sequential fueling for the 13b???
 

Hi,anyone try the sequential fueling on the 13b?

and how I wire it with staged injection?:scratch:

thanks,frank

Sequential fuel does not work with rotary trailing ignition on the ms2.

Ken

ahhhh so bad, it will in the future?

Does semi-sequential work? Have you run it? See any improvements?

Has this changed. I really want to go sequential. if I use a sequential driver board can I bypass this?

Nope, it is currently a hardware limitation with timers on the ms2 chip. It's not something we can work around. If you want staged sequential, get an ms3.

I know this is a really old thread, but for the record I wanted to share that the first ecu I ran came from Australia and was a Stinger 4424 ecu and the fuel injection was sequential. However, if I remember correctly, the leading and trailing split was at 0 all around and not adjustable. The car ran really well with it and got the best gas mileage we ever saw - it consistently averaged 25 mpg or a bit more and never went below 20 or so. I was really impressed as it was a large streetported 13b with ITB's and a to4b. Unfortunately, no one was familiar with that particular ecu, and seeing as it was my first one, I had a hard time with it and sought a reputable tuner. He also had a hard time and gave it his best, but It didn't turn out the best, so I went to Microtech and never again saw that great a gas mileage. It averaged about 18mpg from then on. From there I went to Megasquirt and never looked back. The gas mileage is about the same as the Microtech setup was.
So yeah, I just wanted to share how that first setup gave great gas mileage being that it was sequential. I can't see how else it could have.

Which MS do you have? I got a MS3 Pro which does full sequential & any split you want(even negative).

Your mileage loss was likely due to the fact that Microtech's interpolation algorithm is absolute and utter crap. It's nearly impossible to get a smooth tune with bins every 5" apart in vacuum and interpolation that doesn't seem to exist. It's like the ECU only recalculates the space between the bins every second or so. So while Microtech is sequential, it barely matters.

18 MPG seems a bit low though, however the ITBs likely have a major role to play with that. I've been able to get MPGs in the low 30s (highway, of course) on even old batch fire MS1s and street ports.

Just to add something to the thread, MS3 supports sequential when MS3X is installed (as it should always be). MS3-Pro supports sequential out of the box. Anyone running a MS3 level ECU should be sequential.

Now have I noticed much of a difference shifting injector angle around on MS3 at idle? Well, not really. I was expecting a dramatic difference in wideband readings as I moved the injection angle but didn't really notice a thing.

When I first put sequential on my basically stock S4 NA, I actually noticed a pretty big difference at idle. I kept changing the angle and there was a "sweet spot" where it run most rich... I set it there and leaned it back out to the AFR I wanted. On a whim, I set it 180 deg out from that value (tried to get it as wrong as possible) and the engine wouldn't stay running at any ignition timing I tried.

I tried other angles 10-20 degrees away from the bad angle, and it ran fine again, though the AFR wasn't exactly right, and was a bit leaner (maybe .5 AFR off) from where I tuned.

So I think it probably depends greatly on the porting, condition of the injectors, etc...

I did find that I was able to get better gas mileage with seq on my setup as well once I did the same exercise of adjusting timing to what made it run the most rich, then leaning the VE table back out. Eventually I went to negative split as well. I never quite got it into the 30's for MPG, but I was able to get mid to upper 20's.

Using EAE for most of my accel also helped my mileage and helped drivability a lot.

Ken

I'm eager to perform the same test on my Cosmo. The FC I tried different injection timings with has old low impedance injectors and resistors. Likely not the best conditions unless the injector lag times are dialed in perfectly.

As my Cosmo has RX-8 injectors, I expect a much more precise control and am fact counting on it with the hopes of being able to run a cat without an air pump. Idle is my only unknown as even batch fire will run cat-happy ratios everywhere else.

I'm eager to perform the same test on my Cosmo. The FC I tried different injection timings with has old low impedance injectors and resistors. Likely not the best conditions unless the injector lag times are dialed in perfectly.

As my Cosmo has RX-8 injectors, I expect a much more precise control and am fact counting on it with the hopes of being able to run a cat without an air pump. Idle is my only unknown as even batch fire will run cat-happy ratios everywhere else.

Not to beat a dead horse, but I recently upgraded firmware and the 3.4.1 has an batched timed injection angle. Can this be used with factory ignition being I'm not using the 3 and 4 injectors?

I will have to check how the timers are used. Been a very long time since I looked at that code.

Update?
 

Has the code changed regarding how the timers are used in the last few years?
Currently running the latest MS2/Extra 3.4.2 firmware on the 3.0 board with an unmodified CAS.

I ask this because, in the latest MS2 hardware manual:
1st): Under section 6.9.10.2 (NipponDenso CAS with two G teeth), it states "On a rotary such as the RX7, or a two-stroke engine, full sequential fuel and spark is possible as the engine cycle spans 360 degrees".
2nd): Under section 4.10.4 (Sequential Injection 'mod'), it provides the steps and mods necessary to provide sequential fuel injection for up to 4 injectors.

Is this now possible on rotary applications with the latest firmware and the necessary mods being performed?
I was wanting to install the jbperf Peak&Hold Injector Driver Kit for all 4 low-Z injectors and to run them sequentially now.
Can this now be done?
I wanted to verify before installing the P&H board and doing said mods.
If anyone can let me know, I'd greatly appreciate it.

https://cimg8.ibsrv.net/gimg/www.rx7...502f3cc18b.jpg

https://cimg7.ibsrv.net/gimg/www.rx7...f8ff5c1022.png
https://cimg5.ibsrv.net/gimg/www.rx7...1454c7cf6f.png
https://cimg9.ibsrv.net/gimg/www.rx7...603b6d45c9.png

Unless this was the final say (?) regarding the MS2 that Ken stated almost 6 years ago:

As far as I understand it..not enough timers in MS2 as one is used for rotary trailing.