Timing retard under boost

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subcom

subcom

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I'm building a single turbo setup for my 5.9 build and am exploring options for timing control. I know most folks use the MSD 6530 unit but are there cheaper alternatives? My build will be an E85 blow thru, non intercooler and I don't intend on going past 8-10psi. I currently run one of the HEI ready-to-run distros and I love it. Is there anything on the market I could plug into it and map out timing retard under boost?
 
for that little boost i would just dial back the mechanical advance. leave the vacuum advance hooked up for better timing while cruising.
 
NA I'm currently at 38 degrees all-in. What would be a good starting point? Remove 2,4,6,X degrees out of that?
 
I used a live shaft Lean Burn distributor. I added a breaker plate and vacuum pod from a regular electronic distributor. Fixed timing at say 19 or so with a vacuum advance set to manifold vacuum-pressure. Not sexy but it works.
 
There is a lot that goes into play here. Most folks start out by pulling 3 degrees per lb of boost from the total timing and work their way down to 1 degree per lb of boost after getting the tune just right. You have E85 so that's an advantage, but not an intercooler. So there really isn't a perfect answer.
 
T56MaxTorq said:
There is a lot that goes into play here. Most folks start out by pulling 3 degrees per lb of boost from the total timing and work their way down to 1 degree per lb of boost after getting the tune just right. You have E85 so that's an advantage, but not an intercooler. So there really isn't a perfect answer.
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Thanks for the feedback.
I'd rather pull timing than just lock it somewhere and hope for the best. But back to the OP, is there any other way to pull timing aside from the venerable 6530?
 
do some searches on google. back in the day volvo had a vacuum advance/boost retard diaphragm. if you can find one and retrofit it that might be an option. the 6530 is probably the better way to go though.

my initial timing is 12*, i limited my mechanical to 6* and have the vacuum advance still hooked up to give me 28* total while cruising and 18* on boost. it starts right up and moves out pretty good. i have plans of going the 6530 route when i have the money for it though. a little more timing in certain conditions would help.
 
you can also look at the hei conversion with the 5 or 6 pin module (i cant remember which it is). one of the pins on module pulls 10* of timing out. hook that to a hobbs switch set for 2psi and have at it.
 
This is the setup I was thinking about with the 273 w/roots blower. Did you put a check valve inline to the distributor so it did not get boost to it? I am just curious what the timing would do if the pod saw boost.
 
the way the advance pod is made it wont let it go back any farther then it already sits at rest. i have no check valve, it sees 25psi of boost. no problems with it so far.
 
The HEI 5 pin module looks interesting. Apparently the 5th pin pulls 10* when grounded. I might try it out.
 
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