My 427 SOHC Build..... Finally the time has come!

[My427stang]

OK, so, here is what I think

Distrib Base deg = Adjust this to get the timing light timing to match the displayed Spark Advance at low RPM . It’s recommended to set this as high as possible, because the amount of advance range  from min to max is limited due to the rotor and cap being in a fixed relationship.

I think this is a correction factor input.  The fact is says low RPM is that it likely can be checked anywhere that it isn't advancing significantly.  So if you read 12 degrees on your light, but the hand held says it's currently at 10, you add or subtract to that figure to correct the ECM so it knows where it is.  I would note though that they are trying to get you to use a narrow curve range.  So, you know best total to make power, I would set initial at the highest point that the starter will turn the engine hot, using the timing light, set up your curve limits (maybe 18 initial and if Jay says 30 total is right for the engine)  and then if it pings on the fuel you want to use, adjust how fast timing comes in as opposed to changing the end points

Idle Advance = The spark advance desired at idle

Once the ECM has the idle timing corrected and the 4000 rpm advance corrected, it now knows where it is, so I think this is your desired idle timing and the ECM puts it there.  So if the first one is a correction, this one is a command.

Overall, I think the Distributor Base and the VR Advance 4000 are corrections to make the handheld match what your timing light is honestly telling you because it has no way of knowing.  Then most, if not all, the others are timing curve inputs that you command.

[cobracammer]

Thanks Ross and Jay.  I think this is all becoming a little bit more clear.  Of course I am marking up my instruction manual with all of these notes.  I actually started the car last night.  within a few minutes, I had the IAC where it should be, the Idle RPM's where they should be, and also had the Idle AFR up to 14.0:1 with no pinging!  If you remember with the FAST system, I had the Idle AFR at 13.5 to 13.7.......  With a little more experimentation, I think I will get it right where I need it.

Thanks again guys!

[My427stang]

Just realize that I assumed that looking at the instructions, I would take your timing light and check the timing at idle and at 4000.  If they match what you command, you are all set.  If they don't then you may need to play with the adjustment factors

Cost of being wrong is either too much timing or not enough, one can hurt, one can take power away

[sixty9cobra]

I would hope a car never pings unless its driven. If you hear pinging and its sitting still you have big problems

[cobracammer]

Thanks Ross.  Yes, I read that and planned to do it soon.  I have many "Elderly" neighbors currently, so Hard to go any higher than Idle  LOL

I have a workshop at my new place with really no neighbors, so I will get it to 4000 RPM's, make sure with the light we are right on, and also Phase the rotor (if its needed).... when I get there next month.

Also, I think I should explain when I said Pinging.....  With the Fast system, When I would adjust the fuel to go a bit more lean, it was more of a popping.  Most likely a misfire.  Since the fast system was requiring 10" of vacuum, I am not sure exactly what was going on, but when I tried to go leaner than 13.5-7 range....  I would start to get that noise.  I may have used "Pinging" in error.  :0)

Either way, with a low Vacuum setup , the Fitech seems to be working well for me so far.

[sixty9cobra]

I wouldn't go nutty for 14:1 anywhere 12-13 is fine its not an economy motor. Richer is safer in my book

[jayb]

+1 on what Harry said.  Don't get hung up on the numbers!  Tune for what the engine wants, not some A/F value.  If the engine is idling better at 13 or 13.5, don't try to force it to 14.7 if it doesn't want to run well there.

On the dyno we use the A/F numbers to get close, then go up or down in fuel to maximize power.  A good example is my race SOHC, which makes best power at an A/F of 13.3:1, not the 12.5-13 that most people will tell you it wants...

[cobracammer]

Thanks.  The only reason I though I would try and go a little leaner was the fact that when I pulled my spark plugs last time (Pictures a few pages back in this post), they were solid black.  Since the car was mostly only at idle (Never really been driven far or long aside from getting the wheels aligned), I figured it was the A/F.

I actually saw Barry's last Cammer engine on the dyno (He posted a video on YouTube).  I noticed that it was the same stroke and CI as my motor and it seemed to be idling at about 14 to 1 AFR.  LOL  I can definitely go richer.  When I change the AFR on this system, there was no audible difference between being set at 13.5   or being set at 14.0.  How would I go about knowing where the engine is "Happiest" without being able to hear the difference?  Is there another way to tell?  Thanks again guys!

[jayb]

I'd suggest you lean it out until it starts to run poorly, then richen it back up a few steps.  That ought to get you close.  Watch the plugs to see if you may need more incremental changes after that.

[WConley]

Also, I think I should explain when I said Pinging.....  With the Fast system, When I would adjust the fuel to go a bit more lean, it was more of a popping.  Most likely a misfire.

Yup - That's what you have.  It's a lean misfire.  Won't hurt anything, but as Jay says you want to be well into a comfortable A/F ratio for good idle quality.  Sounds like you're on your way!

[blackthunder1970]

hi
any up dates yet on the fitech
cheers
barry

[cobracammer]

Hi Barry,

None yet.  I am in the process of moving, so will be fine tuning the timing in about a month or so.  Thanks for checking in.

[cobracammer]

Hey Guys!  Move complete....ish.  I am now at a point where I want to get started on refining (or  ...  um... understanding) the timing a bit more.

OK so to recap, I have a brand new Pro Billet MSD distributor installed and its Locked out since I will be using the FiTech system for timing control.  The following values are what the systems asks for as far as timing.  I have filled in the values as they told me based on an base timing of 12 degrees (I think on a earlier post we have decided to up that to 16-18 degrees) and an all in timing of 30 degrees:

*Distributor Base Timing: 10 degrees (I double checked on this and the tech said 10!)  Also re-read Ross's Post, but I don't think I am fully understanding why 10  LOL  Since you have to check timing at a high RPM because the timing jumps around at lower RPM's due to the computer control, I don't know how I could adjust using this field when the low RPM number moves around.  Maybe I am totally off.  I understand the concept Ross described, but the moving timing number (at low RPM) throws me.

*Idle Advance: 12 degrees  (I think this will need to be changed to 16 degrees)

*1100 45kPa:  25 degrees

*3000 45kPa Cruise: 30 Degrees

*6000 45kPa: 30 Degrees

*WOT 1100 95kPa: 25 Degrees

*WOT 3000 95kPa: 30 Degrees

*WOT 6000 95kPa: 30 Degrees

Followed by this excerpt: 

SPARK MAP: The spark advance uses a 3x3 matrix table to allow flexible spark advance control. This can allow distributor simulation, locked timing, boost retards, high RPM advancing and other strategies to optimize the ignition spark advance angle. The distributor must be locked out. Spark advance during cranking will happen at or after the VR tooth crosses the sensor. Above cranking, spark advance will only be equal to or more than the base advance, regardless of the value entered in the handheld for timing. Distrib Base deg = Adjust this to get the timing light timing to match the displayed Spark Advance at low RPM. It’s recommended to set this as high as possible, because the amount of advance range from min to max is limited due to the rotor and cap being in a fixed relationship. VR Advance 4000 = Adjust this to get the timing light timing to match the displayed Spark Advance at 4000 RPM. This is adjustment for the small lag inherent in VR signals. It can add up at high RPM. Idle Advance = The spark advance desired at idle. 1100 45kPa = Spark advance used just after throttle opens from idle. This value shouldn’t be much more than the Idle Advance, for this reason. 3000 45kPa Cruise = Spark Advance used in a light cruise at 3000 RPM and throttle barely open. 6000 45kPa = Spark Advance used in a high free-rev condition, perhaps also seen when autocrossing and just tipping-in in a low gear at high RPM. WOT 1100 95kPa = Spark Advance at low RPM and “full load” – perhaps the throttle is as low as 20% to see this much load. Spark is based on MAP, and MAP (and thus “load”) can get pretty high even with low throttle openings at low RPMs. WOT 3000 95kPa = Spark Advance at high loads and 3000 RPM. This could easily be deemed “total” timing when comparing to a distributor, but due to the flexibility of a 3x3 matrix, this doesn’t limit you as such. Handheld Controller Feature Definitions 4 WOT 6000 95kPa = Spark Advance at high loads and 6000 RPM. At high RPM, some engines require more or less spark advance than at 3000 RPM. This allows you to set the timing there. Boost 1100 180kPa = This is full throttle but with a supercharger or turbocharger boosting to about 11.6 psi. If no intercooler is used, the engine may require very little spark advance. Remember that timing less than the base advance “Distr Base Deg” is not allowed, so choose the base timing carefully. Boost 3000 180kPa = This is full throttle but with a supercharger or turbocharger boosting to about 11.6 psi. If no intercooler is used, the engine may require very little spark advance. Remember that timing less than the base advance “Distr Base Deg” is not allowed, so choose the base timing carefully. Boost 6000 180kPa = This is full throttle but with a supercharger or turbocharger boosting to about 11.6 psi. If no intercooler is used, the engine may require very little spark advance. Remember that timing less than the base advance “Distr Base Deg” is not allowed, so choose the base timing carefully.


So I guess I want to know a few things:

- First, that 10 Degrees at Base timing.  If my Idle timing was 12 degrees (soon to be 16 degrees), what is the 10 Degree Base?  Is it a degree of timing just used for cranking the engine over?  And then when it starts, it does to the Idle Advance value?

-Second, in the excerpt above, it says that 1100 95kPa should not be far off from the Idle Advance-  "Spark advance used just after throttle opens from idle. This value shouldn’t be much more than the Idle Advance, for this reason."  Doesn't 25 degrees seem far off from the 12 degrees of Idle Advance?

-Third, when I change the Idle Advance to 16 Degrees as suggested earlier, what should I change all of the other values to?  I know I need not go over 30 Degrees Total timing, so with that in mind....?

- Fourth, it does not seem like after I change the Idle Advance to a Value of 16 Degrees that I will be able to accurately check it with a timing light (since the computer is constantly adjusting-According to the tech).  I need to check timing with the timing light at 3000 or 4000 RPM's (since that should be steady) and then as long as the value I see on the balancer matches the 30 degrees total timing, in theory when I let off the throttle, the computer will control the timing to ensure the idle advance value of 16 degrees is met.  Does this sound correct?

[cobracammer]

Its been a while so I had to read back through some older posts on here and I think Ross had already answered the 10 degree question  :0)  LOL

I also have a question out to Tech Support at FiTech for chainging the Idle Advance to 16 degrees (How it affects 1100 45kPa's value and WOT 1100 95kPa)
I will post as soon as I hear back from them.

[cobracammer]

So I was able to speak with the Tech support at FiTech this morning.  Here is what I found out:

Since my timing is already dialed in at the original 12 degrees initial (they call it Idle Advance), if I need to make any changes, it is all done in the handheld and not by touching the distributor.  So as suggested, I will make a change to have Initial (Idle advance) at 16 degrees.

Now with that being said (and I am sure I have been told previously, but with the Move and Job change, my mind is fried), Base timing is also an input for this system.  As per the Tech, this will not change from its current setting of 10 Degrees no matter what my Initial(Idle Advance) or Total timing is.  The Base timing value is what the system will use to start while cranking.  I think I understand that at 10 degrees (BTDC), you are compressing the Air/Fuel mixture for longer before ignition.  In theory, this should make it easier to start.

Given Base timing wont change from its current 10 Degrees, and we are changing Initial (Idle Advance) to 16 Degrees......  And most importantly, my all in timing stays at 30 Degrees.....

The only other values that will have to be adjusted are:

1100 45kPa will change to 22 Degrees (It was at 25 degrees when initial timing was 12 Degrees)

WOT 1100 95kPa will change to 22 Degrees (It was also at 25 degrees when initial timing was 12 Degrees)

I also asked about IAC.  With the FiTech system, they suggest IAC on a hot engine be between 3 and 10.  With the engine hot, I am bouncing around between 3 and 10, but on a cold start-It does not "Fire right up".  I have to tap the throttle a little.  As soon as it fires up, it will stay running at the correct RPM and all, but I was supposing that I should not have to tap the throttle to get it to start up.  The Tech suggested getting the IAC number a little closer to "0" (and as a side note, he said it should never be greater than "10".  The Closer to "0" the IAC is, the more air its letting in.  I will also do this.  Unfortunately, the engine has to be at temperature to make the adjustment, and then you have to let the engine get cold again to see if it worked.  So not instant gratification on this one.

Lastly, I asked him about AFR in relation to IAC.  I was curious if you adjust AFR's richer, would you have to adjust the IAC to let more air in.....  He stated "No".  I had him on the phone so I asked just to ask (didn't really think it through).  Another good to know.

So there it is....  I will adjust the timing to 16 degrees initial(Idle advance) and just to double check will check with timing light at 2000 + RPM to make sure my handheld matches the strobe light.

I will play with the IAC number a little more to get it to fire right up as soon as I hit the start button (not super pressing, but it would be nice)

I will used the AFR inputs to play around a bit (but stay on the rich side because it seemed to like them with when I had the FAST EZ efi system installed)