quest for 20+ 5.0mpg w/ 33" tires and 3" BL

[gear_grinder]

hi,

I know it may sound ludicris to try and get 20+ mpg on 87 octain gas w/ a lifted, 4x4, 5.0 explorer and 33" tires. but this is the direction i'm moving in.

As most of us with 5.0Ls know, 97+ have the GT40P motor (i think?). This is what I belive should be the best base to start with because of its better flowing intake (and maybe heads?). And being such, it shares alot of componets with the Mustang 5.0L motors and Cobra 5.0L motors, so aftermarket parts are avalible and can be picked up for a deal second hand.

ok, my list for things that would increase milage goes like this:

-TM headers

-Some larger size pipe header back system (i live in MI so emition regulations
are not somthing i have to deal with), i'm thinking 2.5" true duals w/ thrush tube glass packs for my truck.

-K&N drop in filter (the stock box is riged for a factory "CAI" system w/ a tube that runs directly behind the passenger headlight, so i think a drop in filter would be sufficnet.)-DONE! (i've also heard that there is an intake baffle that can be removed??? but i havent done this myself)

-BW 4406 T-case swap-DONE!

-light weight Aloy 15x8 wheels

-synthetic fluids (engine oil, tranny fluid, front and rear axle fluid, etc...)-DONE!

-lucas engine oil additive-DONE!

-good alignment

-semi aggresive mud tire (i am thinking of purchasing these when i get to the stage of needing/wanting 33" tires; (http://www.herculestire.com/catalogHercules/herculesTT_MT.asp) or aggresive A/T tire (example; BFG A/T KO)

-E-fan

-75mm TB (http://store.summitracing.com/partd...908331+4294908395+4294840126+115&autoview=sku)

-Throttle body spacer (http://store.summitracing.com/partd...908331+4294840126+4294907915+115&autoview=sku)

-UIM to LIM 1" heat spacer (http://store.summitracing.com/partdetail.asp?part=TFS-51520020&autoview=sku)

-Jet preformance programer or equivilant (http://store.summitracing.com/partd...925143+4294839059+4294891971+115&autoview=sku)

-Accel Coils or equivilant (http://store.summitracing.com/partd...925143+4294839065+4294890813+115&autoview=sku)

-premium wires or equvilant (http://store.summitracing.com/partd...4294925143+4294756594+400070+115&autoview=sku)

-Platinum plugs (http://store.summitracing.com/partd...889096+4294925143+4294839068+115&autoview=sku)

-A/C eliminator bracket and pulley (http://store.summitracing.com/partd...925232+4294923430+4294851751+115&autoview=sku)

-Underdrive pulleys (http://store.summitracing.com/partd...889096+4294925232+4294839035+115&autoview=sku)

-higher compretion pistons (because 8.5 to 1 for a N/A engine is just sad and a waste of displacement...), i'm thinking 9.5:1 or higher.

-Large aftermarket Engine and (in addition to the factory external Trans cooler) Transmission Oil cooler


thats about all that i can think off of the top of my head, but i do have some other questions about some other engine parts to see if they could be changed to raise the MPG of our 5.0L

QUESTIONS:

-what type of lifters do our 5.0Ls have?? if we have flat tappets, I think some valve train resistance could be relived with rolers, thus raising power and MPGs

-can MPGs benifeit from a mild (towing) camshaft?? I mean, as long as you dont increase the fuel imput at any given rpm and throttle position, but raise power output the engine will have to work less hard to move its self down the road, and thus using less fuel.

-What is the highest compretion you can go on 87 octain fuel safely? and how would i calculate the compretion ratio with the GT40P heads?


I hope to have my truck up to these specs in a few years, as i have to finish my RX-7 (well, atleast get it so that i can use it for a summer DD, lol).

Thanks.

 

[damarble]

You're not asking too much. I pull 18 mpg on the hwy at 80 mph and higher if I slow down (rig in sig). And my motor is still dead stock, I'd see more gains with a few simple mods. Granted, I have the 4.0, but I've seen the 5.0 can get just as good mileage. Gearing is going to be very important in this quest with those tires. I'm guessing 4.10 is the ticket. Interco's new MT/AT "hybrid" would probably work great for you.

 

[gear_grinder]

You're not asking too much. I pull 18 mpg on the hwy at 80 mph and higher if I slow down (rig in sig). And my motor is still dead stock, I'd see more gains with a few simple mods. Granted, I have the 4.0, but I've seen the 5.0 can get just as good mileage. Gearing is going to be very important in this quest with those tires. I'm guessing 4.10 is the ticket. Interco's new MT/AT "hybrid" would probably work great for you.

i've got 3.73 gear ratio stock, i figured that would prolly be low enough for the 33" tires.

the interco hybrid?? do you mean the thronbirds?? those things are worthless, seen them in action. i think some passenger car tires would work just as well as those things do in the sand, snow, or mud. They are a sweet looking tire, but thats about it.

I like the way the Terra trac M/T looks like a less agressive version of the Nitto mud grapplers. (they prolly wheigh less too) So thats why i'm leaning twords that.

I'll clarify, i'm talking about 55mph roads.

who knows? maybe could hit solid 25+.

 

[damarble]

i've got 3.73 gear ratio stock, i figured that would prolly be low enough for the 33" tires.

Maybe. I use 4.56 and am still wondering if 4.88 would have been better. Trying the 3.73's is free though!

the interco hybrid?? do you mean the thronbirds?? those things are worthless, seen them in action.

Agreed, just awful. I mean the SS M-16. Looks like it should be good.

http://www.intercotire.com/tires.php?id=2&g=1

 

[gear_grinder]

Maybe. I use 4.56 and am still wondering if 4.88 would have been better. Trying the 3.73's is free though!

yeah, i figured i'd try this first and see if i need to gear it lower.

Agreed, just awful. I mean the SS M-16. Looks like it should be good.

http://www.intercotire.com/tires.php?id=2&g=1

Those look like sweet!! i've never seen them before, but i bet like most interco tires, they like to take your wallet.

I bought the set of 31" TSL radials on my sploder now from a friend for $250 w/ only 2 runs through a mud pit on them, but he told me they retailed for around $130 each.

I bet the Terra Trac M/T is alot more wallet friendly then the SS M-16s, but i'll check them out non the less.

 

[damarble]

but i bet like most interco tires, they like to take your wallet.

I don't know if I'd say they are that expensive, my 33" Trxus MT's were $150 ea new but I had to shop around to find the deal. A BFG MT would have cost more and a lesser tire IMHO.

 

[gear_grinder]

yeah, BFG = no money, lol.

i've also though about getting a set of Trxus STS radials, they look like a well preforming tire. i like drving through sand and snow, so i think this one would work well.

 

[HahnsB2]

Consider the BFG MT or AT in a 33x10.50, 33" height with less rolling resistance and they run about $35 cheaper per tire than the 33x12.50s.