Whats the point of running low boost? Honestly....there isn't one. If you're putting on a charger, you're gonna let it do its job. If you wanted to increase power just a little bit, you wouldn't go forced induction.

I've said the same thing before, only in regards to the 3.8NA having a 3.8 charger dropped on it. High-volume parts are generally weaker which is true in this case as well. Your longevity is going to be screwed. And its not worth dropping a charger on if you're only going to let it feed the engine 3 or 4 pounds of boost - hardly worth the cost.

 

these engines cant take 6-8 psi tuned?

 

V8's respond nicely to 8psi..even better with a good tune. IMO...6-8psi is considered low boost.

 

The Lightning shortblock differs from the standard only in that the pistons are forged instead of cast and have a 1 point lower C/R. Forged cranks, while once available are not commonly found in the later "L"s. Both engines have identical rods.

This conversion is not difficult, and not expensive. As a matter of fact, the entire conversion can be done for less than $3000 which makes it the least expensive, intercooled supercharger setup.

If you want more info, send me a PM or an e-mail.

 

Did you finish up your project? I too am thinking of doing this on an 04 Expedition.

 

Just one additional thought, according to specs on 4R70W transmission it is rated to handle 550 ft lbs of torque. Well within the torque range of a Lightning engine. Over time I'm sure it would have some negative effcts on the longevity of the trans, but a lot of that is also dependent on how it's driven. According to specs as well all post 03 5.4 ltr cranks were all forged, not sure on what was in them before this though.

 

JARP,
The 04 expy's have a completely different computer in them then the previous years. You may run into problems with getting it properly tuned for a supercharger. Thats why if you look into getting a chip for your 04, you can't readily find one.

 

Do you think the 04 computer is different than the 03 and if so I wonder why being I believe most of the mechanicals are the same? I did find out that my 04 has the new trans the 4R75W, not sure if that is just an updated 70 or not.

 

I'll just add my 2 cents worth here. I have a bone stock 91 F250 with a powerdyne blower that runs 6 #boost. It has been on the truck 3 years and 40,000 miles and nothiong has broke yet. It's worth about 100 HP according to my tests with a G Tech performance meter. I would think you could run at least 8PSI on the newer type engines without problems. That would give him 50% more power than stock and have excelent manners and drivability. On a supercharged engine better heads and exhaust improvements will realy help increase the power. From what I have seen with my truck I beleve low boost with good heads and exhaust will probably beat a high boost application with no other improvements.
It sounds like an interesting project.

 

The Powerdyne is an apples to oranges comparison. Centrifugals are MUCH easier on stock parts than the positive diplacement blowers like the Eaton. A positive displacement blower builds boost at any RPM based on throttle position. That is why they are more fun to drive. The internals of the N/A 5.4 will last just as long as the forged Lightning/Harley stuff with the proper tune. Why does Ford bother with forged internals? I'll tell you. Because a certain percentage of Lightning/Harley Edition buyers will take their stock trucks, swap the pullies, and now be making upwards of 15 or 16 lbs. of boost. Then begin what I like to call "Detonation Tuning". These trucks are warranteed not to break. The dealership has no idea what abuse they endure but they still have to honor the warrantee and fix them. Forged parts will last longer under these conditions. Many people don't realize that Hypereutectic pistons run much tighter, quieter, and cooler that forged pistons, actually helping to prevent detonation...With PROPER tuning these "cast" pistons can live at ridiculous horsepower levels(1000+) just as long as forged ones can.

 

I've now got about 3,000 miles onthe SC'd application. I'm running 10 lbs boost. WOW, what a difference. Tuning is just about dead on and the heavy EX makes my wives stock 02 Mustang GT feel like a slouch.

I had some issues with plugs, I'm running the NGK Iridium's and they made a noticeable difference in power. This is one mod that if you have the resources I would highly recommend!

 

I would tend to agree that centrificals are easier on parts. It would realy depend on the displacement of the blower and how fast you want to turn it as to how much more boost at low RPM you would get over a centrifical type. I do see boost anytime the throttle is opened but typicallly only 2-3 at part throttle.
You could set your centrificial to be alot more at 2500 RPM but you will overspeed the head unit at high RPM. Anyway the lightning unit is a pretty good set up and if you don't go too high with the boost I think the stock engine would be fine. If the AF ratio is correct I would expect the stock head gaskets to give out long before any internals broke.

 

I'm not so sure that centrif's are easier than posi disp sc's on the engine. My understanding of how they work is that boost is a direct result of the position of the throttle plate and RPM. This to me means that even if you are running down the highway at 2000 rpm's and the throttle plate is not open enough to utilize the boost that is being created by the blower you essentially have vacuum being created by the blower which doesn't produce heat and requires much less hp to turn. This would also to me make sense why with a posi disp sc you have instant boost because all the blower is waiting for is the throttle plate to open up thus allowing for instant boost.

 

I have a P1-SC ProCharger on my 5.4 F-150. If crusing on the highway and mash the gas the needle jumps to ~5 psi instantly and climbs from there. Most kits have some type of bypass system to shed boost when not needed.

 

It's not the pistons that you have to worry about when it comes to higher boost levels with a 5.4, it's the rods. They are prone to breakage at higher boost levels (even with a good tune) because of how weak they are. The GEN 2 Lightning guys will tell you that, and some may even show you carnage pics too. And at that HP level (1000+) you will "noodle" those rods any day of the week, and twice on Sunday.
As far as cast and hyper-t's go, I've been running a Vortech SQ on my 94 L with about 14 psi of intercooled boost for roughly 2 1/2 years now, and the motor has held together very well. I pulled the heads off after the first year to put in stronger head gaskets and ARP hardware and the pistons (stock hyper-t's) were in perfect shape.
In the end, If the longblock is in good mechanical shape, then a blower, of any kind, will be a lot of fun. However, I would recommend doing a leakdown and compression test before throwing a blower on it...especially on a high milage motor.
Like I've said many times before...a good fuel system and tune will be the key as to how much power you can make and how long you motor will last. If either one of those is comprimised then you motor will become a very expensive yard ornament.