[Formulajones]

I run manifold vacuum for the vacuum advance timing as I've found the engines just like that better with more idle timing, cooler temps and smoother idles that help the engines produce more vacuum.

You may find your engine would like even more idle timing than 14. Most guys running these EFI systems now with programable timing are up around the 20 degree range.

I actually use the ported vacuum on the Sniper to control my charcoal cannister switch for tank ventilation, just like I did when it had a carb and it still works well with the Sniper.

[1funride]

Really 20 at idle?
What is the timing curve, initial, full, and all in by?
I'm not running EFI timing yet, using an MSD distributor.
Is it hard to start with 20 degrees initial or do they start at a lower timing then switch to 20? Interesting.


I guess this is the age-old question port or full vacuum, and I admittedly have not set up my car for full vacuum timing nor have I driven it that way. I went port since I wanted the timing to pick up right off idle rather than drop, then pick up. My idea being this is easier to tune and offers a smoother timing curve and maybe a little more timing at part throttle cruising where the mixture is lean and needs the extra time to burn.

[JLMounce]

I run about 24 degrees initial on my 462. This is where the car likes it. Runs cool at idle and helps overcome some of the altitude related low vacuum issues.

If you have your FiTech controlling timing, starting is not an issue. It will start the car at whatever base timing you have set. For me that's 12 degrees. It won't command idle timing until the engine is in run state vs crank state.

For the curve, plot your total WOT advance at 3000 rpm on a grid back to your idle rpm and set your 1100rpm 45kPa idle setting based on that linear graph to start with. That will get you close to similar for how the car would behave with a traditional distributor weight setup.

I do also add 2 degrees of advance at 6000 rpm and the engine really liked that extra timing up there. Best way to think about all of this is that you're doing the same thing electronically that you're doing mechanically if you're tuning a traditional setup.

[1funride]

I have one of the original early Fitech units 30004 600 Power adders and an older MSD ready to run distributor. The distributor does not have a tach output, so I am using a basic MSD 6A CD ignition for tach signal generation. Do I need to do anything other than lock out the distributor, remove the weights, and install an MSD phased rotor to get the ignition timing controllable from the Fitch?

Sounds like a great option.

Has the Fitech ignition feature evolved overtime from the original units?
Do I need to, or is it recommended to run the Fitech CD box in place of the MSD 6A?
How does the Fitech ignition control compare to a Progression Ignition Distributor?

[Formulajones]

Originally Posted by 1funride

Really 20 at idle?
What is the timing curve, initial, full, and all in by?
I'm not running EFI timing yet, using an MSD distributor.
Is it hard to start with 20 degrees initial or do they start at a lower timing then switch to 20? Interesting.


I guess this is the age-old question port or full vacuum, and I admittedly have not set up my car for full vacuum timing nor have I driven it that way. I went port since I wanted the timing to pick up right off idle rather than drop, then pick up. My idea being this is easier to tune and offers a smoother timing curve and maybe a little more timing at part throttle cruising where the mixture is lean and needs the extra time to burn.

It's easier to do all this with the EFI timing control for sure. With EFI timing control you can have as much initial timing at idle as you wish, but it doesn't have to crank there. In order to accomplish that with a mechanical distributor you have to run the vacuum advance to a manifold source. So it will crank on the initial timing and then once running the additional timing is added via vacuum advance on the manifold.

However this takes a modified vacuum advance and other modifications to work well.

The biggest difference between the mechanical way and the EFI controlled way is that the EFI is much more stable and is not affected by altitude. A mechanical vacuum advance is only going to be as good as the engine is at making vacuum and the elevation you drive the car at.

So yes to your first question. What I do with the mechanical setups.....

First I modify the breaker plates and/or weights to limit advance to about 16 or 18 degrees at the crank. Then I set my initial to 16 or 18 depending on the total I'm looking for. Total depends on where it made best power on the dyno.
Some engines I run 34 degrees, some 36 or 38 degrees. Either way I modify it to end up with about 16-18 initial timing and yes all the cars crank perfectly fine this way.

From there I modify the vacuum advance. I start with an adjustable unit and set the spring tension to start working around 6 inches and all done by 8-10 inches. So when it's on manifold vacuum and idling, all the vacuum advance is in and stable at idle as most engines should idle with at least 8-10 inches of vacuum even with a pretty rowdy camshaft. This also helps with idle performance as far as vacuum generated, how smooth it is, and how it idles in and out of gear with very little rpm drop.

Second thing I'll do is weld the slot on the vacuum advance to limit it's travel. I usually shoot for .200" to .250" depending on the breaker plate, and this gives me about an additional 10 degrees of vacuum advance.

So at idle, with 16 or 18 initial, and vacuum advance added in, it actually idles around 26-28 degrees. Provides good idle manors with big 260-ish @ .050 camshafts on tight LSA's and actually makes them very drivable.

At light throttle cruise I'm usually seeing 46-48 degrees of timing with vacuum advance added. This returns good mpg.


But as I said, all of this is much easier to accomplish with EFI timing control.

[1funride]

I have one of the original early Fitech units 30004 600 Power adders and an older MSD ready to run distributor. The distributor does not have a tach output, so I am using a basic MSD 6A CD ignition for tach signal generation. Do I need to do anything other than lock out the distributor, remove the weights, and install an MSD phased rotor to get the ignition timing controllable from the Fitch?

Sounds like a great option.

Has the Fitech ignition feature evolved overtime from the original units?
Do I need to, or is it recommended to run the Fitech CD box in place of the MSD 6A?
How does the Fitech ignition control compare to a Progression Ignition Distributor?

[JLMounce]

Originally Posted by 1funride

I have one of the original early Fitech units 30004 600 Power adders and an older MSD ready to run distributor. The distributor does not have a tach output, so I am using a basic MSD 6A CD ignition for tach signal generation. Do I need to do anything other than lock out the distributor, remove the weights, and install an MSD phased rotor to get the ignition timing controllable from the Fitch?

Sounds like a great option.

Has the Fitech ignition feature evolved overtime from the original units?
Do I need to, or is it recommended to run the Fitech CD box in place of the MSD 6A?
How does the Fitech ignition control compare to a Progression Ignition Distributor?

The FiTech needs a two wire distributor. So yes you’d need to take the guts out of the ready to run distributor and convert it. Locked out with an adjustable rotor will get you there.

The FiTech has a built in spark commander. You do not need to run an external CD box. I am not on my setup. However having the CD box has some benefits to idle quality, and in boosted applications.

I have an early FiTech as well. The only real thing that has changed from early units with the t195 software to the t198 software is the ability to lock timing which aides in syncing the distributor with the computer.

In regards to the progression ignition, that unit has a more granular spark map than the FiTech has. That said it’s not talking to the FiTech either and it simulates load from a vacuum signal. If you have the ability to get the FiTech up and running, I’d lean in that direction. If you had a FiTech that doesn’t command timing, I’d definitely recommend the progression ignition.

You can install the t198 software if you’re after an easier setup.

[napster]

I wish you luck with it. I sure didn't have luck with it. Swapped it out for Holley Sniper and not looking back.