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View Full Version : Flat Spot Autotune


purrvert
February 19th, 2006, 07:02 AM
Hitting a flat spot at 4000 rpm, C6101 has been increased by 175%, rev limiter set to 6500. Commanded AFR drops from 14.63 to 1.0. None of my tables reflect that change. Any tips for where to look?
Some odd things I've found B3618 is shown in AFR but description identifies as EQ ratio. B6611 appears like it is being modified. :nixweiss:

Edit: Was just running the log again and saw that while playing back the increased throttle and Commanded AFR 1.0 are seperated. Far left for increased throttle/rpm, far right for AFR at 1.0. In the Stop Playback mode they line up. Which one can you believe??? See Now what.jpg
Black02SS
February 19th, 2006, 07:42 AM
You need to change B3618 to show the correct EQ and not use AFR. That is part of the problem. If you want to use AFR, then you need to change the setting in the tuner to reflect that. Only certain tables can be viewed in AFR while the others are EQ. If you stoich AFR is 14.63, then change that to 1.0.
purrvert
February 19th, 2006, 07:53 AM
That makes sense, I've never changed it. What would make it kick in at just 4000 RPM?
Black02SS
February 19th, 2006, 08:22 AM
I dunno to be honest. Can you send the tune and log and I'll take a look at it if you like.

black02ss at gmail dot com
Black02SS
February 19th, 2006, 08:50 AM
Reason it does that is when PE mode comes into play. Change the modifier to 1.0 or disable PE altogether as you have it already in the OLFA table. Give that a whirl and see what you come up with.
Black02SS
February 19th, 2006, 08:52 AM
Also when this happens, the actual AFR goes lean to ~14.0. That is part of the reason as you are losing a lot of power.
purrvert
February 19th, 2006, 09:14 AM
Also when this happens, the actual AFR goes lean to ~14.0. That is part of the reason as you are losing a lot of power.

Thanks Chad. I see the commanded AFR go all the way down to 1.
Black02SS
February 19th, 2006, 09:16 AM
Anytime, let us know if this fixes the problem.
purrvert
February 19th, 2006, 11:21 AM
Anytime, let us know if this fixes the problem.

Changed B3618 to 1 EQ, doing just one thing at a time. That solved the problem. Still wondering why it stayed subdued till 4k.
Thanks again.
Got more power than I've ever had and I'm just starting to tune.
It's also the first time I goosed this car without any sign of knock.
Black02SS
February 19th, 2006, 11:30 AM
Reason it happened is you were in PE mode. PE mode is partially determined by TPA. You were in your normal OLFA table up to that TPA. When you hit a certain TPA, it will go into the PE table bypassing the OLFA table causing the car to hit the flat spot. It seems like everytime you hit 4k is when you were applying more throttle forcing the car into PE.
purrvert
February 19th, 2006, 11:41 AM
B3616??, I had not payed any attention to that table.

Any thoughts about B6611? Why it looks like it's being moded. Every tune I open looks like that.
joecar
February 19th, 2006, 10:01 PM
Changed B3618 to 1 EQ, doing just one thing at a time. That solved the problem. Still wondering why it stayed subdued till 4k.
Thanks again.
Got more power than I've ever had and I'm just starting to tune.
It's also the first time I goosed this car without any sign of knock.
Good work, mate.
:cheers: