When does DME pull timing because of IATs? (slip and log inside)

boostd92 · 08-31-2012, 12:42 PM

First, let me apologize for putting N55 stuff in this section, but it's a ghost town in our forum, and this question applies in a more general way to Procede/BMW IAT intervention.

I went to the dragstrip a few nights ago chasing a mid 12 but was dissapointed again

Still, ran my best mph to date, I guess.

My mods:
Procede rev3
Catless downpipe
Vanguard V2 exhuast
4 gallons E85, rest 93 octane Shell

I was running map 1 with boost upped to 16psi. I realize now that not running map 2 may have left some power on the table.... the open loop ignition for map2 shows quite a bit of advance over map 1.

That being said, in 3rd and 4th gear I'm maxing out timing at 3.5 degrees (NOT GOOD). I have a stock FMIC and my IAT's start at 117F in the beginning of 3rd to 145F at the end of the strip in 4th. The procede does not start pulling timing until 158F.

Is this the DME retarding ignition because of IAT? Does anyone know what those thresholds are?

OpenFlash · 08-31-2012, 12:53 PM

That tiny single turbo is generating a lot of backpressure that those boost levels. To avoid knock retard (a byproduct of high exhaust pressures) you need more octane. And if possible, some type of charge cooling (meth or upgraded fmic). There is really no other way around it.

Ænema · 08-31-2012, 01:23 PM

Here's a pic someone posted up in the Cobb thread showing the stock timing correction factor tables(it shows it as a stage 1 map but the tables are the same.) This is N54 but I'm betting the N55 follows a similar routine. At 145F you're balls deep into the table lol

08-31-2012, 12:42 PM	#1
boostd92 Captain 62 Rep 759 Posts Drives: '11 E92 M-Sport Join Date: Jun 2009 Location: Chicago, IL iTrader: (1) Garage List 2011 BMW 335i M-Spo ... [7.26]	When does DME pull timing because of IATs? (slip and log inside) First, let me apologize for putting N55 stuff in this section, but it's a ghost town in our forum, and this question applies in a more general way to Procede/BMW IAT intervention. I went to the dragstrip a few nights ago chasing a mid 12 but was dissapointed again Still, ran my best mph to date, I guess. My mods: Procede rev3 Catless downpipe Vanguard V2 exhuast 4 gallons E85, rest 93 octane Shell I was running map 1 with boost upped to 16psi. I realize now that not running map 2 may have left some power on the table.... the open loop ignition for map2 shows quite a bit of advance over map 1. That being said, in 3rd and 4th gear I'm maxing out timing at 3.5 degrees (NOT GOOD). I have a stock FMIC and my IAT's start at 117F in the beginning of 3rd to 145F at the end of the strip in 4th. The procede does not start pulling timing until 158F. Is this the DME retarding ignition because of IAT? Does anyone know what those thresholds are?
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08-31-2012, 12:53 PM	#2
OpenFlash 1737 Rep 17,960 Posts Drives: A Lot Join Date: Sep 2006 Location: SF Bay, CA iTrader: (0) Garage List 2018 Ducati Panigal ... [0.00] 2016 Mazda CX5 [0.00] 2017 Aprilia Tuono ... [0.00] 2019 BMW M2 Competi ... [0.00] 2015 BMW M5 Competi ... [10.00] 2016 Ducati XDiavel S [0.00] 2016 AMG GT S [0.00] 2011 Ferrari 458 It ... [0.00] 2017 Charger Hellcat [0.00] 2015 KTM Super Duke ... [0.00] 2016 KTM RC390 [0.00]	That tiny single turbo is generating a lot of backpressure that those boost levels. To avoid knock retard (a byproduct of high exhaust pressures) you need more octane. And if possible, some type of charge cooling (meth or upgraded fmic). There is really no other way around it.
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08-31-2012, 01:23 PM	#3
Ænema Captain 14 Rep 961 Posts Drives: BMW Join Date: Aug 2012 Location: Arizona Bay iTrader: (0)	Here's a pic someone posted up in the Cobb thread showing the stock timing correction factor tables(it shows it as a stage 1 map but the tables are the same.) This is N54 but I'm betting the N55 follows a similar routine. At 145F you're balls deep into the table lol
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