jeffstar

iTrader: (6)

Just wanted to give some information that may help the next guy out. I searched for resolutions to this issue on the forum for a few weeks and couldn't find anything that was helpful. So hopefully if someone finds the same issue they will discover this post and some ideas will apply to their problem.

I've been trying to get my SD tune perfect or near perfect as I could get it. WOT and idle came along fine (with my AEM wideband and logging). Cold start and warm up came along fine as well, changing the parameters noted in the help files (and applying logic and using this forum) so that was great.

Some may notice I had some decel issues and by adjusting DEFCO for my engines new MAP/DECEL values (because of the large cam) I got that resolved.

However, after all of that I had a strange issue that I couldn't seem to fix. The car would pop/miss through the exhaust around 2800 RPM to 3300 RPM when moving between 50 gms to 90 gms on the timing map.

What I found was my motor wanted the base timing in those areas to be down around 18/19 degrees. Once the RPMs get above 3600 RPM the timing can phase right back up to say 26-28 degrees. Also, if the load is near WOT areas in the timing map I can phase the timing back in to 26 degrees in those same RPMs and obviously lighter load the car doesn't mind higher timing in those same areas (but not too much). Interestingly enough this at some points in my map are less then the factory timing maps and in some areas more. Another item I found was 2400 to 2800 the entire SD/VE map had a dip causing a lean area/shift when sweeping through that area of the MAP. Adding fuel in that valley and smoothing the opposing peaks out a tad also helped tremendously.

My cam is a custom cam from ECS that was ground on a +6 ( i wish I really understood what they meant by that ) The heads are from TEA and they are TFS heads milled to create a CR of about 11:1.

WOT feels ridiculous, many cars have made at or right around 500 rear wheel with my setup (on the stock short block) and the car feels that fast right now. My Single turbo supra had more power and did feel slightly faster but not by much.

Now that I have the timing down the car drives like a dream. I'd like to lean the map out in some areas to promote MPG but for the most part this is a fantastic tune and I did it all myself with help from the forum. Of course it's still a work in progress but I'm really happy as of now.

If the weather is kind Saturday I should have some dyno numbers.

LostCauseZ06

iTrader: (4)

good to hear!! im actually having a similar problem currently, i was thinking i had burnt a valve though and thats why it was poppin/missin. ill have to check out what your sayin

jeffstar

iTrader: (6)

Where and how is it popping? (under what grams/sec/cyl) and what rpms?

LostCauseZ06

iTrader: (4)

i cant remember now lol , it was just odd because it was always popping while we were logging and i was like "dude .. pull some timing or fix the fuel its detonating" to my buddy next to me lol. hed look down and say, " it not knock i duno WTF is it lol"

ill go log some later and see if it still does it.

jeffstar

iTrader: (6)

Yeah I never had knock. Just the popping and stumbling sound (with some actually jerkiness as the engine lost power)

Bink

It means the Intake Centerline (ICL) of your cam is +advanced 6* from straight up. Straight up would be the same number of degrees as the Lobe Separation Angle (LSA) of your cam (LSA is "cam degrees" and ICL is "Crank degees" - remember crank turns two revs for each rev of cam).

hope this helps some

jeffstar

iTrader: (6)

Sorta...but only sorta because I'm a dumbass

Let me ask this, would +6 be somewhat the factor / issue I was having at those light throttle ranges? Meaning did the cam put me in the position to have the issue and me pulling timing electronically clear it up?