sscamaro387

iTrader: (1)

ok i talked to my guy at FFP, and he said it was cause the of the Idel curve(I believe)It's something u can't find on LS1 Edit, u have to go directy with GM Software. I will be going up there in a couple of weeks, so when he figures out what the issue is, I will post it.

AzzHauler

iTrader: (3)

Guess I'll throw in 2 pennies here. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

When I had the maf in the stock ati location, it idled fine, except for about once every 2-3 minutes the idle would drop to like 500 then recover but run rough for, say 20-30 seconds. I looked at a lot of stuff on atap while it was doing this. It seemed when idleing fine, it was constantly lowering the Strims and IAC(allowing less air I assume). It'd do this just fine then for some reason loose it and drop down. The IAC would jump back up, but still run rough. The Strims would start coming back up to. Once they came up about 15% from where it stumbled, the idle smoothed out, and it'd start the cycle over. I also noticed, when idleing fine, the a/f gauge would be in the green(~900mv), and occasionally swing like when cruising. When running rough after stumbling, the a/f gauge would barely light up one red bar(~028mv).

Relocated the maf, and now that big surge seems to be gone, but it has a small surge, like from a cam now. I haven't been able to sit and watch it like this yet, maybe this weekend. Although the a/f gauge doesn't seem to be acting the same as before.

Edit:I got to look at it tonight for a bit, and looks like it's acting the same way as before, just not surging as severely. The o2's won't swing back and forth like they do at cruise, they'll sit at ~0.895 for a bit, then drop instantly to ~0.030. It'll stay in one state for about 20 seconds or so, then go to the other one. It's got me beat.

PS. I think I killed this topic. <img border="0" alt="[jester]" title="" src="graemlins/gr_jest.gif" />

1dirtyZ

iTrader: (1)

in a nutshell i think the problem is how short the pipe is from the filter to the maf to the inlet of the blower .
the maf ends up sitting too close to the filter and also is close to the BOV. this causes turbulence , especially when the BOV discharges ( after WOT) the air will actually go through the maf backwards which causes stalling.

the remedy : it's kinda hard but you need to make the inlet to the blower longer , like putting it on the other side of the car , this way you get alot smooter air flow through the maf and enough distance away from the bov.

hope this helps.

02BlackWS6

After looking at the Vortech setup it does look like the MAF is far away enough from the surge valve and the filer/airlid. Or Vortech uses a better surve valve to stop reversion is also possible. Well I spoke to 3 different shops today, one of them being ATI, and they all recommend laeving the MAF before the TB. And ATI says to leaving in the screen, that cuts down on surging. But I would figure that if the surge valve was doing it's job properly that we could pull the screen and still only get alittle surging. I don't mind alittle surge, like the kind you get from a cam, but the stalling is asking to much. We'll see what happens I guess.

Den

1dirtyZ

iTrader: (1)

don't remove the scerrn , the screen actually smooths out the flow regardless of BOV location.

when it gets warmer here (AZ, which is pretty soon) i'll be getting a dual fan setup from spal.
this will help free up some space behind the radiator and then i might be able to extend the inlet tube.
i'll keep you posted on the progress.

if you want a fix that worked for me, i suggest raising the idle using the screw on the throttle body. it seemed to quite my problems quite a bit.
just screw it in till you reach about 1~2 on the IAC count.

02BlackWS6

Ok this is getting really confusing. I like the idea of relocating the MAF. Now does Vortech guys have this surging problem??? I haven't seen 1 Vortech guy complain about stalling. How is their surve valve hooked up? I know they run their MAF before the blower. I would like to get this resolved because when I get custom tuning the MAF location is going to be important for proper tuning.

Den

02BlackWS6

Well i have LS1-EDIT and i can set the idle to whatever stops the surging. Maybe I'll leave it at 900rpm where it is now. I'm just more curious why Vortech kits don't surge or stall. If i leave the MAF in the ATI location then i'll leave the screen in. But i'll remove it if i relocate the MAF.

1dirtyZ

iTrader: (1)

it's up to you , but i'd rather leave the screen in no matter what. it's not hurting anything ( air is forced in instead of drawn in)

as for the idle raising: if you have a surging at idle do raise the idle and see if it helps.
but if you have a surge while crusing and/or a wierd hesitation/surege as you tip into the gas: raise the idle using the screw and bring your IAC count to 1 or 2 . this seems to smooth it out.

1dirtyZ

iTrader: (1)

what table do you use in edit to adjust iac counts??

02BlackWS6

Ok i'll try that..My IAC's are at 30 now for the heads and cam. I have barely no surging at all, but EDIT lets you change IAC numbers so maybe i can change something there. But I'm going to start by leaving the MAF before the throttle and see what happens.

02BlackWS6

It's in the latest version 1.21. You can change IAC numbers to get a car to hot start for big cams. I just saw the post about adjustign that 2 weeks ago and I had Carputing email me the update. I still haven't tried it yet, but NoGo explains it better now to adjust IAC motor for better idle.