twister7

iTrader: (3)

86 na no cat stock other wise
What do u guys usaly shoot for as far as spark advance?Like how much and at what rpm,, do u want in all in at 3000, maybe take away a few degs at peak tq?

Jobro

iTrader: (2)

This map has too much timing at cruise rpm when you are barely on the throttle, around 2500 or so rpm, need to put your foot down more to stop it from popping.

I haven't had a chance to change it and road test it yet...

Also the Timing values at full throttle are also pretty agreesive, I've been told Its really hard to get an NA rotary to ping, but if you are a worry wart I guess you could make the limit around 24 or 26 degrees, and then scale down the rest to suit


Oh btw, this is a tune converted from Hitman for a 12A mild/extend (small street port). Works very well for me.

As I said shave say 4 degrees off the whole map, and give it a go

twister7

iTrader: (3)

Thanks Jobro
I guess my map i made up was closer than i was think it was!!
Any one see any issues with this one?

dbgeek

Twister - it looks like you are trying to control a lot in the lower RPMs. You can probably lose the 500 RPM column in favor of an 8k RPM one. My squirted 7 never sees 800 RPM, either. It likes to idle at 1000, which seems to be dictated by spark reliability or VR pickup - anything lower will let a stumble stall the car. I'm also using 27* at WOT advance as my max. I don't see why you would back off from 26 to 25 from 4k to 5k RPM, either.

Also, if your start and warmup settings let the car rev a bit, the advance you are putting in at 1500 RPM around 30-45 kPa will cause the warmup to surge as it crosses the advance from 5* to 17* - Mine would oscillate a good bit (500 RPM oscillations aren't minor) before stabilizing at the warmup idle. Hot starts worked fine because the advance curve isn't changing near as much. Looking at my logs, the Idle DC would remain almost unchanged while the advance would drive the oscillation on cold starts.

I'm also using closed loop idle control, which works well once you get it tuned.



I haven't tuned for fuel economy on cruize yet, but this table has performed very well on road courses, with smooth tip in and good power to 9k.

Jobro - 21* advance at 2500 RPM WOT caused a ping in my setup - I backed it down to 18, and there is still good torque through the lower RPMs.

twister7

iTrader: (3)

“You can probably lose the 500 RPM column in favor of an 8k RPM one. My squirted 7 never sees 800 RPM, either. It likes to idle at 1000, which seems to be dictated by spark reliability or VR pickup - anything lower will let a stumble stall the car.”

I put the lower in the 500 column in to attempt to cure the idle dropping below 700 and to fix the stock tack from turning off,,it normally idles fine at around 780 or so but some times when I am getting off the gas and coming to a stop the idle drops just low enough to turn the stock tack off!! I think I just need to raise the idle rpm up a tad!

“I'm also using 27* at WOT advance as my max. I don't see why you would back off from 26 to 25 from 4k to 5k RPM, either.”

I took away timing at 4k and 5k thinking that is were detonation would accrue since from my ve map 5k is were peak tq should be,, most required fuel=peak tq right? Any ways I think I am really thinking way to hard about that in a stock s4 na witch I still have not heard/felt or even ever had the idea that it was detonating ,,its not like it’s a 25psi t2 or any thing lol!!

Ok now for the new stuff I am figuring out,, when I was searching around for timing info I came across this http://www.tprmag.com/issue/11/11_rotary_1.shtml at the bottom of the page it says

“”The physical shape of the depression at its leading edge has a lot to do with the maximum usable leading ignition advance. You can understand this better if you set a late-model rotary at 35 degrees BTC, take out the #1 leading spark plug, and took into the spark plug hole (a mirror and light might be helpful). What you will see is the curved flank of the rotor rather tight up against the bottom of the spark plug hole. If the spark plug were to ignite at this point, the engine might misfire because the flame front might be snuffed out (quenched) when it hit the rotor surface.
If you now turn the engine to 20 degrees BTC, the way is open to burn into the mixture in the rotor depression. This is an important part of the reason why nearly all 1974 and later engines can run no more than 20 to 25 degrees ignition advance at high power (earlier USA model engines had a very long, shallow depression that allowed more advance). As I explained earlier, there are some parallels between rotaries and recips here - combustion chamber and piston top design are major concerns in recips - but there are some distinctive items to consider when working with rotaries. “”

So I decided to see if this was right or not ,so since I have a few cores sitting around I decided to set half of a motor up and see where the plug would fire at what ever degree. I set up a front pulley as described here to see what degree I was at.

http://www.yawpower.com/pultime.html

From what I could tell 35 deg is about the max the lead can fire before the spark plug hole stars to be covered up buy the flank of the rotor and is no longer firing in the camber and is firing on the flank of the rotor itself also I found the stock timing map of a n326 ecu s4 na and there was no number in the map over 32 deg

Fyi at 45 degs only half of the plug hole is covered up buy the rotor flank!

Fyi a s5 is different at 30 the plug hole is open and at 35 the hole is half covered this need to be double checked I was using a s5 rotor and housing but s4 pulley and e-shaft not sure if either is different! S5 lead plug hole is farther down than a s4!

Any one know else know any thing about this??

pmrobert

Yes, I might have some links to info on that. It's early stuff from Mazda engineering folks ( I think) but there is definitely some info in these ref the rotor depression and plug location.

http://smrmicro.com/re-ky.pdf

http://smrmicro.com/re2.pdf

-Mike

monkhommey

mike! thats amazing.. thanks for posting!!

Eagle7

Very interesting. I'd guess the vertical axis is load of some sort. Do you know what the units are?

twister7

iTrader: (3)

Basically its the air mass flow that is read by the AFM and corrected for ATP and air temp.

As far as the max timing number's before the plug hole is covered this is what i found out so far!
From s4 to s5 to s5t to s4t is different !
S4 na
@ 35 degrees is about the most u can run before the spark plug hole is covered up buy the rotor flank!
@ 45 degrees half of the spark plug hole is covered by the rotor flank
@ 25-30 degrees the beveled edge at the lead side of the rotor before the combustion chamber starts to migrate up to the rotor flank is centered!
Stock map shows a total most advance on the map of 32 degrees

S4 T2

Think it is different because stock map shows a max of 42.5

S5 n/a and s5t2

@ 30 degrees is about the most u can run before the spark plug hole is covered up buy the rotor flank!
@ 35 degrees half of the spark plug hole is covered by the rotor flank!
@ 50 degrees all of the spark plug hole is covered by the rotor flank!

Notes:
S5 housing mover the lead spark plug hole center about 5 degrees down from so u cant use as much timing on s5 housings!

S4t2 stock map show’s total timing of 42.5 @ very low loads there has to be some thing different about the rotor! No s4t2 rotor I cant check it!!

FD 93 TT
@ 43-45 (44 I think) degrees is about the most u can run before the spark plug hole is covered up buy the rotor flank!

i would bet a 12a would be differant also,if any one has a na spark map that they have tuned in on the dyno i would love to see that i think that is the only way to get it right any ways!

Jobro

iTrader: (2)

I actually used to run 22 Degrees there myself, but Hitmans tune only used 21, so I dropped it a point, just to be consistant with his map.

PS, 28BTDC and 0 Split made 86rwkw with a stock nikki jetted to 12.8:1 AFR, short primary exhaust, small streetport

Heres my dyno sheet, for you to check the full throttle values.

http://img156.imageshack.us/my.php?image=dynorunea4.jpg

2Lucky2tha7

iTrader: (3)

Hey TWISTER7, would you happen to have an "easier to read" graph of the attached file that you have from post #5 on this page? I need better timing numbers for series 4 housings, because my max timing is about 24 degrees and I know I can get more, but just not sure what my max timing can be at WOT, as well as all my other numbers on my timing map.

Brian

twister7

iTrader: (3)

1st download save cherish and read 50 times what pmrobert posted lol

http://smrmicro.com/re-ky.pdf

http://smrmicro.com/re2.pdf

also read some here http://www.yawpower.com/techindx.html

From what i have found from searching around it is some were between 24 L and 27 L for the max amount WOT in a S4 n/a , but with out a dyno run who know’s!! as far as the easier to read graph i came up with this map based on the so called stock map i posted (see pic) i was guessing that the stock load is close to the kpa we use in ms,, i just divided the rows up and tried to equal them out! There are parts of this map that don't make since to me such as at 70kpa and 3500rpm is only at 19 when 80kpa up is at 21 it should have more at 70kpa then at 80kpa (up) as you're AFR is leaner requiring more timing and you're load is less (maybe that part of the map is just the transition period of the oem map when going from lean to rich) !As far as the "I know I can get more timing part"
from what I sorta understand lol,, A rotary's compression and combustion stokes are 1.5 times longer than that of a reciprocating engine (the rotor moves slower than a piston) = more time to burn the mixture and u have 2 plugs to shorten the combustion time once its started,,then u have the greatest mechanical advantage the rotor has over the eccentric shaft at around 45 degrees ATDC and peak cylinder pressure at around 20-23 ATDC!! What all this adds up to is less advance than a piston engine! If you are thinking about trying anything over 27 WOT, I would not go over 30 and I would make sure I had some split like around 10 if I went to 30 anywhere on the map!
Other things to consider is the burn rate of the fuel you’re running, the AFR you’re running, the RPM and the load (kpa) and also you’re stock timing mark could be of by 3 degrees depending on how it was bolted up (with the bolts in the front pulley,, but not tight,, u can move the pulley 3 degrees)!
Afr 12.9:1 to 13.2:1 fastest burn rate needs less advance anything richer or leaner needs more advance with the most at leaner mixtures (14.7:1 more advance)!
More PRM more advance
More load (kpa) less advance
86 pump fuel less advance 92 pump fuel more advance

twister7

iTrader: (3)

Oh ya as far as the

"I put the lower in the 500 column in to attempt to cure the idle dropping below 700 and to fix the stock tack from turning off,,it normally idles fine at around 780 or so but some times when I am getting off the gas and coming to a stop the idle drops just low enough to turn the stock tack off!!"

that was caused buy the throttle cable being to tight, i put my foot under the gas peddle and pushed up and hum what do u know the rpms dropped!
any ways thats fixed

dbgeek

Thanks for the update. Before I went to CMP on May 5/6, I did basically the same thing. I lined up the stock numbers against the bin values from the MS and used the ones that matched, discarding the rest. My best stock dyno was with 6 degrees of advance added, so I added 0-6 deg from 0-100 kPa, but subtracted some back out on the higher RPMs. Then I re-tuned the fuel map, closed loop idle, and idle advance.

The result is a spark map very close to what you posted, which drives very well - smooth power application on throttle tip-in with no jerks, slumps, or other surprises. I'm running an S5 engine, so some values are different. Max advance of 29 L at peak torque 5500 RPM or so. Keep in mind that I am running 029w, which has some hardware latency per spark event, which means that full advance drops some as RPMs go up. Once I test against a timing light, I will update to the code with this latency 'corrected'.

pmrobert

Here's a relevant page from the FSM regarding timing curves.

http://smrmicro.com/v-web/gallery/Ma...t/Mazda?full=1

dpf22

A good thing to remember about timing is that a technical service bulliten was released about the n/a fc that said that it required the use of low octane fuels. It is entirely possible that the timing curves for the n/a were meant to be for low octane/fast burning fuels and the subsequent maps s4-s6 turbo were ones that would require higher grade fuel and thus use more advanced curves as such.

Just a thought.

dpf22

coldfire

iTrader: (1)

i am assuming everyone is just setting the timing adjustment of the CAS to the stock factory idle setting? and also assuming using 86/87 octane here talking about NAs.

also there isn't much talk about what split to run, or how to select split based on the various factors. any comments on that?

muythaibxr

the "latency" is not actually "code" latency.. it's mostly hardware latency on the v3 board. We added the latency option in the code just to account for the hardware latency.

Ken

Jobro

iTrader: (2)

In Australia the Choices are

91RON (no ethanol)
95RON (no ethanol)
98RON (no ethanol)

95RON (10% Ethanol)
98RON (10% Ethanol)
100RON (10% Ethanol)

I personally use 91RON (no ethanol)

I find that 5 degrees split is a very good starting point, for you tune, and play from there. Less split makes less torque in my experience, and from what I've read.