Anyone know how to manipulate the Charge Temp Blending (or any other table) to richen the AFR as intake temps rise at prolonged idle? (this is for an open-loop tuned car)
Anyone know how to manipulate the Charge Temp Blending (or any other table) to richen the AFR as intake temps rise at prolonged idle? (this is for an open-loop tuned car)
Last edited by SSpdDmon; July 9th, 2006 at 03:31 PM.
Look at your A0014 if your using a custom operating system, and increase the VE multiplier as the IAT's get hotter
2000 Corvette Twin Turbo
2004 CTS-V TVS 1900
2006 TBSS TVS 1900
All Tuned by
Rad Tunes by Troy
aka Vetteboy2k
This effect is caused by the IAT reporting a heat soaked temperature and the pcm causing less fuel to be put in to mix with what is in reality much colder air.
The best fix is to move the IAT to a less heat soaked position.
The blending just pads it out with a more stable number.
But the actual leaning out will be right through the rpm range until the actual IAT sensor more accurately matched the true intake air temp.
Do you think this is a problem on the vette???? it seems to me its in a very good position....
"All that is needed for the triumph of evil is that good men do nothing..."
If you log as much as i have in open loop you would see the data very clearly. The issue makes cars lean at launch at drags and rich at the end. If the IAT was further forward it would be possible to get more steady afrs. I am certain of this and will be doing it soon.
Oztrack
EFILive Tuning Consultant
Worldwide Remote Tuning Service
2006 NSW Super Street Drag Racing Champion
www.oztrack.com.au
I can understand the lean at start due to heat soak concept, buy why does it cause them to be rich at the end? In fact, I would say this is the opposite of what many people report as their experience. I have seen numerous threads/debates regarding why cars go lean on the top end. There a fairly recent discussion here: http://ls1tech.com/forums/showthread.php?t=530395Originally Posted by Flyer
Anyone ever prove whether or not this was the solution to the problem of leaner AFRs as temps rise? I've been thinking of going to an open-loop tune for better part throttle performance and don't want to worry about 17:1 AFRs when the IATs jump from 60*F to 100*F.Originally Posted by oztracktuning
My IAT tables (still stock) don't pull timing until you hit .22grams/cyl of airflow. True, pulling timing significantly can alter AFRs some. But, that has to be a significant change in spark and it typically richens AFRs. For example, when the trans shifts and TQ MGT pulls timing down to 3*, my AFR will drop from 14.5:1 to 14:1. The kind of lean AFRs being refered to in this thread are more along the lines of 17:1 and 18:1.
Ive seen cars drop -2* of timing on the dyno and start reading 2% leaner when in actuality it wasnt IAT over 120*. As a test my bens were dialed in with a current timing table. After driving to work I flashed a tune with -2 across the whole board and noticed all my 1.00 changed to 1.04 which would equate to about 15.2:1
Also because of the staging lanes I have 0'd out some of my IAT table. The reduction in timing was enough to cause the car to perform terrible going through the 60' until the IAT started dropping enough where i was getting full advance back