Engine/Transmission (1994 - 1998) 96 12v timing for mileage

[SFlowers]

does anyone know if you can advance the timing on a 96 12v with the fuel plate modified? i cut the fuel plate all the way so with it being a pretty radical plate, will this cause problems? my main thing is mileage#@$%! i have built a hydrogen fuel cell for it and gained about 1. 5 mpg... keeping it at 60mph and taking off slowly , shifting at 1750rpm... im getting 21. 77mpg... not too bad for a extended cab 4x4 5 speed, with tool box and extra 100gallon fuel tank... well any ways, does anyone know if advancing the timing will really get me more mpg's? i very rarely tow anything... thanks a bunch for the info...

 

[JGK]

Timing is unrelated to the profile of your fuel plate so far as changing it goes. You can change the timing on any P7100.



Generally, advancing the timing will improve mileage. I don't know if there's a point where it will hurt it but if there is, it's far beyond where you'll likely set it for a daily driver.



It appears you're still using a stock head gasket and bolts. You can advance the timing to 15. 5* +/- and still be pretty safe with regards to the head and you'll find the truck runs a little better and your mileage should improve a bit.



-Jay

 

[Forrest Nearing]

timing for mileage depends on the RPM range you cruise at...

 

[Chrisw]

timing for mileage depends on the RPM range you cruise at...

lets say i run 2000 rpm, what would be the best timing

 

[Joseph Donnelly]

I found 15. 5 degrees to be good at 2000 rpm on the highway.

 

[bmoeller]

Mine is 16. 2*, and still running the stock headgasket. Never saw a difference in mileage, but did lower the EGTs by 150*.

 

[Chrisw]

I found 15. 5 degrees to be good at 2000 rpm on the highway.

If you didn't have to tools to do it your self. Would you have someone bump up the timing on your tuck. Any changes I make have to be made with towing and towing heavy in mind.

 

[Willys]

I've heard of some folks setting timing in the 20-30 range and had mileage in the 20-30 mpg range as well, on trucks bombed for speed and not towing so far as I know. Has anyone here set their timing that high?

 

[tp0d]

anything over 16 will kill a stock headgasket, and is not very street friendly. typically anything over 20 includes an aftermarket cam.

i set mine at 16. 5, runs nice... I did notice a change in exhaust smell, more acrid, stinkier. . but i did lose some egts, and possibly gained a little mpg, but I didnt calc before and after.

-j

 

[RHestand]

What is stock timing on a 98, 180 HP 12V?

Are there any books available like "How To Hotrod A 5. 9 Cummins"?

Thanks for any info. on this,

Ray

 

[tp0d]

stock is usually 11-13°

yes theres a book. . its called the TDR

seriously tho, I dont think there is any other source

 

[Willys]

This is a good discussion on how to hotrod a cummins, for cheap. Well, at least it will get you started. A stock automatic transmission won't handle it.

Best Everyday P-7100 tweaks on the cheap - Competition Diesel. Com - Bringing The BEST Together

There are some charts showing the specific stock timing for each CPL # around here somewhere, do a little searching.