| [GMCnet] Fi Tech - any downwsides [message #299611] |
Sun, 24 April 2016 12:43  |
glwgmc
Messages: 1014
Registered: June 2004
Karma:
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Senior Member |
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Interesting that I have not seen any mention of the aftermarket automatic spark controllers with knock sensors like the one JimK sells for $595 called “Safeguard Knock Controller” . On paper it sounds like it may do something like what the EBL does for the Howell EFI and if memory serves me correctly the EBL adder is that price or perhaps more. Anyone have experience with any of these? Do they accomplish the same thing? Do they work with HEI? Are they worth considering for use with the self learning EFI systems like FiTech or MSD Atomic?
Here is a comment the owner of the Safeguard company made a few years ago when asked about the knock sensor hearing pre-detonation or piston slap on race engines. Not sure it has any applicability for our GMCs, but sure sounds like after market knock sensors can be a touchy subject:
"Our latest units are calibrated for Bosch or other brand "donut" style knock sensors. We no longer use GM "one wire" sensors, as included with the MSD Knock Alert. That's a clever analog design from the 1980's and works well with a quiet engine, but it has no micro-processor or other logic.
John Pizzuto
J&S Electronics”
I am also wondering about the base economics of trying to eek out another mpg or so by trying to advance timing more than a properly curved HEI will do under similar circumstances. Not trying to sell any thing here as I have no dog in this hunt. Just thinking through all I am reading -
A new engine costs somewhere between $3500 and $15000 with the R&R depending on lots of things. I will use $5000 as a rough average. We drive our two coaches a lot each year, but I doubt if most of our owners drive more than 10,000 miles a year, if that. Depending on how fast one drives, how loaded the coach is and where they drive (mountain west or flatlander) most GMCs will get 8 to 10 mpg. Lets use 9mpg as an average for this purpose. At 9mpg over 10,000 miles one will burn about 1100 gallons of fuel. At, say, $2.50 per gallon that is about $2,750 per year. With absolutely perfect spark control what is hear is the gain could be maybe 1 to as much as 2 mpg. Lets use 1.5mpg. 1.5 on 9 is an increase of a bit over 15% which would mean a savings of around $400 or so per year. At this rate the perfect spark control savings would take somewhere around 9 to 30+ years to equal the cost of one engine R&R if the spark control was not perfect and/or the aftermarket knock sensor failed to retard adequately or fast enough to keep from burning a hole in a piston or worse. Hmmmm…..
Food for thought, anyway.
Jerry
Jerry Work
The Dovetail Joint
Fine furniture designed and hand crafted in the 1907 former Masonic Temple building in historic Kerby, OR
glwork@mac.com
http://jerrywork.com
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Jerry & Sharon Work
78 Royale
Kerby, OR
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