MSD 8762 boost ignition retard

mark houghton · 05-31-2009, 07:32 PM

Well I finally got the MSD ignition retard module all dialed in today - finally, after first sending my injectors off for cleaning and repairing the broken IC mount on the boost recirculation valve housing (thanks to all of you who offered to sell me a replacement, but I was able to fix it).

For my '87, stock settings at idle with the vacuum lines attached is right at TDC, and at 4000 minus the vacuum hoses she's at 26 BTDC. I set the MSD retard to begin shaving off timing at 5 psi (about .3 bar) and to drop off 1.5 degrees of timing for each 1 psi after 5. I advanced the timing at idle to 8 degrees BTDC, and with the MSD settings I figured it would retard about a total of 10 degrees at .8 bar boost. Before driving the car, just sitting at idle with 8 BTDC showing on the timing light, I put pressure (12 pounds) to the MSD and watched the timing retard 10 degrees. Good to go, took her for a spin.

Yes, it does wake up the response low thru mid-range, taching quicker and boosting quicker as a result. Huge night-and-day-smoke-your-tires difference? I wouldn't make that claim, but am happy with the performance overall. My timing at .8 bar should (should) now be 24 BTDC since my net change was to lose 2 degrees (I added 8 and programmed the MSD to take 10 off).

One final note: The 8 degrees I added by turning the distributor is all I could get, since that put the distributor at the end of it's maximum adjustment range. Again, this is with all hoses attached. I guess I find that kinda strange, but I wanted only 8 degrees anyway.

Easy installation, by the way.

JFairman · 06-01-2009, 07:18 AM

That sounds interesting.

Could you get more advance range by sliding out the distributor and advancing it one gear tooth where it engages the intermediate shaft?

Or, you could take a 1/4" straight carbide bur on a die grinder and lengthen the slot in the cast aluminum housing where the stud for locking it in place goes through so you would have more adjustment range to turn the distributor one way or the other without removing it.

fredmeister · fredmeister's Garage

What is the wheel hp and torque seen with your set up now?
No pinging at the new timing?
How are the A/F with the WUR set up?

mark houghton · 06-01-2009, 11:21 AM

[QUOTE=JFairman;4695255] you could take a 1/4" straight carbide bur on a die grinder and lengthen the slot in the cast aluminum housing QUOTE]

That's kinda where my head was going. It wouldn't take much to get several more degrees timing.

mark houghton · 06-01-2009, 11:43 AM

Quote:

Originally Posted by fredmeister

What is the wheel hp and torque seen with your set up now?
No pinging at the new timing?
How are the A/F with the WUR set up?

Don't have access to a dyno, so I would only be guessing. Probably about 370 HP at the flywheel. Torque....no idea.

No pinging...and there shouldn't be since I've actually dropped two degrees of advance at full boost (now 24 instead of 26 BTDC). And it's an easy twist of the dial if I want to retard even more...say get it down to 20 degrees at full boost as added insurance.

My A/F gauge was frozen up when I did my test run (took it apart and fixed it just last night). A/F's prior were running low to mid 11's at full boost with a 4200 rpm "pill" in the MSD rpm switch to delay the WUR boost enrichment. I would like to be high 11's to low 12's but am OK where it is for now.

JFairman · 06-01-2009, 11:54 AM

I have my summit digital rpm switch for the boost solenoid set to 5000rpm, fwiw...