Advice:Ignition split..tuning myself
 

I got to tune myself..no tuners in my area.
setup: 1993 S6, stock motor/injectors, gt40r single conversion, EMS Stinger ecu.

Goal 12psi.

I know the basics for tuning regarding timing, but I am not too experienced with rotarys. My ems has an option for trailing split from .00*trailing to 16 trailing*, and thats the only option for split. There is no grid for me to vary the split based in manifold presure or rpm. I assume that the setting wil be fixed for all loads or rpm.

Is this safe and what degree should I set the trailing plugs.

I am pesently running .00 trailing (no split I assume) and boosting about 6psi with timing about 24* BTDC

I would set the split to about 8-12.

You should be fine at 12*, but does it have a different setting for idle? At idle you really should keep the stock 15* split, 5 and 20 atdc. Under full throttle, low load (vacuum) you can drop that split to basically zero, but once you get into the higher load maps, up to 12 psi, 12* would be fairly conservative.

Now, you have stock injectors? on that GT40R -whether it's the 4088 or 4094- you will be sitting atleast about 50 lbs/min at 12 psi and high rpm. That translates to about 440 flywheel HP on a rotary, and your stock injectors maxed out will only handle about 420 flywheel HP (based on RX7.com's calculators.) So, you'll definitely need more injector.

No seperate settings for idle, just a setting for the trailing split.
Can I just set it to 12* trailing and leave it there? This would mean a constant seperation of 12* under all conditions.

On my car, I think I have 15 degrees across the grid. This is obviously a point on which people may have their own opinions, so just take this as one more data point.

One thing that I think is sort of interesting is to take some spare engine parts (half an engine), and turn the E-shaft 15 degrees.... do you see that the rotor barely moves much on the spark side? Do you think 12 or 15 or 18 makes a big difference? I don't.

There are people running 0 deg split and their engines work.

There are people like me running 15 and mine works too. I just happen to think that I am right :) heh heh.

Well as a general rule, running less split produces more power, it acts similarly to advancing the timing. If your car will idle fine at 12*, then I'd do it that way. If you have to, widen the gap until you get a good idle, and leave it at that.

I've never noticed any appreciable difference from reducing split by just a couple degrees--like no real increase on the dyno from 10 degrees split versus 12.

Split at idle just depends on what your motor likes. Idle tuning varies so much with idle speed, porting, etc. My car with a big streetport and a target 850rpm idle liked 20 degrees advance and 3 split (on Power FC with manual idle control). That's just what it liked best. Some people run negative split at idle and low loads. Rx-8's run negative split from the factory in some areas.

If you have to have one split setting for all operation, I would do 12 or 15.

Im not sure what you are asying here......Is'nt full throttle considered high load? Where can I use zero split? at high load (12psi) or at low load

He means if you have the choice, run zero split in the vacuum/very low boost rpms under full throttle. It increases EGTs and will help spool the turbo.

Some EMS's have multiple maps, idle map and load map (or more), and it switches to the load map(s) by TPS reading (more then say, 25%), but this isn't what I'm talking about, everything I've mentionned is referencing to your load map (under full throttle)

By high load I mean into boost, zero split like mentionned above helps cause much more combustion pressure and spools your turbo much quicker (I've even heard of running negative split to help spool) under vacuum , but you need to be sure that by boost you start running some split.

Zero split in all vacuum loads. Using pump gas, taper split from Zero at 0psi manifold pressure to 10-11* by 14-15psi of boost, quickly ramp up to 15* split, then remain. Using 100octane and above race fuels, depending upon aggressiveness of lead advance, taper split from Zero at 0psi boost to 6-7* by 14-15psi of boost and keep flat.

B

This is why you shouldn't really buy an EMS that doesn't allow split tuning based on MAP and/or RPM. There's plenty of best split #s for different situations.

I agree your stock injectors will be maxed out at 12 psi with that turbo. Mine were maxed out at 10 psi with a t-61, although my engine is ported. By maxed out I'm talking I saw 100% duty. Afr's never leaned out, but I upgraded my injectors immediately.

You could safely run 10 degree split in all areas @ 12 psi, (that's what I would run) but if you decide to run more then 12 psi I would run 12 degree split. Less split increases cylinder pressures and creates more power, similar to advancing timing. Safe splits will also be determined by how much advance you run at the Leading plug so be sure you don't go crazy with IGL timing.

Thank you guys for the help.... I set it at 10* split for all conditions.

How's your idle at 10*???

I have not done split yet ....still at zero split

I thought you said you set it at 10* split.....

The Idle is fine ...no complaints

interesting thread, I have a ems stinger 2rotor version. the software is setup for a rotary engine is this the same one you have jetlude?

will upload my maps soon to see what you guy's think, i made 396whp@14psi pump gas but i have no clue what split I'm running. will ask tuner this week.

I believe you have the Stinger S2R which is designed specifily designed for the rotary engine. Mine is the normal Stinger V4 ecu which does not have split ignition. Stranegly though, the stinger does have an area on the tuning screen to input the training split amount, however, there is no actual change to the trailing timing when checked with the timing light. This had me fooled for a while. I have been running without split timing ever since.

yes i have the S2R, did you dyno yet with no split? on pump fuel?

I have not dynoed. I have run as much as 23psi on my Garrett GT4094R turbo on a large street port. I believe that I have broken the 500whp mark, but not 100% sure. Yes on pump.