Write-Up: Installing FWI Filter, Heat Shield, Air Scoop

That was kinda the idea I was having. I mean, it'd help keep the channel of air focused, keep stagnant/ambient heat from the engine bay out, and even help keep the filter clean just that much more!

You might be able to pull off an true sealed CAI box inside the engine bay, with a hose connecting down to a duct like this one, mounted in the plastic underpan.

https://www.pegasusautoracing.com/productselection.asp?Product=3629

I was just thinking of sealing out the area around the filter w/in the fenderwell but I kinda like that idea and it gives me somethin more to try and compare results. I've got the 95 so direct drop into the fenderwell is pretty easy as it is so I'll probably try that first while I plot the Cai setup. I like that though. Like increasing outside flow into the current well protected setup

The more I get thinkin about it all, would I just be askin for trouble with a naca duct and fwi? I only mean w/re to water mostly. I mean most of the year here its rainy/puddles all over the road.
If I were to shield off the engine-side wall similarly to what you (Aaron) did, and had the duct slightly in front of the placement of the cone, should I really even still be worried I wonder?
I'm thinkin that during snowy months (no salt is really used around here and plows are rarely seen so the snow tends to remain where it falls) I might rig up a plate to cover up the duct until everything thaws out.

Everyone seems to be worried about getting the filter wet. Either there's something to it or this G8 driver is a total ignominious. I'd like to think there's something to it..

Picture comes from an album by Buapo (Ben) linked from this thread:
https://rivperformance.editboard.com/t5094-write-up-flexible-tube-fenderwell-intake

In my area its as simple as 99% of the time there's significant upspray and water on the roads. I put in a temporary shortram but even sitting in place of the stock box even in the engine bay it was getting wet in our lovely weather here. I'm looking into a three stage filter setup now. Grate in naca duct up to a thin excess water guard inline the ducting into an inline filter. still calculated to handle 475cfm so I figure I'm more than good and still greatly increased intake vs stock

Different people are worried about this for different reasons. There's a crowd that thinks inhaling some rain water or splash is going to hurt the engine. I'm not one of these folks. You would need to submerge the filter to bring in enough water to cause damage, imo.

Then there are those who are concerned with decreasing the life of the intake components, such as the air filter and MAFF sensor, and maybe the intake tube itself. I agree with this reasoning. The more outside the car you place the filter, the more likely you'll be replacing these components. My first filter was a cheap cone and rusted after a year. I replaced it with a K&N unit, which I'm still running several years later. My MAFF sensor is original, but I do clean it once per year. The price we pay for high flowing cool air!

But isn't that the entire point of a filter?! And a quality K&N at that? I have yet to see one of these filters in person but I do recall seeing a high res image on the net. don't think these things would have the slightest problem mounted under the car like the G8. Why hasn't anyone on the Riv team tried it yet?


K&N (AKA Gauze)
The next most common type is the gauze or K&N type. K&N is very well known and they should be as they really are the ones who brought performance air filters to the aftermarket world. Their principle works very similar to a paper filter, but 2 things make it work much different. The media is much more open (significantly bigger holes), and the media is oiled! The filter media is a few layers of very open gauze material. The larger holes/air passages are what make this flow so well. But the bigger holes mean more dirt gets past it, right?? This is where the oil comes into play. The oil creates a sticky layer that as the dirt runs into the media, it gets stuck in it. So instead of blocking dirt it’s catching it! Oil on the filter is what really makes this rather “open” filter work.

This joint comes from an article that argues how foam filters are superior to every other filter known to man. I have to say, he presents a pretty good case. Please read.
FOAM FILTERS ARE THE BEST FOREVER NO MATTER WHAT.

couple of questions:

I don't wanna spend hundreds on a kit and i wanna make it myself which I've already done before but I made mine out of household ghetto items hodgepodged together.



It started off as a short ram air intake with a custom venturi design I made which questionably worked well enough.



I ended up turning it into a regular fenderwell intake for colder air. funny thing is my venturi intake made me idle funny and even choked the engine out sometimes because of probable air fuel ratios. it even idled better when I put my hand over it and had tons of suction. I think it was confusing the MAF sensor.




I got that air intake pipe you see on that wrecked semi out of my step dad's towing lot. He was happy to let me have it

I know I can fab it no problem but I need to know a couple things first.

A:

How much can I cut out of the fender itself safely and not compromise the integrity of the fender? this thing is pretty big so the less I have to funnel and reduce the size, the easier. the second question is:

my intake box has extreme corrosion  on the bolts and I forgot what socket to use and its in a really tight spot and I can't even remember how I took it off but it doesn't even feel like a nut holding it on. can I get detailed info on that before I  try to rip it out? I'm thinking spraying pb blaster on it every day for a week, cutting out the plastic box partially manually with a router cutting bit and using big pliers to unscrew it off and see it better but I think it's just corroded really bad and I don't like the 5 horsepower loss anyway

Another reason I'd like to know the max recommended size is the bigger a filter I can get in there the better.

EDIT: i now remember reading a couple years ago browsing that AA cut his fender to a 4 inch hole? can I go any bigger?

I made a fenderwell intake with only two parts lol like 15 bucks pretty much.

The reason I used the stock intake tube is because it's already ribbed and more articulate than most tubes which gave me a greater tolerance of space to fab up the connection points to put the filter where I wanted.

I had to cut a hole in the fender bigger than the existing one. If I did it again all over I'd probably fab up a fiberglass patch over the current hole then use an actual hole saw so that I didn't have to waste hole space, also  my grinder was jumping around quite a bit because I couldn't fit the handle screw on piece to work in the fender. either 10+ dremel bits and patience is a better bet with a flex attachment, or the better choice, fab up a fiberglass or weld in a patch plate then use hole saw wouldv'e been a better quality job.

It's no biggie though cause I can just drill some holes and bolt in a couple of high tensile steel brackets for added strength in the fenderwell, which it could have used anyway lol.

I took out my horn to fit my 9 inch spectre hi flow 4 inch inlet filter (was $40 at advance)

All in all for a cold air intake that cost me$65 and a couple of grinder cutoff wheels is a lot cheaper than an aftermarket cold air intake for a grand prix, and will probably yield colder air in my fender than the usual insulated intake box would yield.

I also threw in a can of seafoam in the main vacuum line, and added half a bottle of lucas upper cylinder treatment or whatever the call it cause I actually trust lucas as a brand lol, then dogged it for a full tank of gas (I had more treatment in the tank than I needed). Plan was I looked at the old filter and decided that being 100k miles old and looking like that, it probably sent some bad stuff in my engine lol.

I cut out that hole in my wheel well panel with sheers, and I plan on getting a vent type thin panel with cutouts like the rear quarters on those aftermarket mustang window cover things to decrease dirt and dust from building up on the filter with more access to cold air.

I Can definitely feel a difference driving it. It breathes a lot better than with my crappy old filter and in the fenderwell it has more response. traffic driving is more pleasant and so is cruising because it shifts differently now. it used to always pick a lower gear on hills but it only does that now if the hill is super steep. I got 21mpg in city driving traffic even dogging it a little cause it was mildly addictive to make pulls passing people going from 60-90 really quick (I do not recommend driving like this) but when I'm being a tame driver, it stays in a taller gear, and pulls in that taller gear a lot more effortlessly. if I'm not dogging it I can gently put my foot half an inch down and it will eventually pull from 30mph in fourth to 65-70, with literally no effort from the engine. That's nice if you're trying to save gas lol.

EDIT:

Also put in some temporary kicker speakers in the front door panels, put my Alpine type S 6x9 in the deck, put in better wiring for the amps

and best of all:

I got a really good condition M90 snout for $20 off creigslist on the way to michigan cause mine needs a snout rebuild. from a grand prix owner that put a turbo in his. it looks really good and clean. I got it in michigan and there's no corrosion at all on it which is good. no carbon buildup at all. 100% tight no pulley play or wear. I could still see the injection molding seams on the couple which looked brand new almost too. guy said it had 60k on it and I'm thinking it was a a remanufactured snout from ZZP or the like because of how clean it looks and I can see that it used to have paint on it that was polished off. it doesn't have enamel on it which means it can't be OEM I think?

Only problem is that it has a 3.4 inch pressed pulley on it and I don't have the tools to remove it and put my pulley on it lol so I"m thinking save up for an intercooler some time soon, put the *180 tstat in it, get used ceramic headers for cheap, a downpipe and resonator delete, $100 ported lower intake manifold from ZZP, an engine tune and I'm good to go?

Umm....are you planning on driving in the rain?

Abaddon wrote:

Umm....are you planning on driving in the rain?

I seriously doubt rain will do much to it when I get the panel overlay epoxied on soon? they are gunna have slats in them kinda shaped like blinds if I can find panels like that lol.

worst case scenario I can make my own slats.

I mean I could be wrong but unless I'm in a flood I should be okay right?

No. Ya know that mist that gets all over your windshield even when it's done raining? That filter will act like a vacuum and suck it right up. Enough of it makes drops....

I think most ppl with an FYI still have the fender liner intact. Or am I looking at it wrong?

yeah, for sure the fender liner is intact.

Why the heck did you cut it out like that?

Yeah but nothing, and I mean nothing can fully prevent that mist from being there.. you'd need to seal the engine bay water tight with compressed air fed into the engine bay for that which is unrealistic at best.

in my opinion if water isn't just splashed on the filter in huge chunks then it should be fine? also keep in mind that tiny amounts of water won't just get sucked into the engine and clog it up then hurt the pistons.. it's a gradual process that means first it has to get sucked through the filter (that right there spreads it out a lot if its bigger than a droplet) then has to go through like 3 feet of 4 inch tubing, then it has to go through the honeycomb compressed disk filter thing in the throttle body, then it has to get chopped up by the twin screw roots supercharger which would probably reduce those droplets to mere microns at that point?

Also in my opinion  it wouldn't hurt my engine any more than 10% ethanol gas? because alcohol has to absorb the tiniest amount of water for some reason. to my understanding getting that last 1% or so water out is insanely hard hard and it will suck up water moisture from the air really easy to gain a tiny bit of water?

So in my somewhat uneducated opinion, you'd be sucking up basically humid air at the point when it gets through the intake valve and probably just rob a tiny bit of horsepower and cause the slightest amount of corrosion throughout the engine over the years. Bad if it rains every day? Maybe. A huge risk? I don't think so unless I'm otherwise corrected in which case I'll repent, then seal it back up and I would have learned the lesson of ask professionals if I'm unsure lol.

charlieRobinson wrote:

yeah, for sure the fender liner is intact.

Why the heck did you cut it out like that?

lol I suck at using scissors but the plan is to put a vent over it soon unless it proves to be dangerous in the rain in which case I'll pretty much find another piece of tough plastic and seal it up, having caused more effort than needed.

EDIT:

no way in hell I'm just gunna slap in a 3.4 inch pulley lol I'm torn between trying to ride out my snout which needs a rebuilt or trying to put mods in to accept the 3.4 inch pulley so I don't have to mess with pressing it and all that.

Mods I'd do to accept the 3.4 inch pulley are as follows:

-Intercooler

-*180 tstat which I have but need to install

-headers

-downpipe

-resonator delete

-ported lower intake manifold


all of which but the intercooler would be cheap but cold air= better anyway

The purpose of an FWI is to get the filter away from the engine bay heat, not make a pavement-level Ram air. The tire is going to kick up a shit-ton of water, and the engine is going to suck it right in, even with louvers over that hole. Yes, you have to go through a few feet of 4 inch tube, but you're sucking through a Supercharger dude. The amount of CFM that it can suck is the greater than that of a small leaf blower, and you can't stop it. Even if it didn't reach the engine, your introducing water into the Supercharger itself....

Also, you mention it being microns once it comes out of the S/C. What happens when you compress a gas? Or a mist?

Seriously dude, just put that cone filter on the end of your stock intake tube and build a box around it. I had a fwi for a while, and even with the liner in good shape, it got really dirty.

Omg lol I guess I'll seal it back up. But you gotta point about the box intake and I actually plan on doing that later on with a bad ass filter I got for grow houses lol it looks awesome but it's too big to fit in the fender. It was way bigger than I had imagined before I ordered it. It's way bigger than I need yeah but still had ass.  I think it's rated for 450cfm and has only a 10 % loss in flow from the filter. It uses activated charcoal I believe as well lol.

So in order to use it when my crap spectre filter goes bad.. I will have to get a custom smaller coolant expansion tank, I'll get a smaller window washer tank and such, a custom radiator with inlet and outlet holes on the passenger side maybe from a 3000 GT racing 6G72T racing part which would require a little fabrication, and basically redesign it so all the hot fluids and coolant flow as much as possible is on the passenger side. I'll also have to move some fuses to make stuff fit if it's possible but I think it's doable and some other stuff I forgot but I'd have to peek in the engine bay again lol.

Retarded? Maybe. But if you think about it.. why the he'll did the engineers make the heat on the same side of the engine bay coming from the radiator as the intake goes anyway.. which also flows all over the sensors and whatnot.. The air gets nearly hot enough to convection cook something between the radiator hoses when it's running hot. I hate that to no end.

But yeah a project for when I have much more monies later lol and at the moment just an idea to toy with.

And yes compressed air will make droplets again but mixed in the air fuel mixture getting atomized with everything else it's not like you're just putting water bubbles in the pistons. Like I said even 10% ethanol has SOME water, and any tiny bits of water will get sucked into the ethanol mixture of gas real quick and be very hard to separate from the alcohol mixture if I'm likely running e10 gas anyway since ethanol free is nonexistent here.

Just saying maybe a little less risky than others claim cause it's not like I'm sticking the filter out of the car lol. Plus look at other cars like the Viper with a big ass hole in the hood right next to the filter. Bigger hole by far than my slats would be. Does a viper break down in the rain? I bet that giant 640 horsepower 8.4 liter engine sucks a lot more air than our buicks

Just an example

EDIT:



Oh snap that's a big hole :o

And before people say that the tire is gunna spray water all over the filter.. yes I know it's true but most of the water goes behind the car and not in front. I mean I could be retarded and I'll seal it back up anyway cause it seems like more people who are smarter than me think the slats is a bad idea..

But I would think that through the hole of that viper hood has a lot of opportunity for water as well cause the filter is literally inches from that big hole.

Some interesting discussion here. I merged these posts with an older FWI thread that deals with some of the same issues. The same questions were being asked when I cut slots in the panel that seals the fenderwell from the bottom. I planned to mount an air scoop. Could water go in there?

Scott is correct that some mist and splash will make it up to the filter, especially with an open window right next to the tire. BUT, what a lot of folks don't realize, and what I figured out about a year after installing my FWI, is that some of the water will get to a filter in this location from the engine bay side. After several months, I noticed the filter was clean near the scoop, but the entire side of the cone facing the engine bay, next to the transmission, was covered in dirt and the steel mesh was starting to rust a bit (when I had the cheaper filter on). The intake was sucking water from the engine bay - the opposite wheel, and probably from nearby splash that reached the cradle, trans, etc.

So I created a shield (see page 1 of thread) that not only prevented splash-up, but also less heat was being sucked in to the intake from the engine bay (heaters are hot!). I noticed an overall decrease in IAT, and much faster recovery from idle as well.

After buying a K&N, which is constructed of better materials, I now clean the filter once per year, but it is holding up well, and it's not nearly as dirty as before the shield. I no longer have the scoop, but the slots in the bottom panel are still open the road.

For what it's worth, I know that over time water hit that original filter and got into the intake. I could see evidence as residue on the inside of the intake tube. My MAF sensor became mysteriously covered in dirt during this time and required cleaning. Did it hurt the engine? Not in my opinion. That was back when my engine had ~85k original miles. When I took the blower off to rebuild the engine, it still had all the Teflon coating on the rotors, from what I could tell. One of the cautions when doing water/meth injection is introducing atomized droplets in the intake, pre-rotor, can eat away the coating, lowering the blower's efficiency. If this is true, whatever water made it to my air filter was enough to foul the MAF and dirty up the intake tube, but it was not enough to harm the supercharger, and probably ended up in the engine as steam - the engine probably figured it was a really humid day.

PS - that Viper hood scoop is a bit miss-leading. The engineers located the intake ductwork forward of the scoop, so that no water wil travel upstream into the intake. There's some discussion about it here at Viperclub.org:

http://forums.viperclub.org/threads/622650-2008-Hood-Intake?s=bed173bedc924890e54b872df542571d

Here's what the Viper intake actually looks like. The scoop is located above the V10 8.4 on the airbox:



Like Scott was saying, there's really little point in trying to "push" air into a giant engine. The suction from the intake is much greater than any "ram air" force could generate. It was fun to see from Pontiac, and I'm sure the air was nice and cool (good), but no measurable "boost" could ever be made that way.

I think what you mean by upstream is the fact the scoop is lower than the manifold? Also aerodynamics probably has a lot in play to reduce water getting ducked in.. but I figured the distance the water has to travel from my wheel well all the way through like 4 feet of tubing into my supercharger then through the manifold would be a hard journey for water droplets lol.

Also that viper probably sucks 3-4 times as much air as our 3800?

But the fact your engine seems unharmed makes me relieved. Can you give me a link maybe to your shield your fabbed up so I could rethink it and maybe get a good idea?

Quote :

I think what you mean by upstream is the fact the scoop is lower than the manifold?

What I mean by upstream is that the air box is forward of the scoop. Water drops or objects that make it through scoop will splash onto the top side of the air box, so will not make it into the intake stream. Look at any factory (functional) hood scoop design, and you will see there is some sort of a provision for keeping water and debris out, by using a plenum or other kind of directional trap that uses the inertia of incoming objects (water, debris, bugs weigh more than air) to keep them from being sucked into the air stream.

Even with such mechanisms, you can still find some of the lighter stuff getting through the trap. It will be caught in the filter, or laying on a tray in front of it. 2000-ish Audi S4s use a long maze of intake plumbing to source air from the front grill, yet keep the air filter from getting wet or damaged. Same principle as the Viper, more effectively executed.

Quote :

but I figured the distance the water has to travel from my wheel well all the way through like 4 feet of tubing into my supercharger then through the manifold would be a hard journey for water droplets lol.

Once water hits the air filter, it's going to be sucked into the engine. There's so much air blasting through at such I high rate of speed, the water must go with it. The questions are, how finely are the water droplets atomized through this process? How how much water is getting to filter? Unfortunately we don't really know, and it depends on conditions, so can't easily assume how much water would enter the intake.

The Viper's scoop keeps most water from even getting to the filter, so they could make the assumption that little or no water would ever get in. A member on the Viper board made a good point, though. If it were ever raining hard enough that water should enter the scoop is such amounts to cause an issue, the engine wouldn't be sucking much air at all - because due to traction issues, the driver would not apply enough throttle under these conditions. The SRT engineers surely thought of this, and concluded it would rarely be a problem.

Quote :

Also that viper probably sucks 3-4 times as much air as our 3800?

Closer to 2-3X. I think I once calculated our MAF at 500-550 CFM. The Viper's twin thottle bodies are rated 697 CFM each.

Quote :

But the fact your engine seems unharmed makes me relieved. Can you give me a link maybe to your shield your fabbed up so I could rethink it and maybe get a good idea?

Keep in mind that was a temporary situation that I fixed by installing the shield. I would not run an intake with a filter purposely exposed to rain or splash water. You are in the shield thread. Check page 1 and 2.