Throttle Area Opening Rates?

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10-07-2012
10_SS

Throttle Area Opening Rates?

Has anybody tried using the Airflow/Electronic Throttle/Area Rate Limits/Opening Rates/ settings?

It does not work on my E38 2010 LS3 Camaro.

They only list 1000-5000rpm, and they say 100% (As default) will disable them, but I see no difference with 25%.

I would like to do reduce the opening rate of the throttle slightly, just enough to allow the MAP reading to catch up with itself (wacking the throttle between shifts on a Whipple boosted LS3 manual trans causes lean situation due to MAP SAMPLE DELAY).

I've analyzed a couple other Whipple tunes and see the same problem and would like to resolve this nasty issue.
10-07-2012
Chris@HPTuners

25% is still very fast, this value is updated every 6ms

stock calibrations that use these tables have numbers like 1-5% in there.
10-07-2012
10_SS

cool thanks, I'll give it a shot. If it works do you know if the last table (5000rpm) is the cutoff for these settings, or would the 5000rpm setting also work/carry over through 6000rpm, or any higher than 5000rpm?
10-08-2012
Chris@HPTuners

anything higher than 5000rpm will use the last column
10-09-2012
10_SS

Perfect... I feel the way to help my stock LS3, Clutch, Trans, Axles survive the Whipple abuse is to have the throttle blade opening rate a bit slower.

I know I get pretty excited when shifting at that high RPM and all that boost coming and going cant be good for things based on a log where I shifted very fast and slammed the throttle open very fast at high RPM I noticed the MAF reacted instantly, but the MAP reading took a couple frames to log the boost, but by that time I had 10 degrees of KR and very lean fueling... as soon as the MAP reading hit the 90% kpa PE fueling mark it added fuel and all was well.. but that 10 degrees of knock retard and 6 cylinders of knock status bit's lit up scares me.. and makes me think I will kill the pistons if this keeps up.

Hope this setting works on my 2010 Camaro LS3, as there any reason you can think that it wouldn't?
10-09-2012
ingsteve

10degrees of knock?have you already increased power enrichment?i think 10 is pretty dangerous
10-09-2012
10_SS

Quote:

Originally Posted by ingsteve

10degrees of knock?have you already increased power enrichment?i think 10 is pretty dangerous

Yes is dangerous that's the whole point of this post. It's not related to PE enrichment AFR, it's related to the delay in the amount of time it takes for PE to become active... I dont think it has anything do with the Truck PE delay people see since it seems the MAP sensor is slow to respond is all.. but maybe it does.

When shifting into 2nd gear around 3500rpm I smacked the throttle down FAST.. then later I looked at the log and it's lean at that transition since PE (MAP) was slow to react.

Attached is the file that shows the MAP delay, causing lean, and lots of knock. Compare the Throttle opening to the MAF flow, then watch how much later and the Commanded AFR changes, the excessive lean is show'n by the low 02 numbers meaning the AFR is above 14.68... once the commanded AFR goes low, the 02's snap back up pretty quick.

You'll have to zoom all the way in at frame 23734 the scroll to the point I hit WOT, you'll see first the MAF pegs higher than any normal reading at the time the throttle opens, then you'll see the delay in commanded AFR causing a lean situation, then the MAP spikes up much higher than normal (189kpa) then at this point PE fuel kicks in as knock kicks in then 02 AFR's go high and things return to normal.

This is what's making me think it's more due to the combination of high rpm, the whipple boost, and instantly opening the throttle causing an inrush of air that the MAP/ECU simply cant react too in time, though the MAF see's it instantly.

Seems like I could use the Spark/AFR correction, I think it would be tricky to setup right though and not sure how effective it would be since knock was starting at the point the AFR went from 14.68 to 11.83... but might still help.

I may continue trying to get the Throttle area opening rates to work, and have it simply slow the rate enough to stop that initial rush of pressure/air... that might be all it takes.

I'd really like to see a ZR1 and ZL1 log during the exact same conditions, and see how it's PE reacts.

EDIT: To make it easy, I broke it down in the amount of time it takes to get into PE after WOT is reached:
1) 46.328: 100% WOT/Max MAF Reading, and 02's start to drop
2) 46.438: MAP catches up and PE fueling turns "ON", 02's drop to an all time low of 80-250mv
3) 46.547: 02's finally go rich, knock is at 10 degrees, then drops to 0 over the remainder of the run.

So there's 2/10ths of a second delay from the point of WOT until PE fueling kicks in for whatever reason. The MAF responds instantly, the MAP takes about 1/10th seconds, and PE fuel another 1/10th.

Edit again: Looks like the problem is the MAP delay, and the WHipple tune sets it at 89kpa where I would like it, but this log shows 180kPA boost with no PE! but the ZR1 and the ZL1 have MAP set at 15kpa so it's based on TPS, so I may have to go that route if I can figure out what sensor to LOG that matches with the PE/Throttle Pedal scale (both of my current throttle paramters do not log the same scale)
10-10-2012
DSteck

Your MAP sensor isn't slow to respond. Your problem is from not having the SD coefficients tuned. GM uses them for a reason: transients.
10-10-2012
10_SS

Quote:

Originally Posted by DSteck

Your MAP sensor isn't slow to respond. Your problem is from not having the SD coefficients tuned. GM uses them for a reason: transients.

I thought about that, but in the log, MAP pressure simply doesn't go above 89kpa in time, so either way there's no way for PE to kick in, in time.

If I use ZL1 and ZR1 settings (15kpa PE), and ~17%TPS then PE kicks in BEFORE I even get to WOT which is the way it should be on a boosted motor, though I really wanted to use 89ish KPA. And now, I don't want keep testing this for delay since I could blow up my motor doing so, I might just switch to TPS mode like ZR1+ZL1, figure they do this for a reason.

MY LT1 wasnt like this.. it would show changes in MAP pressure instantly, not sure if that's a difference between the Whipple and Procharger or what since I know they feed differently.

On a side note, how would I go about tuning the SD tables in the boosted regions, without actually using them (while using the MAF)? Can I use one of the VE/SD histograms since they still update and show VE error?

I reduced the Throttle Rate Of Change settings down to 3% and it's doing exactly what I want so at least now I'm safe.
10-10-2012
DSteck

Wow, I'm amazed all the Whipples I've done haven't blown up then.

You talk about the MAP sensor being slow to respond... Do you honestly think the blower is actually capable of completely repressurizing the manifold instantly?

Your LT1 had a drastically slower data rate.
10-10-2012
10_SS

Quote:

Originally Posted by DSteck

Wow, I'm amazed all the Whipples I've done haven't blown up then.

I really smacked it down for this to happen, would expect this not to happen normally as all of my other WOT transitions are normal, and dont have this problem.

Plus I do have my SD tables correct up to 100kPa (the standard Whipple tune doesnt go much above 100kpa anyway).

HPTuners = 19pts/sec, my LT1 had 11pts/sec.

Im checking other people's LS3 whipple logs, and guess what, they also have LEAN 15-18AFR with knock in this same instance, and just so happens they use 90kpa as PE also. I just to happen to smack the throttle down on that example very fast.. so made things worse.

I think the key might be in the ZR1/ZL1 15%kpa and 15%TPS PE enrichment, and/or slow the rate of throttle increase just a bit. That's the easiest thing to do.

You talk about the MAP sensor being slow to respond... Do you honestly think the blower is actually capable of completely repressurizing the manifold instantly?

Your LT1 had a drastically slower data rate.
10-10-2012
10_SS

Quote:

Originally Posted by DSteck

Wow, I'm amazed all the Whipples I've done haven't blown up then.

You talk about the MAP sensor being slow to respond... Do you honestly think the blower is actually capable of completely repressurizing the manifold instantly?

Your LT1 had a drastically slower data rate.

I really smacked it down for this to happen, would expect this not to happen normally as all of my other WOT transitions are normal, and dont have this problem.

Plus I do have my SD tables correct up to 100kPa (the standard Whipple tune doesnt go much above 100kpa anyway).

HPTuners = 19pts/sec, my LT1 had 11pts/sec.

Im checking other people's LS3 whipple logs, and guess what, they also have LEAN 15-18AFR with knock in this same instance, and just so happens they use 90kpa as PE also. I just to happen to smack the throttle down on that example very fast.. so made things worse.

I think the key might be in the ZR1/ZL1 15%kpa and 15%TPS PE enrichment, and/or slow the rate of throttle increase just a bit. That's the easiest thing to do.

EDIT: Frame 23734, shows 189kPa of boost!! AND, the PCM is still commanding 14.67AFR... So yes there's a delay with MAP entereing PE even if the MAP sensor see's major boost. 189kPa of boost... imagine how much air is entering the cylinders through open valves! One more reason to use TPS to trigger PE, and reduce the opening rate just enough to stop these pressure spikes from occuring. Automatics and turbo's are easy, at least best case scenario. Whipple's and Manual's are not as easy, or worse case scenario.

But somehow I made my 120k LT1 with stock pistons with 10psi procharged boost last 30K miles then decided to rebuild with forged, and the stock 10 bolt in the same car last 14 years, the last 6 years with over 600rwhp on a Mcleod twin disk and street slicks..... As weak as those parts are... I dunno... Maybe I can knock the LS3 to death at random and it will be fine but I would rather make it not possible to happen by fixing the problem. Thanks for understanding.