MPG question 5.0 HO in a wagon...

[drhill]

I hate to start another MPG thread but I just want to make sure I'm not missing anything obvious.

Over the past year I swapped a 5.0 HO into my 84 wagon plus some extra performance parts like headers, 2.5 duals, ported heads, 1.7 rockers, trick flow intakes, 65mm tb, 73mm maf and maf conversion, Mark VII aod with HO governor and Mark VII converter... I still have the stock 3.08's in the rear and the best MPG I could do the other day was 18 on the hwy. This was at 70-75 mph for about 150 miles up and down small grades but usually a good mpg stretch of road for me.

I thought the HO/SEFI swap would get me at least 20 mpg? I do know this car had piss poor mpg with the CFI (13.5 to 15.5 hwy at the same speeds) if that gives you any ideas. Timing is just above 10 degrees at idle with spout connector out, idle vacuum is a bit low in this car (17-18 inches, occassionally lower) but it runs so sweet. No signs of brake drag like excessive dust. Had smog checked at a local station and it's running clean enough to pass which means the equipment is working.

I was planning on some road trips in this wagon but 18 mpg isn't going to cut it...I hate to take my roadmaster sedan that gets mid 20's if I don't have to. The wagon works so much better for all the stuff we carry as a family.

Thanks in advance for any advice!

[sly]

do you have the 4-hole injectors or the single hole squirters? The 4-hole do better for MPG. Also, if you deleted the EGR, that'll tick a little off the MPG. You might try advancing the timing to 14 or so. I know the HO in my Mark works fine with 20, but does better for driveability at 14.

[drhill]

good question on the injectors - I bought them refurbished on line...I think they are the original one hole...also, I'll try the timing...I'm using 87 right now and I'm at about 12 degrees, I see just a bit on detonation when the water temps get to 190 or so and I'm low speed in OD so I would have to use decent gas with more timing...

What kind of MPG are y'all getting???

[turbo2256b]

Best MPG in my 2 door was with ported heads, ported lower, ported LOPO upper. FMS Mass air conversion kit, 3.55 rear gears, timing set around 12* with spout removed, EGR working. Got 27 to 32.9 highway depending on conditions. Think I used a 60mm TB might have tried a 65. Swapping a HO upper or ported ho upper seemed to hurt economy and low end a bit.

Right now my wagon gets 13 to 14 at best in town with only 1st and 2nd gear and keeping it at 45 or less, 3rd and 4th are toast.

[pantera77]

My 256k mile beater lopo wagon with 3.55's get's 22-24 on the highway.

It's also faster then most HO powered cars.

[drhill]

I wonder if the rather large ports in the trick flow upper and lower are hurting economy?

[gadget73]

They're a little overkill, but I suspect the tall rear gears have something to do with it. The HO engine isn't making much torque at 1800 rpm (which is about what I expect 70 mph is for you) . I wouldn't be surprised if you gained some economy with a 3.55 or 3.73.

[turbo2256b]

Been debating on porting a set of lopo heads, they would flow about the same as ported E7s. Using them along with the other componets I used to get 32.9 MPG another guess is that 3.27 geras might be the best for this set up. My wagon has 3.08s currently so will go with that at first.

[P72Ford]

Gears, and drop your crusing speed 5-10 mph. At 75 mph, assuming other constants, you're going to have 33% more drag than you do at 65 mph. Drag is a function of velocity squared; any increase in velocity is subtanstial. And these cars aren't aero friendly to begin with, especially an earlier box.

3.55s are an ideal compromise for economy/ performance.

What heads are on it? Has the fuel pressure been upped/ any chages to the fuel? The engine could be running lean, which is cheating you on power. That can actually lead to decreased economy.

[SVT98t]

Using them along with the other componets I used to get 32.9 MPG

Lol.
Sure.


-ryan s.

[turbo2256b]

Lol.
Sure.


-ryan s.

Visiting my son up in Mich kicked it down with a 03 Marauder with that build Marauder lost bad LMAO

[SVT98t]

I don't understand what you're trying to say. Your sentence doesn't make any sense.

-ryan s.

[turbo2256b]

My 32.9 MPG 87 grand marquis beat tha crap out of a 03 MURAUDER

[SVT98t]

I'm sure it did. In fantasy land.
Time slips?
Video?
I would love to believe this.


And my 46 MPG 93 Grand Marquis beat the crap out of a GT500.

-ryan s.

[porschpow]

This is a good point, Does anyone know what gears a 1989 LTC has?

I have the same issue, I drive to work 70 miles and since most of it is highway, I expect 20+ mpg, instead, I get 18-19 mpg. I usually cruise 65-70 mph. I KNOW these things get good mileage, but this is ridiculous