Help with IAT advance pulling timing

[vortech]

I ran my best the other day, a 9.84@137 but I noticed in 5th gear the car was pulling timing. I noticed in 5th the IAT advance was -7.7 degrees and MAT was only 138 and IAT 2 only 75. I had my tune set to not pull IAT timing until it hit 171.6. I am confused as to where this IAT retard is coming from.


Thanks!

[jpierro79]

the one data log i dont see is intake valve temp open loop modifier. At your O2 based readings your running lean. Where is wideband if so what what wideband are you running. The more time under load the higher the intake valve temperature the less the fuel modifier adds. You cant just log iat as this is not the only modifier of afr ratio. Especially open loop. also your predicted axle torque is really high. Reading 883 mv on o2 is lean. especially wot. where is your wideband and your car is pulling timing all over the place. i see knock retard from 2200 rpm as much as 10 degrees at 5200. If your at 883 mv on o2 thats barely 14.0 if your lucky. Any wideband???
standard o2 can read 950mv and be anywhere from 11-1 all the way to 12.5-1. Log with intake valve temps post original tune and are you running a wideband?

[vortech]

I'm not sure where you are seeing any knock retard? There is none reported on that run and the EQ ratio reported is .81 throughout the whole run.

[LSChev]

Curious if you ever found an answer for this? I have been having the same issues. It does seem to be the IAT spark modifier doing it because if I zero it out the car stops pulling timing. The axis values are obviously not correct though.

[vortech]

Did you zero out the entire table? I would think it would be IAT since IAT advance is showing the retard. I'm going to try to go back to the track this week and try again.

[LSChev]

I have zero'd the entire table yes. I have since started to ignore the values on the axis and just change the numbers based on what the log shows. It's almost as if there is a gear based modifier for the IAT timing modifier.

[vortech]

whats wierd is it never did it in the summer, just now in the cooler months and its making about 2-3 psi more.

[ddtech]

Post the tune.

The IAT pull is a combination of calculations from ECT/Manifold temp and etc, you need to be logging manifold temp I can tell you this, it has to do with how the timing is setup, i'm beginning to think HPTuners made a mistake on the IAT pull table and its not setup correctly.

[sevinn]

Post the tune.

The IAT pull is a combination of calculations from ECT/Manifold temp and etc, you need to be logging manifold temp I can tell you this, it has to do with how the timing is setup, i'm beginning to think HPTuners made a mistake on the IAT pull table and its not setup correctly.

Agreed. Either that or a multiplier is missing.

[ddtech]

For example, according to his log, he's getting mid 140s? low 140s?.. IAT retard table pulls like -4 at 15x IAT, where does this 7.7 come from if the multi tables are all 1.00.
I've seen this on a few customer cars, and trying to figure it out myself. Cars run great, but it is annoying to see this much IAT retard for no reason.

[vortech]

For example, according to his log, he's getting mid 140s? low 140s?.. IAT retard table pulls like -4 at 15x IAT, where does this 7.7 come from if the multi tables are all 1.00.
I've seen this on a few customer cars, and trying to figure it out myself. Cars run great, but it is annoying to see this much IAT retard for no reason.

I had the IAT table setup not to pull timing until it hit 171 degrees. I was only at 138. Strange thing is never pulled any retard in 5th in the summer months when it was 80+, its now in the 50's.

[LSChev]

Agreed. It acts just like a modifier. Maybe there is some torque based modifier that we don't have access to?

[ddtech]

Is there a HPTuners rep we can get to explain how timing pull works on the LT4's then, cause its apparent that the regular IAT table isn't following the proper thought process lol

[LSChev]

Is there a HPTuners rep we can get to explain how timing pull works on the LT4's then, cause its apparent that the regular IAT table isn't following the proper thought process lol

I will try sending this thread to support, see what they can do.

[jpierro79]

I'm not sure where you are seeing any knock retard? There is none reported on that run and the EQ ratio reported is .81 throughout the whole run.

you can command an eq .81 but wheres your wideband it didn't show up on my log read. You command .7 but without eq of wideband it wont matter doesn't mean its accurate. I threw every wideband option inthere I don't see one on log never mind I found it
it says your short 5 percent. 5 percent off of an 11.85 afr is close to 13 and change your lean
your maf from 9400 and above show over 4 percent lean which is huge in maf terms 1 percent can be .8 on an afr scale/ on ve scale your negative 2.5 or higher from 4800 up. your def lean
it can command it all day if your maf and ve are off it will never actually reach those fuel commands.

[sevinn]

you can command an eq .81 but wheres your wideband it didn't show up on my log read. You command .7 but without eq of wideband it wont matter doesn't mean its accurate. I threw every wideband option inthere I don't see one on log never mind I found it
it says your short 5 percent. 5 percent off of an 11.85 afr is close to 13 and change your lean
your maf from 9400 and above show over 4 percent lean which is huge in maf terms 1 percent can be .8 on an afr scale/ on ve scale your negative 2.5 or higher from 4800 up. your def lean
it can command it all day if your maf and ve are off it will never actually reach those fuel commands.

His wideband is showing 4-5% rich through most of this run not lean other than one learn spike in the beginning and when it did a fuel cut on the shifts.

The torque model seems to need some work here however. The shift recovery doesn't look great to me.

[jpierro79]

His wideband is showing 4-5% rich through most of this run not lean other than one learn spike in the beginning and when it did a fuel cut on the shifts.

The torque model seems to need some work here however. The shift recovery doesn't look great to me.

sorry for some reason my vcm wouldn read it. torque management plays a huge role but i see a massive of individuals playing with timing charts like iat instead of recovery and high octane not understanding their roles and along with mulitpliers so without seeing oem tune and changes we fly blind trying to help these peoplel. Im not perfect but i like to see all changes made for a reason. If he/she changes any multiplier you can imagine the consequences.

[Wheeler]

the one data log i dont see is intake valve temp open loop modifier. At your O2 based readings your running lean. Where is wideband if so what what wideband are you running. The more time under load the higher the intake valve temperature the less the fuel modifier adds. You cant just log iat as this is not the only modifier of afr ratio. Especially open loop. also your predicted axle torque is really high. Reading 883 mv on o2 is lean. especially wot. where is your wideband and your car is pulling timing all over the place. i see knock retard from 2200 rpm as much as 10 degrees at 5200. If your at 883 mv on o2 thats barely 14.0 if your lucky. Any wideband???
standard o2 can read 950mv and be anywhere from 11-1 all the way to 12.5-1. Log with intake valve temps post original tune and are you running a wideband?

Any idea where these IVT temps should run for maximum power on forced induction applications ?