99 4.6l MPG/POWER?

[RobertNol]

Okay guy I've been really torn between a lot with my truck and I'm about to receive my much desired 'bonus' if you will. I've thought about a 5.4 swap, v10 swap and just going out right crazy.

I've decided to stick with the 4.6l until I've paid it off(about a year left). :/

So I'm wanting to do some other upgrades until then. And if I like the setup then maybe just stick with it.

With all that being said I defiantly want to do a smaller lift with 35's.

That's where I'm torn again. I don't know it I want to do something to increase the power(which I can't find anything other then tuner, throttle body so any where to find performance upgrades would help). Then again I dont know if I want to upgrade to help with MPG after the lift.

Any help, opinions or advise would help.
Also if your in the same boat or you were at some point and have started with either of the ideas let me know what your result are/were.

Thank you in advance.

 

[Thermo]

RObert, not to throw a kink in things, but an option that you can think over is I am selling my Expy that has a 4" lift, 37" tires on it already and has the 5.4L motor in it (with a few minor upgrades to aid in mileage). For what you are going to drop in lift/tires and power mods, you can get something like i have.

If you are wanting only to build up yours, let me know what you specifically looking at. I will be able to talk you through everything.

 

[RobertNol]

Yeah I defiantly need to keep mine thermo, I tried pawning mine to the fiancee but she don't want any of that. Lol

But yeah right now I found this kit from performance accessories and its a 5'' lift(think its a 3'' body and a level and spacers, I believe.) And I can get some 35s pretty cheap. My problem is the power and MPG thing any ideas?

Was yours 4.6 when you bought it?


Anywhere to find any 4.6 mods? Like I said I found tuners, and throttle body but that's it. Anything helps guys....

 

[98EXPY 5-0]

Crownvic forums?

 

[Thermo]

Robert, the modifications that you do to a 5.4L motor work on the 4.6L motor for the most part. They use the same block and a lot of the other parts are carryovers. The only difference is the crank which shortens the stroke, which therefore results in the lower displacement.

For the dollar, the best "power" mod I can recommend is conversion over to e-fan. The big benefit of this is you get low end grunt out of the mod. Most other mods only give you the gains at top end. Face it, how often are you at say 4,500 RPM verses 2,000 RPM? Where do you truely need the power? After that, a good exhaust system will do wonders for gains (but again for the most part will only be seen up high and if done wrong, can result in significant low end losses). For exhaust setups, going with a single 3" setup or true dual 2.5" setup with a 70 or 50 series muffler (ie, semi restrictive mufflers), you can have the best of both worlds (low end gains with some upper end gain too). You open up the exhaust too much and it will be great for high RPM blasts. But you will pay for it when you drive in town (loss of back pressure causes low end torque to drop).

With the 35's, what gears are you running now? If you have 3.73 gears, then the 35's will do ok with those gears, but you will want to recalibrate your speedo to ensure the tranny shifts at the correct points. I didn't initially recalibrate my speedo and I lost 4 mpg putting the bigger tires/lift on the truck. After recalibrating, I gained 2 mpg back. Ideally, you would want to upgrade to 4.30 gears. Unfortunately, they don't make a 4.30 gear for the front of our trucks. So, you have your choice of either 4.56 gears (great for off-roading, but can hurt the highway mileage) or 4.10 gears (great for highway, but may limit low end grunt when playing).

I would also recommend modifying the intake. You can either do the GOTTS mod, or spend the money on a cold air intake. From the dyno results I have seen from another site, both ways will net the same power gains (regardless of the aftermarket intake, they all netted about the same power when placed on the same truck, same day, same dyno).

I am not a big fan of the tuners mainly because a lot of them force you to use premium fuel. Some are setup to allow use of regular, but if you want the power or the better mileage, you need to use the higher octane fuels. Besides, if you have the power, you are going to want to use it which will only cause your mileage to drop since you are going to have your foot into the gas more often.

This should give you a place to start pondering.

 

[toms89]

Robert, the modifications that you do to a 5.4L motor work on the 4.6L motor for the most part. They use the same block and a lot of the other parts are carryovers. The only difference is the crank which shortens the stroke, which therefore results in the lower displacement.

The 5.4 uses a taller deck block. They share the same bore but longer stroke as said. Heads and cams are interchangable but the intake is different due to the wider valley of the 5.4. Its easy to see the difference when you look at the valley.

 

[RobertNol]

So question, with this being said could I potentionally use a 5.4 turbo and build it for my 4.6? If so is it the same process or would it be over my head? Im not a mechanic but im also not an idiot. XD

Also... if It can be done I've read some stuff about used turbo systems?? Where can I find them? And are they typically in decent condition?

 

[toms89]

So question, with this being said could I potentionally use a 5.4 turbo and build it for my 4.6? If so is it the same process or would it be over my head? Im not a mechanic but im also not an idiot. XD

Also... if It can be done I've read some stuff about used turbo systems?? Where can I find them? And are they typically in decent condition?

There are no turbo kits available for the expedition 5.4 or 4.6. It would have to be custom fabricated.

Check out qcksnakes thread: http://expeditionforum.com/showthread.php?t=16129

 

[supermario]

If you had the $, you could always add a Kenne Bell supercharger? That way you have the power throughout the rpm range and If tuned properly it shouldnt affect gas mpg that much.

 

[RobertNol]

If you had the $, you could always add a Kenne Bell supercharger? That way you have the power throughout the rpm range and If tuned properly it shouldnt affect gas mpg that much.

How do I go about that? I do prefer a super charger over a turbo.

 

[toms89]

If you had the $, you could always add a Kenne Bell supercharger? That way you have the power throughout the rpm range and If tuned properly it shouldnt affect gas mpg that much.[/QUOTE

Thats not effective because you will find it hard to stay out of the throttle!!
I am trying to make it through a tank of gas with out getting on it at least once but dont think it is possible.

 

[supermario]

Call them up and tell them what you have. They will let you know if they have a specific kit for you or perhaps which mustang kit you could use. Im sure they have a supercharger that would just bolt on. But you probably would want to do some research and find a high performance shop thats local and familiar with supercharger installs or even mustang hi performance shops, since our engines are almost same as mustangs. They kinda pricey but that would be awesome. Im hoping to supercharge mine next year. But I have alot of places and shops that can do it. If you do get one, just make sure they tune it and keep it to a minimum boost so it dont blow your stock engine. Otherwise you can rebuild and install forged internals and then not worry about it. But just remember, your Expy wasnt meant to race around. So I would install supercharger and keep the boost at a low safe level. You will still have plenty of power.

http://kennebell.net/KBWebsite/Contact_Us_pg/layouts/contactus.htm

How do I go about that? I do prefer a super charger over a turbo.

 

[toms89]

Whipple also makes many kits. Don't think they have one specifically for the 4.6 2v expy but I believe they do have them for the mustang 4.6 2v which you may be able to adapt to the expy.

http://www.whipplesuperchargers.com/

 

[RobertNol]

Y'all are the bomb! Ill be giving them a call... im sure I wont have the funds to do it with this extra cash ill be receiving but ill give it a few months.

You all seem pretty dang smart and know what looks and runs best with these expeditions. So what would yall do with a 99 4.6l 4x4($2500 budget for now, budget can go over a little )