From Cobb: ECU Behavorial Differences Between Gen1 and Gen2 MS3's

[Fobio]

I don't visit their forum enough...

ECU Behavorial Differences Between Gen1 and Gen2 MS3s.

This post is intended to help MS3 AccessPORT owners and ATR users understand the differrences in ECU behavior between the two vehicles.

Gen1 = 2007-2009 MS3
Gen2 = 2010+ MS3 Thus far, this is only valid for the 2010 MS3. I have not tested on the 2011 MS3 enough to know how it behaves and the 2012 does not exist so this just pertains to the 2010 MS3.

Hardware Differences = Both vehicles appear to have very similar hardware, but the calibration of these vehicles is entirely different due to the differing ECU behavior (detailed below).

Boost Control = Both vehicles are set up to manage boost by targeting load values. This form of boost control tends to create boost spikes and gives the vehicle a bit of a touchy throttle (some like this, some don't). Thus far we are using the custom AccessTUNER pressure-based boost control logic that we recently implemented to create all OTS calibrations for all 2010+ MS3s becuase this help eliminate boost spikes and can keep the boost levels within the capabilities of the stock CDFP for all S1 calibrations.

Fueling = Both vehicles work generally the same using a MAF sensor to measure air mass for fueling calculations. Both ECUs have higher resolution tables for Closed-Loop (CL) fueling targets, then switch to more simple RPM-based fueling tables for Wide Open Throttle (WOT) conditions. Calibrating the MAF sensor is the most critical thing to to on both of these vehicles in order to allow for consistent fueling under CL and Open-Loop (OL) conditions.

The Gen2 platforms appear to have very different logic when it comes to fueling during boost spool up. The Gen2 vehicles appear to not be using the delays as the Gen1 vehicles did. The stock settings for the CL/OL transitions work very well on the Gen2 platform, but the Gen1 platforms need to have these tables refined to allow the car to fuel properly upon spool up and between shifts.

The Gen2 platform demonstrates a very different response when DI Fuel Pressre drops. As DI Fuel Pressure drops below ~1600psi on the Gen2 platform, the ECU will immediately increase fueling by increasing the Injector Pulse Width (IPW)...which puts increased demands on the fueling system further dropping the DI Fuel Pressure. The additional fuel is a good safety measure, but this behavior makes it so Stage1 (S1) calibrations will be calibrated to stay within the capacity of the stock Camshaft Driven Fuel Pump (CDFP) and not calibrated to their full performance potential. Yes, a S1 vehicle with a upgraded CDFP will likley be able to make more power because more boost can be safely generated and higher DI Fuel Pressure can be targeted.

Ignition Advance = Both vehicles have higher resolution tables for ignition controls, although the Gen2 ECU has slightly more resolution in the ignition advance tables and the factory ignition curves are much more aggressive. These aggressive settings further stress the fueling system as they respond to Knock Retard values.

The maximum ignition advance tables are much higher as well.

Knock Retard = Both vehicles behave very similar. The decrement values for the 2010 MS3 have higher resolution (.001 vs .35) for KR responses). The 2010 appears to be a bit faster and adding ignition advance back in. Both vehicle add fuel immediately when KR is reported.

Variable Valve Timing = The Gen2 VVT has very different settings for the partial throttle areas.

Things to note...as with previous MS models, running with a good intake and TIH allows the turbo to spike more easily. Running catless in addition creates severe boost spikes as well as over boost conditions. I have a few Alpha testers running a calibration with pressure-based boost control to see if we can eliviate or lessen spikes. This new logic runs the cars richer than desired when the DI Fuel Pressure drops so you can have higher boost an less KR, but also less torque production due to the excessive fuel that is injected at lower pressures.

No Stage2 (S2) calibrations will be created using the stock CDFP unless users want to have boost limited to ~14psi.

Any vehicle making over ~330 WHP will need to also have the in-tank feeder fuel pump upgraded to keep up with the aftermarket CDFP. Fuel supply is only as much as is greatest restriction point...which is the stock in-tank fuel pump at this time.

Overall, the ECUs are very similar, but behave very differently for some critical features.

COBB Calibration Team.

[-cj-]

I find it interesting that an in tank pump upgrade is necessary... I wonder why not many people have run into this with BT's.

[CelestSpeed3]

I never even heard of anyone doing an in-tank upgraded pump yet.

Has anyone local done it?

Mine you I'll be happy with 300whp so I probably wouldn't need to upgrade mine.

[-cj-]

Im pretty sure no local has upgraded their in tank pumps yet, but there is one guy on MSF with dual Walbro's... Everyone thought he was nuts.

[Fobio]

Im pretty sure no local has upgraded their in tank pumps yet, but there is one guy on MSF with dual Walbro's... Everyone thought he was nuts.

At a certain stage, the whole fuel system needs to be upgraded, including boring out the fuel lines, etc. or modified to run E85 as they do in the states, no surprise there...is it worth it for this car? That's a question we all have to answer oruselves.

[-cj-]

Well im stuck with this car for a few more years, so I need to make them count. My plan is to make the car seem better/different every year so I don't get bored lol.

Providing you can keep the power planted, I think it's worth it. Just need upgraded fuel lines, I wouldn't modify the stock system.

There seems to be a lot of interest in the platform lately. People are doing a lot of good things and it seems like these engines are capable of making power. I just hope the MSFers can refrain from chasing off every potential company before they get off the ground. I can't believe how quickly people turned on CPE over a price increase.

[starscream]

Seems like the Gen 2 ECU is better in a few ways then the Gen 1 ECU. Does anyone know/Has anyone tried to swap ECU's (provided they get someone to swap the VIN in the ecu for the killswitch stuff). I dunno if they are the same connectors but looking at a few pics they might be.

In either case glad to see this platform going in the direction it is, lots of interest in the platform as cj said.