My experience was an overly rich a/f ratio with two mods, intake and HFC's. So much so I felt like I needed to tune. My dyno was nothing extraordinary but it did show my a/f ratio in the low 10's, even high 9's.

The results after tuning are a noticeable midrange and top end punch that I didn't have before. I could feel the engine falling on it's face above 5500 rpm due to the air fuel ratio. I haven't strapped it to a dyno yet with the tune but the traction light will come on in the first four gears (7AT) under hard acceleration.

On gas mileage...when you're cruising on the highway, you're in open loop and the ECU is taking feedback from the 02 sensors. It has a target A/F ratio it shoots for (stoich usually) so a "tune" won't affect that. What WILL affect your mileage, and I experienced this first hand, is the throttle hijack and the amount of time you spend hooning the car at WOT with your new power. But seriously, the more aggressive throttle does take it's toll on mileage, especially around town. It is better from a dig (stop) but I don't always like it coming out of a corner or when rolling slowly and then accelerating.

Personally, I like a more progressive throttle and I have two throttle maps, both more aggressive than stock. One is moderate, one is highly aggressive. I'm actually going to lower the moderate to minimal. I'd rather have a more linear ramp up to WOT, especially when it's wet out.

The other benefit to ECUtek is timing control and performance traction control which is better than the VDC system. If it's really nasty out, I'll use VDC.

I also noticed the throttle hijack screws with the transmission's shift logic on the 7AT. I actually liked the 7AT but I also knew how to drive and program it (it's adaptable) to my driving style. The hijack sort of ruins that magic and it can hunt for gears a lot more when not going all out.

And don't forget to have them up the line pressure on your tranny if you have the 7AT. I have a mild bump and the actual shifts are more firm and faster than stock. It won't change the time from clicking the shift paddle to the time it starts to shift but it'll shorten the actual shift time. Doesn't seem to upset the stability of the car. If you have a manual, just ignore this portion.

I was told that a 1-2 MPG increase is likely although, I am not getting the tune done for that reason. When I drove home from ZdayZ in 2015, I was averaging 30 MPG when I pulled into my driveway (all freeway).

Unsure what your bolt-on's are...as I can go 500+ miles on a tank of fuel @cruising speed of 70-75mph.
28,29mpg on Hwy.
24,25mpg spirited driving; all after tune w/CAI,free flowing exhaust w/test pipes.
Ensure that your tire diameter is oem/as a shorter tire will mislead your mpg.
#1 reason for my tune (ensure proper air fuel ratio@wot)
#2 maximize hp/tq from money spent on bolt-on's
#3 felt like I gave it a small shot of nos after tune...as you can see that most people gain 20whp (+ or - a tad) no fuel mileage hurt on my end.
#4 no speed-limiter anymore,,,so no need for explanation here.
#5 knowing my engine is healthier & not leaning or over fueling.
Money well spent!
:)


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Well, it's been a while since I started this thread, but I wanted to provide an update...

Got the Z tuned at Dynosty on Tuesday, May 17th on the way to ZdayZ. Below are some of the final results:

1) With HFC and CBE: 288.45HP and 240.07TQ (tested on a Dynojet from another tuner)
2) With HFC, CBE and CAI: 295HP and 250TQ (approximate numbers from Dynosty on Dynojet)
3) With HFC, CBE and CAI (and Ecutek tune): 312.06HP and 260.58TQ. I am really impressed with these numbers as I was HOPING to get to the 300HP mark.

The car now has a proper A/F ratio at full throttle (was way lean before) and the drivability is markedly better. While driving the "Dragon" I could keep the trans in 3rd or 4th gear more that I used to because of the lower and mid-range power. The throttle response is also more linear and direct than it used to be. The MPG has increased slightly too, but this was not a deal breaker if it didn't.

All I can say is that if this is something you are contemplating, I can say with 100% certainty that I made the right decision. I also want to give a big shout-out to Logan and Hal at Dynosty for their care and concern for me and my Z during this tune. They are professional, courteous and they know WTF they are doing. This is by far the best $$$ that I have spent on the Z to date.

They sure do go the extra mile!

Mine's there now.

Awesome. I have similar mods - RTP, K&Ns with MAF tubes, catback - and am hoping for ~310whp. Scheduled for June 23rd with Hal for an EcuTek tune and cannot wait, will be making the trip all the way from KC. Can't wait to see power under the curve and throttle response improvement, hoping to leave with a much more intuitive and active car.

If your signature has the current HP/TQ numbers, they are almost identical to mine. You're gonna love the car even better now...

Like I've been saying, you're gonna really like Dynosty and the people there. You'll never realize why you didn't get the tune done sooner.

I got there at 8:00AM and was on the road about 10:30AM...

Any places for tunes in north Florida? Is the E-tune worth it with mods being under drive crank pulley, K&N drops, Stillen HFC, and thinking about aftermarket CBE?:driving: