MPG before and after CZ
 

If this has been posted before, I haven't seen it, so I figured I'd start a new thread. I know in the very beginning of development CZ found a good improvement in MPG with the CZ unit. Now that there are a bunch of them out in the real world, what kind of gains (or losses) in MPG have y'all found? Did anybody track their before and after numbers?

It seems to me, when tuned right, both more power and better fuel mileage should be attainable. The power has been documented and quantified, but I don't know if the mileage has.

Thanks!

~ Matt

Mine hasn't changed that i can notice. I think I drive it harder....with the same mileage....so I guess its a bit better :D

with the stage 1 and the stage 2 maps i dont think my mileage increased. plus i had to use 93 octane gas(without it i can use 89). In the end it is more expensive to use the cz but hey power is power you pay for it one way or the other. One thing though --my exhaust tips sure don't carbon up as fast with the cz in! Also the exhaust has a differant tone to it with the cz in.
olddragger

Anyone do any long freeway trips? That would be a good indicator.

~ Matt

Interesting, I have yet to install mine but will be doing so soon, how would you
describe the tone change?

I wonder why there is such a variation in MPG between cars then? Also, the way I understood it, you can adjust the fuel map below 5000 rpm, if you desire.

~ Matt

Is this because the car is essentially running in closed loop? If the AFR is still a little rich, shouldn't we be able to lean it out a bit?

I thought variances in the MAF readings was causing a difference in the AFR, even at cruise. If this isn't the case, why do different RX-8s vary so much in their freeway mpg? I guess my understanding isn't complete. Thanks for the help.

By the way. A friend of mine has a CAN enabled OBD scanner and, when doing some 3rd gear test runs last night, my AFR gets as low as 11.1 at full throttle. Rich!

~ Matt

as far as the tone of the exhaust, i swear my exhaust note gets a little "deeper" when my unit is activated. I run the RB catback. I and others can tell a differance. Anyone else noticed this?
olddragger

Mine gets deeper and a bit quieter? with the CZ on

Note is deeper in mine too. I have tuned it to change 2% airflow down in the 2500 - 3500 rpm range. It hasn't affected much in city driving except more power after 3000 rpm (I have M flash). On freeway driving though, I used to get just up to 17 MPG with 50% freeway on a tank. Now, I get up to 19 MPG. I have stopped posting about my CZ experiments because I have been so busy lately and plus nobody gives a crap about MPG around here anyways. Too many stuckup skeptics.

I care about mpg, but a lot of it is the lack of range on a tank. I just hate having to worry about constantly finding a gas station. Anyway, when I get a CZ unit, I'll probably PM you with some questions.

~ Matt

deeper and quieter would be cool with me, I need to install and start tuning.