I was reading some in the single turbo section about split. Is anyone in here running no split? How would you set that up? Would you decrease leading and up the trailing so they meet in the middle??? I dont really understand how this would work? Do you just make the trailing map the same as the leading map?

Thanks,
STEPHEN

 

to do it on the FC you just make the trailing match the lead map.

 

I (and others I assume) have a lot of 0 split cells in the vacuum areas of the map. It's not a good idea to do so under boost if you are relying on a J&S knock sensor (essentially renders it useless as it only retards leading). Otherwise, I won't speculate.

Alan

 

You only want 0 or very low split in non boost cells. Go read about split on the single turbo forum (old thread).

 

I did read about it in the single turbo section and reading Rice Racings input is what spawned this thread. I'll post 2 statements by Rice Racing so you can read them as well. I might not be understanding him right but it looks to me like not only does he run 0 split but he actually has his L & T wired together which would mean he runs that thru the entire power band. He also says he sets his customers cars up to run 0 split even with a Power FC (he sets the Haltech to run low split because its not as accurate according to him)

Here is one post by Rice Racing.....
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Here is my opinion & testing results, (it is the same opinion as Mazdaspeed, RE Ameya and other "notable" tunners)

You will get a much higher and fatter pressure rise in the combustion chamber when you run the plugs TOGETHER, which will result in higher BMEP and higher power output.

In the 787B 26B engine and Jap tunner 3 plug engines ALL THREE plugs fire at the same time for increased power and high speed fuel consumption benefits.

I happen to fire my plugs together (I have no option with Autronic ECU).

Back in the 70's and even today with lattest SAE papers on the subject ALL show higher power with same T&L firing order, I have all the data to back this up along with other major manufactures results.

Now Mazda mainly for emmisions reasons at low to medium rpm's also for engines with "gay" port opening closing characteristics.

On a ported (street or higher) there is no better way of making power than running t&l together

Just my results and other "tunners", please no flames...thankyou


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I'll do another post for his second post

STEPHEN

 

Here is his second reply on the subject. All this can be found by running a search on "timing split" in the single turbo section. The thread is the only one that says timing split in the title so its not hard to find.

Here is Rice Racings post..................
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No disrespect to either of those guys but I would **** that off all together!

I did a test on a rx7 sp (Australia special) and on it we put a POWER FC, this has a VERY advanced split mapping stratergy and you will find these maps under the power fc forum.

Basically from what I could determine due to extensive testing is that, my practical experience of running the T&L close together is the way to make most power...

The only issue I can see arising is how accurate the Haltech system is at firing the plugs, as large problems can result if the trailing fires before the leading (this is very dangerous).

I know the Haltech is not as accurate as the Autronic in regards to ignition accuracy and as a result you may want to run a minimum split of a couple of degrees to take this into account, I am not a Haltech expert and this may be something you need to ask Haltech direct..."If there is any chance of the trailing firing before the leading when they are set together?"

As I said in an Autronic it is not an issue (cause of extreme accuracy) the same can be said for the ECU'S the factory race team use.

Getting back to the power fc, when I changed the ignition maps to the same as run on my Autronic cars. I noticed a pick up in mid to high rpm power, there was NO bad side efects in terms of loss of spool up time or increased knock. The total level of ignition advance is far more important than is the split in regards to these issues, as is the a/f ratios you run at part throttle and wot at the atmospheric and low boost condition.

I would verify with Haltech designers what the "chances" are of ignition firing at the wrong point before making them the same....I think they have a + - 5deg resolution???.

E-mail me and I will send you my ignition map.

riceracing@ozemail.com.au


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Let me know what you think about this. It sounds very interesting but I'm a little hesitant about doing it without getting more opinions about it.

Later,
STEPHEN

 

Stephen,

When looking over your map (thanks for posting it by the way) I noticed that your pressure numbers (kg/cm^2) on your IGL maps are alot different than mine. Are you sure about yours?

 

Are you refering to the # all the way over to the left of the map with a black back ground that goes from .1 - 2.0 or are you refering to my data that I typed into all the fields. If your refering to the .1 - 2.0 those were already in the spread sheet when I downloaded it and I didnt change any of it. If your refering to the actual timing #'s that I entered in for all the fields they are exactly what was in my commander.

Please let me know for sure so I can research what the difference is. I just want to make sure I know exactly what numbers your talking about.

 

Yeah I could have been more clear on that, The numbers I'm talking about are the ones all the way to the side of your map with the black backround that go from .1 to 2.0.

I think it's possible to change those values via power exel or datalogit software, but I've never seen a map like yours with no vacuum.
Its my understanding that the numbers represent absolute pressure, so to get manifold pressure you need to subtract atmospheric pressure. Here are my numbers which I came up with on my own, I'm not sure if there 100% correct, but I think there in the ballpark:

P01 thru P10 are in mmhg (vac)
P11 thru P20 are in kg/cm^2 (boost)

P01 = -687
P02 = -613
P03 = -540
P04 = -466
P05 = -392
P06 = -319
P07 = -245
P08 = -172
P09 = -98
P10 = -25
P11 = 0.07
P12 = 0.17
P13 = 0.27
P14 = 0.37
P15 = 0.47
P16 = 0.57
P17 = 0.77
P18 = 0.97
P19 = 1.17
P20 = 1.37

 

I just want to repeat what adax said .... don't reduce split if you are running a J&S because you are not going to like it.

 

FD Racer - What does yours show?????? I just downloaded 5 maps and all of them showed either P01 - P20 or .1 - 2.0 (which is the same thing without the "P").

Does your show something other than that???



Spyfish - I'm not running a J&S

Later,
STEPHEN

 

Stephen,

I think you hit the nail on the head. The boost column is labeled P01 to P20 and I'll bet at some point someone got careless and made those represent boost values.

Here's what the manual says on page 20:

What is a Pressure Value?
If the press. value is [20000], it is equal to 2.0 kg/cm^2 of absolute pressure. Atmospheric press. is about [10000] of pressure value.

See below for the boost settings at N01/P18. The number 20000 represents kg/m^2. Subtract 10000 to compensate for atmospheric pressure and you get 10000 kg/m^2. Convert that to kg/cm^2 and you get 1.0, which is ~ 14.22 psi. Pr01 through Pr09 are vacuum, P10 is zero boost, and P11 through P20 are boost.

 

I know you are not ... but the info is worth repeating for all to see in case they missed the info on the big list.

 

Well, no one has yet talked about reducing the split with the PFC.

Has ANYONE done it?

No, I don't have a J&S.
Yes, I finally have my commander

 

Two important facts:

1) The last above pressure conversion is wrong.
If the presure value is 20,000, the 2.0Kg/CcmSq is correct, but: 2Kg/CcmSq = 28.5psi absolute, minus 1 ATM of 14.7psi gives 13.8PSI realtive or as we call it boost gauge pressure. You have to calculate absolute first then subtract 1 ATM.

2) If you run no timing split, then you have to also run less total timing advance due to the faster pressure rize in the combustion chamber. No one has listed such map for the PFC yet! Feel free to experiment for us!

 

I have no fear

A few things I need to clear up first, and a few others, though.

I just got my commander in. I'm going to soon be running some tests to see, if any, what differance I am running from boost on the commander to boost on my gauge. I'm also going to be voltage tesing my MAP sensor to make sure it is up to par, and also make sure the filter in front of it is as freeflowing as possible. I also want to start checking out my knock readings to see what the hell I am getting across the board when compared to everyone else.

Now regarding timing...
I keep reading that raising the timing will bring knock. After speaking to a friend which seems to know his rotaries failry well, he mentioned that it would not affect knock. MY understanding is that detonation GIVES knock, raising your ignition = cleaner combustion which then = running leaner. True or not?

I don't have a Dataloggit thing yet, though. Posting maps would take me some time when the time comes. Oh and I have a basemapped PFC.

 

I'm running no split with more timing than the XS single turbo map. It seems to work ok for now, but I'm trying to finish my dash project so I can complete my EGT install.

Advancing the ignition will cause the fuel to ignite sooner and will raise the pressure faster and/or sooner. If the pressure increases faster than the flame front of the spark plug then the fuel will combust on its own from the high pressure and hence you will get detonation. Retarding the timing will slow the process down but you will loose leverage on the eccentric shaft(hence power output will be reduced) but you will gain some margin.

 

During boost or during vacuum and boost?

 

all the time! :d

 

Are you running the same maps for the PFC (lead/trail) or doing this through paralleled ignition coils, etc....

How long have you been running this setup and what have you noticed?

Rob

 

I realize that with a J&S it's possible for the leadings to fire before the trailings, but just curious, what is the effect of this? Please pardon my rotary ignorance .

 

Detonation is could be the result of leading firing after trailing.

I have been running no split for about 3 weeks. It runs smoother at idle and on top end. I simply made the maps equal each other. I have a Jacob's ignition box for the leading at the current moment.

 

Carson,

If you plan to remain no-split, then Kyle K. had a very good idea. Remove the leading coil and replace both trailing coils with leading coils. Use only the trailing ignitor signals to fire the new coils. Each coil fires it's own pair of L&T plugs. This way the coils fire half the rate as a normal leading coil. Helps them to run cooler, and produce a hotter spark.

Both plugs would always fire in sync!

How much retard did you put in to counteract the faster
rize in combustion pressure?

Send me a copy of your IGL or IGT.

 

As of right now I haven't retarded the timing .... I personally think it was too far retarded from your maps, which I started with initially.

The idea you mentioned is what I have been wanting to do and hence what started my investigation into complete control over the PowerFC. I got into some discussion with Rice Racing in the single turbo forum on this topic. I hadn't thought of the cooling advantage you would gain though-so that is a nice addition.