Manifold barometric/pressure compensation

Give input on tuning as well as any tips and tricks you may have. Also feel free to share base mapping files for various engine types.
fast944
Posts: 12
Joined: Sun Mar 15, 2015 4:38 pm
ECU Model: S40 Pro

Manifold barometric/pressure compensation

Post by fast944 »

On boost application, let say around 25 psi, is it better to use the compensation table or use the main map to reduce the timing advance and some one have some number in mind to start
Thanks
Alain
stevieturbo
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Joined: Tue Aug 02, 2011 12:08 pm
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Location: Norn Iron

Re: Manifold barometric/pressure compensation

Post by stevieturbo »

Entirely personal choice.

IMO, unless you have a reason to use TPS with MAP compensation, do not. It just makes things more complicated for no good reason.

Of course there will be those who say it makes it easier.
fast944
Posts: 12
Joined: Sun Mar 15, 2015 4:38 pm
ECU Model: S40 Pro

Re: Manifold barometric/pressure compensation

Post by fast944 »

No reasons, but right now I use TPS with MAP compensation, what will be your suggestion ?
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
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Location: Norn Iron

Re: Manifold barometric/pressure compensation

Post by stevieturbo »

Well as I said above...unless there is a good reason to use TPS vs MAP.....do not...which implies I would not and pretty much have never used that method unless I had no other choice. ( which was the case with the P8 when I first used it back in 2002 or so )
fast944
Posts: 12
Joined: Sun Mar 15, 2015 4:38 pm
ECU Model: S40 Pro

Re: Manifold barometric/pressure compensation

Post by fast944 »

No good reason, I start using DTA before P8, just bad habit ? do you have a basic map for fuel and timing to start with I am using a GM 3bar sensor, 3000 cc 4 cylinders Porsche, Garret ball bearing.
Thanks
Alain
stevieturbo
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Joined: Tue Aug 02, 2011 12:08 pm
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Location: Norn Iron

Re: Manifold barometric/pressure compensation

Post by stevieturbo »

If it's working for you and you're happy with it, then probably no reason to change.

I just find it much easier with MAP vs RPM, and the numbers you see on those tables more closely resemble what is happening at the engine without even more compensations going on in the background to change them.

You can select the GM 3 bar from dropdown menus, and you'd need to sort your own tables for your engine, spec, injectors, crank/cam triggers etc etc.
fast944
Posts: 12
Joined: Sun Mar 15, 2015 4:38 pm
ECU Model: S40 Pro

Re: Manifold barometric/pressure compensation

Post by fast944 »

Oups, no tables to look at :)
Alain
iceman_n
Posts: 141
Joined: Mon Jan 16, 2012 1:39 pm
ECU Model: S40 Pro
Firmware Version: 58

Re: Manifold barometric/pressure compensation

Post by iceman_n »

thats a map that came to me today

i dont understand why to reduce fuel with map compensation (either cold - hot engine) and at the same time to add fuel using water compensations when engine is cold...

i am missing something here or its pointless ??
Attachments
dta.jpg
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Manifold barometric/pressure compensation

Post by Alex DTA »

If you're mapping using speed density, all MAP compensations should be zeroed. They make no sense.
However, it won't cause any problems, it's just flattens out the fuel map.

Water temp compensations were used before the start fueling was available, so this is probably just an old map.

There will always be conflicting compensations. If the engine is cold, it needs more fuel. MAP is irrelevant to temperature.
If the throttle is closed, it needs less fuel. Temperature is irrelevant manifold pressure (ish).
However, they all end up working together.
iceman_n
Posts: 141
Joined: Mon Jan 16, 2012 1:39 pm
ECU Model: S40 Pro
Firmware Version: 58

Re: Manifold barometric/pressure compensation

Post by iceman_n »

thanks Alex...i agree with you

thats why i ask about it...thats not an old map is the map that the car uses right now, it works ok but it is a bit odd the way the mapper do it
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