2.8/3.1l !!!! difference??

[BigZ24]

somebody told me that the difference between the 2.8 and the 3.1 is the stroke...the bore is the same! so...i am asking myself aboutthis...can i put the 3.1 cranckshaft. connecting rod and piston on my 2.8???? somebody can answer me and explain please why or why not is possible!!!!

[Guest]

Yes, that is how you stroke a 2.8 to a 3.1. The difference is the crank and pistons, rods are the same.

[BigZ24]

ok! now my question is ... if i put the 3.1 crank and piston in my 2.8..i will probably keep approximaly the same HP than an 3.1 ..yes or no ???? and if yes...the computer will accept this or its going to bug ????

[geoffinbc]

Yes and Yes. Going from 2.8L to 3.1L is no big deal. Infact if you swapped chips and injectors to 3.1L stuff your car would never know.

[GordSipko]

The 2.8 and 3.1 injectors are the same @ 15 #/hr. You might want to search out for differences in the ECU/memcal!

[BigZ24]

ok but Im going to put an aftermarket chip on my computer like superchip or something like that! do i have to put an 2.8 or 3.1... and why put the 3.1 injector its not the same like 2.8 ????? im busy whit this ???

so now! i have a 2.8l. i put the 3.1 crank and piston, i put the 3.1 chip and injector... i put some 2.8l performance camshaft whit an port and polish heads whit a 3 angles valves job, whit a port match intake! AND all this things will works togeter perfectly ????? All right

[robby1870]

The 2.8 and 3.1 injectors are the same @ 15 #/hr. You might want to search out for differences in the ECU/memcal!

19#/hr

[eurolumina92]

is the same true with 3.13.4 crankes can you switch those to???????????

[robby1870]

is the same true with 3.13.4 crankes can you switch those to???????????

why would you want to? They are the same stroke

[Guest]

The 2.8 and 3.1 injectors are the same @ 15 #/hr. You might want to search out for differences in the ECU/memcal!

19#/hr

Umm since when? Research tells me they are between 15 and 17 lbs/hr.

[Norm '88 GT]

BigZ24, I went from a 2.8 with Superchips, Inc., chip to 3.1 bored .030" over and had no problems running on stock fueling. Updated injectors or ECU to 3.1 maps will help fueling if your going to run in the 14's at the strip.

[BigZ24]

re:

i dont really understand what you meen!! what im better to do...put an 2.8 chip on the ecu and modified for the crank and piston of 3.1 OR just put an 3.1 chip on the ecu ????

[johnc]

One thing to check on is the main journal diameter. It has to be a larger diameter 2.8 crank engine if you want to use the 3.1 engine. Your main dia. s/b 67mm. If the engine is 1986 or newer, you should be fine. Some 1985 engines had the larger journal, but you will have to measure to be sure.

[BigZ24]

ok i make some search and i found this! the main bearing journal diameter for the 2.8 is 2.4397-2.4946 inches and the 3.1 is 2.6473-2.6483 inches . So what can i do for this ....if its like i thing the 3.1 cranck shaft will not fit on the 2.8 block ???? what do you meens????

[geoffinbc]

No only really early (pre 1985/86) had the small main journals. After that all 2.8L 3.1L and 3.4L's had the same main journal size.