ 232/234 595/598 112 cam, the timing was the surge culprit and it wasn't jumping more than +/- 5 degrees while the torque converter was locked. At 1600 rpms in 4th gear, it felt like your neck was going to snap in half. I set the timing to a single number from ~2000 rpm to ~1200rpm and 90% of the surging went away. Fueling was in closed loop maintaining a stoich AFR with the NBO2 sensors.

Im sorry read your post above where even u state its either fuel or timing, obviously your car isnt running enough timing at that rpm/load for this cam, to cause a major surge at cruise with only 5 degrees timing variation. and u can still have a air/fuel ratio of stoich, but what about your fuel trims, if your ve table is out and trying to go to closed loope this can result in a sure as well.

Im sorry you are the expert, running a 12.5 with a huge cam, etc.:Eyecrazy:

and i dont own a Blown forged ls1 with a cam as well running 16psi. and running on 12 on the street to stop the power sliding when accelerating over 100km/h.

But anyway back on with the thread.........

[VYSSLS1]

No its in CL when it does it. It surges when the temps are around 100 outside, at night when its maybe in the 80s it surges less.


any new logs on this.

[SSpdDmon]

Im sorry read your post above where even u state its either fuel or timing, obviously your car isnt running enough timing at that rpm/load for this cam, to cause a major surge at cruise with only 5 degrees timing variation. and u can still have a air/fuel ratio of stoich, but what about your fuel trims, if your ve table is out and trying to go to closed loope this can result in a sure as well.

Im sorry you are the expert, running a 12.5 with a huge cam, etc.:Eyecrazy:

and i dont own a Blown forged ls1 with a cam as well running 16psi. and running on 12 on the street to stop the power sliding when accelerating over 100km/h.

But anyway back on with the thread.........
I was merely commenting on the bolded part of your response. I never claimed to be some kind of expert....only to have experience that contradicts your exaggerated statement. In my experience, timing is what cured both of my friends' surging issue (yes they both are running that cam). Fueling was already in line since the cars were in closed loop with minimally negative fuel trims. My car may not be forged and blown like your almighty wonder. But it did manage to rip off a 12.5 on stock internals with a little room for improvement thank you very much. Try not to assume too much. It makes you look like even more of an ass with your 9 posts.

FYI - those cammed cars were running 38*~40* timing (stock) at the conditions I mentioned in closed loop with -1~-3 LTFT's. What I was trying to explain was the surging was coming from the timing jumping in and out of different cells. More timing (43*) helped along with the fact that changing the surrounding cells to be the same number (43*) is what eliminated 90% of their surging. Their timing wasn't jumping between 20* and 40* like your statement claims is a requirement for timing to be the culprit for such massive surging.

[joecar]

I'm watching... so everyone keep it civil...

[SSpdDmon]

I'm watching... so everyone keep it civil...
Sorry Joe...his response was just a bit uncalled for. BTW, can I change my title from Lifetime Member to Self-proclaimed Resident Expert of Cammed LS1's? ;)

[VYSSLS1]

I was merely commenting on the bolded part of your response. I never claimed to be some kind of expert....only to have experience that contradicts your exaggerated statement. In my experience, timing is what cured both of my friends' surging issue (yes they both are running that cam). Fueling was already in line since the cars were in closed loop with minimally negative fuel trims. My car may not be forged and blown like your almighty wonder. But it did manage to rip off a 12.5 on stock internals with a little room for improvement thank you very much. Try not to assume too much. It makes you look like even more of an ass with your 9 posts.

FYI - those cammed cars were running 38*~40* timing (stock) at the conditions I mentioned in closed loop with -1~-3 LTFT's. What I was trying to explain was the surging was coming from the timing jumping in and out of different cells. More timing (43*) helped along with the fact that changing the surrounding cells to be the same number (43*) is what eliminated their surging. Their timing wasn't jumping between 20* and 40* like your statement claims is a requirement for timing to be the culprit for such massive surging.


9 posts means nothing:nixweiss:

so anyway, back to it, the combination that car was running didnt have enough timing, as i said in above post without even knowing a log, and with the size of the camshaft fitted and the rpm range of the cam arnt even close, hence why it was affected so severe.

its just like trying to drive a manual in 6th gear at 20km/h, it can be done if all conditions are perfect.......

i never assume anything, this forum is for questions and answers not comments on Not true, When tuning a ls1 a4 with such and such a cam....

anyway on with the THREAD, on what the problem is with this car.

[SSpdDmon]

i never assume anything, this forum is for questions and answers not comments on Not true, When tuning a ls1 a4 with such and such a cam....

You must be a selective reader. So, I'll make it as clear as possible for you regarding what I was talking about.


the most common cause of surging is fuel, timing would have to be fluctuating near 20 degrees to cause a major surge.

This statement here - you see where it says 20 degrees? That's an assumption.


Im sorry you are the expert, running a 12.5 with a huge cam, etc.:Eyecrazy:

And this one - who ever said it was my cam? I don't see a cam listed in my sig...

That's what I mean by assuming.


The car at hand (in this thread - the one with the problem) had a very similar setup with the size & duration of cam/heads he's running. That's why I mentioned the fact that it was a 232/234 car earlier - to say, "Hey, I've been close to where you are and this is what I did in that situation."

I know more timing helped my friends. I know the stock timing table was too low. I fixed it well before you came along. The only reason I said "not true" is because you made a gerneralized statement about timing swings that someone else without as much experience might read and misinterpret. Don't take it personally and attack my lowly 12.5 second car. :mad:

I'M OUT.

[TAQuickness]

so anyway, back to it, the combination that car was running didnt have enough timing, as i said in above post without even knowing a log, and with the size of the camshaft fitted and the rpm range of the cam arnt even close, hence why it was affected so severe.

its just like trying to drive a manual in 6th gear at 20km/h, it can be done if all conditions are perfect.......

Care to elaborate?

Not that I make a habit to drive 20 in 6th, but it is the only way I can hit some areas of my VE table. I'd like to get this fixed up in case i decide to lug the bird around.

[eboggs_jkvl]

Are you talking about B5933 and setting the spark from 800-2000 to a more constant number, say in the 20 or 25 range? I have a stock LS6 cam and I'm still chasing the mini surge monster.

[minytrker]

Wow I missed alot. Well here is an update. I changed to 36lbs injectors, went and retuned the car on the street and its running like a champ getting......get ready for this.....30-33mpg at 70mph with the cruise set and a/c on. This is going down hill, this is on level interstate. I have the dyno booked for this afternoon after the shop closes to get some new numbers. The car is running 1,000 x better but by the butt dyno it doesnt feel as fast.