13brenova

iTrader: (2)

I'm a convert from the piston world to the rotary world, and need a little help with timing and split on a rotary. There doesn't seem to be a consensus on what the curves, total advance, and split. Understandably, all should be tuned to the specific combination, but it would be cool to see what some of the bigger horsepower guys are doing. If you are willing to share, please post a screenshot of your timing map (so everyone can see regardless of ECU) and trailing map to help us noobs. Along with this, please add your engine specs, quick list of mods, boost level, fuel type and any AI. Enlighten us!

peejay

RICE RACING posted a guide here on turbo engine ignition timing (several times) about 7-9 years ago when he was active here. If it's gone, I have it saved to disk somewhere around here...

For a non turbo engine, you can't go wrong with 22-24 degrees for a 12A, 24-26 for a 13B. No split required, no variation on RPM (strictly) required, and you can add a bit in the low load regions for better fuel economy, but there's little point in going over 35 degrees.

It does help idle quality to pull some timing out at idle - factory is 5ATDC to TDC. Stockports will run just fine with full advance at idle but the more port you have, the less timing you want, if you want it to be drivable.

13brenova

iTrader: (2)

Bump-diddy-bump-bump. Just popped a motor! Need some timing help!

bumpstart

taking random numbers off the net may well prove very risky
particularly when you realise that between ECU's ,, apples are not necessarilly apples

- for example,, most EFI rotaries have a timing mark for 5 ATDC for the leading
and 20 ATDC for the trailing
when you relate that to a timing number in a map,, some ECU dont use negative numbers,, and all numbers are representive as BTDC

-- ie,, 5 ATDC is in effect -5 BTDC in those ECU's,, and cannot ever be achieved

reality is,, the -5 will be used by those machines as DATUM ZERO
so all map timing numbers listed will be ( X ) -5 = real crank degrees
IE,, a 30 in a micro timed with -5 as datum zero will in effect amount to 25 BTDC


if you now take that 30 number and apply it onto a machine that IS operating in real crank degrees
-- then you have potentially killed the engine under load
( cause 30 is too much ,, when it should be seeing 25 ,,then subtracting any correction in the tables for boost from that )

in effect,, under boost,, this engine is 5 degrees more timing than intended !!


when taking examples off the net,, you MUST be aware of how that original machine was timed,, and what effect this has when translated to your machine
-- it may prove apples to apples,, and be AOK,, it may be apples to oranges and be out by 5 degrees too much,, or too little if a vichy versa trade


to muddy all this more,,,, some people will be using that posted map on variously configured engines
-- with potentially 4 different selections of rotor compression,, and two different selections of rotor housings with differing leading sparkplug locations

to further muddy this,,,, some machines are designed to work from TTL,, or hall effect timing signals
-- your mazda rotary has reluctor senders for timing
-- in all the translations from reluctor to TTL,, and in machines with limited logic to interpret the reluctor zero crossing point
may just smudge the timing as revs increase ,, and this smudge may well be accounted for in the timing look up tables
-- using that timing number data on another machine without the smudge may give inadvertant results
IE,, apexi has the timing smudge at RPM,, its usually expected and thus accounted for in the look up table
using those apex i numbers directly into the micro ( which has rather good reluctor zero crossing analysis )
will amount to slightly differing timing at RPM

note,, my timing maps are public,, for all to see,, in the micro maps sections
great pains have been taken to advise all that this map uses -5 as datum zero,, and hence these numbers are all smudged by +5 degrees if using on another machine

note the map total timing is deliberately about 3 degrees off under load
-- to allow for some margin between differing motors and allow the tuner to sneak them up under controlled conditions
ie,, this map will be 19- 22 degrees BTDC rev depending under load,, no boost
and this could be as much as 22-25 degrees in some engines,, particularly 8.5 compression ones

as such,, consider it a reasonably conservative map

disclaimers apply,, use at discretion according to your engines setup

T map
idle=0
-25=7
-20=6
-15=5
-10=3
-5=2
0=1
2=0
4=-2
6=-4
8=-6
10=-8
14=-13 ( -12 )
16=-16 ( -14 )
18=-18 ( -16 )
20=-20 (-18 )
T RPM
idle =10
1000=10
1500=14
2000=20
2500=22
3000=24
3500=24
4000=24
4500=24
5000=24
5500=24
6000=26
7000=26
8000=26
9000=27

split
idle=15
1k=15
1.5K=15
2k=14
2.5k=12
3k=10
3.5k=8
_______________

Rub20B

Thanks for sharing.. I was also questioning if it would be much different on a renesis with 10:1 rotors? I'm running a stock 6port renesis, 98oct fuel and megasquirt ecu, atm I'm running 22° over the rpm range, -5° to -10° seems the sweetsport at idle

this should be actual crank degrees atleast if this drwaing is correct