I have always found that on long trips cross the US that if I locked in at about 72mph the RPM would hover at 2700 and I typically got my best milage on those trips pushing 24mpg over a 800+ mile run. After the tune it look as if at 72mph the car now sits at 2500 rpm to hold that same speed. If that is what is happening and not a change in the guage then it could be that the car is using less fuel to create the power needed to hold speed . Over time/miles that is going to net some additional miles per tank. Keep in mind this won't really show up around town (atleast I am not seeing it) but if one is out on the highway locked in at a single speed for say a few hours then it should begin to show up in the mpg numbers.

 

In keeping with my theme, I just had my 2013 smog check. I run a stock pulley and engine with no mods, just heavy suspension updates. California 91 crap octane, with the awesome winter additives that make the rating even worse for pollution control (which is needed mind you, the air up in NorCal is pretty nice). I passed my smog check with flying colors. Here are the numbers from my test:

2005 Chrysler Crossfire SRT6:

15mph: 1421 RPM
CO2 measured: 14.7
O2 measured: 0.0
HC (PPM): (MAX ALLOWED: 55, average: 4) MEASURED: 0
CO %: (MAX ALLOWED: .50, average 0.01): MEASURED: 0.01
NO (PPM): (MAX ALLOWED: 437, average 16): MEASURED: 48

15mph: 1497 RPM
CO2 measured: 14.6
O2 measured: 0.0
HC (PPM): (MAX ALLOWED: 39, average: 4) MEASURED: 0
CO %: (MAX ALLOWED: .48, average 0.01): MEASURED: 0.00
NO (PPM): (MAX ALLOWED: 724, average 15): MEASURED: 50

So, aside from having more NO PPM than average, the Eurocharged tune does hit the mark for CA smog. In fact, the RPMs only go up by 76 RPMs to get from 15mph to 25mph which also shows some serious low-end gains in torque at low RPM engine speed differentials. That's the initial "feel" I felt after the tune... I stabbed the gas pedal and felt more seat-of-the-pants torque/movement of the car from changing throttle tip-in at low speeds.

 

Torque does not come into it, rpm's determine speed, 76 rpm never, 760 rpm more like it.
Torque determines stump pulling ability.

 

OK, whatever. I read the numbers off the smog check. It was as stated. 76 RPM difference for 10mph increase in speed on the rollers. It's all computerized and measured, printed. Granted the rollers are way less resistance than a street/pavement, so it would be different on a street where the tires have different contact. Try to understand that this was a controlled environment test, required by California, not an actual "dyno". Drink some coffee and relax. Just providing fellow Californians some numbers to go by when their "time comes" for a smog check on 91 octane, using the Eurocharged tune, with stock motor.

 

thank you cudaman i think this info helps give us calif. drivers with the tune some insite....i know E/C has tunes for your upgrades and i had my srt tune redone after i did a 65 pulley, 55 air intake. and the retune did make a difference i could feel ...so what tune do you have?( just wondering if all the tunes will pass....and do we have to take all our motor upgrades off to pass? )

 

Before getting the tune, EC has you fill out their form with your mods. Since I had none, at stock, I put "none". did put CA-91 octane on their form. So, they most likely have a bevy of tune files for various octanes (most important), and tunes that they've done on modded Xfire or SLK platforms using the same engine. I would contact EC to get their list of tunes, with various pulleys, intakes, etc. They more than likely have one that is pretty close to your mods. They seem to know their stuff much moreso than I. I just want to pass smog, have some fun, and get a bit more punch on the pedal. No track time, dynos, or proof that I have a large male organ. My girlfriend likes my Xfire and my organ, and she's the only one I have to please other than myself. I don't need a tune on that, either, thank goodness. But, I have enough confidence in EC that if they made an male-organ tune, I would try it out.