I am road tuning my car that has multiple mods, what rough AFR are people running for best power? My butt dyno tells me that the car like 13.0 AFR at redline the best, even at 12.8 I feel it pull less, and if I can feel it then it must be considerable difference.

Another issue I found is that even with Hondata intake manifold gasket, TB heat gasket and TB coolant bypass, the IAT sensor gets heat soaked and doesn't show well the temps of the actual air entering the engine. This throws of my tuning cause if I do a pass after idling vs one after driving for a minute, the IATs would be different, but the sensor shows them as being the same.

 

There is minimal power difference around that AFR point, better to stay a bit richer (safer) especially at redline
I recommend you to watch this video.

 

As for the IAT issues there is always a possibility to relocate the sensor.
But are you really sure that the sensor is reading incorrectly? Sitting at idle the manifold will heatsoak quite a bit even with a thermal gasket.

 

Yes that is the point, it heat soaks. Let's say I idle and go for pull right after, fair enough IATs are higher. But after driving for 1 minute, the cool air (like 50F ambient) should drop it down closer to ambient, but it shows maybe 2Celsius drop, definitely not realistic.

 

Yes, safe is better, but I have seen dyno charts from all over the forum and many times seen as low as 12.5 AFR from like 5/6k RPM onwards.

 

It's going to take longer than that to cool down the intake manifold.
Are you looking at the AFR and seeing it going super rich at the same time? If that is the case then you will probably will get big improvements relocating the IAT sensor.
If AFR is looking good then IAT is true.

 

The heat of the intake manifold doesn't affect the temperature of the air entering the cylinders, the air is flowing fast enough and the volume of it is so large that it doesn't have time to considerably heat up. The intake manifold doesn't have much surface area per the volume of air that travels through it to affect it much. The only reason why the IAT sensor reads high is due to the heat soak. The AFRs vary and since the air passing through the sensor also cools it down a little it's hard to get consistent repeatable runs to be able to tune the car.

Now considering moving the IAT sensor, can that be programmed into the GEMU? It's probably the most primitive of the ECU options for the S2k, mine is an AP1.

 

A heated up manifold will for sure affect the air going in the cylinders, just look at the tests done with and without the Hondata gasket.
I do I agree the IAT sensor gets exaggerated readings, but how much is pretty hard to tell until you actually measure this.
I've used and tuned the GEMU on my car before so I'm a bit familiar with it but I'm not sure what you would need to program when moving the sensor?

 

No programming needed when moving the IAT sensor, you can do it on a bone stock factory car with favorable results. I have data logged a good average 40F difference from moving off the manifold to in front of the TB on the intake tube such as DBW factory location. That means less heat soak and in turn less timing being pulled from the ecu and that is probably the biggest improvement in net power you will find overall short of tuning. 3hp per 10F IAT differential on average.

Cut the harness near the connector, solder on a set of long enough wires to relocate and enjoy.

 

What sensor could I use to put in front of the TB that won't require me to re calibrate for different voltages that the sensor reads?