CSL MAP Sensor Solutions

[karter16]

IMO, the real benefit comes from the sensor reading a smoothed pressure wave with the OE CSL or brake booster solutions (thanks to how far away the sensor sits from each individual cylinder), instead of a series of pulses with it right next to the throttle body on the Kassel solution.

I'm running the OE CSL rail and Bryson has the brake booster kit. Our readings are pretty much bang on. I should have bought an extra sensor and left the Kassel kit installed to do some AB testing, but I can for sure say that readings looked like pulses instead of a smooth wave with it.

+1000 to your tune comment.

Ah I'd forgotten the Kassel solution sits right by the TBs - great call.

[Cubieman]

On my car the Kassel location did create "waves" on the datalog as compared to the COVID sensor location that was more or less a continuous line.

That said, when even light throttle input was introduced the waves smoothed out. I did contact Kassel about this, they were apparently fully aware of this fact an said it was not anything to be concerned with.

Side note, I really need to try this Mullet tune!

Post 71 shows what what my vehicle did, others also had data posted.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/17227-map-sensor-wiring-help-please/page5

[heinzboehmer]

On my car the Kassel location did create "waves" on the datalog as compared to the COVID sensor location that was more or less a continuous line.

That said, when even light throttle input was introduced the waves smoothed out. I did contact Kassel about this, they were apparently fully aware of this fact an said it was not anything to be concerned with.

Side note, I really need to try this Mullet tune!

Post 71 shows what what my vehicle did, others also had data posted.

https://nam3forum.com/forums/forum/m...p-please/page5

Nice, I remember that thread. Kassel kit didn't seem to affect how the car drove much at all until I got on an tune that is actually optimized (mullet).

There were clear drivability issues at very small relative openings and steady throttle pedal inputs that went away when I swapped to the OE CSL rail. You can see the pulses in the readings at low throttle here: https://nam3forum.com/forums/forum/m...9010#post29010

So, data seems to coincide with observations on this.

[karter16]

Nice, I remember that thread. Kassel kit didn't seem to affect how the car drove much at all until I got on an tune that is actually optimized (mullet).

There were clear drivability issues at very small relative openings and steady throttle pedal inputs that went away when I swapped to the OE CSL rail. You can see the pulses in the readings at low throttle here: https://nam3forum.com/forums/forum/m...9010#post29010

So, data seems to coincide with observations on this.

Oh man! I hadn't seen those comparisons before heinzboehmer that's a huge effect!

The MAP sensor AD is read every 1ms and the MAP sensor RF calculations are every 10ms, so it's not surprising that it had a noticeable effect for you!

For others who are wondering, the reason why I say that, and the reason you probably haven't noticed this effect if you're not on the Mullet Tune is due to two reasons:

1: The MAP sensor based RF calculation is tuned for the CSL. This needs to be adjusted for cars with M3 cams. If this is not done then it is chasing the wrong RF, and hence fueling. The end result is the MAP sensor correction factor tends to saturate to one of its two limits.

2: If you have M3 cams the VE map is so off in most CSL-based tunes anyway that you don't notice #1 anyhow.

The Mullet tune addresses both of these things, hence it becomes very apparent when your MAP sensor is screwy in any way. (As an aside, MAP sensor DTCs don't throw a CEL. I'm fairly confident there'll be a number of people out there who believe they're running a MAP sensor, who are actually effectively running Alpha-N because their MAP sensor has silently thrown a code).

[elbert]

(As an aside, MAP sensor DTCs don't throw a CEL. I'm fairly confident there'll be a number of people out there who believe they're running a MAP sensor, who are actually effectively running Alpha-N because their MAP sensor has silently thrown a code).

Out of curiosity, do you know offhand what code number and/or description that would be?

[heinzboehmer]

Oh man! I hadn't seen those comparisons before heinzboehmer that's a huge effect!

The MAP sensor AD is read every 1ms and the MAP sensor RF calculations are every 10ms, so it's not surprising that it had a noticeable effect for you!

For others who are wondering, the reason why I say that, and the reason you probably haven't noticed this effect if you're not on the Mullet Tune is due to two reasons:

1: The MAP sensor based RF calculation is tuned for the CSL. This needs to be adjusted for cars with M3 cams. If this is not done then it is chasing the wrong RF, and hence fueling. The end result is the MAP sensor correction factor tends to saturate to one of its two limits.

2: If you have M3 cams the VE map is so off in most CSL-based tunes anyway that you don't notice #1 anyhow.

The Mullet tune addresses both of these things, hence it becomes very apparent when your MAP sensor is screwy in any way. (As an aside, MAP sensor DTCs don't throw a CEL. I'm fairly confident there'll be a number of people out there who believe they're running a MAP sensor, who are actually effectively running Alpha-N because their MAP sensor has silently thrown a code).

Yep! Pulses are crazy. What was originally hidden by a combination of (1) + (2) became pretty apparent once the rest of the tune got dialed in.

Fortunately Bry5on is using the brake booster adapter, otherwise he would have probably been chasing his tail for a while with this.

[karter16]

Out of curiosity, do you know offhand what code number and/or description that would be?

Yep:

223

0xDF

pressure intake manifold

Charge-air pressure sensor, range check

[elbert]

Yep:

Awesome, good to know. Thank you!