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      10-03-2014, 11:45 AM   #23
loesch
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Drives: 2011 BMW 135i M Sport
Join Date: Feb 2012
Location: State College, PA

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Quote:
Originally Posted by Socal_Aviator View Post
Have you had any idle issues running the Dinan Stage 2 flash combined with your downpipes?

There is a lengthy thread on this site about people with downpipes and stalling/idle problems. I am considering a Dinan stage 2 with cat back exhaust and downpipes but that thread made me very worrisome.

I love downpipes on turbo cars but the fact that most piggy back systems and Dinan do not incoporate software to compensate for downpipes worries me. Adding downpipes to a turbo car changes the flow characteristics and air fuel ratios quite a bit which combined with a software "flash" that doesnt take this into effect can lead to lean mixture right?

On my Nissan GTR, adding downpipes made a HUGE change to air flow and this required large changes to injector flow to compensate for a safe air fuel ratio otherwise the car will run extremely lean. Downpipes= tune mandatory. I know these are two totally different cars but how do you compensate for the downpipes?
The DME in these cars compensates for all kinds of intake and exhaust flow changes. It has set targets for AFR and will compensate to keep the engine within range. That's why we need a flash when we start pushing lots of boost. The DME still thinks we should be having an AFR of 15.5 tapering to 13 when we should be more like 13.5 tapering to 12. I'm not sure where the rough idle stuff is coming from with DPs. I didn't notice any difference.
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2011 135i M Sport 6MT LeMans Blue | Active Autowerke Gen II axle back | Berk d******* | N54 gutted mids | FuelIt Walbro 450 fuel pump | Pure Turbos Stage 2 | 3.5bar TMAP | Pure Turbos inlet pipe | BMS intake | BMS oil catch can | ETS intercooler | ETS charge pipe | BMS JB4 w/ ISO firmware | BMS backend flash stacked on PPK | Eibach springs | Whiteline rear subframe bushing inserts | cosmetic tidbits
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