Incredible good mileage 1984 Town Car CFI

[Arquemann]

though I´d love to get better mpg, of course.

SEFI swap, make it breathe better, throw the Thermactor crap into a pond and get like 2.47 gears
Then again you're driving a BOAT that was designed with a straight edge and cocaine.

[gadget73]

honestly I don't really think you'd get much improvement out of multiport on the highway. Around town probably, those long runners make more torque down low.

[VicCrownVic]

SEFI swap, make it breathe better, throw the Thermactor crap into a pond and get like 2.47 gears
Then again you're driving a BOAT that was designed with a straight edge and cocaine.

2.26 was an option on '79 panthers (maybe other early years), that's what Grand1 has in his '79 Marquis. Hillbillycat has the same problem as you, he's on the wrong side of the world to just find panther parts like I can in Detroit. Makes swapping to factory options from other years a little harder/more expensive.

[Hillbillycat]

Exactly
BTW Thermactor stuff is longe gone.

[DerekTheGreat]

2.26 was an option on '79 panthers (maybe other early years), that's what Grand1 has in his '79 Marquis. Hillbillycat has the same problem as you, he's on the wrong side of the world to just find panther parts like I can in Detroit. Makes swapping to factory options from other years a little harder/more expensive.

The 2.26 was probably only available with the tree speed trans. Would need to swap that tall thing in if a fella wanted it, for some unbeknownst reason. Another thing to keep in mind is that just because you made the engine turn slower at a given speed, doesn't mean it'll also use less fuel. Ever try riding a bike up hill in a high gear? Legs going slow, but holy hell what a sweat.

[mcb82gt]

Ever try riding a bike up hill in a high gear? Legs going slow, but holy hell what a sweat.

Very good point! Its all about the powerband of the engine, and where you are in it.

[Arquemann]

On bigger hills my 3.08 geared CFI drops to 3rd gear. I doubt a LoPo would need 2nd even with 2.26 gears on hills at highway speeds.
Tall gears just give more potential for maximum MPG. If my CFI LoPo is a dog of the line, the taller gears must be real fun!

[JeffBoudah]

My first 90mgm, I put together a gt40p head, stock bottom end, HO cam/upper/TB, Systemax1 lower, 19lb w/ lsc ecm, AND.... 4.10's... It got 20mpg @ 70 if I wasn't pedal happy. Sounded awesome singing along at like 3krpm. Had a small idle surge, but it ran like a raped ape when you got into it, and got single digit mpg.

[gadget73]

consider a 2.26 with a 3 speed is pretty much the same as a 2.73 with an AOD in terms of RPM. You get much better acceleration from the 2.73 though, so in-town driving is probably more efficient than with some overly tall gears.

[mercurygm88]

honestly I don't really think you'd get much improvement out of multiport on the highway. Around town probably, those long runners make more torque down low.

I’ve definitely noticed that. My ‘88 MGM stock had low end torque you could feel. The Mark VI with CFI not so much. You can floor it from 25mph and it just makes noise and slowly advances.

The SEFI panthers may not have much power but they at least feel way faster than a CFI car. The real big difference is going to the ‘02 LSE from the Mark VI it feels like I’m driving a race car.

[DerekTheGreat]

I do recall feeling the better grunt off the line with SEFI vs my CFI car I had. But, once you get going, they're about the same. Kishy and I raced and were neck at neck, his '84 vs my '88.

I also do not think the SEFI 302 makes enough steam for 2.26's. You might notice an improvement between 50-60mph, but I'd wager it would be marginal at best, and negated by the significant loss of MPG in town. When I "upgrade" my 305 TBI Fireturd to 3.23's over 2.73's, mileage in town as well as stop light to stop light driveability feel went up. Could definitely tell it wasn't working as hard to get up to 45. Highway MPG dropped from like 24 to 21/22.

[kishy]

I’ve definitely noticed that. My ‘88 MGM stock had low end torque you could feel. The Mark VI with CFI not so much. You can floor it from 25mph and it just makes noise and slowly advances.

The SEFI panthers may not have much power but they at least feel way faster than a CFI car. The real big difference is going to the ‘02 LSE from the Mark VI it feels like I’m driving a race car.

I think that's more of a heads thing, than an injection system thing. Mark VIs all have worse heads than 85 CFI cars - I am not sure about 84s.

My 84 with 3.08 in the back has no issue getting off the line quickly. Same with my 85.

It is also worth noting that the CFI system between 83 and 84 is not even really the same animal. EEC-III vs EEC-IV. The 84-85 CFI system is ran by fundamentally the same computer and code as what runs the SEFI cars. I've only driven one EEC-III CFI car (an 83) and it ran too poorly to give it any consideration here. Neglected car and I had been asked to give thoughts and diagnose.

[Stocker]

That's not too surprising. I used to get 20 out of my '85 on a trip that's about half freeway and half rural highways. (That same route has since dropped to 14 since the car runs pig rich now and I can't figure out why.)