Auto 8 tuning and the CZ unit
 

Hi Folks:

Well after a day of crossing my fingers and a little bit of optimism, Speed Racer and I have forged ahead and did some tuning with my automatic 8 and the CZ unit. I know there will be many questions asked but please read our findings and then ask away.


Comments from Speed Racer:
Before we started to tune my10ae's auto RX-8 we verified that the electrical connections needed for the CZ unit were identical between the 4-port and 6-port motors. The electrical schematics showed that the connectors were the same and the pin-outs for power, ground, ignition, MAF, throttle position, etc... were identical. Looking good so far.
Yesterday morning we did several baseline runs in 2nd gear and recorded them using CANscan. The results showed that the car runs extremely rich in the upper RPMs, just like the 6-port engine. The lower RPMs look great and they should because the engine is running in a closed feedback loop.


Then we installed the CZ unit per Canzoomer's instructions. Detailed info and photos can be found in his vendor section of the forum. We only saw one minor difference during the install. The harness that plugs into the ECU only has 4 connectors (versus 5 connectors for the 6-port engine). The first map that we loaded on the CZ unit had the Air and Ignition maps set to zero. We wanted to make sure that the car ran the same as stock and it did. Above 4600 RPMs the car ran extremely rich and in many points the A/F ratio fell outside of the range of the wideband O2 sensor (A/F < 11)! :eek:

Over the course of many runs we slowly brought the A/F ratio up towards 13.5. This seemed to make a noticeable difference and I'll let my10ae fill in on the driving impressions:


Comments from my10ae:
First off I would like to state that even with these few tweaks we have done, the auto is still not as quick as the 6sp. With that said, the amount of tuning Speed Racer and I accomplished is a leap for fellow auto 8 owners. We did tuning from 4600 RPM to redline (approx. 7350 RPM) and have adjusted for the 2 port openings at approx. 6100 RPM and then again at 6900-7000 RPM. At these particular RPM's, we saw the car was going lean and adjusted accordingly. At the end of the day, the 2 port openings are very smooth and power seems strong till redline. The major tuning was done from 4600 RPM's to redline while in 2nd gear and in "manual" mode. The car revs much more freely and power can be felt from 4600K+. The power can be felt (read that as seat of the pants) when shifting from 1st to 2nd revving it to about 6.5K. Power that was not there before is there now. With over 150 miles on the car since yesterday's tuning, everything seems to be in order with no changes in the maps <yet?>.


Right now our plan is to make sure that the A/F ratios are stable and optimized before we make any changes to the ignition maps. I will drive the car for a week and we'll recheck the readings next weekend.



So far it is all good and the results look very promising! :D



P.S. Before anyone asks for the CZ maps, I need to point out that my10ae's CZ unit is slightly modified and it has all of the latest tweaks (i.e. full RPM readout and positive numbers in the Air table lean out the A/F ratio).

Very interesting--so what HP number are you all looking at from this preliminary tuning?

So far we are just tuning the A/F ratio to a more reasonable level (aiming for 13.5). We haven't dynoed the car so I can't give you hard numbers on the performance gains. In my opinion (take it for what it is worth) I believe that we gained at least 15Hp on this first attempt at tuning the 4-port engine. Nothing dramatic but you can still feel a difference.

I agree that it would be nice to see some dyno graphs but I'd like to hold off for a little while. At least give us a chance to optimize the air and ignition maps. Then, if my10ae is interested, we can do an A-B comparison between the stock and tuned maps.

We'll post up a graph of the A/F ratios that show the difference between stock and this first round of tuning.

Wow guys, as an AT owner I have to say thanks to you guys for such hard work and excellent research. However, as an idiot, I also don't know what any of this means :) I look forward to more conclusive tests and hopefully some Tuning the RX-8 for Dummies posts :o

13 - 15hp for theautomatic would put us backwhere Mazda originally claimed we were. When the automatic RX8 first cameout it was supposed to have 210 horsepower. So this tuning sounds great already. Maybenow we could reach 60 in the mid to upper 7s

Wow, that's cool! Good thing something good for power is coming out for you A/T drivers. Speed Racer knows his CZ goodies, he helped me out too.

Whoa - what a coincidence. Thanks for that! dmp also gave me a basic explanation - at least now I get the gist of it. Now I need the cz unit :)

You knowthe funny part about this my10ae isthat you posted about this almost exactly a year ago from today and Maurice saidtheyd have to make a completely separate unit for the automatic.


So I guessits time for me to order one or is there something else I need in additionto the unit?

I would hold off to see how my complete tuning unfolds. Speed Racer and I adjusted the A/F ratio, which helped, but we still have to tune the ignition maps. I am hoping better throtle response in the lower RPM's once the tuning is complete.

Here is what I bought when planning this project:
1. Dell refurb laptop on Ebay to do the tuning
2. Used CZ Unit 1.1 with cable
3. CANScan unit (serial) from Harrison R&D

My hopes are high as testing and tuning so far are going well :)

As promised here is a chart of the air/fuel ratios. As you can see the stock map looks great up to 6k RPMs then it completely tanks and drops below the range of the wideband sensor. Our first runs focused on trying to lean out the mixture above 6k RPMs. If you look at Run 12 you can see that we were able to make a significant change.

Tuning this car is a bit of a challenge because it feels like you are always aiming at a moving target. Making a change to one area can effect everything else around it. This is clearly shown in the midrange on Run 12. See how it is much richer than stock.

On the subsequent run I tried to clean up the midrange and it looks a lot better but I still need to smooth out the dips. The big dip around 6k RPMs will be a little harder to tame because it is very sensitive to any changes and tends to exaggerate any adjustments. There is also more work to do near redline.

Anyways, the main goal of this exercise was just to prove that the CZ unit could be used to tune a 4-port Renesis. So if you are interested in tuning your auto RX-8 I'd suggest picking up a CZ unit and giving it a try. :D

Did youguys say redline 7350 RPM? Whathappened to 7500?

Since the A/F ratio is off the chart, we compromised and went to 7350 as redline.

All this technical info within one week. My brain hurts. how would this affect the mpg?
i assuming it would get better because the higher rpms are being leaned out.

Sound like I'll pick up a CZ and installing before the turbo kit. Good luck guys with your tuning.

I have not seen a change in MPG. I have refilled the car once so far and still averaging the same distance. Yes I know the "same distance" is not a factual measurement. I have not taken the time to actually figure out my exact gas mileage. I do know that when the tank is full I can run 240+ miles before refilling.

On that note, I will be doing a few more runs and sending them off to Speed Racer. He wants to check and see if anything has changed in regards to the maps. Car feels the same, strong pull from 4600+ with no lag. Reviewing the maps will verify and if there are any spikes or drops, we will work on smoothing things out.

More info to come...:D

Good work--we'll be waiting on the updates

It looks like we have had a small set back with the tuning. my10ae sent me a couple of data logs and it appears that ECU has undone our changes with a long term fuel trim. If you look at the chart you will see that it is running extremely rich again. :(

my10ae and I live about an hour apart so it is a little challenging to get together frequently. Right now the plan is for us to meet up on Sunday and try again. So look for another update on Monday.

Back to the drawing board. :( At least I still have the zero map to start out with and then do some subtle changes to the A/F ratio. Hopefully we can get this adjusted so the ECU doesn't reset itself back to stock.

More tunage this Sunday. :D Anyone want to head up our way to see how its done? Drop me a pm.

i wondering if this happens to the 6 speeds ??? iam thinking you went to aggressive all at once and it sense it.

Yes, I have seen the same issues on my 6-spd and that is why I wanted to wait a few days to see if the changes actually took.

Anyone out there with an auto have a CANscan unit that can check something for me? If you have one, please check what your throttle position at idle and then again with your foor to the floor. I used my CANscan unit and finding at idle I'm at 16% throttle and at full throttle I'm at 78%


Anyone else experencing this?

We get 78% as full throttle also in the 6spd

any new developments?

Considering a foot and a 1/2 of snow fell over Sat night into Sunday, we cancelled the tuning day yesterday. We are shooting to do some more tuning on Feb 6 (BEFORE the Super Bowl). We will let everyone know what we did/checked on that day.


Sorry for the delay...

The throttle value has to be converted to a 100 scale.

use x-12*1.5...will give you real value.....