The EFI 5.0 Mustang guys are all aware that advancing the base timing from 10 degrees to 14 or even 16 degrees BTDC nets a discernable increase in performance and driveability. Does that same philosophy hold true for the trucks, and is there any harm in trying?

Regards,
Bob P.

 

Bob ,
The 5.0L Mustang engines are calibrated differently than the truck engines . Advancing the timing will cause the engine to run hotter under higher loads . Plus Ecu 's derive all their info from sensors like we use our senses to decide on things . The Ecu's and sensors all have parameters they operate within . For instance if an engine calls for a base timing of 10 Deg Btdc , then changing that affects what the computer sees ...sort of like if you put on someones glasses when you dont wear glasses . The world looks like your 10 ft tall . Trucks run in a different world than high performance vehicles like a Mustang do . I dont know for sure what the long term affects of advancing the timing on a truck engine would do . The Ecu is constantly changing the timing to optimize it based on the data it recieves from the sensors . Thats why it has to have a fixed point of reference . If you advance it beyond what is recommended you may see performance on some levels , but I suspect in a situation where one uses a truck as a truck , Ie: towing , hauling etc you will actually see performance loss .
Paul

 

Bob,
Awhile back I did just that, advanced my timing on my 90 F150 with 4.9L just to the point that it would ping on hard acceleration, then backed it off just until the pinging went away (as recommended by some who advocate that Ford base timing is always too low). The result: better acceleration, but VERY POOR mpg...went from 17-18 in town and 19-20 highway to 12-13 and 15 mpg. Not acceptable in my book. Then I went the other direction, remembering that my '68 and '81 300's were set at 6-8 degrees BTDC. No real change in performance, and again, poorer mpg. Guess the speed density computers in our trucks have to have 10 degrees BTDC to calibrate the computer/engine performance. Can't speak for Mass Air equipped trucks...don't know if your 93 is mass air?...but from my perspective, Ford built these to operate best at 10 degrees BTDC. If your 4.9 is running good and gets acceptable mpg, leave it be. If you just want more mpg, you can drop in a K&N filter. Some here have said they notice a 1-2 mpg gain, but I haven't seen such. If your truck is acting up and timing is right, learn how to run the engine self test from manuals or this site:
http://dalidesign.com/hbook/eectest.html
and then proceed from there.
Another good site is at:
http://www.westecauto.com
look under Forums, then Ford.

 

Thanks very much for the advice, guys!

Bob P.