School me on 5.0 efi's

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rockdog

Guest
Ok, heres the deal. I've got a 89 tbird with a 5.0 in it. I'm not sure if it is a speed density or mass air motor? And I'm not sure what the difference is between the two? I'm gonna put this in my toy this winter.
Thanks, Phil
 

forotacobra

5.0 INJECTED TOY
Location
PRICE,UT
the mass air set up has a sensor in the air intake tube the speed density does not. if it does not, i have the diagrams and parts list to convert speed density to mass air very easy takes thess then 1 hour to convert and very worth it. that swap is not that hard to complete either .
 
R

rockdog

Guest
the mass air set up has a sensor in the air intake tube the speed density does not. if it does not, i have the diagrams and parts list to convert speed density to mass air very easy takes thess then 1 hour to convert and very worth it. that swap is not that hard to complete either .

Um, why is it worth it? I'm not a ford person so I'm asking seriously. If I did convert it will the stock computer work? I'm gonna have it reflashed, so I can get rid of as many sensors as possible. This is going in a trailer queen so I really don't care if I have 300 horses. I just want it to be dependable.:D
 

Taco4life

Registered User
Location
Bountiful
I am right in the middle of my EFI swap and actually have 2 EFI set ups if you need anything let me know or have any questions I have found a TON of information and done my research so let me know. You can email me I check that more often, at guts0007@hotmail.com
 

Fuller

Formerly limegrnxj
Location
Riverton
i thin the 89's are a speed density, my wife had a 87 mustang that she rebuilt the motor in when she was in high school and put a bigger cam in it and it wouldnt run right because of that she needed to do the mass air flow conversion ithink they started the mass air flow in 90
 
R

rockdog

Guest
I am right in the middle of my EFI swap and actually have 2 EFI set ups if you need anything let me know or have any questions I have found a TON of information and done my research so let me know. You can email me I check that more often, at guts0007@hotmail.com
Thanks, I appreciate the offer. Still don't know the difference between the two. I know that one is controlled through the air intake, but what are the disadvantages to the speed density? Less power? More problems?
 

Taco4life

Registered User
Location
Bountiful
Speed/density is an openloop approach which infers what the engine reqires
from throttle position and vacuum with the actual fuel delivery based on preset mixture maps.

Speed/density must have the mixture maps revised if the engine is
modified.
This is not a trivial task as the original maps were established using
laboratory test systems and instrumented road testing of the engine.

Mass airflow systems measure what the engine requires using the air mass being injested and supply the fuel required to provide the optimum mixture
at that moment while closing the control loop by sensing the oxygen content
in the exhaust.

Mass airflow systems adapt to the actual engine combustion conditions.
This
is an imoprtant capability when engine modifications are made or
anticipated.

A desirable feature of either system is the use of a single throttle
valve.
A single throttle valve eliminates the problem of sychronizing of
multiple
throttle valves.

Just a quick summary of the differences I found on the net, most everyone will tell you to run the mass air because it is a lot more desirable when you decide to hop up the engine. I decided against it, and picked up a speed density unit. Because it was cheaper and the fact that if ever in a water crossing and the mass air senors get water on them they will fry your system which isn't so with the speed density.
 

Fuller

Formerly limegrnxj
Location
Riverton
I decided against it, and picked up a speed density unit. Because it was cheaper and the fact that if ever in a water crossing and the mass air senors get water on them they will fry your system which isn't so with the speed density.

that sounds like it was a good choice espesialy if you arent going to hop up the motor
 

forotacobra

5.0 INJECTED TOY
Location
PRICE,UT
before i converted mine from speed density i was getting around 9 mpg and running very rich at an idle, after the conversion i was getting 18 to 19 mpg and ran 100 times better all the way around and it was in a 84 toy with 36" swampers as a daily driver. as for getting the sensor wet and smoking it i believe it to be a myth i done it many times with no problems !
 
R

rockdog

Guest
Thanks, thats exactly what I was trying to figure out. I'm pretty sure the 5.0 I have is a speed density. I don't plan on adding any extras for power. So it sounds like I'll be ok with the set up I have. Sure is nice to have people willing to share their knowledge with us less gifted.:D
 

Bart

Registered User
Location
Arm Utah
I modified my buggy 5.0 to mass air and it worked well, but I was told the Speed density is fine if you don't mod the motor. Since I rebuilt mine, added GT40 alum heads, and a slight cam, the mass air worked better for me.

BTW, mass air was availabe in 89 and before, in the Mustang HOs.
 

yellowbronco

Cuts Through Grease !!!
Location
Moab
I'm pretty sure the 5.0 I have is a speed density. I don't plan on adding any extras for power. So it sounds like I'll be ok with the set up I have. D

You will definately be fine.
I've got an 87 5.0 with speed density, it is totally reliable, plus has decent power. I love it! Mine is also a trailer queen like yours.
 
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