I have run no split for a couple of years and have had no problems.
I just wondered what other people set the timing at as compared to
normal. I run low twenties in vacume and 6 degrees in boost
at 26-32psi. Ralph

 

Wow...still no replies....

Hi Ralph...I've tried very low split(not 0-yet) my self and yes it seems to make more torque and bit more power. But full advance for leading needs to be less compared with running split.

Under vaccum I run no split with 38 to 28 degrees @ 0psi.

Have you tried running higher then 6 degrees at full boost??? seems low.

JD

 

Yes ,Ihave run up to 10-12 with 9:1 rotors but I havent figured out what to run with the 9:7 rotors. I run the PFC but fire both plugs off the trailing
map only. I poped one motor with zero split running both maps and
I dont think the PFC is accurate enough for in that setting.

 

I don't understand.

You said you have been running zero-split for a couple years, yet you blew up prior to that?

How do you run low-20's in vacuum under idle?
With the 9.7:1 rotors?
This is next to impossible.
Some other vacuum units other than inHg?


-Ted

 

Hey Ted,

I think he was refering to the timing being in the low 20's in the vacuum map matrix.

 

Doh, that makes a lot more sense.
I think I need more sleep.

As for answers, I think there are too many variables to keep track of to give you a definite answer.

I prefer 0 split under load, but I haven't done anything over 20psi.

Mazda does program a 0 split on their stock ECU's up to 10-12 psi or so.

Others have gotten good results changing the split under load.

All I can recommend is get the car on a dyno and see what your car likes for split.



-Ted

 

Most of the settings in vacume and lower boost I have set to where
the car drives the best. I have spent a lot of time trying diff combos
and basically using the butt dyno. The only reason I screw with this
is to make the T72 more drivable in town etc. I probaly wouldn't
care with a smaller turbo. But I am hooked on acceleration.
Also I was refereng to 20 degrees positive timing approx

 

Ralph.
I run 12 to 15 deg. on the leading and 0 deg on the trailing with the 9.7:1 rotors on C-16 fuel. I'm not a fan of advanced trailing timing under high boost applications because to me the little benefits gained are not worth breaking a motor for. The front housing on the REW is pretty weak and loves to crack! I just finished tuning a street ported 13B-REW with 9.7:1 rotors and it made 615 RWHP/479 RWTQ at 32psi. Wanted more but as usual the injectors were at 100% duty cycle!
I'm in the process of a build up using rx-8 rotors also for a turbo application.

 

Crispeed: 12-15 degrees for leading and 0 for trailing......so we're tlaking about a 12-15 degree split, correct ??? or 12 @ peak torque and advancing to 15 degrees by end of rpm band and a constant 12 degree split.

>>>615 RWHP/479 RWTQ at 32psi<< as usual, very nice.

Ralph: I've also tried few combinations (w/powerFC) and found car idles clean with some split and from there on I run NO SPLIT all around 'till I get into boost. I add split under boost to 8 degree split, lately I'm trying 12 split.....to 19-20 psi on pump gas.

Running now a T70 and trapped 103.5 mph in the 1/8th @ 18.5 psi so its making more power then the T63.

 

John you're correct.
Even on my all motor car I run a couple of deg. of split just to be safe especialy when you're at +25 deg. on the trailing side!
As of late on pump gas I've been running around 8 to 10 deg on the leading around peak torque. The knock sensor have been a little more active as of late with the usual 12 to 14 deg timing on the leading. I guess it have something to do with the abnormal hot summer this year or lower grade fuel at the pump!

 

>As of late on pump gas I've been running around 8 to 10 deg on the leading around peak torque<

Chris, at what boost ??

JD

 

Chris thx for the input. I run the no split because using the PFC in order to run individual msds on the leading with no wasted spark I have to use
the trailing controls only, so basically 2 channels. I found that when I got
away from wasted spark, the car ran better and less egts. Dont you rum microtech? and it has individual channels for lead and trail? Like motec?
Also the AFRs I measured with and without wasted spark were different,
wasted was leaner if I remember. Thx Ralph

 

Around 20 psi!

 

good info

 

Yep! Lots of veteran rotorheads posting on this one. Please make this a sticky!

 

i`ll just add my input... I`m currently run a microtec LT8s and i also have been playing with the timing.


But what i`ve done to avoid detonation is to run the timing together (no split at all)
eliminate the trailing spark plugs by plugging the wholes with aluminum inserts
use the trailing coil wires to fire the leading plugs...alls good

 

see i've thought about this as well. but wouldnt this affect idle and maybe even over all power? i'm curious.

 

I would have to agree, please sticky this thread. Too much valuable info to get lost.

Zach

 

Have to agree!

 

I ran no split for years on my old RX7 because that is all that ECU would handle at that time, I basically ran -3 deg timing (CAS retarded base -5 deg) as ECU cant set - ign timing, worked fine and never had high EGT either.

98Ron pump fuel + WI @ up to 23psi boost 472rwhp on dynapack T04S turbo were the specs.

 

I have a 1987 Turbo II with an SDS stand alone ECU. The SDS has no split. A lot of puertorican rotary mechanics recommend running aprox. 10 - 12 degrees of split. What I did was I bought a Crane ignition amplifier with the retard option and hooked it to the trailing coils. Now I can adjust the trailing I want with a potentiometer. It would have been easier buying a Microtech but I didn't know SDS have no split until I bought it. I was able to make 452 whp at 17 psi on 93 octane fuel with no problem keeping 12 deg. of split.

 

I see alot of people using pfc and microtechs is there anybody that would like to share the advantages and disadvantages of 0 split timming with the haltch e6k?

 

DON'T DO THIS WITH HALTECH!

 

Yes, since the timing on the E6K is not so accurate, it might fire the trailing before the leading... So there goes your engine...

 

how much power difference are we talking between running 12 degrees split and 0 degrees split? Say the car made 400 rwhp with 12 degrees split, ruffly what kind of results would the 0 split net?

Adam