Engine 87 mustang injection HELP!!

[Indianacoach]

Buddy and I are building a 87 302 ho we have upgraded the injectors to 24lbs but now it’s running rich do we need to change the ecu to accommodate the bigger injectors or ad a maf sensor? It’s .30 over 303 thumper cam gt cobra heads ported has. 70mml intake.

 

[General karthief]

Maf or speed density?
If no other mods try some 19lbs injectors.

 

[Mustang5L5]

Speed density can’t handle the cam or injectors.

Convert to mass air

 

[Gs1987GT]

Speed density can’t handle the cam or injectors.

Convert to mass air

100% correct. With those mods you must convert to mass air

 

[MustangIIMatt]

I've only known one person who successfully made a speed-density Mustang run 24lb injectors on the stock computer without a custom tune. I haven't talked to him in about 10 years though. That guy was a math wiz who figured out how to balance the amount of air going into the engine with the increase in fuel while keeping the vacuum within the range the ECU was designed for so that it wouldn't know the difference. Even then it would "hunt" at idle when cold until it warmed up, but once warmed up it could even pass California smog.

That guy was weird. He was also one hell of a good friend. I drove the car once, it was a beast.

Everyone else goes mass air for a reason, it's far easier.

 

[Indianacoach]

Speed density can’t handle the cam or injectors.

Convert to mass air

70 or 80?

 

[Indianacoach]

100% correct. With those mods you must convert to mass air

70 or 80?

 

[Blown88GT]

70mm to match the intake. 80mm won't hurt but won't help.