Open Loop VE IAT Multiplier Values

[oztracktuning]

What values is everyone finding suits the B0014 Table.
I think i may have been thinking i would have to correct the wrong direction? So i have set mine back to 1.00 at the moment.

Can some people share their numbers for this table.

[Tordne]

I have had a brief play with this a while ago.. All mine are currently set to 1 at the moment as well.

The numbers will likely be different for everyone. For example, if your VE is dialled in at say 30*C IAT and someone else's is dialled in at 20*C IAT then the point at which your B0014 table will be 1.00 is different to start with.

Basically my approach to this was to get my VE dialled in at a particular IAT temp range (i.e >= 25 & < 35 would be working in only the 30*C IAT cell). Once that is done I made a map that mirrored the B0014 table and then used a filter to select Fuel Trim 22 cells (cause they should be more stable than decel etc.) and used the averaged BEN factor as the data. My thought was that I could copy this data straight into the table because hopefully the 30*C IAT cell would be 1.00 and say 20*C IAT might be 0.98 ad 40*C IAT might be 1.01, all for examples.

Hope that helps?

Cheers,

[GMPX]

I have mine set to 1.00 as well, it seems to be an issue when you hit 50+degC IAT's, i.e, like a blown car.

Cheers,
Ross

[Tordne]

I have mine set to 1.00 as well, it seems to be an issue when you hit 50+degC IAT's, i.e, like a blown car.

Cheers,
Ross

HA! I can get 50*C IAT sitting at a light for a while, and this is in Auckland let alone somewhere real hot (like Australia). I previously had a metal intake tube as well and actually recorded IAT temps in excess of 70*C IAT :Eyecrazy:.

I think my next mod is going to be an OTRCAI, the cam is just going to have to wait :bawl:

[BowlingSS]

I have my table set to stock also. I read one member changed his by 1% every 10 d.

Bill
:cheers:

[oztracktuning]

Someone quoted that for every 11*F changes air density 1% then every 10 deg C has a change of 1.6% density. So maybe the number that we need is going to be about 1.6% difference every 10 degrees.

I have mine set at 2% every 10 deg C at the moment and its getting close - but i think i now need to tweak the ECT multiplier table as well.

[GMPX]

HA! I can get 50*C IAT sitting at a light for a while, and this is in Auckland let alone somewhere real hot (like Australia). I previously had a metal intake tube as well and actually recorded IAT temps in excess of 70*C IAT :Eyecrazy:.

I think my next mod is going to be an OTRCAI, the cam is just going to have to wait :bawl:

Ah, you still have the factory heat box.....err I mean air box?.
OTRCAI is good, but it doesn't 'sound' as nice as a cammed motor!.

Cheers,
Ross

[Tordne]

Ah, you still have the factory heat box.....err I mean air box?.
OTRCAI is good, but it doesn't 'sound' as nice as a cammed motor!.

Cheers,
Ross

I actually have a Kosteci airbox with a K&N pod filter, and now a carbon fibre/fibreglass intake tube. Actual air deliver is really good and possibly won't by hugely improved upon, but the IAT temps are killing me. I am recording into the 50*C IAT range and it just takes ages for the IAT's to recover, and they usually only recover to as low as perhaps 35*C. Ambient temp in Auckland is approx. 25*C, so there is a huge difference.

Prior to the carbon intake tube I was logging temps into the 70*C range :bawl:.

Hopefully I'll be getting a OTRCAI soon (next few weeks), just trying to decide which one.

[McRat]

Just rambling about IAT's in general.

Often the true IAT has nothing to do with what the sensor tells the engine. Sitting on the line in the summer, a Z06 will report over 150degF to the engine when the air going into the engine is only 80 deg.

If cannot relocate your IAT sensor outside the engine bay, you should at least zero out any effects that are in the "stupid range". Anything over 90 degF should probably be ignored. For racing, I zero out all effects of IAT.

The difference it made in 1/4mi ET was .48 seconds.

[oztracktuning]

Doesnt IAT and ECT effect the VE tables effects anyway? Maybe im wrong but i thought that was we needed the correction tables??

You are right the IAT heat soaked can say the airs much hotter than it really is. This is an issue.

[Draco]

I have similar problems with IAT in SD open loop using a v3 OS. When the car has been idling or sitting in traffic for a while and warms up to 50*C+ IAT the result is a lean condition (17:1 or higher, way above commanded). I definitely believe the air under the hood is getting as hot as 70* and that the SD tune is not compensating. I have tried maxing out the IAT VE multplier at higher temps to 1.300 with zero success - it does not appear to help the mixture richen up at all.

Help?

[ringram]

I have had good results using 1% per 10*C close to the number mentioned by others in this thread. (eg) 0.99, 1.00, 1.01

Im currently trying to find someone in Oz who wants to send me a OTRCAI in NZ. Delco is out of stock apparently. Im waiting on Orssom to get back to me at the mo. IAT temps must die!

[Draco]

Hmm, I've tried a full 30% added in the 50-70*C area and it didn't appear to have any effect on my warm idle lean condition. Perhaps I'll try again to see if I was on crack - maybe my VE value at idle was just too far off base. I guess I'll try to write my own PID to calculate what the airflow would be with this 30% added in, and compare to the grams/s that the PCM is measuring.

[Delco]

The IAT correction was added in like the Boost spark retard for the occasion when you need it.

Do all your base tuning with it set at 1.0000 , same as the factory would have had it , if after doing all your tuning you see a AFR shift at different IAT values then dial in your IAT correction table as required.

We found with blown combo's that this was required , not as essential with a N/A motor but it is another adjustment that can be used if and when requried.

[Extinct]

Just rambling about IAT's in general.

Often the true IAT has nothing to do with what the sensor tells the engine. Sitting on the line in the summer, a Z06 will report over 150degF to the engine when the air going into the engine is only 80 deg.

If cannot relocate your IAT sensor outside the engine bay, you should at least zero out any effects that are in the "stupid range". Anything over 90 degF should probably be ignored. For racing, I zero out all effects of IAT.

The difference it made in 1/4mi ET was .48 seconds.

.48 seconds is a helluva lot ! I would have to spend a lot of money to drop my et that much, or would be major league pissed if it went up that much !

Maybe you mean .048 ?

[GMPX]

Hmm, I've tried a full 30% added in the 50-70*C area and it didn't appear to have any effect on my warm idle lean condition. Perhaps I'll try again to see if I was on crack - maybe my VE value at idle was just too far off base. I guess I'll try to write my own PID to calculate what the airflow would be with this 30% added in, and compare to the grams/s that the PCM is measuring.

How did the updated file go?

[McRat]

.48 seconds is a helluva lot ! I would have to spend a lot of money to drop my et that much, or would be major league pissed if it went up that much !

Maybe you mean .048 ?

No, in the case of the stock Z06, reported launch IAT was ~156°F, which pulled about 9 deg timing. It ran 12.46 @ 1 (12.46@1)10, then I wiped out the IAT retard table and it ran 11.98 @ 114 with no other changes. I could have iced down the MAF and got the same effect, but I'm not into dripping water down the track. This is one explanation why some magazines say the Z06 runs high 12's.

The LS6 MAF has the IAT sensor imbedded it in, and it's an aluminum body. The radiator heats it up to near water temp due to it's location. But the actual air going into the motor comes from in front the radiator in the empty nose, and is only a bit warmer than outside air.

It wasn't a "gain" in horsepower, rather it was a recovery of lost HP. Any Z06 you see running 11's stock has addressed the issue one way or another.