Ok here are the maps. Leading, trailing, and split. I'm into boost by P9. This is one of the reasons I'll probably switch to a Haltech E11 if the car comes back together. It has a larger 32x32 cell tuning map which will allow for much finer tuning in vacuum/boost and I'll still be able to have a 24psi + map.

Map is definitely older than the one I'm currently running but it's only different in a few areas. I can see I was messing around at idle (PFC won't give up idle mixture control) with this map and a bit at highway cruise. But it's mostly the map I run daily. Again, lots of work to be done to it but it seems to work just fine.

Thanks RX7TT95 for the negative split maps.

I'll try it after my 1600cc injector install is completed and AFRs retuned.

wow. . . interesting. . . VERY interesting. thats A LOT of negative split!!!!!

thanks!!!

No kidding! When you were talking about negative split, I didn't realize you were talking about that much! Sweet!

-ROb

Yes, LOTS of negative split. Chuck, I'll upload my current map to the Datalogit forum when I get a chance.

ill keep an eye out for that one as well. . . hmmm. . . maybe i should just take my motor out and have it built like yours (kinda. . . not an RE) at CLR. i could totally use a killer setup. hahaha. bah, i better save cash for the "next generation". hahahaha

3 reasons.

1. rx8 has higher compression
2. they need to tune it more conservatively, car needs to be reliable for any and everyone.
3. they have a recall for the car melting, higher temps would be bad

Been there done that. But you need to have massive amounts of timing, like firing the trailing at 180degBTDC or more....

It's easy to do, too, just get your trailing wires reversed! Or stab the distributor in 90 degrees off and fail to notice it because you have direct-fire on the leading.

With the negative split application being under vacume to 0 boost how would it apply to different motors and porting? Under boost and torque load the timing is very engine dependent but even then Steve Kahn admits to using a "safe" timing map for ported and nonported motors alike. (FAQ in Timing).
Could a negative split map be applied in the same way since its is mostly under vacume?

I did this today and could definately feel improved bottom end/midrange. Throttle response and drivability are better also. Engine is a 12a pp with gen1 electronic distributor. I did the same as rotarygod and hooked a vac line to trailing, leading is locked at 22deg btdc and trailing at 20deg btdc no vac. Trailing now advances to around 37deg btdc full vac and ofcourse leading doesn't move. It took 5min and cost me nothing. I expect to use less fuel also.

Chuck any update on your results/interpretations of negative split?

Very interesting thread thanks guys.

heh, no problem. of course the people actually trying it out and implementing this are the ones that really need to be thanked :)

UPDATE

Still going fine and fuel economy has definately improved.

bump for westbrook...didnt use I dont think.

Bringing this back to see if anyone has updates.

just a side note, i'm going to find out if the Megasquirt EMS is able to do negative split, since i will be going to that in the near future. it seems that this might actually have some use for non-turbo cars, so it would be interesting to try out.

Well I'll give this a shot on my daily driven full bridgeport and keep tabs on fuel use. Anything that can help me save some right now would be great. After all whats 5 minutes and 12 inches of vacuum line in comparison to the savings. Gas prices are starting to catch up for us soldiers here in Germany.

No it can't. It only has a range of 0-20 degrees split. If you enter in -1, 21, or any other number, the trailings shut off completely. I've been trying to get someone to change the code for a while now.

yeah, i know that the current MS-1 code for rotary doesn't have it in there, i should have mentioned that, but i do believe someone was going to take a look at it.
it doesn't seem like it would be a very hard modification. i know a bit about the coding, but i have only looked at it briefly so i am not quite sure (i have actually looked more at the MS-2 C code than the assembly of MS-1).

Wow ... those split numbers look huge,

I have been having a play with neg split whilst running in my new lsd. i m only at -3 deg neg split at the mo but the car seems a lot quicker through vacum and also strangely a lot more drivable.

I need to go a bit deeper in but in gonna start to try and shape the vacum timing map a little to see what results i get.

So far very good.

Scott

Anyone have anything new to share?

Several people are running it now. It works. There are a few people in the Megasquirt forum who use it.

Anybody know off-hand if Microtech's can run a negative split? I don't have my LT8 near me...

That's a huge difference from a few years ago when everyone was saying how evil negative split was.