speed density - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old 11-03-03, 06:34 PM Thread Starter
Registered User
Join Date: Feb 2003
Location: southern california
Age: 31
Posts: 32
speed density

i have a '94 Ford F-350 with the 7.5L(460ci)V8. I have heard that it has a speed density type fuel injection. how does this work and what are some positive or negative things about it? also, can it be upgraded at all? thanks for the help.


if it's fun it's probably illegal

my truck hauls like one of those big aussie road train things
SSpeeDEMONSS is offline  
Sponsored Links
post #2 of 3 (permalink) Old 11-03-03, 07:33 PM
***** Idiot....
LunaticSVT's Avatar
Join Date: Feb 2001
Location: The Sticks of Central TX
Posts: 10,560
Re: speed density

Speed density is great realistically a lot simpler than Mass-Air, but terribly inflexible. After you radically change/improve VE of the engine, the speed density system will tellyou to bugger off because the load/fuel mixture tables are chiseled in stone. They are buried in the processor, so when you exceed these parameters the system can no longer effectively compute injector pulsewidth "f/a ratio" and timing. The net result is loss of driveability. In extreme cases, engine failure due to detonation caused by lean mixtures and/or over-advanced timing.

You can burn a chip....if you have access to a chip burner and a dyno with A/F monitoring equipment, but do you want to reburned every time you make another mod or change to your system? Yes you can change the air/fuel/timing parameters in the speed density system, but the inherent inflexibility that is designed in to the system you can not get rid of.

You can do a Mass Air conversion. I know there are kits out there for that, but I do not have info on them for a 7.5L 460ci. I have seen them for other engines throughout the Ford lineup.
LunaticSVT is offline  
post #3 of 3 (permalink) Old 01-09-04, 07:09 AM
AUPS Member
cheahman's Avatar
Join Date: Oct 2003
Posts: 668
Re: speed density

cheahman is offline  
Sponsored Links

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > The Garage - Tech Forums > Engine Specific Tech > 429-460 Tech

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome