LA3 and mpg

[SVTpower]

Whats the difference between LB3 and LA3?

[tateg]

Whats the difference between LB3 and LA3?

LB=Auto trans... LA=5spd

[speedfreak78]

LB3 = Auto Turbo coupe ECU
LA3 = Manual Turbo coupe ECU

I'm pretty sure, although definitely not certain, that they're the same other than one having the provision for the Auto.

[NavySVO]

you can use an LB series in a manual trans car without any problems

[jayG]

I've read tons of threads of people upgrading to the LA3 ecu from the 88 T-birds. The ratings on those cars were 190hp and said they got 24-28mpg..

most of you have upgraded for the power, but has anyone seen a gain/loss in mileage? that is my main concern. efficiency is my goal here along with reliability.

I've read there is an instant power increase across the rpm range, but nothing about mileage..

My 84 went from 20 to 24mpg with the swap. My 88 TC gets 30mpg.

[BrianO]

are the tbirds lighter or what? same engine, same computer.. interesting

[jayG]

are the tbirds lighter or what? same engine, same computer.. interesting

Not lighter but have milder cam profile and geared different and smaller turbo. My SVO has more torque by far.

[jamman16]

how much of an effect would changing the 5th gear ratio to .63 have?

[tateg]

how much of an effect would changing the 5th gear ratio to .63 have?

None for in town driving; transmission gearing has little bearing on in town driving. On the highway it will increase mileage substantially.

[jamman16]

.63 is the highest gear for 5th correct?
how do i figure the benifit of switching gears out?
in AK pretty much anywere you go is a long way off average driving distance is like 60 miles fairbanks is like 250, homer 230 there aint much benifit for modding the trans for "intown Driving"

[Kendal Coker]

I put 3.08's in my turbo gt convertible and didnt get any better gas mileage, I just changed it back to 3.45.

[jamman16]

i think its all the stock svo set i just took mine apart and replaced the worn and chipped ones (3rd,And 5th driven)
and the rest of the stuff in the rebuild kit
if you changed the input to countershaft gears woulden't you have to replace the countershaft aswell as all your other driven gears to mach the new countershaft?

[SVTpower]

so with the LA3 there is more fuel up top under a heavier load but less fuel up top under a lighter load?

[BrianO]

from those charts that looks to be exactly correct. It's just a more efficient setup it seems.

[SVTpower]

so whos all done this swap and is it really worth it? Is the LA3 easier to tune also? I've been thinking about a Mass Air Conversion and i want something that works the best