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      05-02-2019, 02:13 AM   #1
sirhodjibob
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Alpha N

As someone still new to this platform (and Alpha N) I came across this article and found it helpful: http://www.bayareamotorsport.com/alphan.html

Hopefully someone else will find it helpful too. Many years ago I deleted the MAF on my DSM- but when tuning those, we replaced it with a GM MAP sensor and ran speed density, so the concept of Alpha N hurt my brain a little bit on how the ECU was measuring the volume of air entering the combustion chamber.

I just finished installing an Evolve carbon fiber airbox and I'm anxiously waiting to install the tune from TTFS, so I'm curious to see how the car performs without the input of a MAF/MAP firsthand and I'm busy researching the impacts. I do see the E46 M3 guys switching to a CSL rail and MAP sensor- just out of curiousity, has this been done on our platform? Is this even possible (or worthwhile) with our newer DME?
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      05-02-2019, 12:57 PM   #2
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Pretty sure no one has defined the tables in the include a MAP, alpha N is the one way to go
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      05-02-2019, 11:52 PM   #3
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A MAP sensor isn't feasible due to the ITB's. A MAP sensor must be placed in between the throttle body and cylinder head, and with ITB's the only place to put it is in an intake runner which won't give accurate readings.

A MAP sensor would be useful with an aftermarket ECU and forced induction... layering a fuel compensation table (based on boost pressure) on top of an alpha-n base map. RB's use this technique.
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      05-03-2019, 12:54 AM   #4
sirhodjibob
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Quote:
Originally Posted by pokeybritches View Post
A MAP sensor isn't feasible due to the ITB's. A MAP sensor must be placed in between the throttle body and cylinder head, and with ITB's the only place to put it is in an intake runner which won't give accurate readings.

A MAP sensor would be useful with an aftermarket ECU and forced induction... layering a fuel compensation table (based on boost pressure) on top of an alpha-n base map. RB's use this technique.
Well, E46 CSLs use a vacuum rail along the ITBs. But it makes sense. Has anyone tried on our platform?

No shortage of people happy with their Alpha N tunes here it seems, I'm just curious. And trying to pass time while I wait for my tune from TTFS.
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      05-20-2019, 01:32 AM   #5
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Quote:
Originally Posted by sirhodjibob View Post
Well, E46 CSLs use a vacuum rail along the ITBs. But it makes sense. Has anyone tried on our platform?

No shortage of people happy with their Alpha N tunes here it seems, I'm just curious. And trying to pass time while I wait for my tune from TTFS.
Tried with the Infinity, had huge issues with signal stability / spikes from the MAP sensor, now running Alpha-N.
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      05-22-2019, 09:39 PM   #6
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I installed my TTFS tune and as part of the custom remote tune I had to datalog. While datalogging the car was actually reporting a MAP value...so it seems to have some way to calculate this and measure manifold pressure. Not sure how, but it was there.

Car runs smoother than stock after Alpha N, and I've tried at sea level and 10,000ft.
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