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 Post subject: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Wed Apr 04, 2012 12:50 am 
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Joined: Wed Apr 04, 2012 12:40 am
Posts: 36
ECU Model: S80 Pro
Firmware Version: 62
Ok guys, I have a BMW M50 non vanos engine and am running a S80 pro.

I have the engine running and driving but I want to confirm a few things before I continue tuning..

Firstly, sensor position. I worked mine out to be 88 degrees, but I wasnt sure where to start counting from the missing teeth. It seems to be close with the timing light, but does anyone know for sure what the sensor position is for the BMW M50 non vanos engine?

Load axis... TPS or MAP? MAP makes more sense to me, and thats what I have been using and feel most comfortable with. When using MAP as load, are the MAP compensation tables active? (Actually just checked and seems these can be disabled). Am I correct in thinking that I should disable this table when using MAP as load.

My engine appears to idle best at around 12.5:1 AFR, this seems far too rich to me for idle, if i bring it up to around 13:1 i start to get misses or pops out the exhaust. I am using a Innovate MTX-L wideband and what reads on the wideband gauge is accurate with what the DTA is seeing (so seems to be no voltage offsets). I wonder if the wideband is reading incorrectly, or maybe timing can or will affect what an engine likes for idle (comes back to is my sensor position is correct?)

I think this is all for now, and I feel I need to clear these questions up before I should continue tuneing and further.


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Wed Apr 04, 2012 1:51 pm 
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Joined: Tue Aug 02, 2011 12:08 pm
Posts: 2906
Location: Norn Iron
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It shouldnt be close with a timing light, it should be accurate. That is the only way to determine correct missing tooth position.

MAP compensation tables are always active. If using MAP as load zero them.

If the engine has multiple throttles then TPS as main load is probably better. If it has a single throttle, wont really matter either way. Whichever makes the most sense to you for tuning purposes.

If it's a pretty standard engine 12.5:1 is very rich, you should have no difficulty getting it to around stioch.


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Wed Apr 04, 2012 3:21 pm 
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Joined: Fri Dec 04, 2009 1:45 am
Posts: 588
Location: Pennsylvania, USA
ECU Model: S80 Pro
Distributor: DTA UK
Firmware Version: 73
Troy I calculated mine out to be 84 deg. I used a trigger wheel printed out and rotated the engine until the TDC marks lined up. Made 700 rwhp that way so I think it's pretty damned close. If you want to use a timing light on these you need to put a spark plug wire between the OUTPUT of the coil and the spark plug. Clamping around the input to the coil (COP) can cause interesting results.

I idle an 8.5:1 M50 Non Vanos at around 16 advance and 13.5 - 14.0:1 AFR using an NGK AFX properly calibrated and grounded so that DTA and NGK unit read the same.

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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Wed Apr 04, 2012 8:27 pm 
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Joined: Wed Apr 04, 2012 12:40 am
Posts: 36
ECU Model: S80 Pro
Firmware Version: 62
Ok, I will go with what you have calculated (84 degrees), and then check with a timing light. I checked with a timing light earlier, but its such a pain in the ass, there is so little room, I need to remove the radiator just to get a timing light in there, and then remove the water pump pulley to see the timing marks.

I've got a spark plug lead I use between the coil and spark plug when using a timing light, so no issues there.

My wideband and DTA both read the same, so I don't think I have any ground issues in that department, but I question the calibration of the wideband unit ( i did calibrate it before use, but I will do it again to be sure.)


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 12:29 am 
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Joined: Tue Aug 09, 2011 2:54 pm
Posts: 318
Location: Stevenage
ECU Model: S80 Pro
Distributor: Roverdose
you dont need to see the actual timing marks, line up tdc, get some tipex out on the bottom pulley and cam belt cover wherever you can see it/get the timing light in.

Drew


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 3:36 am 
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Joined: Wed Mar 17, 2010 9:24 am
Posts: 329
ECU Model: S80 Pro
Firmware Version: 62
troy wrote:
My engine appears to idle best at around 12.5:1 AFR, this seems far too rich to me for idle, if i bring it up to around 13:1 i start to get misses or pops out the exhaust.


Are you running big injectors?

And are you running sequential fuel and is the injection angle right?


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 4:46 am 
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Joined: Wed Apr 04, 2012 12:40 am
Posts: 36
ECU Model: S80 Pro
Firmware Version: 62
60 lb siemens deka injectors, running sequential, injection angle is not some thing i have fiddled with (injection angle map is all zeroes).


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 4:52 am 
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Joined: Wed Mar 17, 2010 9:24 am
Posts: 329
ECU Model: S80 Pro
Firmware Version: 62
I had the same problem with 50lb Bosch EV14 on my old 2.9 VR6 Turbo. Anything lower than ~ 2ms gave a poor idle.

Currently have a VW R32 engine running off my S80, which is standard, and that can idle at 15-16 AFR all day long.

Try 53 in the injection angle (Sequential settings) and see if the pops go when you lean off the idle fuelling.


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 5:41 am 
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Joined: Wed Apr 04, 2012 12:40 am
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ECU Model: S80 Pro
Firmware Version: 62
Will give that a try tomorrow. It's currently set to 185.


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 Post subject: Re: BMW M50 NV Tuneing. Also MAP vs TPS for load.
PostPosted: Thu Apr 05, 2012 5:51 am 
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Joined: Wed Mar 17, 2010 9:24 am
Posts: 329
ECU Model: S80 Pro
Firmware Version: 62
OK, cool. 53 is a number Allan suggested some time ago and it does seem to smooth things out for me!


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