I have noted on this forum and others that users post this popular Mustang plenum as a mod on their F150 4.6L trucks.

In speaking with C&L, they have no way of telling what others have done, but suspected that hose rerouting and EGR valve location might be an issue.

Anyone able to fill in the blanks?

Other suggested sources? Accufab?

Thanks,
John Larsen

 

Those "plenums" are really a big aluminum paperweight. You'll gain very little to no measurable power from them, and definitely not enough to justify their cost. And that's on the Mustang or other car with the better flowing intake manifold. The truck intakes are terribly restrictive, and putting larger inlets and throttle bodies on them is like putting a dress on a pig. While it might "look better"-you'll accomplish nothing more than having a lighter wallet.
JL

 

Thanks Johnny. I was beginning to think this forum was located at the old folks home as no one was chirping up. Maybe that's the reason - people are sitting out there with a paper weight on their manifold. Me included.

Just to make clear, I am talking about the stock inlet elbow which I agree, is very restrictive. Not only that, when putting the BBK 75mm throttle body on, the TB is oversized to the stock opening, so it renders it ineffective right there. However, I have seen the cut aways of the stock elbow compared to the C&L and AccuFab products and can physically see that they are opening the throat of the elbow up. Logically, this has to allow better airflow. Johnny, are you talking about restriction at the joining point of the elbow and the intake manifold?

Trying to understand how they can suck (ha,ha) so many people in.

Thanks for the response,

John

 

I'm talking about the intake manifold itself. It's VERY restrictive in order to increase velocity for cylinder filling which creates low RPM torque. It doesn't matter what you bolt onto the flange of the intake before it hits the common plenum and distribution to the intake runners-it's not going to make any more power. "Bling" sells alot of crap on the market, and the practice of using dyno sheet "proof" of their part's gains can be deceptive to the uneducated consumer.
I've seen dyno sheets with stock parts that are very rich, but by simply cleaning up the air/fuel on the next run-the engine "magically" gains 10-15rwhp with no other changes whatsoever. Ever notice you don't see any air/fuel trace on those dyno comparison sheets of before and after?
JL

 

Thanks Johnny. I am beginning to understand. Strange I never found any discussion like this in all my searching of F150 forums concerning plenums, TBs or use of aftermarket heads.

So, again logic says air will flow better in a ported and polished head. Or with improved valve positioning such as Trickflows product. Is this also totally useless without a good intake manifold?

Why am I digging into this? I would probably have a Lightnin' if it wouldnt get stuck in snow and/or spin-out on ice. So I guess I am a wannabe with a 4x4 which only gets used occasionally. Otherwise my truck is limited to street use and road trips and I prefer snappy.

Thanks,
John

 

You typically won't. Most of the internet post-*****s don't do their own work-so they hawk whatever parts their preferred vendors gives them or sells them without any knowledge of how they actually work.
Yes, that's exactly what I'm saying. I've been there, done that on my Tbird.
Details here:
PI vs NPI-data - Modular Depot Forums
I'll warn you,it's a LOOONNNG read, but it explains what I've found. The truck intakes are very close to the old NPI car intakes in terms of flow-they're actually a bit worse for flow than the NPI car piece is.
Results from swapping a better flowing intake onto my old ported heads(not a truck, but the principal is the exact same):
Results - modified PI intake on NPI heads - Modular Depot Forums
JL

 

Bingo. That's the kind of article I have been looking for.

Thanks,
John L.

 

Okay. Read two pages of comments on the first post and got tired of debating the same thing over and over. So have to admit, I jumped to the end of the book to see how it turned out. The second post pretty much sealed the deal.

So, that now begs the question. What intake, aftermarket or stock, will allow a NA 4.6L to breath the best?

John L.

 

What are you intended uses of the truck?
JL

 

Per above. The truck admittedly is a 4x4 which only goes into gear in snow about 3 days per year. It goes to construction sites weekly, so the clearance is nice, but I would rather have it lowered as well.

Otherwise, street, highway and road trips. I want more zip. Also having fun seeing what I can get out of a 4.6L. I even looked into dropping a 3V into it, but quickly gave that up when I realized the computer issues involved.

So, no good reason other than the latent hot rodder in me resurfacing in my old age, now that I can afford some of this foolishness. My stated reason to my wife is my quest for ever improving gas mileage...

 

With the weight of the truck,and the loss of torque with the lower-profile,larger runner car type intakes, you'll probably not like one of those intakes on the truck. You could try using the '07-up 2V truck intake-it's very similar to the car type intake, and should flow better than the older type truck intake. It's a compromise really-good, strong torque where a truck will find it more useable, or higher torque and power in the upper rpms where a lighter car would find it more useful.
You also have to be careful of the rpm limits of the torque converter if the truck is an auto. The stock 12" torque converter on the trucks is only good for approx 5500 rpms before it balloons and causes damage to the rear thrust bearing on the engine amongst other things.
Basically, a good torque converter with a bit more stall speed (3000-3200),and a better flowing intake will really wake the truck up, but just be aware that it will feel sluggish at lower rpms.
JL

 

Thanks for the feedback Johnny. I think we are heading toward some solutions. Unfortunately, I made the mistake of checking back on a low mileage 07 4.6 that has been listed on CL the past two weeks and am now mulling a different tack.

One last question to close this thread off. Is the extra 17 HP listed for the 07 a major result of the improved intake manifold, or are there other issue contributing?

Is there a way to continue this discussion outside the forum or through a "Private Message" function. We are going to get "off topic" otherwise. Namely, I am at the point where other vehicles and issues, unrelated to the intake discussion will be involved. (Namely, putting the 2003 4.6L under discussion into my 56 F100...)

Forgot to mention, I have a shift kit in my AT tranny which the builder said was good for 650HP, although it is on the "street rod" setting.

 

There's not really any need to go to PM's-this discussion could be helpful to others in the future.
The resulting higher power is likely from the intake change since there's not another single part that was changed on the engine from '06. I'll assume that's a 4R70W in your truck. I don't really like any of the "shift kits" that are commonly sold out there.
The 4R70W really doesn't need much done to it to be a really good trans that'll handle alot of power, and most times those "kits" don't address those things, or at least not properly.
JL

 

Some forums get uptight when the topic drifts, but since we're the only ones posting on this, I guess it really cant be complained about.

My 03 spec says it has the 4R70E tranny. Dont know what that last digit means, but could be the electronics on the newer one. The reason I beefed up the tranny was the number of horror stories I started hearing about modified trucks with issues showing up at the AT. Especially with the superchip tuning options when not paid attention to.

So, here we go on the "off topic" idea: When you mentioned the 07 intake, a light went off about that used 07 engine that was available several weeks ago. Before I got into the whole intake idea, I was considering swapping out my current 120K used engine and holding it in reserve for my 56 project down the road. Since the 07 had all the electronics included, I thought why not grab it, do any upgrades on the shop floor, do the swap out and voila, I end up with a low mileage (35K)higher performance engine in the work truck and a decently running engine for the project truck. The reason I dropped the idea is that I thought the 07 was a 3V engine and figured the whole PCM programming nightmare would result.

Several issues come to mind:

1.) Will I need to transfer all the 07 electronics to the 03 for the engine to function properly. The seller has the tranny too, so I could take advantage there if there is noncompatiblity on the AT.

2.) Is this upgrade a good idea? I would probably still do the Trickflow type heads, but without the cam. Could then do it on the shop floor with less down time is one advantage. Less of an advantage is not fully knowing what I have in terms of the 07 engine regardless of low miles.

3.) I have a t-bird SC donor car for my 56 project. I am using the IRS from it as there are adapter kits for it. I was then thinking of perhaps using the whole DT including the supercharged V6. Something you dont see in hotrod PUs. Plus I think (please confirm) that the electronics are simpler than say the 4.6. And it also has the 4R70W tranny, recently rebuilt, so it could be hooked up with either engine. But I have found absolutely no previous history of putting the SC engine in ANY hot rod. Of course, not many rodders are getting weened of the carbed engine for that matter.

Well, hope this isnt going too far down a bunny trail for this thread...

Your feedback is valued, knowing you have t-bird experience as well.

Thanks,
John L.

 

Your truck has a 4R70W-It's referred to as a 4R70W, 4R70E, AODE-W, etc, etc, etc...basically those are all the same trans except for erroneous names given by those that don't know any better. The only internal mods that are worth doing on that trans are adding a couple of clutches to the forward and direct clutches for more capacity when needed, and removal of the 2-3 accumulator springs to clean up the shifts. The rest can be taken care of via a good PCM tune. Trying to fix problems with the trans externally because of "tuning limitations" is an excuse for idiot tuners that have no business tuning anything. I see that alot from those that do not understand the control system or the trans tuning parameters and how the entire powertrain works as a system. If someone starts talking about doing mechanical mods to the trans because of tuning issues of the PCM, then you need to run, not walk away from them.
The '07 4.6L 2V longblock is mechanically identical to the '03 4.6L 2V in every way-use the '03 control system with a custom tune to get the appropriate spark tables and knock sensor tables as are appropriate with the new intake. You can do the TF heads if you'd like-they'll work ok with that intake-FAR better than they would with the older, more restrictive PI Triton intake. You'll probably like the results-just be careful of CR-there are a couple of versions of that head being cast, and one of them has a fairly smallish combustion chamber which would put your CR a bit high for a truck-esp if you want to retain the ability to use 87 octane fuel. Just be sure of which one you're getting if you come across a deal that is good.
The 4R70W used on the 3.8L's has a different bellhousing than the 4R70W used on the 4.6L, so you'll need to use the 3.8L SC engine with it's trans for the '56 project. While some would consider the EEC-IV used on the SC's as "simpler", I see it as ancient in ability and processing power and would go for EEC-V myself. You then have the ability to flash the PCM instead of being limited to "chips" and their inherent issues and limitations. The PCM and harness could be sourced from a '96-up auto trans 3.8L Mustang for that application.
JL