2Lucky2tha7

iTrader: (3)

I figured that I should post this up while I'm working at it.....
Basically, is the resolution on the MS-I processor "good enough" to "handle" above 7k rpm's? I'm wondering because although all of my afr's at WOT are aimed at 13, They seem to deviate a little bit at higher revs, along with all of my other readings that seem to fluctuate quite a bit above 6k, even though all the surrounding values for my spark and fuel are the same-- my pulse widths, afr's, MAP readings, etc. Everytime I get to about 7k and up, it "hiccups" and slight detonation comes and goes. 2nd gear up to 8.5k seems ok (now), but 3rd gear above 7k usually produces slight detonation. To remedy this, I am currently at 22 degrees leading at 6k, 19 degrees at 7k and 18 degrees at 8k and up with 10 degrees of split from 6k and up. I tried 5 degrees of split and the detonation is intolerable. The only things that I can come up with are that I have a: mallory hyfire ignition box, series 4 turbo block that's street ported w/ 9.7 rotors, a modified CAS, and an MS-I processor. I'm honestly not sure as to which part would be the real culprit. I know that the series 4 blocks had less timing from the factory, and it's hard to blame the ignition box because that really wouldn't make much sense, I know that the MS-II processor has a higher resolution, but I am using a modified CAS. When I spoke to someone at Mazdatrix, he recommended running about 24-26 (sometimes 28) degrees of leading on 87 octane at WOT with about 4 - 6 degrees of split. Well, I seem to be departing from those figures quite a bit and it has me wondering. Does anyone have any input?

Thanks
Brian

13bdarren

Which version code are you using I have read on other forums of poeple having the same issues. Some of the early code had timing problem at high rpm. I have experience the same problem you had. I have broken many engine trying to fiqure it out. The newest code out is suppose to have fix it. I was running 11 and 12 deg of timing and still having issues @ 15psi. I need to build another engine and test it again. I did manage 390 hp, I hope to make more with timing problem fixed.

2Lucky2tha7

iTrader: (3)

029y4 (the latest one available). It's on a 3.0 board.

Jobro

iTrader: (2)

Have you got your timing zeroed correctly on the marks on the crank and front cover?

You don't have hardware latency set too high so it advances more?

The figures that mazdatrix told you, I have used those on a nonturbo 12A streetport also they work really well.

There isn't really resolution lost with the modified cas, What you loose is noise immunity and that should not really be a problem with higher revs as the cas generates higher voltages which should be much stronger than any noise.

It is possible that your CDI is causing noise on the cas lines. Crane Fireball Hi-6 suggests that it creates more Electromagnetic Interference than OEM ignitions. I know you are using a different brand but I'm sure the problem is very similar.

All you know at the moment is the symptom and if you keep detonating the engine you will be rebuilding it prematurely even if the detonation does not kill it on the spot I've had an engine let go quietly a few months later. Quick blat and it threw 3 apex seals under 6000rpm.

You really need to find the problem. What spark plugs are you using. I have had no end of troubles with non-resistive plugs. I'd suggest BR8EQ/BR8ET or BUR7EQ leading BUR9EQ trailing (you can go a grade lower on the BUR plugs if you mainly do city driving).

2Lucky2tha7

iTrader: (3)

It's def. zeroed correctly.
Please explain the hardware latency part please....
I guess it's possible that the CDI might create noise........ It's a digital one, not an analog one like MSD.
As for spark plugs, I've been using bur9eq all around as always.
Lastly, I'm not too worried about the detonation in short spurts. That's why I always build all my engines with RA seals (personally). I've detonated on these seals off and on for the last 40,000 miles and they still work the same as they always have. Compression is still about the same too. About 2 years ago I was adjusting the CAS (advancing it) on my stock ecu to get a little more power, but I ended up taking it a little too far and let's just say that it sounded like a group of people standing next to me "clapping" 2x4's really fast and loud when I got above 5k.

Jobro

iTrader: (2)

Its not the analogue or digital part of the CDI that is the problem, the problem is the EMI caused by the coils cdi box causing interference in the ECU/on the CAS (vr sensor) wires.

BTW my ecu works fine upto 9554rpm I took it once there by mistake running 28 degrees with 5 split. no ping for me, and as I said the CAS works better at higher revs

muythaibxr

The first rx7 I megasquirted worked fine and pulled hard at full throttle up to 9000 rpms. I don't think it's resolution on the MS causing your problems.

Ken

AlexG13B

iTrader: (7)

i think cdi box is the culprit if timing is set right.

2Lucky2tha7

iTrader: (3)

What would you guys recommend I do to remedy this without having to take out the CDI box alltogether? Do you think that it's the physical location of the box itself? Or is it in the wiring as well? Is there a way that I can "supress" the "noise"? It definitely gave me ALOT more low and mid-range power.
....Actually, now that I think of it, Before I had the box, I remember having somewhere between 28 - 32 degrees of leading advance.
Hmmmm.........

Jobro

iTrader: (2)

Supressive leads, supressive plugs.

Shielded cas wires.

I can't remember off my head but either parallel or perpendicular orientation results in minimal e field coupling. I really should remember that lol.

Easy fix would be, disconnect trailing, throw in a FC leading coil pack and see if the problems go away.

Using B9EGV plugs causes my mega to reset at least every 5 minutes, sometimes it locks, and if its lucky the inj will be grounded, and stay grounded. Makes for lots of smoke and clean air for the future!

2Lucky2tha7

iTrader: (3)

If this helps:
Magnecore 10mm wires with bur9eq plugs (resistor type). When you mention supressive leads and plugs, are you referring to having resistor type plugs, etc.?
Also, my CAS wires are shielded the whole length with only 1 side of the shielding grounded.
Lastly, could you slightly elaborate on the FC coil pack thing? I'm currently using an FC coil pack for my leading. Just trying to understand.
Thanks.

Jobro

iTrader: (2)

It all sounds right. Thought you said you were using an ignition booster. Are you using it to boost the factor leading coil?

2Lucky2tha7

iTrader: (3)

Yes, I am using it for the factory leading coil.

Jobro

iTrader: (2)

Have you still got the ignitor inside the leading coil? Disconnect the cdi and plug the standard module back in?

muythaibxr

Actually come to think of it, tofuball was running an ignition amplifier box for a while on his original S5 setup, and he had strange problems with it... we ended up taking it out, as the engine ran better without it. We also were able to pull strong all the way to 9000 rpms without any kind of dropout.

Ken

2Lucky2tha7

iTrader: (3)

^^I've been thinking about it for the last few days and I'm going to (unfortunately) bypass it. The amplifier definitely gave me better low and mid. Oh well, I'd rather have my entire rpm range instead.

And yeah, I'm still using the factory ignitor.
It's wired: ignitor--> cdi--> coil

Jobro

iTrader: (2)

Oh ok, well you better hope that it doesn't fix the problem! :P I kinda hope it doesn't to, because I wanted to use a pair of Crane Fireball Hi-6's eventually.

2Lucky2tha7

iTrader: (3)

Well, I bypassed it 2 days ago, but since I haven't gone past 5k since then, I don't know yet. However, I do know that it sometimes randomly stalls out now when I come to a stop with the clutch in.

Jobro

iTrader: (2)

The CDI can probably fire and ignite a leaner mixture. I know I had lots of problems holding off a stall coming back to idle at T intersections. Its damn annoying having to hold it running isn't it!

2Lucky2tha7

iTrader: (3)

Yep, that's why I'm glad that I keep my laptop right on the passenger seat!!

muythaibxr

Usually if it stalls pulling up to a light, you can slightly increase dwell, tweak timing, and tweak the BAC valve config to keep it from doing that.

Ken

2Lucky2tha7

iTrader: (3)

I have it at 25 degrees so far with a slight amount of detonation happening, but I still have a hiccup (or more like a backfire actually) at 7k rpms. <--I forgot to mention that one before. It'll keep going, but once it gets around 7k, it "bucks" and keeps going. Sometimes it happens a few times in a row. This is in 3rd gear btw.
All in all, my car feels slower now though......
I'm about to hook my cdi back up and just have my 80 - 100 kpa timing values set very low again above 6k.

muythaibxr

What dwell are you running with the stock coils?

You're running a modded CAS as well, so I wonder if that might be causing some of your problems. Are you running the 025 decoder or 024?

Ken

The Griffin

Would a cap across the leading coil help with noise using a cdi box since the cdi is after the ignitor? I seem to recall people fixing some noise related issues doing that on the MS-e forum.

2Lucky2tha7

iTrader: (3)

Well, I definitely am going to hook up the cdi again because my rx feels slower now, but:
Should I install a noise filter like this one ( http://www.crutchfield.com/S-vEVvfk9...03S25A&tp=2653 ), or can I install a capicator (or a few) somewhere? I know this is wayy left field, but will turning the potentiometer (I forget which one) clockwise a little bit help? Would the noise filter feature on the MSII help to fix this problem? (When I get it, that is...)
Also:
I am currently running a dwell time of 2.6 ms w/ min. discharge of 0.5 ms. I am also running with the 024s9 style decoder.
BTW, I read elsewhere that I should set my coil dwell time at 4.5 - 5.0 ms when using a cdi.