Thread: Msd 6al 6462
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356-930 356-930 is offline
Acceleration Junkie
Join Date: Aug 2007
Location: Laguna Beach, CA
Posts: 263
Originally Posted by dsiegel360 View Post

My PLX system (AFR, Boost, Vac- on 1 screen )is limited when trying to manually log data. Having a passenger helps.

The Warm up regulator sets enrichment pressure when boost is pushed into the WUR port. After the heating element rises to warm temp, with CIS fuel gauge on the WUR, I can mity vac pressure into the port to find out exactly when pressure changes from 3.75 to 2.2 bar.

Can the 6462 boost retard be adjusted by the fraction? come in at 6.25 psi rather than 6,7,8, etc.?

If timing is set at 26 at 4000 rpm's unplugged, is this max advance or would it continue when at 5000rpm's?

If I put mity-vac pressure into the retard side of the dizzy while at 4000 rpm's , will I see the amount of retard...without damaging anything?

I'd love to see some pics of your set up. Snow performance seems interesting.

Thanks again,

Sorry I donít know the word ďmity.Ē
I don't believe having a passenger act as a data logger can be effective or accurate. Perhaps if they were taking a video of the gage that could be studied after the fact. You're looking for events that occur and change over a period of a few tenths of a second at best from which to make adjustments.
I don't have knowledge about the PLX unit. Perhaps it has output capable of interface with a computer?
The MSDís onset boost retard pressure level can be infinitely set. Keep in mind the max rate of retard is 3 deg/psi. If you delay retard to begin at 10-psi you can pull out only 15 deg of timing at full boost.
Max advance will occur somewhere closer to 3500 than 4000 rpm. Distributor timing with vac/press lines removed/plugged will not increase once the distributorís full mechanical advance is reached, likely 3500 rpm +/-. 4000 is used to be sure all mechanical adv timing is in.
No need to test distributorís boost retard at high rpm. If you remove vac from the distributor at idle, timing will advance 20 deg and idle rate will be high, around 1500 rpm. Apply pressure to the boost retard port and monitor timing, see how much timing is removed, how much pressure it takes to retard timing. To assure loss of engine speed associated with boost retard pressure did not affect the distributorís mechanical advance, take engine rpm back to same rpm engine ran without vac or press. On my 79-930 8 deg of timing is out at 5 psi and more pressure has no effect.
Since you asked, Iíve attached some photos but thereís not much to see. The MSDís timing module and water/meth electronics are hiding behind the black plate (fuel enrichment electronics) in the back seat area of the car. The water/meth injection line is the red polyvinyl line (looks like one of the plug wires) entering the boost plenum assembly adjacent to one of the engineís boost sensors (roughly in center behind middle of fan assembly).

Old 04-16-2008, 08:11 AM
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