Need advice for tuning max timing

[Hang-on]

Hi everyone. I'm looking for advice on the best way to safely squeeze all the timing I can from my 514. I'm running multi-port fuel injection controlled by a Holley Commander 950, so setting timing for the entire operating range is easy, but (as I saw in another post) I fear I won't hear a ping when present. I saw a thread on making your own knock sensor, and am curious about that too.

Vettestr - You mentioned using the ECM interface from your Holley injection. Are you running a Commander 950 also? I noticed a lead in my wiring diagram for a knock sensor. Can this be utilized with the home built unit? Can a complete sensor unit be bought to save the trouble of building one?

I'm also curious as to whether a knock sensor is necessary, or if dyno-tuning the car eliminates the need for this (assuming we could set max timing for most conditions on dyno with a temporary knock sensor).

Here are my stats:

- Motorsport 514
- swapped cam for slightly milder one (232/240 duration vs. 258/268 original)
- Victor Jr. intake modified for MPFI
- Holley Commander 950 system controller
- Currently running 27 degrees of initial timing and maxing out at 41 (engine runs rough with less initial timing. I was told that BBL's often want up to 28.)
- The car currently runs very well - no burps or pops (or pings that I know of), and very strong... but I suspect there is more power to be had within a safe margin.

There is a picture of my timing advance map in my gallery. Any feedback would be greatly appreciated.

[Tom Wells]

Hi Hang-on,

Similar setup to what I'm using!

Still have an MSD w/centrifugal advance so can't really compare notes - yet!

I've sent for the wideband upgrade. When it gets in, I'll eventually allow it to control the spark too - I'll let you know. Probably at least a month from now anyway...

Tom

[Hang-on]

Hi Tom,

By the way - my name is Danny (forgot to put that in). I saw your profile a few weeks back and have you on my buddy list - I figured we might be able to share fuel and spark map info. Also - I have the wideband upgrade kit you mentioned on my system. It works great!

Danny

[mr0077]

A caution I've heard might be worth thinking about...because the dyno only "flash" loads the motor, tuning for max power on the dyno is not wise unless you're doing drag strip runs only...for sustained loading, the word was to back the timing a couple of degrees below the best power point on the dyno...any comments on that theory, guys?
Let us know what total timing you come up with.

[vettestr]

Danny,
I looked at your engine specs and am not sure if you have an ECM other than the 950 unit. I have built a test box to install on engines with a knock sensor as part of function. The sensor is an off the SHELF purchase and just need black box to record or warn when triggered, I run the older brother to your Holley 950 or the 4DI reworked to the max. to fit my needs.
The electronic curve is the only way to fly as you have a fixed or solid mount for the pickup and computer moves timing. The vibration added to the plate then moved by vac is sloppy by design magnified by 7000 rpm. It does work but it has room to be improved also.
I admit this is extreme aurgument but I have been raised in the day of dual points (huge springs ) on a plate shaken by the gear drive. Todays stuff is already better than even the Vertex/Hunt mags or yesterday.
This article says the newer 950 interfaces with a knock sensor. http://www.popularhotroddingweb.com/...k/0305em_musi/ If so just buy one off the self for an injected 5.0 mustang and you are set. It functions as an on/off sw. to be basic in theory. On means retard and off means keep programed advance. The turbo boys have this to a science !!! Have fun and if going to push the limits with timing you do need a sensor, jeff c

[oleyellar]

The Ford Motorsports guys say to go no more than 38 degrees total timing on the 460 stuff. You should recurve your distributor so the initial is where you want it at idle and then stop it at 38 for the other end.

I run mine at 36 total, and actually I have never even checked it at idle.
41 just seems like a lot to me.......

[Hang-on]

Thanks for the replies guys. Jeff - thanks for that article link. This looks like just the information I'm looking for. I've found the area in my software that works with the knock sensor now too, so I'll be off to pick up one of those off the shelf units you mentioned. This will be my little piece of mind when I put my foot into it!

Oldyellar - Thanks for the input. I've heard similar numbers to what you quote on max timing, although I did also hear (from an engineer at Holley who's been helping me) that some big blocks may want up to 42 max and up to a whopping 28 initial. He told me this when I called him to ask why my motor ran so well at 28 initial, and somewhat poorly at the more common 22. From what I've been learning, the amount of timing an engine requires is inversely affected by the efficiency of it's combustion pattern. I have a custom muti-port injection design, so it's possible that my injectors are not in the very best locations, or that maybe my heads simply don't produce combustion efficiency on par with most others. I realize this is not likely though. In either case, my aim is to optimize my spark timing safely, and a knock sensor will help me do that.

Thanks again, and if anyone else has opinions or advice - I welcome it!

Danny