Strange VE Table?

[tinindian]

The attached VE table is what I get after running AutoVE or CalcVE (basically the same). The strange thing is the really high numbers between 15-20 MAP and 2400 & 4800 rpm. I've never seen another VE table quite like this and I have to assume there is something not right, maybe a vacuum leak or ? I have a custom PCV system but I'm using the stock PCV valve so I don't think that's the problem. Can anyone take a guess? TIA.

[macca33]

I know from when I've done autoVE logging, those two MAP rows are sometimes difficult to hit with sufficient number and often, only when on deceleration. I haven't seen enough VE tables to say whether yours is normal, or not, but it is a fair bit higher than mine is in those particular cells, so there may be an issue.

What sort of set-up are you running?

Hopefully someone who knows what they are doing can assist you.

cheers

[tinindian]

I had quite a few hits in those cells and as I mentioned they looked the same in AutoVE & CalcVE. You are correct in that those areas are active under decel from a hard accel. That's why I was thinking vacuum leak or PCV since the throttle is closed and the motor trys to pull a lot of vacuum. I have a EPS 226/230 cam, ported 241s, LT headers w/o cats, stock LS6 intake, P & P throttle body, and M6. I still have a bucking problem I can't get rid of too, maybe these issues are related.

[WeathermanShawn]

If your MAF-Enabled (have to be in CALC.VE) and if your LTFTBENS or SELBENS are near 1.00, then that data is 'valid'. Some of the problem is that low MAP area is that you hit it normally when you take your foot off the throttle after WOT. So your getting cells included as PE transitions to closed-loop.

About all you can do if filter. I sometimes run a filter that excludes all data that is changing more than 0.0 TPS % per 100ms. You could always filter out based on excluding any deceleration and only include those with steady throttle (very hard to do).

The other point to ponder is does it really matter? Its hard to get your injector flow that low anyway. I have experimented with all sorts of values in those low MAP areas and it has made no difference in fueling.

For comparison I attached my current VE table, constructed entirely by the new CALC.VET method of Tuning. I do hand-smooth around the edges and interpolate cells that I never hit.

The bottom line is that I doubt it really matters in that area (IMO).

Good luck and good question..:).

[tinindian]

Shawn - Thanks for your review. I agree - it doesn't really matter. The engine is fully unloaded and there's no chance of damage. I'll try some more filtering to see if that makes a difference. What I'm really wondering is if this points to a vacuum leak. On the other hand a simple leak would just let in additional air across the MAP range (more at high vacuum).

[joecar]

tinindian,

can you post a screenshot of your BEN map that produced that...?

[tinindian]

tinindian,

can you post a screenshot of your BEN map that produced that...?

I'll have to do that later this evening.

[5.7ute]

Do you have DFCO active?
Personally I filter out anything with TP under 1% & hand fill these areas.

[tinindian]

tinindian,

can you post a screenshot of your BEN map that produced that...?

This map was taken from an AutoVE log run where the VE table was manually tweaked down in the 15 column. You can see a couple cells where the BENs want to pull it back up again. I don't recall for sure but I think there were more than 20 hits in those cells.

[tinindian]

Do you have DFCO active?
Personally I filter out anything with TP under 1% & hand fill these areas.

DFCO is not active when AutoVE logging but I turn it back on after. I've just been manually tweaking those areas.

[mr.prick]

Try filtering out MAP changes of +/- 5% to +/- 10%

calc_pid for "delta MAP"

#Units Low High Fmt Expression
#------------ ---------- ----------- -------- ----------------------------------------

*CLC-00-003
psi -16 16 .0 "({SAE.MAP.psi})-value({SAE.MAP.psi},frame()-1)"
kPa -105 105 .0 "({SAE.MAP.kPa})-value({SAE.MAP.kPa},frame()-1)"
#Code PRN SLOT Units System Description
#-------------- ----------- ------------------- --------------- ------------ ------------
CALC.DELTA_MAP F003 CLC-00-003 "kPa,psi" Air "Delta MAP"

[tinindian]

Thanks everyone for the ideas.

Cheers :cheers: