muythaibxr

no, at 255, he's going to be rounding due to use 8 bit variables to store pulse width.... the transition will likely take no more than 25-30 cycles (I could do real calcs if you want).

I actually added code to end the transition early if rounding causes it to need to end early.

Also, it's ignition events not cycles, not sure why James changed the label to cycles.

Finally, like I've said, I never knew my stutter was a spike on the VR circuit until about the 3rd or 4th drive when a long enough spike happened to cause a visible spike in rpms.

SCCA RX7 RACER

Hi Guys,
As you can see in my settings I did what you have posted. The hysteresis pot (R52) was turned CW for 12.5 turns until the car would not start. At this point I turned it CCW .5 turns. Stage injection was set at 50. The 255 was changed to 187.

I ran the car 18 times. I cleaned up the idle and the typical driving around pit speed. I moved the secondary up to 4800 RPM when they come on. I smoothed out the best that I can before and after the 5800-6000 RPM range. When you look at the data logs pay attention to the second set of shifting points the first set is just me going to the end of my parking lot area. The second set of shift points is when I’m hard on it (First and second gear only I run out of room). My car will be on the track pulling between 5300 RPM and 8500 RPM so don’t pay attention to the slow drive around operation or so much or the first gear pull. All my races are all flying starts and I will be in second gear and at 5500 RPM.

As before my main concern is the stutter at 5800 to 6000 rpm. It is not random it is like clock work. In first gear, second gear or just standing still if I rev it up it hits that 5800-6000 RPM wall.

I have two sets of logs T4 and K4 are with the RPM values on the VE table with standard spreads. Then I change the spread to a narrow up the area where I am having the problem. I thought that may be because of my porting I needed to fine tune out the VE table in just that trouble spot. But it did not change same RPM trouble spot. So if you look at the RPM1 data you will see what I have tried to do. I all so thought it my help in trouble shooting this on spot.

Have a look guys and tell me what you think it could be. Also to note before I installed the injectors I ran injector cleaner through all 4. Primaries are 460 and the secondary are the 800.

Looking forward to a positive reply.
Best Regards,
Kim

SCCA RX7 RACER

Have to post each one seperate

SCCA RX7 RACER

More Data For Ya

SCCA RX7 RACER

DATA for K4 is too large. But if you could see it it has the same layout as the RPM data log. The only differance is like I mentioned earlier the spacing is wider on the RPM ranges and thats it.

Best Regards
Kim

SCCA RX7 RACER

Data 4 was to large and 3 is very close to 4 have a look. More information is better in this case

SCCA RX7 RACER

The differance from 3 and 4 is that number 4 was a litter closer to the 14:1 AFR I was looking for.

muythaibxr

These datalogs CLEARLY show rpm dropouts and general electrical noise. Where do you have your MS grounded?

Basically if you sort out your electrical problems, these noise problems will go away. I never saw any of the dropouts at the same point where you're noticing your problem, but you're definitely getting dropouts.... some of them may just be too short to be shown in the datalog.

Also, please stop posting new threads.... this is the same problem as the last several threads you've started. I'm merging this thread with those.

SCCA RX7 RACER

Hi There
I have all my grounds except #7 returning to the DB 37 then to the floor of the car. From the floor ground lug I have a cable going to my battery negative. From the engine block to the frame under the hood I have two other grounds one on each side. The CAS shielding ground is located on the engine block. The ground for #7 returns to the DB37 terminal #7 then has it's own wire returing to the negative on the battery. Aso I followed the method of the O2 sensor grounding them on seperate wires and spots.
Kim
I did not know about the thread thing sorry.

Eagle7

Kim, looks to me like you've got way too little fuel in your map. I've got a setup similar to yours except no porting and stock injectors. I just went to the dyno yesterday. Peak torque is at about 6600 RPM, which is where it needs the most fuel - there's a big peak there in the VE map. I've attached my VE table, which produces a nearly flat AFR from 4400 to 8000 at 90 kpa. The rest of the map is questionable.

muythaibxr

I think this is your problem. Instead of running a ground from the MS to the floor to the battery, I would run the MS grounds to the engine, and run another engine ground to the chassis or battery. Running to the chassis directly is a good way to get ground loops and other noise... and looking at your coolant sensor signal and air temp signal, you're getting noise all over the place, which could mean your ground is floating around.

Also, you are running a bit lean, I'd suggest running 13.2:1 above 85 kPa on an NA... maybe even 13:1.

SCCA RX7 RACER

Hi Guys,
I moved the ground wires from the chassis ground to the engine block for the Mega Squirt. I have the sensor wires going to the engine block for ground. I installed a large main ground wire dedicated to the Mega Squirt wires and ran it to the negative pole of the battery. I replaced the shielded CAS wire with another one and have that grounded to the engine block (One end only). Also the CAS wire runs 8-12” away from any other electrical cable and is in its own loom. I also crossed the Neg (White) and Pos (Red) wires of the CAS to see what would happen. It started but ran like crap so I now I had that right (Switched them back of course) All my electrical connections on the car are silver soldered and shrink tubes. Ever wire and electrical switch on this race car is new. All the wiring for each electrical system is ran separate and in its individual loom. Each electrical system has its own fuse to protect it. Spark plug wires are new and resistor type and run away from any other wiring.

I tried going extreme on the VE table 100 in each slot from 40 to 100 MPA and in the RPM range of 5500 to 6000. All it did was run rich 10.5 to 12.7 and still hit that cut out wall at 5800 RPM. Just as before.

Before I put the MS in West-se looked at it and found that he had to change 3 items around on the V3 board. I did not build it I purchased it from a company on line. Two of them, both needed the same changes. Is there some thing in the MS that can cause this problem to happen at the same time every time like clock work?

Running 460 on the primaries and 800 on the secondary is this an issue? Could the Injectors be a problem and if so would it be as consistent as it is?

If this glitch was at 2500 to 3500 I would say screw it but it right in the power band and I can’t run it. Still looking for an idea

Kim

muythaibxr

I don't remember from your settings, and I am not near my laptop right now (~30 miles away from it), so can you tell me which style wheel decoder you're running? 24s9 style or 025 style?

Noise from various electrical sources can cause this, something might be causing an ignition reset for you at that rpm. Nothing else will cause the staged injection to turn off.. I've had various stuttering problems at around that same rpm when using 025 style though.

Try this: Instead of using an rpm-based switch point for staging, change over to MAP or TPS. If this is really an rpm dropout, you might still get a bit of a stutter there, but you shouldn't go lean at least.

Before doing that, if you're using 025 style for the wheel decoder, switch to 024s9.

Eagle7

Ken, can you explain the difference between the 24s9 and the 025 wheel decoders? I've always assumed the 025 was better (because it was newer).

SCCA RX7 RACER

025 was not the right setting once I changed it over to the other I did the Test at Idle No studder. WOW unreal,

THANKS YOU GUYS EVERY ONE IS TOPS IN MY BOOK!

Every little bit helped. Now I,m going to put back the wiring in place and do a few runs. I'll work on tuning this week and I have a race next week. It's at our local track (Mission). West-se if you see this give me a call if you want to come down. Free entrance to the track and food for the whole week end.

I'll Post some information for tuning for the next guy once it runs a little better.

THANKS, THANKS AND MORE THANKS,

Best Regards to all,
Kim

muythaibxr

025 has some averaging to help get rid of noise, but I've found that on wheels of less than 36-1 teeth actually have problems with that code.

024s9 doesn't do any averaging.

Neither of them make any difference unless you're running a missing tooth. With a stock CAS you can choose either one and it won't change a thing.

Ken

Eagle7

Thank you very much.