Secondary angle split help!
 

I've been trying to set up my staging but I'm having problems. I can get my engine to rev perfectly to red line (no sputters) when I un-click the staged injection icon. So yea the primaries are doing all the work. As soon as I enable staged injection and move the staging bar to a low load region (so I can get them to come on in light loads and adjust the angle) The engine sputters and wont rev. My secondaries are mounted about 4" higher up the runner than on the factory 20b LIM. I'm using common mode. I've tried adjusting the angles up and down while holding the revs at 2k but cant get it to run smooth at all when they kick in. I have noticed that my injection times for the secondaries are the same as the primary. Thinking it was over rich, I lowered the mS values in the 2k region in half but it still doesn't help. I'm running the factory 20b primary and secondary 550cc injectors. Now my engine is still on the test stand so I don't know if not having any engine load is why it's doing this?

My guess is you're flooding the engine with fuel when you're attempting this. Injection angle won't help a bit until you get the fuel right. If you're interested in optimizing the secondary angle, maybe connect the secondary injectors to the primary connectors and run the engine just on the secondaries?

I think your right about the flooding because on two occasions I thought I had the split correct but it only happened while I was running out of gas. As soon as the fuel pressure droped to 30psi, it ran pefect till it it ran out of gas.


Hmm didn't think about running the secondaries as the primaries. If I do this, then how will I calculate the angle when I get thing back to normal? The thing that confuses me is, shouldn't the secondaries kick in eariler than the primaries since they are higher up the runner? The angle split page shows to be able to only adjust them for after the primaries fire. :confused:

If you want the secondary to fire 20* before the primaries, program the split for 340*. ;)

You're working at this way too hard. You won't find much in split angle once you're off idle, especially on the secondaries. The chaos of air moving back and forth inside the manifold combined with an injector that is open for 50+% of the cycle means the practical result is less than nth degree requirement of precision.

Gotcha! What can I say? I tend to be over excessive when it comes to trial and error. When I build something I want it to work to perfection (or alteast the way I imagined). It's the best way for me to learn things. Since I've never tuned anything before. Thx for all the help! :)


One more thing! I've come to find out recently that my engine has been running perfectly with 4ms on my LS1 coils. Before I was having weird rpms glitches above 6k on the Halwin gauge page and the engine would sputter. It was like I was hitting an early rev limiter (which I have set at 8,500rpms. I thought it was my trigger. After adjusting the Ms values to 6ms it got worse. Curious I dropped it down to 4ms just to see what would happen and the engine revs beautifully with no breakup. :confused: Any idea what that's all about?

No harm at all in experimenting to learn!

No idea on the charge time. I have LSx coils running on a few cars with no issues. I set charge time to 5.5ms on most of them. One is a road race car that gets shifted at 8000+ and it runs with zero issues. Breakup could be trigger related or simply the ignition giving up on you. Any chance you changed fuel mixture along with altering the charge time?

I haven't changed fuel at all yet. It's just a night and day difference. Well I know with my fd trigger set-up I had to set the angle all the way to 81 before the pointer lined up when I was zeroing my timing. I'm not sure why I'm so much higher than everyone else. I have my trigger harness completely away from the main harness all by itself. It runs on the passenger side and runs underneath the Fd water pump. I'm getting ready to put up a video of it running in the next couple days. I can change them and show you what's happening. I also remember it running really well in the past at 4ms. At the time I didn't know what was going on. I bought these coils used so there may have been a problem with them from someone else trying to run 5ms or higher.

For what it's worth, here is information from Mazda on fuel injection timing and staging for the 2009+ series 2 Rx-8:

https://www.rx7club.com/attachment.p...1&d=1287102850

https://www.rx7club.com/attachment.p...1&d=1287102850

https://www.rx7club.com/attachment.p...1&d=1287103233

Series 2 Rx-8 has four injectors just like the s4-s8 Rx-7. This certainly looks pretty sophisticated. I find it interesting that during staging the primary pulse goes up and down in steps while secondary pulse is increasing mostly linearly.

Maybe i'm stupid... what the eff is 455 degrees?! Does that mean it's waiting for an entire rotation and then some more rotation?

That is timing during cranking or maybe right as the engine is firing up, so it's not using this calculation all the time. If two rotations equals 720 degrees we can sort of count backwards. The CAS may sync at TDC (so start at 720 degrees), then wait 265 more degrees, which would equal 455 degrees BTDC timing. Then it yes fuel injection would be advanced more than one full rotation.

Take a look at the first graph again, it shows the 455 degrees and the 275 degrees used during normal calculation.

Confirmed it was overly rich during staging. Now I have a damn oil leak. :mad: The hose I'm using is rated at 250-300 psi. I guess it can't handle that pressure along with hot oil temps. Oh well the joys of modding.