Blew my intake apart last night

McTeague said:

Easy there JayC, Gearbanger is a Ford tech AND a power adder expert... Instead of trying to prove how smart you are try listening to him instead, you might learn something

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Sigh...here I am, late as usual. First off, thanks for the props KT….er…McTeague, but you should know that I'm neither a Ford Tech nor do I consider myself a Power Adder expert. JayC is as welcome to his opinion on the subject as I am mine and I won't fault him for it.

The last thing I'm trying to do here is start a pissing match, but I'm also not going to crawl into a corner because someone doesn't agree with my general reasoning for the Direct Port kits use. Especially when talking about a 4.6L modular engine, myself and several other consider the direct port systems to be a safer and superior alternative and I'll tell you why.....

Wet shot kits are notorious for nitrous backfires, let's not beat around the bush! Do I really need to dig up proof of this, or can we agree on this fact? What makes it worse for the 4.6's are a couple of things. First off, as we all know, the stock manifold is made of composite plastic. No where near as durable as an aluminum unit and even more subject to catastrophe under backfire conditions. Secondly, you'll notice that in order to facilitate a runner length while retaining a compact design, Ford engineered these manifolds to start out with an almost immediate 90* turn after the throttle body, from which point it must travel across, and downwards to the bottom half of the manifold, then upwards, across and downwards again through the snake like runners after finally turning almost a full 360* before entering the head.
(shown below)

View attachment 457062

For what it was designed for (moving air), the intake serves its purpose. The long runners allow for better low end torque and the composite plastic material is lighter weight, cheaper to mass produce and less prone to heat soak when compared to an aluminum unit. (hooray for Ford)

….but, the problem with this design, is that for one….wet systems like short, strait shots into the cylinder. Great for an old 5.0L OHV with a carburetor, or short runner strait port after market design, but since the NPI/PI intakes were designed to flow air only and the long twisty runners were necessary for length and packaging, the wet shot in this case is far from ideal! As I’m sure you know fuel, nitrous and air flow at different rates. This is why intakes with sharp bends and complicated runners (like those of the NPI/PI Modular units on the SOHC’s) are prone and often devastated by backfire. The small valley at the under side of the manifold, where the air flow is collected before its distributed to each runner, is also a perfect location to amass fuel “puddling”. Is it a guarantee that this is going to be a problem…..probably not with light conservative usage and pill size, but if you’re the type who’s always filling your bottle and lives for running large amounts of giggle gas both on the street and at the track, then nitrous backfires are probably a regular occurrence for you. Since this particular manifold is inherently weak based on material design alone…..you often get what the poster of this thread has just experienced. And that’s not even a bad back fire. I’ve seen hoods blown completely off of cars. There was even a video running around a while back of a guys ZO6 that burnt right to the ground because of one.

Now we get to the direct port set up. Do I personally own one, or have I worked with one….no, I honestly can’t say that I have. But I’ve seen a few of them run at the track as well as up close in the pits while being tuned and have talked to a couple of owners/tuners who’ve run wet kits in the past, that now swear by the direct port set up. They’ve actually stated the exact opposite opinion as yourself and consider the Direct Port kits easier to tune (once you know what you’re doing) and provide the opportunity for far more power than your basic wet kits do because of the ability to tune and run larger amounts in each individual runner. You want to compare time slips.....I'll tell ya right now, time slips mean jack to me. They’re not an accurate measure of horsepower as far as I’m concerned and if time slips are what you’re backing your claims with, I’ll be glad to hunt down a few for some high horsepower 12, 11 and even 10-second cars who’s drivers could break out of the 13’s because of piss poor driving habits/track prep/elevation/whatever!!! I find it interesting that you’re the only person I’ve ever heard consider a wet system safer and able to make more power than a direct port system. Direct ports will often supply double the capacity of a traditional wet kit…..but to each their own. Drawbacks…sure every set up has them. Spark plug blow out being a problem…..yeah, I could see that. That’s a pretty unrestricted shot to be letting off only inches from the combustion chamber. And I’m sure that guys with virtually stock cars, with stock ignition systems trying to run large amounts though their engine have probably experience this from time to time. It’s still nothing that can’t be managed with ignition upgrades, and closing the spark plug gap a little….and if they haven’t already, throw the platinum plugs as far away as you can. Stick with the copper plugs for power adders…especially nitrous….not to mention showing a little restraint with the system until the car is able to utilize that much nitrous couldn’t hurt either. Clogging jets, leaking lines are all a reality too….but nothing a filter and a little Teflon paste, along with regular maintenance won’t cure. It’s no worse than having an overworked solenoid stick on a wet system or having one or both stick because of junk in the lines as well. Regular maintenance is all one really needs to ensure a good operating system, with any kit.