Mopar ECU data points

[treynor]

I've had the MOPAR ECU on my '01 RT/10 for about 2 months now, and have the following observations. I'd be interested to know if anyone else has seen similar behavior:

1) Check engine light has disappeared and stayed off.
2) Car runs hotter -- especially when sitting in traffic. I upgraded the stock radiator to a big Fluidyne unit, which keeps the temps between 190 and 205 all the time.
3) Car runs richer at WOT, especially if temps are above 190. I use the Roe Racing A/F meter to keep an eye on the mixture. I've noticed that where the stock ECU would fairly quickly adapt to a "2nd light from full rich" at WOT, the MOPAR computer frequently runs full rich at WOT. This seems to kill power -- I'll dyno 400 - 414 RWHP if the meter shows full rich, and 438 RWHP if it shows one click off of full rich. A/F measurements on the dyno show mixtures as rich as 11.7:1 above 3,500 RPM.
4) Redline has dropped from 6,250 RPM to 6,000 RPM.
5) Idle is much lower (~400 RPM).
6) Low-speed driving is more difficult -- car wants to surge at small throttle settings.

Has anyone else used the MOPAR ECU on a '01 car? If so, similar / different experience? How about on earlier cars -- noticed the car running hotter or richer (or both) ?


Ben Treynor
'01 RT/10, Belanger headers, Belanger exhaust, 3" high-flow cats, MOPAR ECU, smooth tubes & K&Ns.

 

[BurnR8]

ok...I have now gone from pissed to confused...my ECU added power on the DYNO and I lost it when I put the stock one back in...Now DC is coming out with a "better" one so where does that leave me....improved with more room for improvement? aargh!

 

[SoCal Rebell]

Ben, with you and I having the EXACT same mods I dumped my Mopar ECU. As stated earlier I lost 25 hp & 20 ft-lbs. of torque with it. I'll wait to see what the replacement is like. You going to Monterey in June?

 

[treynor]

I've swapped my stock ECU back in as of today. No check engine light so far. I'll be redynoing it this Saturday AM, at the same time I test out the New Improved Extra-Spicy BTR Viper NOS system. Results by Saturday afternoon.

 

[BurnR8]

BT!! You are difficult to keep up with....I guess Steve Blank treated you well with the ISO!!

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Let me know how it goes...I put my stock one back in and went backwards on power...good thing you have ABS in that 01 cuz you are building a monster!! Have fun....BTW- send me a PM on how you like your headwork.

 

[HouseofSpeed]

From my dyno observations...the Mopar PCM is less sensitive to normal OBD2 faults than the the stock ECU..hence the "race only" designation.

REMEMBER...if you do not properly drive cycle after a PCM swap or a loss of voltage to the PCM thru a dead battery, etc...you will have issues. My typical cycle consists of a 15 minute run on the dyno at varying speeds and loads (proportional brake aided). IF you do not cycle the PCM, you will see a dramatic drop in power by making a dyno pull or a WOT blast directly after the swap/recharge/reconnect.

WORD OF WARNING..to those using any of the A/F meters that "interpret" or "extrapolate and enhance" the STOCK 02 readings....these are strictly for squirrel/**** effect and are not a tuning tool...I REPEAT, not a tuning tool. Especially on a heavily modded setup...I can supply you with scads of data on the need for a wideband O2 in performance applications. Suffice it to say that the stock O2 only reads a very narrow (and LEAN) window in its single scalar volt...as such, no professional tuner will use any meter that operates off of an OE 02.

 

[treynor]

Kyle's quite right about the ECU learning curve -- after installing my headers & exhaust and resetting the ECU I picked up 12 HP and 10 ft/lbs of torque between initial dyno runs and dyno runs 300 miles later.

Regarding the O2 sensor, on the dyno we use a wideband O2 sensor, and I agree that you should not attempt to tune a car based on what you're seeing reading off the stock O2s. However, I have found the readings from the stock O2 sensor correlate accurately with the readings from the dyno's O2 sensor so far, albeit with considerably lower precision.

Any ideas about why the car runs hotter, idles lower, and has a lower redline?

 

[BurnR8]

oh crap!! now I have made an *** of you and me....

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