WOT bog from a stop. Lean Spike. Ideas?

[tunedportcj5]

From a dead stop @ idle (in or out of gear) and you hit WOT - I get a bog/hesitation and then it clears up over 2600 rpm or so. I am commanding 1.00eq throughout the entire table (for VE tuning). VE table is happy, car runs excellent at all other RPM ranges - except off idle WOT.

When I hit WOT - it stumbles and the wbo2 maxes out at 20afr (lean spike.. right?) After hitting at least 20 or so counts on the AUTOVE. The 95-105MAP @ 1200-2400 RPM say I need to add 20% to the VE on those cells.

I've added over 40% and nothing seems to change. :nixweiss:

A little about the car:

'98 Z27 A4 3600VIG 3.73s
Cam only LS2 240/244 .598 .610
Fast 90/NW 90
SVO 42s
Racetronix fuel system
...and all of the other usual boltons

It seems pretty obvious this lean spike is causing my bog. I am not getting any KR but my timing appears to be dropping down to single digits and I cannot figure out why.

Would someone mind looking at my logs and tune? (please ignore the skewed VE table)

Thanks,
David

[jfpilla]

With your drivetrain you should be easily breaking the tires loose. Is it possible TCS is active and pulling timing?

[tunedportcj5]

no TCS.... oh, it will break the tires loose. Just after the Boggg..

[joecar]

I don't know why you get lean during WOT... but...

don't run your engine with OLFA/PE commanded EQ 1.0 everywhere...
this is too lean and will surely destroy your engine...
I am surprised you're not getting knock detected...

I'm no boost expert, but that's way too lean for boost.

[tunedportcj5]

I don't know why you get lean during WOT... but...

don't run your engine with OLFA/PE commanded EQ 1.0 everywhere...
this is too lean and will surely destroy your engine...
I am surprised you're not getting knock detected...

I'm no boost expert, but that's way too lean for boost.


I'm N/A.. no boost. I have since modified the upper MAP values for more fuel. Somewhere around 1.17eq.

[Biggsy]

Well, your single figure digit timing figure is actually what is being called for off your timing table, nothing is pulling it back.
2443

[tunedportcj5]

Thanks Dave. I'll take a look and bump up the values in those cells!

Thanks,
David

[Biggsy]

I hope I read your previous post right, you have now richened up WOT from EQ 1 now?

28 Deg timing and EQ1 on my car will make lots of little bits of my pistons!

22 Deg (+/- 2 Deg) and AFR 12.5 @ WOT (LS1 not modified) keeps mine nice and safe. Leaner makes slightly more power but I don't like having my cars "on the edge", better (in my opinion) to comprimise a little power to keep motor safe.

[tunedportcj5]

You are right... I don't run EQ1 at WOT at the upper RPM range. It was only set at 1.00 for AUTOVE tuning. Remember - I am only trying to fix the off idle WOT stumble/bog.

Thanks!

[jfpilla]

no TCS.... oh, it will break the tires loose. Just after the Boggg..

I'm surprised that your programmed timing at low rpms has any affect. With a 3600 stall and 3.73's you should flash right passed that timing.
I hope you let us know if raising timing down low helps.
Did you mean your car has no TC or that you disabled it?

[joecar]

You can still do Auto VE tuning with EQ set to the target value.

[tunedportcj5]

The car does not have TCS. Even if it is in P/N... there is a hesitation. Its just more defined under a load (in gear)