CSL Airbox Hesitation

[Amalgam]

I vaguely remember there was a discussion on M3F about low RPM hesitations with CSL Airboxed cars. If I remember correctly cars that are not running a flap, need to have the flap values set to always open correct? If not, the DME is expecting flap operation when their is not one present.

I'm trying to solve an issue in my comfort tune when getting on the gas below 3000 RPM, it almost feels like there is a half a second delay before the power comes on. Driving the car in sport (with throttle mapping kept consistent) the car feels much smoother and my best guess is this has to do with the flap settings (which are untouched with my tune currently).

[bassel_sy]

Whats your setup?

[Amalgam]

US Spec S54
Stock Cams
Turner CSL Airbox + Kassel Map sensor / Turner IAT
OE CSL tune with US cam offsets

SGT Headers
CPI Euro 200R section 1
OE section 2
SCZA

[COVID-19]

You have the correct IAT scaling?

[sc_tr0jan_m3]

i had hesitation while running on a non CSL DME. if you got on the gas in a gear where the rpm's were below 3500, it would bog down.

i'm now on the CSL firmware and i haven't had the same issues for some odd reason. i haven't been able to figure out why it appears to perform better now.

[skristedja]

i had hesitation while running on a non CSL DME. if you got on the gas in a gear where the rpm's were below 3500, it would bog down.

i'm now on the CSL firmware and i haven't had the same issues for some odd reason. i haven't been able to figure out why it appears to perform better now.

How were you running the airbox without the csl firmware before?

[paulclaude]

Commonly this issue is down to over-rich AFR's and can be fixed through correct tuning. If you are running stock CSL software AFR's will more than likely be far from optimal for an S54 with stock cams.

[sc_tr0jan_m3]

How were you running the airbox without the csl firmware before?

Alpha N


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[skristedja]

Alpha N


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And you're still running Alpha N now without the hesitation issue? That's interesting.

[sc_tr0jan_m3]

And you're still running Alpha N now without the hesitation issue? That's interesting.

Yeah very... Only change is the csl firmware. I haven't been able to figure it out.

[heinzboehmer]

Yeah very... Only change is the csl firmware. I haven't been able to figure it out.

I thought you were running a MAP sensor?

[dl.m3]

Alright, just got the Turner airbox installed and running alphaN tune. I have a hesitation that occurs when I want to downshift rev-match, where I clutch-in, stab the throttle, and then the car sounds like to struggles to raise the rpm unless you hold the gas down for 1 second then it finally blips. Typically occurs after you coast for a few seconds before downshifting.

I recall reading about this on the old m3forum csl airbox hesitation thread. So I wonder if it was ever resolved or just a normal behavior or a MAF-less setup with a large plenum opening?

Please share your knowledge.

[Slideways]

Alright, just got the Turner airbox installed and running alphaN tune. I have a hesitation that occurs when I want to downshift rev-match, where I clutch-in, stab the throttle, and then the car sounds like to struggles to raise the rpm unless you hold the gas down for 1 second then it finally blips. Typically occurs after you coast for a few seconds before downshifting.

I recall reading about this on the old m3forum csl airbox hesitation thread. So I wonder if it was ever resolved or just a normal behavior or a MAF-less setup with a large plenum opening?

Please share your knowledge.

Yup, I have driven two cars with the exact same issue you are describing, one with a TTFS alpha-N tune and one with the stock tune but MAF-less. After upgrading both cars to MSS54HP DMEs with CSL tune, the issue was resolved. The MAP sensor is fairly cheap and worth doing, but I guess you could try it without first to see how it responds, then add it later.

[ATB88]

I still get hesitation running the full CSL software on an MSS54HP and using a MAP sensor.

[dl.m3]

Yup, I have driven two cars with the exact same issue you are describing, one with a TTFS alpha-N tune and one with the stock tune but MAF-less. After upgrading both cars to MSS54HP DMEs with CSL tune, the issue was resolved. The MAP sensor is fairly cheap and worth doing, but I guess you could try it without first to see how it responds, then add it later.

I think the MAP sensor might be what I'm lacking and causing the ECU to be confused during vacuum. Or maybe this is fixable somehow in the alpha-n tune.

I still get hesitation running the full CSL software on an MSS54HP and using a MAP sensor.

The kind I described or a different scenario? I was thinking of going MSS54HP and running CSL (instead of alpha N), the MAP sensor might fix my hesitation which occurs during vacuum (engine braking/coasting) and then on the throttle.