I just wanted to clarify the installation and configuration with a CAS.

Following the FSM, I line up the little dot on the gear with the mark on the shaft and slot it in.

On the More Ignition options screen i have set Fixed Advance: fixed timing

Then I start the car and have to feather the throttle to keep the engine running, as there is no advance at all, its hard to keep going...

Using timing light, monitor the front pulley timing mark and the point to line it up with. Either using the trigger calibration, or turning the CAS, should I line up the first dot with the mark? I think this is right but i'm not sure. Then I configure Tooth #1 Angle BTDC as 5 degrees.

Can anyone confirm or point out the errors in my ways?

Thanks!

Paul.

 

is this ms2-extra?

If that's the case, set the Tooth #1 angle before you set fixed timing, and set fixed timing to -5.

Then line up the timing with the yellow dot on the e-shaft wheel.

You shouldn't have to have someone feather the throttle unless the timing is way off on the stab.

When you line up the dots on the CAS, you'll be on a tooth, but when you stab it, if you've done it properly, you'll actually be between two teeth.

Ken

 

Awesome that makes perfect sense now! I can't wait to get up tomorrow and configure it all

How does this look?


So the trigger offset will change if I try to line up the timing marks with the software, alternatively if I leave it at 60 and rotate the cas until it is correct, that would also do the trick.

I really appreciate the help!!! Getting somewhere Thanks!

Paul.

 

the 60 number doesn't actually do anything when in wheel decoder mode.

You'll want to change the Tooth #1 angle to make the timing marks line up in software.

I would recommend turning the CAS, as the Tooth #1 angle value only gets read on boot, and changes to it won't make a difference unless you restart the car.

Ken

 

Thankyou Ken!!!! It's alive!!!! It even idles and runs nicely

Any tips on the maximum advance I can set, so I don't go too far? I have been searching all day.. currently I'm advancing up to about 32 degrees under load and high rpm, but have no idea if this is close to the limit or far from it. It's a 13B extend port.

I'm going to read over a few books on the rotary to get a better idea about how everything relates.

Thanks again!!! It was a pleasure to drive around the block a couple of times. It drives a lot nicer than when it was on dizzy - seems to be easier to drive at low rpm, plus no more horrid rpm spikes Wooohooooo

PS. Nearly cooked the engine as the thermofan was wired into one of the stock coils which I had cut power to and rewired to a 2nd gen coilpack!! All good though!!!! Noticed immediately.

Cheers!

Paul.

 

Hrmm, for timing, I'd just go to the thread in the megasquirt section that was posted on that topic.

32 seems a little high to me for an NA though...

I'll have to go back and look at what my maps use, I haven't changed them in a while.

Ken

 

I was maxing out around 28 before, then I found a 13bEP map on BDC's site which had higher advance than what I had seen before... after a test drive maxing at 28 I thought the car was not accelerating as well as it had, however that could just be due to my currently EPA approved exhaust system which kills the performance.

I'd be interested to know what your's max out at.

Cheers,

Paul.

 

I'm pretty sure my max for an NA S5 was around 28. With that the car accelerated very well. I didn't have a chance to check last night though, so will have to later.

For an S4, we go a bit higher, as the compression is lower.

We dyno'd the stock computer and our tune back-to-back on our S4 NA and found that we gained about 20 ft/lbs of torque. We were unsure of the max horsepower gain because the dyno operator kept stopping us at less than 6000 rpms, but our horsepower curve was much higher with the megasquirt than with the stock computer.

I think the 32 on BDC's site at 100 kPa is b/c it's for a turbo... which has very low compression.

I believe the factory max was around 25 for the NA, but that is also from memory, and I haven't looked at it for 2 years.

Ken

 

Interesting... the guy who built my engine and tunes as well said I could go up to 35 degrees advance under load at 4000rpm+

I just had my exhaust opened up today so its no longer restrictive... the car still seems to accelerate at a slow steady rate though... not like the way it used to on the dizzy..

Here are some stats:

Dizzy Ignition
2000rpm to 6500rpm: 2.55 seconds

Mega Ignition
2000rpm to 6500rpm: 3.56 seconds


I got this from data logs... so its quite clear that something is not quite on the money here...

This is my current ignition map:


The only difference apart from the ignition is that there is now a catalytic converter at the end of the headers... 2.5" in and 2.5" out.. I am hoping it's the ignition though as that will be easy to fix

What do you think?

 

I would try both reducing and increasing the advance.

I've seen cases where too much advance can cause a loss in power before knocking.

I do find this odd though, are you sure that your timing is dead-on at idle?

If so, you may want to try experimenting with the hardware latency compensation.

Basically, the hardware has some latency between the actual signal, and the MS receiving the interrupt. This can cause spark to retard a bit as revs climb.

To set this setting, fix the timing at some reasonable value, then rev the engine and watch the timing with a light. If the timing retards as revs climb, increase the latency number. Keep increasing it until you no longer see the timing move.

If this fixes the problem for you, that's great. If not, start adjusting the timing carefully upwards. I do find it odd that we had such good results on the dyno with lower numbers on our S4 NA.

Ken

 

Ok I will have a play with it..

I am 100% sure I had the timing set dead on. I configured the MS to fix timing at -5 and then I lined up the Leading dot with the mark. I also noted that as I revved the engine the mark did not move at all, however I will fix timing again and retest this just to make sure.

Perhaps it is advanced too far.. I will have a play with the numbers next week! After this weekend i finally get my weekends back Woohoo

I guess the other consideration is that the Catalytic converter may well be making a big difference!! For that I should get both ends flanged and have a straight pipe i can swap in.

Thanks for the tips!

By the way, do you have the data on the stock timing curve produced by the dizzy? (both centrif and vac advance). I haven't been able to find any raw data anywhere..

Thanks!

Paul.

 

I don't have any data on the dizzy. None of my engines have ever run on one.

Ken

 

I should have said stock dizzy or ecu.. just the stock timing data... to give a base to start from..

 

Hey Paul,

Here you go. This is from the '85 FSM. I am sure the other 1st gens are the same (or very close). Not sure on the 2nd gens. Note: There is a typo on the mechanical advance. Notice that they show the engine RPM as half the dizzy RPM. That is backwards. The engine RPM is 2x the dizzy RPM. I believe the dizzy RPM is correct (top line) because others have stated full mechanical advance is in by 4000 RPM (engine) or 2000 RPM (dizzy). Sorry the quality isn't too good. It is this way in the .pdf of the FSM too.



- Kent

 

Thanks Kent for that! How annoying with that diagram.. there is also a dotted line i think meaning idle??? anyway I updated the diagram as per your take on it to give this:


So it seems vac advance really only does anything at idle or under high vacuum... at WOT it would give no advance, correct?

The guy who built my engine said I could max out at 35 degrees @ 4000rpm under load. Perhaps the stock timing is just very retarded, but it looks like 13.75 degrees maximum advance at WOT?

Unless that is the dizzy's angle of advance, which would be doubled at the eshaft making 27.5 degrees.. ?

I guess a simple test would be to run a timing light on a dizzy operated car and just see at what RPM it stops advancing...

Cheers!

Paul.

 

Paul,

I think you are right that this irelated to dizzy advancement. The FSM does mention using a dizzy tester and follow the manufacturers instuctions and compare to these curves. You could use a marked pulley and disconnect the vac advance tubes to see what the real advance is at 4000 RPM. Perhaps someone on here has already done that. I know many guys (especially boosted applications) will lock the dizzy (fixed advance, no vac advance) and set the timing at 4000 RPM. I can't remember what timing they use offhand. A search such turn something up, though.

Here is the section of the FSM that has this info. The info isn't very detailed, though.

http://www.wankel.net/%7Ekrwright/fi...Electrical.pdf

 

Ah yes it is - early in the document it states that it is dizzy advancement, so actual crank advance would be double.. making the stock timing curve hit 27.5 degrees at 4000rpm and stay there.

Sooo... at idle the most advance we should see is about 5 degrees (stock) and at wot 4000+ rpm 27.5 degrees.

This is a map i've just put together taking the low end advance from the map im using now which actually idles really nicely and has good low end torque.. which im trying with slightly lower high end wot values.



This hasnt been tested yet though, i might get a chance tomorrow or thursday.. or this weekend

 

How does this look- does this look accurate???



I'm pretty tired so its quite possible i mixed something up completely...

Just trying to map out the stock dizzy nicely and avoid the confusion that mazda put in their FSM

Cheers!

Paul.

 

So I've come up with this as a representation of what the dizzy does:


Any thoughts?

Note the RPM bins.. there are too many to fill when just bringing across the dizzy data.. so im relying on megasquirts interpolation between points to do the right calculations. That doesn't make it easily tunable but this is just a quick sample...

 

Just an update, I finally did some interpolation myself to make a more user friendly configurable table that I believe represents the timing the first gen stock dizzy will give you (one that came with a 13b)...



i will finally have some time to test some various tables i have created tomorrow results to come...

 

OK I've tested it and its not bad!! I think I was running a little too much advance...



Here's a graph from today.. The table could do with a little tweaking, as when I passed 4500rpm and put my foot to the floor, this brought MAP up to 100% which dropped the timing back a lot... to 23. I think I'll try running 28 up there and see how that goes

 

I upped all the 23's to 28's and now it drives SUPER NICE ....

I just had a test drive before.. it was great.... i produced enough power to cause oil pressure to be very high and pop off the hose and pump all my oil out onto the road while moving 80kmh@6000rpm!!! car started sliding from being in the oil but shut it down instantly.. baddd lol should be ok just need some more oil and fix oil line theres a suspicious trail of oil from where i was driving back to my house.. i was able to roll the whole way! lol...

 

Good, glad to hear it was too much advance causing your problem and not too little.