A quick and easy way to street tune your CSL conversion for drivability.

[Bry5on]

If you have the flap, it shouldn’t matter if it’s closed or open based on the way the DME works, but I kept mine closed (second gear, comfort mode) just to control the variable, just in case.

[heinzboehmer]

Keep it closed or open? Won't having it closed be an issue in the upper RPMs?

Keep it closed.

The additive VE flap table will take care of the extra fuel needed at higher RPMs.

[Cubieman]

Also keep the flap closed for all your logs.

Keep it closed or open? Won't having it closed be an issue in the upper RPMs?

[heinzboehmer]

Also keep the flap closed for all your logs.

[Bry5on]

I am running the flap, is there another parameter I need to be taking into account?
I'd like to try this method out but not sure if the flap is going to make things a bit more difficult for me as I don't fully grasp the whole tuning deal/programs generally speaking.
Going to at least take a few logs before the weather really turns.

Just don’t touch the flap map and that should keep you in the safe zone. I run the flap as well. I edited the main map and the cold start maps only. The flap map is additive, so it doesn’t need a retune.

[Cubieman]

I am running the flap, is there another parameter I need to be taking into account?
I'd like to try this method out but not sure if the flap is going to make things a bit more difficult for me as I don't fully grasp the whole tuning deal/programs generally speaking.
Going to at least take a few logs before the weather really turns.

[puma1824]

Anyone here from Maryland who can help a local tune?

[BMWfanz]

I don't know is VE map is functional on idle, better to ask it from topicstarter

[0-60motorsports]

Great thanks! Yeah currently I do have the active flap but I do not have CSL cams. What I am experiencing sometimes in low RPMs whether from a stop or even while running, there are some slight hesitations. Additionally sometime,s when first starting the car or when AC on the idle waves / goes up and down. So maybe all this tuning talk and suggestion will help. Problem is I've never tuned before. I don't even have any of the software mentioned. Where oh where to start lol.

I have the same isle hunt with AC on for years lol. Running OE CSL intake and Flap

[puma1824]

The reason is simple: 90% of CSL airbox swaps does not have a stock flap or CSL cams- setup is stock cams or tuned bigger angle cams, more than CSL ones. So most of tuners does not tune partial load maps- cause it is very long story and tune only WOT maps. So if you have CSL airbox setup with no flap or not CSL cams- car have some issues with driveability on partial loads. Its hestitates on low RPMS, struggle acceleration from low rpms etc. Often tuner will say- go downshift and rev it from 4k- but driveability is always what any driver wants. So what about this topic- just easy solving of partial load issues. Great method BTW.

Great thanks! Yeah currently I do have the active flap but I do not have CSL cams. What I am experiencing sometimes in low RPMs whether from a stop or even while running, there are some slight hesitations. Additionally sometime,s when first starting the car or when AC on the idle waves / goes up and down. So maybe all this tuning talk and suggestion will help. Problem is I've never tuned before. Other than Excel or Sheets, I don't even have any of the software mentioned. Where oh where to start lol.

[BMWfanz]

The reason is simple: 90% of CSL airbox swaps does not have a stock flap or CSL cams- setup is stock cams or tuned bigger angle cams, more than CSL ones. So most of tuners does not tune partial load maps- cause it is very long story and tune only WOT maps. So if you have CSL airbox setup with no flap or not CSL cams- car have some issues with driveability on partial loads. Its hestitates on low RPMS, struggle acceleration from low rpms etc. Often tuner will say- go downshift and rev it from 4k- but driveability is always what any driver wants. So what about this topic- just easy solving of partial load issues. Great method BTW.

[puma1824]

I'm trying to learn and understand but still not clicking with me. I'm not sure if I need this or what issue it's trying to solve or what issues I should be looking for in my "CSL" build to determine if I need to go down this path. Is there a dummy version of what this is fixing and what issues I may or may not have to determine if I need to "fix" it? BTW I just got my conversion back a few weeks ago so I just started driving it BUT I think I am experiencing this what one had described in a previous post "....the engine behavior at very low throttle inputs, like when pulling away from a stop or changing gears. Before, the rpms would oscillate quite a bit and make things pretty jerky (sidenote: hadn't realized I was driving around this until now), but that is completely gone now. ...."

[Bry5on]

Just to clarify some details- If i'm not happy with my current tune- before start- i need to use stock CSL tune bin and then corretc VE table? My tuner changed ignition and WOT fuel trims- so as i see- i can go for stock WOT fuel map and just correct VE table, am i right?

You can start from either one, although I’d suggest starting from your tune to keep the extra fuel at WOT. I started from a tune that I wasn’t happy with, then I backed off some of the timing at lower RPMs and returned some of the DME’s overall latitude to pull timing back if it detects pinging. None of the lauded tuner files I’ve seen have touched part throttle fuel, so you’re likely starting from a stock map either way.

[BMWfanz]

For the record, here’s the difference between the default CSL tune and the 5 runs in version using this method on my car. Super clever, thank you for sharing!


Throttle tip in is so much smoother and the motor seems much happier. I agree that a good amount of the rasp is gone in that mid-2k RPM range. Looks like those CSL cams and the SS headers really do make a difference. With these headers, I needed fuel almost everywhere, and particularly in two islands.

My motor is a 180k mile stock internal CSL conversion, with flap, SS v1 headers and matching catted section 1. This tuning was done with flap closed to the appropriate map.

Adaptations are now turned back on, so I’ll be watching what the motor does.

edit: I’d bet that the resonances and jitteriness in the 2k RPM range can be totally tuned by changing the interpolation motor RPMs. I did this for my WOT tune and was able to get a super flat AFR curve by targeting the resonant and nodal frequencies as the interpolation points.

Just to clarify some details- If i'm not happy with my current tune- before start- i need to use stock CSL tune bin and then corretc VE table? My tuner changed ignition and WOT fuel trims- so as i see- i can go for stock WOT fuel map and just correct VE table, am i right?

[BMWfanz]

Is this method is working when cams are changed? Will it work when your setup is need to change injectors for bigger ones?