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View Full Version : All EST are not the same!



EagleMark
02-27-2012, 02:48 PM
Found a good read on EST modules and spark latency tables. What does this mean? Well could be as much as 11 degrees difference in what is at timing mark and what is in bin! Could also mean difference is adding 2 degrees over 3000 RPM or subtracting 4 degrees at over 300 RPM depending on which EST!

What really caught my eye was latency tables for LS1 PCM with coil on cylinder are all same for all RPM. So guys doing LS1 PCM swaps could have some serious timing issues!

http://www.thirdgen.org/techboard/diy-prom/465232-ebl-sa-latency-table.html

93V8S10
02-27-2012, 05:02 PM
That's an old thread, but a good one!

RobertISaar
02-27-2012, 05:07 PM
hmm... 22uSec for LS1 CnP.

the 60V6 stuff (3 coils, waste spark) run 152.6uSec at any RPM.

EagleMark
02-27-2012, 05:38 PM
Big difference if your using a distributor based bin and converting to DIS like corvairnut!!! Or using 411 PCM with a distributor like Dave W!!!

But the math is there, just have to check bin timing to actual timing on balancer after latency!

RobertISaar
02-27-2012, 05:42 PM
yeah, at least it's something relatively easy to test after you disable the idle spark modification stuff, assuming you have a balancer that is marked.

EagleMark
02-27-2012, 05:48 PM
I think they still make timing tapes for harmonic balencers which would give degrees to IIRC 50. My timing light is a dial back with RPM so I guess that could work to. At least getting within 2 degrees... but can you imagine being 11 off advanced? Especally on conversions where knock sensor/module is not totally accurate or high performance engine, headers, noise... and diabling or disregarding knock reading as noise?