IAT VE multiplier table A0014 Q's.....

[WHYTRYZ06]

The table is cool and all BUT, every time I use it it skews w/my WOT AFR's.. Either it makes it richer or leaner, what to do?? How can we get around that???

Do I log it and drive in WOT and and hope it adjusts my WOT to my PE table depending on IAT temps???

I noticed my logs and at IAT's 50*f fuel is off by 1.06 ben and at 68*f off by 1.02 ben this is off my A0014 map in my logs.. This is all in WOT, I used a filter to eliminate all data under 90% throttle. If I dont use the filter @ 50*f its at 1.02 ben and 68*f its at 1.03 ben

So if I use the WOT #'s 1.06 and 1.02 what will happen to the VE table under normal driving, also Im running in semi-open loop.. so im NOT in full OLSD...

Can someone explain to me how the table works when your in WOT.. I use my PE table for WOT fueling...

Or maby use B3647 to control fuel and use A0008 to help w/ getting my fuel the way I want it.
thanks...

[5.7ute]

When you did the auto VE initially how strict were you with your intake temps? I find if you cannot keep IAT's within a couple of degrees A0014 will be near impossible to get into line.

[WHYTRYZ06]

When you did the auto VE initially how strict were you with your intake temps? I find if you cannot keep IAT's within a couple of degrees A0014 will be near impossible to get into line.

Well I could use B3647 to control fuel, and then use A0008 (open loop commanded fuel multiplier) to help trim the fuel cause its easier to keep ECT constant than it is IAT... right?

[5.7ute]

I suppose that would depend on your intake. Mine rarely varies more than a couple of degrees unless I am pulled up in traffic where heatsoak then comes into play.
When I was logging on road I was always doing it at a set time & condition to keep all my temps constant. This kept the transient temps to a minimum & left a lot more useful data.
Also I use a spreadsheet that adds logs together, weighting towards the log with the higher cell count. This helps with marginal cells that are hard to hit on the road. I would do a few days logging without changing the tune, filter to the baseline temp & then put these through the spreadsheet to apply to the tune. I have attached the spreadsheet for you to have a look.

[WHYTRYZ06]

Well I always get ambient on my intake temps... So its hard to keep it stable, depending on weather.. so the way I figure it, its easier to use B3647 and then use A0008 to tailor it if needed..its easier to keep ect stable rather than iat.... I dont want to multiply my VE, id rather multiply B3647. then use A0015 to multiply my VE when useing my dry nitrous...

[WHYTRYZ06]

the spreadsheet looks busy.. ill need a few days to figure it out. But I still dont get how your spread sheet works.... It takes me a little longer than most to understand stuff like this...

[5.7ute]

It,s quite simple really. You need to copy & paste the Ben average to the top table & the cell count to the one under it. The second log is then applied to the third & fourth table. The fifth table is the one you copy paste & multiply to your tune. The reason I added the final cell count table is if you need to add another log then it was just a matter of pasting the totals to the first & second table & then adding the other log. It needs some cleaning up but it works.

[WHYTRYZ06]

this might be stupid, but how does this help me??

[WHYTRYZ06]

what i need is a way to keep my b3647 @ 12.5 at WOT, regardless of IAT temps... cause at the drag strip IAT's can go up very high while in the stageing lanes.... get what im saying???

My problem is, is when im in OL (12.5 afr)fueling is off slightly sometimes.. i need a way to keep it what I command it to...

[5.7ute]

By limiting your AutoVE data to an absolute IAT, A0014 can be utilised to keep your actual to commanded AFR in line. The dual data log addition is needed, as once your data is filtered to an absolute temp, there may not be much left.
Fudging B3647 will not bring your AFR into line under differing IAT's.
So the process is
Redo AutoVE with an absolute IAT. You need to get this close in as many cells as possible. This is the reason for the dual data log spreadsheet as getting a high cell count is near impossible on the road.
Once you have the VE table in line then make a map of the A0014 table using Ben Data & paste & multiply to dial it in.
Heatsoak itself is more than likely part of your problem so you should have a look at SSpDemon,s Iat relocation thread as well.

[WHYTRYZ06]

so what your saying IAT is the end all be all of WOT AFR fueling... its nearly impossible to keep IAT steady ... especially at the track.. So I need to adjust A0014...??

[5.7ute]

Not really. What I am saying is that unless your VE table has been built under stringent conditions, along with the iat multiplier, any change of temp can cause a discrepency to your fuelling calculation. This can be exagerated at WOT because the bias in the aircharge temp is towards IAT.
Do you have a log with the iat,s from the track. It would be interesting to see how long it takes for your IAT's to return to normal during the run.

[WHYTRYZ06]

Not really. What I am saying is that unless your VE table has been built under stringent conditions, along with the iat multiplier, any change of temp can cause a discrepency to your fuelling calculation. This can be exagerated at WOT because the bias in the aircharge temp is towards IAT.
Do you have a log with the iat,s from the track. It would be interesting to see how long it takes for your IAT's to return to normal during the run.

I see, so I have to use the IAT multiplier table.. I just went out and did a couple of runs. Its about 38*f outside. Im running in semi-OL, and at 32*f iat cell is at 1.01 ben... here is the break down of my A0014 map

IAT*F--------VALUE

32*-----------1.01
50*-----------1.02
68*-----------0.95
86*-----------0.98

In the tune it looks like:

IAT*F----------VALUE

32*------------1.029
50*------------1.032
68*------------1.013
86*------------1.074

Why does the # go up in the tune portion, Higher IAT = leans out so it puts a higher # to add more fuel???

So its pretty close, w/ the multiplier table....

Guess I need to use it afterall..

no track logs yet.. ill let u know when I get some...

[5.7ute]

.
Why does the # go up in the tune portion, Higher IAT = leans out so it puts a higher # to add more fuel???



If you had for example a 30 deg IAT sensor reading & the actual air temp was 30 deg then the pcm would compute an airmass of X g/cyl. With the VE table, IFR etc calibrated correctly you should see a ben of 1.00.
If however you had a 30 deg IAT sensor reading, but an actual airtemp of say 25 deg, the pcm will still calculate an airmass of X g/cyl when you actually have a larger airmass in the cylinder. This will then translate as lean & give you a Ben of say 1.03.
This drift from actual to sensed is what could be giving you grief in the staging lane.
This drift can be compensated for with A00014 quite easily as long as the higher than baseline temps are not met. This will result in a rich condition though & will not be harmful.
Have a look at this thread http://forum.efilive.com/showthread.php?t=2270&highlight=a0014 It may give you a few more ideas. It is getting late & I am not being very clear(as usual). I will try & have another go in the morning.

[WHYTRYZ06]

If you had for example a 30 deg IAT sensor reading & the actual air temp was 30 deg then the pcm would compute an airmass of X g/cyl. With the VE table, IFR etc calibrated correctly you should see a ben of 1.00.
If however you had a 30 deg IAT sensor reading, but an actual airtemp of say 25 deg, the pcm will still calculate an airmass of X g/cyl when you actually have a larger airmass in the cylinder. This will then translate as lean & give you a Ben of say 1.03.
This drift from actual to sensed is what could be giving you grief in the staging lane.
This drift can be compensated for with A00014 quite easily as long as the higher than baseline temps are not met. This will result in a rich condition though & will not be harmful.
Have a look at this thread http://forum.efilive.com/showthread.php?t=2270&highlight=a0014 It may give you a few more ideas. It is getting late & I am not being very clear(as usual). I will try & have another go in the morning.


thx ute will do... got the bens in the iat multiplier to 1.02-1.04 from 50*-68* iat*f, in the scan tool... best i can get it.. already seen that thread...