Drayux

Hello! I want to apologize in advance as I know there is much I don't yet know. I'm brand new to tuning cars, yet incredibly fascinated with it and probably too ambitious for my own good. At this time I have roughly 8-12 hours into watching whatever tuning basics videos that I can find, and anything relevant I can find to read.

I recently picked up an Adaptronic PNP ECU for the RX-8, and though everything conceptually makes sense, I've experienced the "slap in the face" of just everything you can do with this ECU. I have gone through the instructed startup: I have uploaded the basemap for the renesis to my ECU, I have configured the open and closed voltages of the TPS and selected the correct injectors. From there I enabled the timing lock, and started the car, using a timing light to adjust the base angle (mine worked out to right at 3 deg of advance to get everything lined up.)

So now, I believe myself to be at the point one would begin tuning the car, and this is where I've accepted that I don't know enough about what's going on such that I can make the correct decisions moving forward. The car idles very rough, such that the entire car shakes. Describing it over text is difficult, but it acts as though it's constantly about to die, and then suddenly starts back up again. Any given second the RPM seems to range anywhere from 1400 to 1650. I don't want to keep the engine running any longer than I have to, because I imagine this is not good for it. I am willing to film a video if that would help anyone help me with the problem.

To fix this, I have attempted to alter both the fueling and the ignition timing (via the trim so as to avoid messing with my basemap just yet) with no luck either way. As of now, in the idle range the engine sits at roughly the following configuration: Leading: 5 deg BTDC, Trailing: 10 deg ATDC, and the target lambda is around .95 (I believe this lead to a fuel value around 66 on the table, but I cannot say with certainty at the moment.)

I have a couple ideas final about why it might be behaving like this, though again, I'm not confident enough in my theory and unsure about fixing the problem in this way.
a) If I'm not mistaken, the auxiliary ports bypass the SSV on a 6-port. Thus the activation for the SSV may have been tuned such that it is starving my engine of air when it needs it most on my 4-port, though I get the reading from the MAF that air went into the engine.
b) There is another "choke" mode configured the basemap I am unaware of.
c) Despite configuring my injectors, the ECU might be treating the estimate like there are 4. Though I am near certain I read somewhere on here only the primaries are used within the idle range, which are the same across the 4 and 6 port engines.

Final things to note about my car:
- I bought it as an automatic, and swapped it to a manual a year ago. I still have the 4-port engine in there, and plan on attempting to bridgeport and rebuild the 6-port out of the parts car. Thus there are no auxiliary ports, and only 4 injectors, the primaries being red 290cc and the secondaries being blue 480cc.
- As of now, I do not have a wideband sensor. I plan on getting one soon, but the target ratio for idle is within the range of a narrowband equipped on the car stock...right? I found very limited information on this, but even with the engine off (and the ignition on) the ECU claims to read .8 lambda, so perhaps my issue lies there.

Thanks to everyone willing to throw their advice at me, be it in the form of where I can learn what I need to know, or some solid ideas what to try next. I appreciate it!

Loki

iTrader: (1)

Can't help with most of that, except this: the stock front O2 sensor is wideband. So you have what you need there.

Also I'm not sure you can configure a 4 port ECU to drive 6 injectors via software. Maybe I'm misunderstanding what you mean here.

UnknownJinX

I just know 2 things:

1. At idle, a stock car should have thet̶r̶a̶i̶l̶i̶n̶g̶ leading spark plugs fire at 5 degrees ATDC, so your t̶r̶a̶i̶l̶i̶n̶g̶ leading timing for idle is way off here at 5 degrees BTDC for a stock car. Also, I believe the trailing plugs fire before the leading plugs at idle, so it looks like your trailing timing is off as well.

2. Bridgeporting a Renesis have been claimed to be a waste of money and does nothing. I know RX7Specialties in Alberta will straight up decline to Bridgeport a Renesis.

Edit: Oh and I almost forgot, but RX-8, in NA and stock form, is very hard to tune extra power out of, so IDK what you are achieving here. Sounds like you need a professional tuner to handle this situation.

Drayux

Oh that's great to hear actually! I thought I read that, but then the startup guide suggested purchasing one as thought it didn't come stock. Do you know of ways I could test to see if this is working properly?

And this ECU should support both 4 and 6 port, as well as pistons and the like. I know that the basemap I loaded to it was originally made to be for a 6 port, and can be modified accordingly. Hopefully that clears things up!

Thank you so much!

Drayux

So idle needs to have a negative split? I thought I heard so elsewhere but I it sounds a little crazy at first glance. Do you know roughly where that split begins to go positive? (i.e. leading before trailing)

Regarding the bridgeport, that's a very tentative plan. I have heard similar, as the biggest limitation on the renesis engine is the size of the exhaust ports. That said, I have seen it done, and it's simply something I'll be putting more research into when the time comes.

Finally, the purpose of the ECU is a number of things. As my car was tranny swapped, I am still somewhat limited by the auto ECU with a redline at 7500. I also am planning on installing a flex fuel sensor so I can primarily run e85 as it is considerably cheaper where I live, and correct me if my chemistry is wrong, but I am told it burns "cleaner" than gasoline as well, resulting in less carbon buildup. This is also an intermittent step as I plan on turbocharging the car in the future once I can afford it, and there just isn't enough configurability with the stock ECU, especially considering I need to fork over at least $500 just to mess with it.

Thank you for the help!

UnknownJinX

Basically, a stock RX-8 is designed to run negative split timing at idle, and positive except idle.

A 4-port engine, even with a manual transmission, will be restricted to a 7500RPM redline. It's made to be slightly torquier than the 6-port, but at higher RPM, the lack of the 2 extra ports will choke the engine. You can lift the redline, but I won't be surprised if you will have basically no torque after the original redline.

E85 will burn cleaner, but your gas mileage will also significantly suffer, so about cancels out the cheaper price of E85.

Drayux

Ah that's a very fair point, and something I'd be curious to find out!

And that is correct, e85 has about 2/3 the energy of gasoline, so you can expect roughly 2/3 the gas mileage. Where I live, ethanol is about $1.90 a gallon whereas 91 octane (the highest I can get) is about $3.50, so it would still be financially viable.

Thanks again!

UnknownJinX

So I double checked the service manual and turns out, I had the spark plug timing at idle wrong. Oops.

At idle, trailing fires 10 degrees BTDC, and leading fires 5 degrees ATDC, so your timing for both of your spark plugs are the negative of what they are supposed to be.

Edit: So I found another S1 service manual that claimed that trailing fires 23 degrees BTDC and leading fires 5 degrees BTDC. Huh. Both of the other S1 manual and S2 manual say it should be the 10/-5 timing combo.

Can anyone with a stock S1 check quickly with your OBD2 reader?